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Forge Refractory


Tyler90

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I'm new to the art and am looking to make a new aluminum melting coffee tin. I just want to do it properly, the first time I didn't use any refractory.
from reading I see kaowool, satinite and ITC are highly recommended.

1) for melting aluminum the temp is so low would just refractory cement be sufficient?

2) if I make one for doing railroad spike work, since the temp is so much higher would just kaowool and ITV-100HT be sufficient? Or is the satinite necessary?

I can't seem to source satinite in my area or find an online dealer.

Ps: as of now I'm planning to use BBQ charcoal I might change to gas later

Any tips appreciated!
Thanks!

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Hi Tyler.

 

Generally speaking, a forge and a furnace work better as two different set ups. Neither one is particularly hard to make though.  A coffee can furnace does adapt pretty well to gas from charcoal.  Although on a propane forge, you want insulation, on a coal forge, refractory is mostly aimed at protecting the forge material itself.

 

For something like aluminum, in something like a coffee can forge, you can get enough insulation from a number of sources. Furnace cement is fairly cheap and easy to get. I've also used the backyardmetalcasting.com recipe for homemade to great success. It's far from professional grade, but fine for something like that.

 

For rr spike work or other small forging, you could easily build a brake drum forge or 55 forge. You may also want to consider using lump charcoal rather than bbq charcoal. BBQ charcoal will eventually melt aluminum with forced air, but it's slow and not particularly satisfactory. Too much silica filler.

 

I strongly recommend that if you're going to cast, you invest in GOOD crucibles and PPE. Casting can be a very dangerous sport. It helps to find an experienced friend or teacher. (if you don't and you do it much, if you're lucky, you'll only have scars.....who me? scars? innocent whistle....) There are a number of casters on here, but you may find some good tips and links at backyardmetalcasting.com. I also reccomend the David Gingery books for the beginner. Good luck!

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Hey Mr Nobody! 

 

thanks for the reply. 

 

So from what you are saying my best bet would be to focus on one at a time. I will start with my furnace for some aluminum casting. 

 

For the furnace I have a coffee tin and will use some refractory cement and see how that holds up. I did one previously with just the tin and no refractory and used a soup can for crucible. it was rather annoying because the crucible is small and annoying to remove slag. I am not doing a lot of Al at one time so I think for now I will use it again but I will think about upgrading and making my own steel crucible out of 1/4" wall 4" pipe and a 3/8" plate welded to the bottom as recommended by Dan Manders in his beginner casting thread. I haven't welded before so am waiting for a friend to teach me before getting into that.

 

The local scrap yard will make it easy to find an old brake drum so ill keep that in mind when i decide to try working some rr spikes.

 

Now reference your PPE comment my welder friend gave me coveralls gloves and a face shield. I didnt use the face shield it seemed like overkill I just wore some ballistic eyewear I have from work just in case something went wrong. Is this safe enough for aluminum work? I see lots of videos online of people in shorts and tshirt doing Al casting so i assume this is more then okay.

 

My goal is to make my own tomahawks, i own about 5 now that i purchased from the store its a hobbie for me so i decided to make my own. I'm slowly working towards it trying to learn more about the different ways to work metal as I go along.

 

Once again thanks for the advice Nobody!

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Now reference your PPE comment my welder friend gave me coveralls gloves and a face shield. I didn't use the face shield it seemed like overkill I just wore some ballistic eye wear I have from work just in case something went wrong. Is this safe enough for aluminum work? I see lots of videos on line of people in shorts and t-shirt doing Al casting so i assume this is more then okay.

Many of the youtube videos should be proceeded with the disclaimer "For entertainment purposes only" or at least "Hey ya'all, watch this". 

 

Let me ask a question. If everything goes south and you have hot molten metal splash into your face, do you want only ballistic eye wear or do you want ballistic eye wear AND a full face shield? Remember it is your face, and YOUR call. Please choose wisely, or ask your wife which she would prefer you to use. Remember scars last a VERY LONG time.

 

We push safety on IForgeIron because many of us have been there and done that. Look for a blacksmith with scars and ask him to tell you what happened and how he got the scar(s). There are some great stories out there. 

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You can melt aluminum in a thick walled steel crucible. However they can and will eventually fail on you. I'd stay away from steel "tin" cans altogether. They oxidize and fail very easily. A steel crucible will also have inclusions of fire scale. Best would be fused silica or graphite. Very cheap compared to hospital bills. Don't bother trying to make refractory ones at this phase, they're a pain, take careful preheating, and can crack open all too easily. There's also some debate about using steel or cast iron with metals like bronze/brass, since pouring temps are kinda close to melting temps. I wouldn't at this point.

 

As far safety goes, in casting, always consider worst case scenario. With aluminum, that means complete crucible failure, or steam explosions. Imagine if that crucible full of molten metal broke open dropping aluminum onto your shoes/legs or blew up in your face. (I have the tiny white scars all over my shins if you know where to look from a failed crucible and splatter back around 2004. Clothes only help so much with 1300 degree metal.)

 

Generally speaking, with PPE, long sleeves and pants (yes some people do it in shorts and short sleeves. I have done it and got away with it, also done it and been burned.) Natural fibers in your clothes, so that if you do get it on you, or too much heat, your clothes don't melt to your skin.

 

Leather gloves with no nylon in them, like welding gloves. Leather, closed toe shoes, (and remember, hot metal will melt into the bottom of your shoes too). A face shield, definitely a good idea. Water in aluminum = steam. Think a drop or two of sweat in a crucible expanding instantly.  Or in your mold. Or in your....you get the idea. For that matter, a headband or a hat to keep from dripping sweat is a good idea. I'd also reccomend a leather welder's apron.

 

For forging on the other hand......similar clothing, but you can back off of a few things. You don't need a full face shield, but safety goggles and earplugs are a good idea. You can forge in shorts and short sleeves......but you will sometimes get burnt by hot metal or hot scale. I barely feel the little ones anymore. Gloves when you need them, but a lot of work can be done barehanded.

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Here's a couple of simple examples of minor explosions during casting. Not that bad.....but what if that was your face or your foot? And yes, you will see videos where people deliberately try to induce one and fail. It doesn't happen every time water's introduced, but why take chances?

 

 

 

A lot of these posts may come across as if we're trying to scare you away from casting, and believe me, that's far far far away from the truth. Want you to have a blast. Just want ya to do it without scars and the trips to the hospital that a lot of us have done.

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