Why I cast my own models

[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.

 

[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

 

[sparky961]

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

 

[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?

 

[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

 

[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.

 

[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

 

[Metal Mickey]

Any clues re suppliers? Mike

 

[rickharris]

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.

 

[tel]

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.

 

[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.

 

[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

 

[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

 

[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.

 

[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

 

[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.

 

[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

 

[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

 

[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

 

[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