NeoTechs newbie melting endevours. ;)

The Shop > Metal Stuff

<< < (9/10) > >>

NeoTech:
hmm, i will try that.. It actually did some pulsing when i didnt open the valve fast enough So if can void that completely i would be one happy camper.

But yes, the flame stability is second to none now, it was really fast up to melting point as well, from cold to 740C it took about 15min. So im happy with that. The crucible do go over to redhot and oxidizes like crazy though. But i guess thats a problem with steel crucibles.. It gives off alot of scales that need to be removed before pouring.

Its all an experiment i feel.. But im now considering doing my ingots in a sand mold.. the damn ingot mold is badly constructed and i need a crowbar to get them out of the mold.

Thinking of making a permanent ingot mold that can be easily rammed up from some profiles i have lying around.. Couldnt find a muffin tin without plastic in em, or made out of steel for that matter.. its all some flimsy aluminium things covered with teflon. ;/

awemawson:
You could use a refractory wash to coat your crucible to avoid the oxidisation. I used to use Zircon washes on my skimmers etc. Get the tool or crucible reasonably warm and just paint it on - as the water evaporates it leaves a chalky deposit that protects the metal.

vtsteam:

--- Quote from: NeoTech on August 15, 2013, 12:25:39 PM ---The crucible do go over to redhot and oxidizes like crazy though. But i guess thats a problem with steel crucibles.. It gives off alot of scales that need to be removed before pouring.
--- End quote ---

That's also a problem of excess air in the furnace. One great advantage of charcoal melting of aluminum is that you automatically tend to get a reducing atmosphere around the crucible. It's surrounded by glowing pieces of carbon. So oxidation is much less.

I found that when melting with a propane burner vs melting with charcoal that propane created more fuel expense, much more aluminum waste due to dross formation, and steel crucibles oxidized rapidly on the outside. Cast iron crucibles seem to last indefinitely compared to steel in a charcoal furnace. Your crucible is very thick so it should last for quite a few melts.

I don't think I will be using propane for melting in future. The iron furnace starts on diesel or kerosene, and burns waste or vegetable oil, and I'll use charcoal or even wood for melting aluminum. The setup for charcoal is also simpler. No tanks, burners, plumbing, or starting fuels. Just a blower. And in 20 minutes, molten aluminum with little dross.

NeoTech:
I actually tend to have very little dross though. But most of my aluminium is sourced from car parts. It has alot of other shiet that burns off during the melt, but the dross skims off easy and is less than a table spoon per melting run. (did about 20 ish runs today).

vtsteam:
Sounds good then.

Navigation

 Message Index

Go to full version