Thanks for the reply - lot's of good info that I really appreciate. What I'm looking for is more about this:

"Making your own alloys is not that simple. Sometimes it is, and sometimes it is much more involved..."

That's all you ever hear about this kind of stuff it's dismissed as "hard" or "not that simple" and that's the end of it. That's what you read when you try to find out how an electric motor REALLY works inside... "it's complicated" - well fine. I know it's not that simple. I still want to do it. Not everything that's worth doing is simple or easy. People are accomplishing difficult tasks every day, and I am one of them. So my question is what DOES it take? If they could mix up a good bronze in the height of the Roman Empire, I sure as hell can do it. They didn't have optical pyrometers, electric air-blowers, welding masks or any of the other stuff we have, so it should be more than doable by someone in 2010, but all you ever hear is that you can't or shouldn't and then you never hear another word. So tell me. What does it take? Some kind of flux? A reducing flame? A pyrometer? A carbon mixing rod?

Again. Thanks for the good info. I'm following some of those leads, and that's the second time I'm heard the "sandbox" suggestion. I'll make one today.

Rich, I am sorry but I would NOT recommend Architectural "bronze" as it has about 3% led in it 40 or so % zinc and the balance is copper. Tough to cast (with home systems that I am aware of) and tough to "weld". Huge color changes in the weld areas (the lead and zinc are burned out and thus much higher copper content that wants to take the patina vs regular areas that "will" take the patine.

As to alloying your own,,,,,, some you can, others, alloying materials may be difficult to obtain, atmosphere over the melt can be very difficult to maintain and great potentials for just plain "messing up the batch of $metal$ as well as the crucible. There is also the problem of batch consistency, even with processors/mfgr's. who's business this is. Batches of silica bronze can very a surprising amount and when I have the amount of time and materials into all that is necessary to be ready to cast, I want to eliminate problems, not make them.

So if you want to go forward with making your own casting metal, for what ever your reasons are, please feel free to do so. Just don't get upset when folks you ask, because they likely know more about what your are asking about than you do, say either be VERY careful or why do you want to do "that" of just don;t do it, don't get upset with them, they are just giving you their best advice and opinion. I once "made" some "ancient bronze" alloy (copper and tin) as the gal didn't get enough from Atlas Bronze, she was at the foundry to take the pieces that day (lived 3+ hours away), had "her" deadline to meet and I the raw materials for the mix on hand and a crucible dedicated to this alloy. Mixed our home make alloy with the purchased alloy and had just enough for the pour, just enough......

Would I do it again???? Not if it wasn't necessary. I would rather be interested in making a great casting than making the alloy, but this is just my choice, not anyone else s.

Visitor,

I was NOT recommending architectural bronze for casting, only recommending it for color since the poster said he wanted a "yellow" bronze, but I'm glad you brought it up. You are absolutely right about the alloying ingredients and the issues with them as far as melting goes. That can be overcome by using an induction furnace with inert atmosphere, but not many hobbyists have that capability.

Thanks also for detailing your experiences with alloying - I've done some of it and I don't recommend it, either. Why bother when I can buy good alloys ready-made from dependable suppliers who will provide me with the certs for the melt if I ask? But then, I'm a professional trying to make a living at my metalwork and don't have the time or money to put into re-inventing the wheel, so to speak. A hobbyist or a different professional may have a valid reason for doing their own alloying and I won't argue with that, but I won't suggest or recommend it, either.

Daverham,

If you're serious about doing your own alloying, you need to do the research on the subject in metallurgical texts. You can find them at some university libraries or possibly through your public library through the Inter-Library Loan system. I don't know any way to make it simple and easy or something that can be conveyed in a few paragraphs.

Rich

Thanks again. I did purchase a couple metallurgy texts from Amazon just a few days ago, after reading many reviews, and look forward to dive into this as a small part of my hobby - which is all this is to me. I don't really "manufacture" anything, everything is a one-off for me. And man - those books are expensive! All the truly specialized/technical books I have come across sure are pricey - for this hobby and others.

I'm curious about the crucible problems/dangers you mentioned in your original reply. What sort of problems have caused injury to people or property, in your experience? Any tips on what to look out for are appreciated.

Crucibles are somewhat fragile, though not unreasonably so. The silicon carbide crucibles are tougher than the graphite ones and commensurately more expensive. There are people who use steel pipe for crucibles, but I strongly advise against this, particularly if you are melting aluminum. Molten aluminum is a pretty fair solvent, it seems and erodes steel crucibles. While graphite crucibles aren't free, the cost is cheap insurance, as far as I'm concerned. Silicon carbide is like a better policy. :-)

The chief reason graphite and carbide crucibles get broken is mishandling - usually the result of having poorly-fitting lifting tongs or a bad pouring shank. Since it isn't difficult to make perfectly fitting tools , there is just no excuse for using ones that don't fit the crucible.

Graphite crucibles should be "seasoned" before using for a melt. You heat the crucible slowly in the furnace and flux it, then let it cool slowly to room temp. Should there be any internal flaws in the crucible, this will expose them without risking a spill of molten metal. It also gets the crucible coated with flux so that there is less chance of contamination of your melt.

Once you have a good crucible and properly fitted lifting and handling tools for it, the next step is to do a dry run. That is, go through all the steps of the melting/pouring process just as if you were doing a melt. This will let you determine if you have any issues with things in your way, poor fits, bad lighting, etc. When you have a foundry up to heat and the metal ready to pour is NOT the time to discover that you don't have room to stand where you need to be to pour, or other problems. Whenit is happening there isn't much time to think, all your actions need to be almost automatic. NOTE: - I am not saying you shouldn't think - of course you should. But things happen quickly and it is easy to get flustered and forget something. (Where's the flux?)

Please get the proper safety equipment! Heavy leather boots, spats, gloves, apron, goggles and face shield, respirator for metal fumes, fire extinguisher and the all-important sandbox to play in. Molten bronze goes through flesh and bone faster than puke through a prom dress, as my old sculpture instructor used to say.

Since minor burns are almost inevitable when working with hot metal, ask your physician for a prescription for Silvadene cream. It's the best burn cream ever invented and speeds healing remarkably. Guess how I know this? (grin)

Be safe, be creative and have fun! We'll be looking for the pictures.

Rich

Thanks for taking the time to write a thoughtful reply! I WILL take the time to setup with proper equipment for safety and good quality castings - especially crucibles. I'm glad to have the voice of experience to guide - this isn't the kind of thing you can just ask around about - nobody else is doing it, in the typical work/family circles.

I did just achieve my first flawless aluminum casting (after about 10 almost-there's) only 30 minutes ago. I'm very excited. I was getting bubbles due to overly damp sand, I think. I am currently using a steel pipe as a crucible, It has been sitting in muriatic acid for 2 days to dissolve the galvanizing off. I dare say only steel remains now. It flash-rusted within moments of removing it from the acid and rinsing. This home-made crucible is temporary, as I am eager to play around and learn right away. I do have the boots, gloves, apron, etc from my welding supplies. I took a class for that. And I made myself a sandbox, per your recommendation last night. I had to do something with the rest of that 100LBs bag of silica sand I got at Home Depot after all. I only used about 15LBs for my casting sand.

I have all kinds of photos on my website, including plenty of hot furnaces and molten metal, if you scroll down: http://davidcolecreative.com/shop.php

I'll post them here as soon as I have some newer ones that show me practicing good foundry habits.

Thanks again.

Just had a look at your website....the furnace looks good except that the air should go in at a tangent to crate a swirling effect rather than straight in and you wwould find that a propane burner would give better control than charcoal.....cheaper too.

Info on building a burner for propane here http://ronreil.abana.org/design1.shtml#Reil

There are lots of other burner designs...

or you can just use a large propane torch ("Tiger Torch")

Tangent for sure. Propane burner we use is 2" black steel pipe, fan in "intake end with device to adjust air flow, hole (to take a piece closed off 1/2" pipe - gas "nozzle" with "in our case 1/16" hole but varies as to what pressure you are able/going to use -- we use 25-30 psi)) drilled down stream of air input and the outlet end is fitted into a hole in the side of the kiln wall at a diag to get the swirl. Cheap, easy to repair (add on pipe when the outlet end gets too burned) and works great. We can heat 100 lbs bronze to 2300-2400 deg F in about 1 hr 15 mins for the first heat, then the rest are about 1 hour. Use KalWool for the walls, supported by welded wire fabric and use nichrome wire in hifh temp. hollow tube (used is electric kilns to hole and protect the elements). Again relatively cheap, easy to build and move and give years of life if kept out of the rain/fog/dew.

Tangent! I had considered that, but wasn't sure if it really made a difference. Now you've confirmed it. I'll try welding a little sideways flange at the end of the air inlet...

Thanks again!