Mako Burner

[bmac2]

During the first melt I was having problems with backpressure and was compensating by adjusting the regulator starting at 3 psi to preheat, going to 7 for the first melt and then 10 psi for the rest. At the time I’d thought “Once the troll gets hot it seems to deal with higher pressure better”. Now I’m thinking that once it gets hot it needs the higher pressure.
This time when the Troll started to surge I was adjusting the burner position in the tuyere until it stopped and leaving the regulator set at 5 psi. I know that just into the last melt the Troll was surging and I moved the burner to get it under control. Thinking back now I remember seeing a small amount of blue flame around the top of the crucible. I think what happened was the gas was only burning in the top half of the furnace and the bottom was basically just getting cold air.

 

[bmac2]

The aluminum looked melted in the crucible, as in shiny and smooth. When I went to stir the melt I think the rod acted like a heatsink taking it over the edge and the burner wasn’t butting out enough to recover. As soon as it warms up a bit I’m going to see if I can melt the gunk out, or use my spare crucible to get the 3% mix and toss in those pennies.

For now, it’s cold outside but driving around today, I’m still living in a Christmas card.

 

[bmac2]

Well with the weather this past week and nothing on TV except another Duck Dynasty marathon on A&E I decided to go play in the shop. ;D
The one thing that comes up on a lot of the web-pages I’ve seen is the Reil burner. This is the burner I had originally thought to build before I made the Mako. Looking through my junk I had an 8” piece of ½” black iron pipe and a 1” reducer but didn’t have all the stuff so I faked one up out of what I had at hand. Going to give it a try, if it works out I’ll have to pick up some parts to do a proper job.

 

[bmac2]

Set up the Mako burner in the Troll with the regulator set to 15 lbs. and 25 minutes later the gunk in the bottom or the crucible was looking a lot more like molten aluminum and poured out easily. It doesn’t look bad so I’ll toss it back in with the extruded ingots.

 

[bmac2]

The crucible is cleaned out so I now have a green light to carry on experimenting with the aluminum/ copper alloys. I weighed out the copper for a 3% and 4% alloy as well as one for .75% zinc. What do you do when Apple won’t let you update your old I-pod? Keep all your threading/machining apps and a spreadsheet on it and let it live on in the shop.

 

[bmac2]

I was having back pressure trouble with the Troll starting to surge when I put the crucible in and again when I put the lid on so I decided to try the Reil. I’ve got to say I don’t think I’ll be going back. Had the regulator set at 7 lbs. and it just runs. Each melt was around 400g and start to pouring was a constant 10 minutes. The way I was getting the copper into the aluminum was to melt the heavier of the 2 ingots first, drop in the copper and submerge it with the second ingot to try and keep the oxidation down but I still got a fair bit of dross. The stuff is light as a feather.

 

[bmac2]

My results.
In the following pictures, on the left is an raw ingot poured from the extruded aluminum and on the right is one with the copper added.
The 1% is soft but not as gummy as the raw ingot.

 

[bmac2]

The 2% is still soft but getting there.

 

[bmac2]

This is the one I was looking forward to last week when my melt went south. The 3% copper cuts much better than the first two and does have a better look to it.

 

[bmac2]

I am glad I decided to try 4%. I’d almost pay money for this stuff. I think I may have overheated it a bit wanting to make sure the copper tubing was melted. It was red hot going into the muffin tin. Looks like I have a lot of reading to do on degasing but it cuts very nicely and has a good look to it.

 

[bmac2]

Can’t see much difference with the zinc but it did cut well in the band saw. And I got to melt some pennies, well half of one.

 

[bmac2]

When I made the alloys I did two pours of each so I could cut one in the band saw to see a cross section and another to put in the lathe. All of the muffins machined, well like aluminum. But I have to say I’m quite happy with the look of the 4%.

 

[bmac2]

I made a stop at Princess Auto on the way home the other day and after getting the parts I needed to finish the Reil burner I took a walk through the surplus section (you know you gotta). Found this little 4” squirrel cage fan for $4.99. (http://www.princessauto.com/en/detail/sony-brushless-blower-fan/A-p8586604e) and just had to buy one.

 

[bmac2]

My original thought was that I might use it to replace the fan on my mini-mill that’s starting to make some noise but I already have a couple of salvaged 12vdc muffin fans that would drop right in so why reinvent the wheel.

I have to wait for spring before I can try sand casting to see if I’m able to actually cast anything other than ingots. But IF I can, and I build a larger furnace I might use it as a blower for forced air. Hooked up to my bench supply it will run down to around 1.5v with no problem so all I’d need to do is make up a quick and dirty variable 12v supply. At 500ma it could easily just run off a couple or rechargeable batteries, one less thing to trip on around the furnace.
[ame]https://www.youtube.com/watch?v=3hf-qR_m55w[/ame]

 

[gus]

Did some gravity casting with Cast Iron Molds. Was casting Automatic Condensate Traps and getting pin holes and leaks.
Bought some degassing agent that looked more like muffins and you need a inverted cup to push it down to the bottom to enable the degasser to produce mini bubbles to bring crap. A refining agent is added on to make the machine surface look good. I used extruded bars and scrap pistons to improve machineabilty.
Foto show aluminum auto trap on the left hand side. Build a steel plate clad furnace with high temperature firebricks and custom cast C.I. crucible. Crucibles made with steel pipe did not last look long. After a few casting sessions the aluminum ate thru the steel pipe.

Casting Temperature. Too high pouring temperature cause excessive shrinkage.Too low and you get cold runs. Pouring temperature has to be figured out. Silicon additives make pouring and metal flow into mold smoother.

Have fun casting aluminum but take extreme precaution and well protected. 1400 degrees Fahrenheit burns very badly. No busy body on-lookers. No visitors. I had zero accidents. Gus was Operations Manager,Ingersoll-Rand,Singapore Small Air Compressor Plant for 20 years till laid off.

 

[darwenguy]

Hi well done on the furnace experiments. I too learnt to cast recently. I made my furnace from an old lpg tank just drain fill with water then cut no prob. I fire mine with coal and a hair dryer. I also added about 6 prcent copper to the mix makes a massive difference when machining tapping. I must thank myfordboy and tubal cain for there videos are more educational then any book. For degassing i use soda crytals and for flux low salt both available anywhere. Good look with sand casting and dont give up you will learn the most from your mistakes (i did). Ive just got myself a ceramic crucible and some scrap cast iron since my furnace melted my steel crucible!!

 

[Beachside_Hank]

I've been gearing up for a home foundry capability and posted my results thus far up on Instructables:
http://www.instructables.com/id/Benchtop-Foundry-And-Forge/

I recently used the lower section from a barbecue cart as the mobile stand for my works after melting down the upper ally firebox

I'm at the stage of "clarification", that is to say making dross- free ingots in muffin tins, ready for the day when I am ready to cast- right now I'm thinking hotwire foam molds to begin with.

I have a propane tank foundry ready for refractory, but so far this little forge has done all I ask, so the big brother is on hold.

My fuel is free, simply hardwood furniture picked up from my neighbors during "asset recovery sweeps" of my 'hood. My main source of ally is
Sears Craftsman radial arm saws, a very- high quality set of castings. Emerson Electric has a recall event going on these saws built 1958- 1992, and pay a $100 bounty for the motor, so all the rest of the metal I get to keep anyway, so I'm kinda swimming in ally right now, have about 50 pounds of clarified ingots in a bucket, probably twice that amount in raw parts to process.

It is unbelievable fun to do this, trouble is it now cuts into my lathe time.