Why I cast my own models

[Doug E.]

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

 

[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!

 

[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

 

[nsfr1206]

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

 

[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

 

[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.

 

[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

 

[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.

 

[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

 

[matt-jaysey]

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+