# Why I cast my own models



## Powder keg

In another thread, Magyver asked about working with a foundry. 

I'll start my tale at the beginning. I had been dreaming about casting metal since my late teens. I read all I could find on it, I dreamed about the fantastic models that I could make, but I never did any casting. I was afraid to try. There was a few things that I needed to build that were time consuming an a little expensive. I didn't want to mess them up. I didn't want to not like casting and be stuck with this stuff. So I was just content with reading about it and dreaming of the great stuff I could build:O)

In a near by town there is a brass foundry. I went to talk to the owner one day about having a couple doodads that I needed cast. I was disappointed and a little mad when he quoted me $500 to cast them. After thinking about it for a while I realized why his quote was so high. He simply didn't want to do them. It's bad business in my book, because you don't know who a customer is. Work asked me about getting some of our stuff cast and his name never came up:O)

Fast forward a year or so. I was still a little miffed that I couldn't get things cast. My wife and I were headed to Oregon for a vacation. Little did she know that the Gears show was awaiting us:O) We saw the sights along the coast and made it to Portland just in time for the shows opening. When we got there I was tickled pink when I found out that there would be a fellow there doing casting demonstrations:O) How great of a surprise is that! Anyway, I watched him closely for the first couple pores. I then asked him if I could help. He was glad to have someone clean and mull his sand. I learned a lot that weekend. The main thing was that it's not nearly as hard as I imagined and that I could do this.

The day after we got home I started rounding up stuff to make my foundry:O)

Later, Wes


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## Brass_Machine

I would love to learn to cast. It is on my list of things to do this year (my wife wants to learn to blacksmith, so I have even more of an excuse for a backyard foundry). 

I would like to have someone experienced by me so I could at least watch once (or more) before I start.

How about some tips for those of us about to start Wes?

Eric


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## Lew Hartswick

You know if people weren't so paranoid about where they lived perhaps some local person would offer
to help. It's the same with a lot of other subjects (ie. not just this one). I for one am not going to 
go to a lot of trouble to find where someone is to offer help. I've never been afraid to use my name 
and where I live on any of the BB s (I read 5 or 6) 
[rant off]
  ...lew...


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## Oldmechthings

Ya know! I was raised on a farm, and one of the pesty things we had to put up with was gophers. So us kids, to have something to do, would take a bucket full of water out in the field and pour it down the gopher hole. When the gopher would come up for air, we'd bop him. 
  Pouring molten metal down a hole in a flask is very much the same as pouring water down a gopher hole. The main difference is you don't get to bop the gopher.
  All I can say to wanabes is try it, I think you'll like it. If you screw up, big deal, melt it down and try again. Every time you have one that does not turn out, not all is lost, you will learn something not to do next time. I cannot count high enough to list my casting failures, and I'll bet Wes is starting to loose track too, but he is catching on fast.
      Birk


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## Alphawolf45

The reason a guy makes his own castings is because he can, and its part of the fun..
.
 I am just started building my first steam engine and am slamming wood together for patterns so I can cast the various parts..Except that I thoroughly despise sawdust in my metals shop , this is going to work fine..


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## rickharris

Brass_Machine  said:
			
		

> I would love to learn to cast. It is on my list of things to do this year ...
> 
> Eric



Casting as such is not that hard - making accurate patterns is quite difficult and for one off work time consuming.

Getting Consistently good casts is a black art. We cast aluminium, pewter silver and some brass when we get enough scrap. Although we have a commercial furnace it's just a big insulated gas hob.

I don't do much of this as I have a colleague who actually enjoys it but have helped and do quite a bit of small scale pewter and silver casting for jewellery. Generally I make moulds from MDF with the CNC router (much more accurate and faster).

We are currently casting a pewter school badge for every pupil - about 700 at 3 at a time. Slow going.

Lots of information on the web - Be careful and for me I would lay down a sand tray to catch any over spill because dropping molten metal on damp concrete is an experience I don't need to have (again). correct clothing is also a good ides including spats to cover shoes, metal splash in your boots makes for an interesting dance - in foundries they often keep a bucket to plunge feet into in such cases.


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## BobWarfield

Casting would be a great way to expand the capabilities of a small CNC router to the world of metal. I have such a router:







It was well under $1000 all in but for the PC. It will cut aluminum but only very slowly. OTOH, it should crank out MDF molds very nicely. You could make any number of small castings for model engines with such a rig.

Cheers,

BW


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## Mcgyver

or complex foam shapes for lost foam casting


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## Alphawolf45

BobWarfield  said:
			
		

> Casting would be a great way to expand the capabilities of a small CNC router to the world of metal. I have such a router:
> 
> 
> BW


.
 Bob
 With that router, yes making patterns for metalscasting is good use for the cnc and too a guy could be using such router for making small plastic injection molds....I been gonna build lil tabletop injection molding machine for a while, there isnt anything to making one yet its then gives new capability for an already capable guy.Always another horizon.


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## Brass_Machine

Wes,

do you feel like taking some pictures of you r foundry setup? Maybe giving a few details on how you made it? I have been researching it and have seen several from Barkyard Casting. Can you recommend any books? Help me get started Wes ;D

Eric


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## Powder keg

It's on my to do list. Not to be confused with my ta da list) I went out to fire up my furnace last weekend and there was 2" of mud all around it( So It will have to wait a couple more weeks till everything dries out a bit. But Yea, Plan on lots of engine related foundry topics. 

I have access to some neat CNC machines right now. I just finished the patterns for another small stirling. I might start a topic on it? I haven't decided yet? Tonight I'm starting on the plans for a larger stirling engine that will have a 2 1/2" power piston. I have some old plans and I'm going to change them up a bit so I can cast it easer. I think they will both work out really great. 

Later, Wes


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## Powder keg

Also, If there are any particular questions, please let me know. I'll do my best to find out If I don't know. 

Later, Wes


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## tel

Hey, I know that voice! Welcome Steve.


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## Alphawolf45

tel  said:
			
		

> Hey, I know that voice! Welcome Steve.


.
 Yeah Hello Terry
 Swede told me about this site when I asked over at the hobby gunbuilding group if anybody knew of an active forum discussing steam engines..This'n is the most actively participated of all I have found..I glad to be here, lots of talented guys gitten'er done....inspirational..
Steven


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## Powder keg

Another reason I like to cast is because it is fun!!! I like the reaction that I get from people that think a screwdriver is mystifying to them) You know who I'm talking about. I like to be able to pore my own parts. Also, I can make a little on the side to help finance my hobbies.


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## sparky961

Here's my $0.02 (CAD):

I wish I could cast metal all day (and still pay my mortgage). I don't know what it is, but there's something mesmerizing about watching metal - which most people think is virtually indestructible - melt away into a shiny glowing liquid.

And all of this for very minimal cost. A fair bit of effort, but all said and done probably $100 - $200 spent when you consider all of the travel, scrounging, and some of the parts that were bought for safety's sake.

Have a look here:
http://s296.photobucket.com/albums/mm185/sparky961/Metalworking/Foundry/

(If you've already seen this gallery, I just added descriptions for each photo that you might want to check out.)

These are photos from around 2003 when I built my first furnace. Although the refractory is now starting to turn to glass, and the end of the tuyere that I so carefully ground to shape is falling apart, it still works very well.

If anyone is looking for advice on getting up and running on the cheap with a home foundry that will melt aluminum (also brass, and glass), I have at least a little bit of experience with this and can provide detailed pictures of any components you're needing some help with.

I learned from a lot of online resources, like BackyardMetalCasting and the Hobby Foundry Ring, so I don't claim to be an expert. But sometimes it just takes someone else who's actually "done it" to clear up some of the things left out of the write-ups.


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## Alphawolf45

Sparky
 You mention your furnace able to melt glass. I wonder if you have done it. I want to do some amateur glass blowing, I would like to know what dirty little adventures I could get into without making special investment , want to just use the furnace I have....And I have heat treating furnace could use for letting the strain out of the glass...Want to blow glass globe for oilers..Reckon I oughtta just try it see what happens?


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## sparky961

Wolf:

I've never done anything useful with the apparent ability to melt glass. I'm not even sure if I'm getting it to the proper temperature to do a good job of it.

I just had some broken glass sitting around and I wanted to see if I could melt it. 

Does someone have numbers handy as to the difference in temperatures required to melt aluminum and glass? Maybe I'm just running my furnace way too hot!

-Brian


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## mklotz

I can't help with the temperatures but I'm sure that information is on the web somewhere - after all, everything else is. Good way to improve your Google-fu.

I can say that I've successfully blown small (<1.5" diameter) glass globes using nothing more than an alcohol blow lamp.


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## Metal Mickey

Hello, I also am interested in casting my own aluminum castings so would like to see how you made yours. Have you any plans or pictures? What fuel does it run on? 

Mike


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## shred

Glass is funny stuff.. it's basically a very stiff liquid at room temperature, and the more you heat it, the runnier it gets, sort of like molasses. You can squash a wine bottle flat by its own weight with 20 minutes at about 1100-1300'F, but it will act like wet leather. Flassblowers can't do the dip-n-swirl thing until glass is over 2200F or more. A pile of broken glass will glue the shards together around 1200'F, but they'll still be pretty sharp. It won't turn into a uniform glob-o-glass until 1600+

What you will run into with glass is devitrification (the crystallizing of the glass, which looks like a whiteish scum)-- happens above 1300-1400F, and if you want to do anything useful with the glass after you melt it, you have to very carefully and slowly anneal it while cooling so it doesn't break-- the thicker the glass the longer you have to cool.

I do 'warm' glass work in a kiln around 1450', and AL melts well below that (sandwich a piece of alu can between a couple pieces of glass and run it up to 1400 and the Al turns into a mass of brown bubbles encased in glass). My kiln goes to 2000, and that's at the very low end for brass-- I have several test pieces of glass with unmelted brass encased in them.

Now there's also a ton of different things called 'glass' too-- those numbers above are for typical window/bottle glass, while pyrex/borosilicate has a different temperature curve (and is easier to work in a flame) while other glasses like quartz can act differently too.


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## BrianS

Hi guys,

I figure most of you that are interested in casting metal at home must have come across this site before, but just in case someone hasn't I highly recommend it. They have some great books on a variety of subjects such as: casting, metalworking and blacksmithing.. You might want to start with Dave Gingery's set of books on "Build your own metalworking shop from scrap" 

It's Lindsay Technical Books and here is the link http://www.lindsaybks.com/ Oh and their catalog is quite amusing too.

Hope this helps.
Brian


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## sparky961

Metal Mickey  said:
			
		

> Hello, I also am interested in casting my own aluminum castings so would like to see how you made yours. Have you any plans or pictures? What fuel does it run on?
> 
> Mike



I have a bunch of pictures of various things on fire, melted, solidified, machined, etc. 

Mine runs on propane, with a bit of added atmospheric oxygen (and whatever else gets sucked in through venturi action). It has no problem with aluminum, and I've made at least one brass ingot as a test melt.

The design and construction of mine is a culmination of a bunch of designs I looked at. The casing is a large stainless steel stock pot. This is placed inside a metal frame that I brazed and bolted before I owned a welder. The burner is made of plumbing parts, with only about two modifications consisting of a few holes drilled. 

The regulator can't be a low pressure BBQ type. Some people get higher pressure "corn cooker" and "turkey fryer" regulators, but I just went with a standard "fuel gas" adjustable regulator. If you went to 3 good auctions, you'd probably be able to piece together everything you need with a bit of creativity.

The stock pot had two holes cut in it - a drain for when your crucible (melting pot) gives up the ghost, and one where the hot stuff comes in (the burner).

Let me know is there are any specific questions I can answer for you, or if you're looking for any detailed photos to help clear up the blank spots.

-Brian


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## thezetecman

I am currently collecting information with regard to build a furnace.

i am happy with all but the crucible.

Options:
 I have seen are heavy wall pipe with one end welded over.
Proper graphite clay one. these seem expensive or very small.
Use some other pot such as an oven pot or something. (flower pot?)
Heavy walled stainless steel pipe welded over. 

I want to design the furnace around the crucible. 
Which of the above options is best?


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## tel

For aluminium the steel crucible will be OK - especially if you coat it with crucible wash (borax/fireclay mixed to a slurry in water). For brass and above you would be wise to seek out a proper clay/graphite crucible


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## Metal Mickey

Does anybody in the UK know a supplier of the lining material used to make a furnace? I intend to have a go at making my own but need a supplier of the lining materials. Thanks.


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## sparky961

When I made my furnace, I made my own. Although the refractory (lining) is deteriorating, it's still performing quite well after almost 5 years (with only occasional usage).

I made it using a combination of perlite, furnace cement, Portland cement, and possibly a bit of sand. I've wished many times over that I saved the ratio of the mixture somewhere, but alas I did not.

-Sparky


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## Metal Mickey

Any clues re suppliers? Mike


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## rickharris

Metal Mickey  said:
			
		

> Does anybody in the UK know a supplier of the lining material used to make a furnace? I intend to have a go at making my own but need a supplier of the lining materials. Thanks.



A builders merchant such as Travis Perkins will sell fire cement and fire bricks for building fire backs and grates. This may well be a good start if not good enough.


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## tel

Metal Mickey  said:
			
		

> Does anybody in the UK know a supplier of the lining material used to make a furnace? I intend to have a go at making my own but need a supplier of the lining materials. Thanks.



I get mine from a potter's supply place not far from me - they have a wonderful range of related materials as well.


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## xlchainsaw

hi i joined this forum awhile back but havent had time to post ect. this is because ive been busy with my backyard foundry melting aluminium cans and turning them into wheels, pulleys,brackets ect for my model steam engines. i am actually quite surprised how simple casting is! my furnaces are small and my biggest melt is 450grs. big enough to pour a 100 mm v section pulley.(not that ive done it yet lol) i have many items to machine and have basic skills hence joining the forum.pattern making is my biggest challenge.


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## buzzsaw

Hello! I am new to this site, but I have been casting aluminum for some time now. I have made my own refractory from fireclay ( try and find hawthorne, as it is the highest rated of the common fireclays) perlite (found in HomeDepot or Lowes in the plant department, or any nursery, and portland cement type II or the fast setting type (as this will have the highest percentage of Alumina) and play sand (The type that they sell in 50 lb. bags. I searched for the clay, and found it at a clay/pottery supplier, and I paid 12.95 for a 50 lb. bag. The sand was about 4.37, the perlite was about 6.79, and the cement was 4.78 for a fifty pound bag. I mix the cement1 1/2 parts to sand 2 parts. perlite 1 1/2 parts mix well, then mix in the fire clay , mix extremely well!!! then just mist the mixture and mix some more. when you get to the consistency of damp brown sugar, then you can ram up your furnace. Oh1 and by the way, I bought my first burner from Harbor Freight, it was the propane weed burner, with the end removed and the handle attached to a burner from the web. It melts about 12 lbs of AL in about twenty minutes, and thats without a blower!! I used to think that foundry work was "black magic", until I actually did it! Now I am on the quest to cast cast iron, and would like to know what type of crucible it will take to melt it in, so if anybody knows, I would sure like to know!!! Fred


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## bronzecaster

Hi Buzzsaw,
  You would melt cast iron in a clay-graphite crucible, but it is much hotter than melting aluminum. Also there are many other things to learn about melting the hotter stuff, like having to weight your molds, judging the temperature of the melt, the different alloys of cast iron and their properties. Of course, protective gear is a little more serious with the hotter stuff and different sands might be needed. (I've poured cast iron into petrobond, but it is very hard on this sand, not to mention the contamination possibilities of using the same sand for different metals.)

 So much to learn, So little time.

Bronzecaster


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## Gearsguy

My reasons for getting into casting are almost identical to powder kegs. Wanted to cast metal since I was a teenager. When I started making models I quickly found out kits were very expensive. I wanted to do aluminum casting but just wasn't sure how to start. I did learn how to cast at a friends shop where he had a professional level foundry but it was 40 miles away and it took quite a bit of the day just going and coming. Some times I screwed up a casting and came home empty handed.

One day at a meeting of our local club, Mid Valley Model Engineers, the host put on a casting demo. Blew my mind! All he was using was three firebricks set up on end with a crucible made of iron pipe and a propane weed burner. Worked great. Obviously this wasn't the most efficient way to melt, but it worked. That got me going.

My first kiln was simply a small stack of fire bricks with a six inch opening in the center and a small opening on the bottom row for the weed burner. Made a crucible from iron pipe and went into business. Made some patterns for a small steam engine and away I went.

Later I made a poured refractory kiln using an old shop vac in place of the usual 5 gal can. Also changed from a weed burner to the Reil Monster Burner. Now I can cast and be back into the shop in about the same time as it took me to drive the 40 miles. I make all my own patterns and am having a lot of fun at very little cost.

Hope this wast too long a post but I wanted to share my experience with those who want to cast but are worried about getting started. It is easy. Just do it.


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## Twinsquirrel

Welcome Gearsguy,

Pictures man!!! I'd love to have a go at casting and always find it interesting to read about the many different approaches but we love to see pictures here, I guess we are just nosey ;D ;D ;D

David


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## Gearsguy

David

I am working on some pictures as I thought there might be some interest. I didn't have a camera the day I saw Rocky melting with just three bricks for a kiln but I doubt you need a picture of that.

I also made a nice Muller for very little cost and will try to post some pictures and explanation on that if anyone is interested. This will take some time as I will have to take it apart to show it properly.


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## Maryak

Gearsguy,

Very Interested, built a forge using a truck brake drum and old vacuum cleaner but so far only melted whitemetal for bearing pours. ;D

Regards
Bob


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## artrans

hello all very new o site but enjoy it very much. I have been trying to cast for a few months one very good site is www.backyardmetalcasting.com also it is not as easy as it looks. I will try aand explain the melting part is easy the mold part is the problem i can make cup cakes aluim all day long perfect the sand is another story althought i got some petro sand which is oil based much easier then green sand water based out of five flywheels cast i got two good flywheels one so so the others not so good. again it not hard but there is a lerning curve like every think in life. If it likes easy its because the guy is good.thanks art


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## Gearsguy

David

Here is a picture of my first kiln. Just a stack of fire bricks and a weedburner. Worked just fine but made a lot of improvements since then.

With any luck a picture should show below. This is my firs attempt to post a picture.







hope it works.

Gearsguy


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## Gearsguy

All

Here are some pictures of some of my casting and finished models.













So far I have had very good results with my castings. Not as good as a commercial foundry but very usable. Occasionally I lose one and have to remelt but most of the time they work. 

I use Petrobond sand rather than green sand. Stinks like heck but since I am casting outside I can always move away from the smoke.

Gearsguy


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## Metal Mickey

Very impressed. I hope to build a furnace next year. Just need to find the refractory clay in the UK. Any sources welcome.......

Mike


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## cfellows

Gearsguy  said:
			
		

> All
> 
> Here are some pictures of some of my casting and finished models.
> 
> Gearsguy



Gearsguy,

Are those aluminum castings or Zinc/Aluminum alloy? Just wondered if you have trouble with the aluminum flywheels being too light in weight? I've used an alloy of Zinc/Aluminum which is almost as heavy as cast iron and actually melts at a lower temperature than straight aluminum. It also machines very nicely and is very strong. 

Chuck


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## Gearsguy

The castings are from scrap aluminum. The flywheels are quite adequate. If you look close you will see they are quite thick and have more than enough mass to run nicely. They are about 7" diameter and with only a 1" bore and only moderate compression I have no problems getting the engines running.

I did get a couple of sets made in cast iron but I haven't tried them yet. I hate turning cast iron because of the grit. Gets all over everything including me.


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## jack404

G'day Gearsguy

got some questions for you if thats ok?

scrap Alu do you mean alu cans? offcuts mixed or all the same??

what temps do you get them to pour ?

do you flux them or add stuff to seperate the junk ( slagging out) 

do you heat the moulds? 

dont want you to give away trade secrets but i cast a lot of things mainly lead for deep sea fishermen at the moment but Brass Bronze Iron but Alu i've always been told needs high voltage electricity to get structural builds ( correct crystalisation or whatever)

cheers eh

jack


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## tel

Yo Jack, if you want my opinion, avoid cans and extrusions like the plague - old auto heads, pistons, manifolds and even wheels are a much beter bet.


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## Bluechip

Hi 

Tel is absolutely right. My old mate Stu., long departed, made a lot of castings in alum. and bronze/brass.

He always said if the material was cast in the first place, it would cast again. Not always so with redundant bar stock.

He had some white powder stuff he put in to improve the fluidity of the melt, but I don't remember what it was. 

Dave.


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## jack404

i dont doubt it 

but looking online does not show much but ad's for very expencive setups or business's that will do it for you

i also doubt i'll be casting anything Alu for a while thanks to my situation,  when i get back to Adelaide sure,

but thats a ways off yet 

but hows too is always good to have .. ya never know..

cheers folks

jack


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## ksouers

Jack,
I'm certainly no expert on casting aluminum but I did try some a few years ago. I did learn a few things. I melted cans and some bits of extrusions I had laying about. Also saved my chips and threw them in the mix. 

Cans have almost as much slag as metal. It's all the ink/paint/varnish, whatever was in the can. It can really be tough to get rid of it, I usually ended up going through a couple refining processes to get rid of it. I'd do a melt and skim out as much slag as I could then pour into ingots. I used steel crucibles so a lot of slag end up sticking to it, as well. After a while I'd end up with a hot spot that would burn through, one time completely filling the bottom of my furnace and clogging up the jet.

When I'd melt with ingots I used a clean crucible used only for ingots. I'd still have to skim slag but not as much. After skimming I'd dip the rod in borax while it was still hot and stir the melt with it. The borax helped bring out more of the slag.

As for the castings, nothing I did came out usable. Everything had bubbles in it. I found out later that there are some tablets you can get that will remove the nitrogen and thus the bubbles.

I'd like to build another furnace and give it another go. Maybe try some bronze this time, too.


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## Gearsguy

Jack,

I agree with Tel, avoid cans and small bits and pieces as they produce a lot of slag. I use the thickest hunks of alu I can get. Never, never use the chips from turning or milling. Pure slag. Pistons work well as does hunks of flat and bar stock. I got fortunate a few years ago and picked up a hundred pounds of ends from a shop that produces shells for telescopic gunsights. The pieces are about 3 inches around with a 1" hole in the center and about 3-4 inches long. Fit just perfect in my 4" crucible. I usually put in one of those and then the spru from earlier melts plus other smaller scraps to fill my crucible about 3/4 full when melted. This gunsight metal when melted alone produces almost no dross. Pours and machines like a dream. Unfortunately I am almost out and not sure I can get more. I got this back when alu sold for 50 cents a pound.

I use no flux. Just melt and pour. I melt at about 1400f. That is a guess but probably not too far off. I judge how ready it is to pour by how clean my stir rod comes up from the melt. After I remove the crucible from the kiln I use a small cast iron spoon to remove any slag then pour. I keep two steel ingot molds ready to dump any left over metal. I always heat the molds and spoon by placing them near the exhaust hole to make sure they are completely dry. I also always preheat additional alu pieces that go into the pot during the melting process.

I would warn you to be very cautious about where you get scrap. Once I picked up some nice looking scrap from a motorcycle junk yard. Aluminum pieces they had separated for sending to the recycler. When I melted some of this I noticed some odd dark grey granuales form on top. I guessed that this was magnesium and knew it was a bad thing. I removed the pot and scraped this stuff off the top and dumped it in my usual spot for dross. It almost immediately lit up and burned white hot. I stepped back and away and a few seconds later it exploded and showered the spot where I had been with nasty white hot burning sparks. Not a good thing. I later figured out that this stuff had melted as it burned and flowed down to a spot where some water had accumulated and the explosion was from steam. Anyway just be careful. I always wear a hat, face shield, welders golves and heavy clothing, boots etc.

Before I got the good stuff I would often melt and pour ingots that then were used to melt for castings. This helped clean up the pour. I also found that you need to use at about 50% new metal in each melt. When I use all sprue that has been recast several times the castings become gritty and don't machine very well. I don't use a lot of extusions like window frames because they seem to create a lot of slag too. It depends how desperate I am for scrap.

Hope this answers some of your questions.


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## jack404

Now thats good info

cheers for that!!

printed out and put away for when i get to do it

thank you very much 

jack


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## tel

Not only do cans and extrusions create excessive slag, they also have a much higher shrinkage rate, you need pretty hefty sprues, gates and risers to try and overcome that.


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## Gearsguy

Jack,

One other note. You mentioned you had been told it requires a lot of electricity to do Alu. Not so. All my melting is done using propane. Same stuff you use to BBQ. Fairly cheap and readily available. I get about 7-8 melts from a 10 gallon bottle of propane. Even commercial foundries here dont use electricity. Most use natural gas.


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## jack404

Cheers Gearsguy

i was meaning passing a electrical current through the molten Alu to "do something" that makes it work better or more stable or whatever

i'll be using a LPG rig i use here for a reference the outer ring burner is 16" in Dia. 







i have a F52 grade crucible ( rated for 3600 deg F) that holds 32 liters of water so dont have worries that way

for lead and bronze i only use the 3 inner burners but for steel i use the fourth outer ring as well

but thanks anyway

cheers

jack


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## tel

Coupla pool shock tablets in the melt work as well as anything.


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## jack404

tel 

sorry mate i dunno anything about pools  

a shock tab to me is about 2" of 60/40 powergel and a number 6 safety det in the end

chuck it in a deep spot in the river and bobs your uncle

fresh trout

is a shock tablet chlorine? if so, is that wise?? chlorine is nasty stuff 

need to edumacate me mate 

i'm like a computer, info is best punched into me

cheers

jack


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## tel

;D Wrong shock tab mate!

Yep, the chlorine tabs, primary purpose is to degass the melt. What you do is break a couple up and wrap 'em in a twist of al. cooking foil - you need a little do-hickey like a short bit of pipe, with 'oles drilled into it, welded to a (say) 1/4" or so dia rod. Pop the 'bomb' in the pipe bit, plunge it to the bottom of the melt and swizzle it around for a few seconds. *DO NOT* stick yer 'ead over the crucible while you are doing this, nor do you use it as the basis of and breathing apparatus.


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## xlchainsaw

ive just come back to this forum and since i last visited the casting subject sure has taken hold. ive been busy on another forum (sorry guys) with metal casting. thought i would post a link.http://www.metalcastingzone.com/metal-casting-forum/brass-casting/molding-my-brass-flywheel-4. it seems metal casters are everywhere!


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## T70MkIII

I've just found this thread too. If anyone wants to build a really cheap foundry to see if they can cast (you can!) or just to do a few bits and pieces, you can do what I did.

I bought a large teracotta flowerpot and drilled a hole near the bottom of it to take 1m of 38mm steel tube for the tuyer (air blast pipe), which I angled to the side so the air would swirl around the bottom of the pot. The air came from an airless paint sprayer, but you could just about anyting handy. My first runs were with an old hairdryer. I fired it with BBQ coals and firelighters, and turned on the air 'blast' once the coals were well lit and starting to glow.

I made a crucible from a piece of 8" OD steel pipe with a welded on bottom and pouring V, with 1/4" steel bent and welded around the outside of top. I made up some scissor like tongs to grip onto the crucible under the 1/4" lip.

My first melt was a couple of pounds of pistons and soda cans, which melted beautifully within about 20mins. Yes, there was some dross, put I pulled this out with a steel rod / stiring stick. I did about 5 good pours from this foundry before the pot (which was bedded into some sand) cracked apart too much to continue to use. I'll just buy and drill a new pot when I'm ready to do some more casting.

Caution: be very respectful of molten aluminium, and have a sandbox around your foundry large enough so it can never get onto concrete (wet or dry). The water bonded into the concrete will instantly vapourise, sending chunks into the air with explosive force. How do I know? I used a ss pot as my first crucible, which pinholed causing all of my aluminium to run into the pot and down the tuyer. Of course, this catastrophically damaged the hair dryer I was using for the air, as well as the concrete. If your tuyer angles downward, you can join a near vertical pipe to it to supply the air, and just tape over the other end of the tuyer so the blast goes into the pot. The advantage of a tilted tuyer that if you get a spill in your foundry, the al will run out rather than ruining it. Not really an advantage for the easily replaceable flowerpot type foundry, however.

Gingery's "Backyard Foundry" is a great primer on building a more proper foundry than the one I describe above, and I highly recommend it. Of course, as mentioned above, there is lots of great information on the www.


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## Bernd

For those of you interested in home foundry techniques you might want to visit this sight if you haven't already run a cross it.

http://www.backyardmetalcasting.com/index.html

He's done a lot of experimenting.

Bernd


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## Peralta

It is nice to hear that you are now doing for real your old dream of learning how to cast. I guess you are sorry for the lost years why you haven't brave to learn them earlier. Well, that is life, it is better to be late than never. You can also try molding plastics that would be an improvement. Injection Molding Indiana


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## Doug E.

Powder keg  said:
			
		

> In a near by town there is a brass foundry. I went to talk to the owner one day about having a couple doodads that I needed cast. I was disappointed and a little mad when he quoted me $500 to cast them. After thinking about it for a while I realized why his quote was so high. He simply didn't want to do them. It's bad business in my book, because you don't know who a customer is. Work asked me about getting some of our stuff cast and his name never came up:O)
> 
> 
> Later, Wes



Wes,

Hobbiests can be big time wasters for businesses. I took a complicated pattern to a foundry to have castings poured, and after discussing what I needed, the foundryman asked "if he poured good parts, would I pay for them?" Come to find out, he had had hobbiests have stuff poured, and then would not pay for them! 

A larger commercial foundry that I have a business relationship with, asked that I not give contact info out to non commercial customers, as they rarely recoup the time invested in them in order to correctly pour the castings. 

That being said, when I have the time, I enjoy doing my own castings also! 

Regards,

Doug


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## john b

My suggestion is go ahead and try it! I started casting about a year ago and I am delighted with the results. I recently posted pictures of my gas beam engine and the process of an idea to castings to a running machine is what this thing is all about.Plus,you can put your mistakes right back into the crucible!


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## Norman

You guys need to check out the casting section on this forum. It's all about what comes out of the sand. Home casting is a hoot! I've built a few things from castings, but no engines so far. But I probably will someday.
My foundry is powered by waste oil very cheap to run. All of my foundry is made from inexpensive materials. If you haven't tried you really need to give it a go you will find that it's habit forming. If it's made from aluminum there is not a need to go buy al. bar or plate just make a pattern and ram it up in the sand and cast it. Then you can machine it to the size/ shape needed.
here's an example of one things I've cast.
http://www.homemodelenginemachinist.com/index.php?topic=10027.0


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## nsfr1206

So I can take any old aluminum and melt it down and use it to cast?


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## ShedBoy

From my limited experience I will say yes but there are some things to look out for. The more exposed surface you have on the charge peices the more dross you are going to have ie: ali cans will produce alot of unusable dross, scum, crap floating on top of the melt. Parts that have been cast originally make good scrap like cylinder heads, pistons, mower engines etc. Just smash it apart with a hammer and don't get too stressed about steel as it is easily fished out once the ali melts. Extrusions and ali offcuts from boat builders are okay too. There is ali everywhere once you start looking.

Brock


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## nsfr1206

Have to look into building a foundry. I am gonna buy an older fire truck with a locked up engine. Nearly the complete hose bed is aluminim. I was wondering what all I should take off before I hauled truck to scrap.


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## ShedBoy

Should be lots of ali, depending on age and type maybe even some chrome plated brass and bronze at hose connections. Depends how much you want to pull apart.

Brock


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## willburrrr2003

Here is why I got into casting... Several years ago, I wanted to set myself up with a metal lathe...but I had no way to afford one. I came across back yard metal casting based on the Dave Gingery series of building your own metal shop from scrap metals (foundry, lathe, shaper, mill, saw, drill press.....and bits and pieces to add to each). I read several build articles on Dave's Charcoal Foundry, and decided I was going to build one.  I picked up a 5 gal bucket, 10 ponds of lincon fire clay, a 12" concrete form and a bag of sandbox sand. Spent a couple hours sifting the sand to get it as fine as possible. I mixed up my refractory, scooped it into place between bucket wall and concrete form. Carefully rammed the refractory tight and solid as I went. Once done, I let it sit for 2 days....filled it with charcoal and lit it. I ran it thru 3 burn cycles to harden properly (and also it burned out the cardboard concrete form during this stage) I made my lid with the same mix on that first day, and baked it at 400 degrees for 6 hours to harden it.  Built a nice little blower made from old stove vent.  Next step was to read as much about building Dave's lathe, I read everything I could find on it, looking at tons of pics, and made lots of notes.  I produced my first parts not soon after, and started building my version of the Gingery Lathe  .  I was right at the halfway point (was just about to power it up and use it to machine itself and parts for itself) when my friend passed away and I wound up with his harbor freight mini lathe.  Unfortunately I have not moved forward on my Gingery Lathe since then. Pouring is a blast, and waaaaay cool!!!!  I tried to plan all my pours for nighttime hehe. My casting were rough, but functional! Since then I have converted my minilathe to CNC, and find myself longing for a milling machine. Now I stand looking at my half built lathe, and see that if I remove a couple things it could easily be the base and ways for Dave Gingery's milling machine.  I don't see myself lucking into a mill, so I am going to have to dig out my furnace and lathe project, and plan a retrofit to make it into a mill instead of a lathe.  

  Plan your patterns and your molds well, a very important thing to keep in mind!  Safety is also a major concern when pouring, as well as preheating metals before dropping them into your cruicible (if they have moisture in them watchout!!)  As mentioned before, pour over a nice sand mold for safety.  Have a place to put your extra melt before you start pouring.  I used a tablespoon wired to the end of a long rod to remove the dross from the top of the melted aluminum. I lacked a good crucible, but used coffee cans. I would get 3 good melts per can before they were useless. Now I find that there is another book by Dave on making crucibles and I will get it soon.

I am planning my first engine block casting to make a miniature mercruiser 120 engine (inline 4 cyl gm). The block will be a challenge, as I want to cast the water passages into place using sand cores. at the same time I cast the block I will cast the head, and oil pan.  There will probably be a followup pour for alternator parts, water pump housing, and exhaust manifold/riser (both of which have water jackets cast into them as well  ) .  I expect this project to take me some time to finish, but I would love to make it as detailed and scaled as possible. 

Casting is very fun, challenging, and cool!!!!  Adds a new dimension to your finished project to be able to tell people that you cast everything yourself!!  My dad and older brother would have loved my little foundry setup, but they are no longer with us.....I think of them every time I look at my furnace and little growing shop and it brings a smile to my face each time 


Best regards,

  Will R.  Everett, WA.


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## cfellows

Casting is fun. It's always pretty amazing to me to shake out the finished casting and have it turn out as good as it does.

I now have a gas furnace as well as an electric furnace. But I have to say that I did some of my best casting with charcoal. Easy to set up, relatively safe, and melts the aluminum fast. 

My electric set up is easy to use. I like to use it because it's quiet and there are no exhaust gases to deal with. But, it does take quite a bit of time to do a melt and I always worry about burning out my kanthal heating element. The gas furnace works well, but takes a little longer to set up since I share the propane tank with our gas grill. It's also pretty noisy and a little intimidating.

By the way, I make my own crucibles by welding a round steel plate onto the bottom of a length of steel pipe, usually with a 1/8" wall. A visit to the salvage yard will also sometimes turn up some useable steal crucibles.

Chuck


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## matt-jaysey

nsfr1206  said:
			
		

> So I can take any old aluminum and melt it down and use it to cast?



You have to be carefull of magnesium based alloys, some new car and motorbike covers and heads have magnesium in them. Magnesium autoignites (bursts into flames) at around 470°C (880°F). Its very hard to put out once started. Sand is the best was to put it out and dont throw water or CO2 at it! One way to test if your scrap contains Mag is to expose a bare piece with a scrapper or screwdriver and tip abit of vinger on it. If little white bubbles appear, it magnesium based. For a comparison tip some water on first and take note of what do/doesnt happen. Magnesium based alloys can be melted but its not advisable.

matt+


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