making metal really hot general

>>1170915
>however i go through most or all of a 20lb tank if i have any substantial amount of cans to melt

wtf, how many cans are you melting? i do about 2-300 cans in this: http://www.backyardmetalcasting.com/bucketfurnace1.html

i weigh the 20lb tank before and after and it's like 2-3lbs of propane

>>1170915
What a cute little furnace.
So where you at and how far are you willing to travel to buy ifb's without paying shipping? Were you looking for k23's or k26's? I bet I can find something local that sells them. Amazon is shit for refractories.

>>1170954
Modified version of Grant Thompson's pipe burner at 10-15 psi in a small helium tank you get from Walmart cut in half and lined with ceramic blanket. I usually get anywhere from 5-10 lbs of ingots depending on how much I saved up.

>>1170955
Fairbanks Alaska. Closest place I can imagine having soft brick is Anchorage but that's 6 hours away so fuck that. Probably k26 just for that extra bit of resistance. Amazon absolutely is shit but it's also the cheapest option that doesn't involve literally $50 per brick shipping.

>>1170960
>Modified version of Grant Thompson's pipe burner at 10-15 psi in a small helium tank you get from Walmart cut in half and lined with ceramic blanket. I usually get anywhere from 5-10 lbs of ingots depending on how much I saved up.

i used a pink helium tank too, inner diameter is ~8", the rest to outer is the fireclay/vermiculite mix. lid is ~3" thick with a 2" vent hole.

but i run my burner at 3 psi, 5 psi max - i have no problem pouring 5-10 lbs in about ~2-3 hours total use time

>>1170961
Yeah mine wont hold the flame at the nozzle below about 7 psi, it will travel back to the propane outlet and become useless

>>1170966
huh

i crack the regulator open a little, start the flame, crank the output until the flame moves into the chamber ( maybe 6-7psi ), then back it off to 2-3psi - and the flame stays in the furnace. i used the backyardmetalcasting burner (same orifice too)

>>1170960

Can't you bodge something from fire cement and perlite like >>1170961?

Home depot probably has both.

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>>1170960
Contact this guy. Potter in Fairbanks. This is right on his site.

http://www.glacierpottery.com/about-us.html

>>1171049
Just a reminder: potters, like most traditional craftsmen are the salt of the earth. They almost always help out other craftsmen. Even scuzzy salvage ifb's are golden. They can be easily cut, mortared together and sanded flush to make walls. You might also start keeping an eye on used kiln listings on craigslist.

>>1170975
My burner is an entirely different design so it behaves totally different I guess

>>1171040
I was considering pouring slabs out of refractory and then bolting them together similar to the op

>>1171049
>>1171056
Well fuck that's 20 minutes from my house! Guess I'll be paying them a visit since I have the day off anyway.
Yeah I wish people sold shit like that here but they never let anything cool like that go unless it's busted or completely worn out or way too expensive. I've been looking for Mills and lathes on and off and I can't really find anything in my price range that wouldn't need 2x the invest to fix up.

>>1171113
So, if that guy doesn't have any brick, just tell him you're interested for when he does. You should totally tell him your intentions. Very likely there's a network of kiln/furnace work craftsmen around there who look out for each other or pool orders for discounts on raw materials.

Another thought occurred to me today. If you have any friends or relatives in the lower 48, you could have them get ahold of some ifb's you could order from their local ceramic supply places (or shipped to them, then they could reship them to you in USPS flat rate boxes. I did a price and box size check for that and it looks like you could get 3-4 full bricks in one of those. Something like $9-10/brick in total.

You know what sucks is there was a ceramic supply shop in town near the college not too long ago that apparently went out of business. And that's another avenue to explore. Everywhere I've ever lived I go meet the art department heads at the local colleges and try to make friends. They tend to have more kilns, foundry, and glass equipment than they can get use of. And you know, it's kinda lonely hanging out with just students all day. I've had several friends in the past who slide into some kind of token part-time "assistant" type position in exchange for unfettered access to their equipment.

As a pro, this is also a great place to find your own part-time assistants. Craftsman networking.

>>1171126
Just dropped by that dudes place and he has PALLETES of bricks. Bought 10 like 8x3x2 or something soft brick and 2 hard brick for a floor for 5 bucks a pop! That's even cheaper than lower 48 pricing in some cases. I'm heading to home Depot for frame materials right now.

>>1171293
Nice. Glad that worked out for you. Yeah, $5 is the 25-brick case price. Potters are good people. Good luck with your new furnace.

>>1171336
Oh, and post some build pics sometime when you get around to it. Makes the board better.

Yeah for sure I was gonna post when I finished up my design.

electric sucks because it's always oxidizing. Go diesel.

also cans suck

>>1171373
You mean Because it doesn't have a flame burning/pushing out oxygen?

>>1171391
right. it'll make a lot more dross, its really only useful for gold and other noble stuff

>>1171403
Shouldn't really be a huge issue unless I'm constantly stirring it and disturbing the oxide layer for no reason

>>1171403
wait, are reducing or oxidizing atmospheres are useful for gold?

>>1171436
it doesnt matter, since it doesnt react with anything

>>1171441
You can always squirt in a little LP through a small inlet hole in an electric furnace to reduce the atmosphere. If you put a pipe over a small flue on top with a little hole drilled in the side you can stick the tip of an auto O2 sensor into it and attach the leads to a multimeter set to DC volts. Ease of heating with electricity, atmospheric control of fuel.

>>1171403

It doesn't make that much of a difference unless you're constantly fucking with the melt for some reason.

If it's that much of a problem, you can always just use a covered crucible and/or flood it with the inert gas of your choice. Assuming the lid/door fits well, you'd use hardly any of it.

>>1171373
I'm using used engine oil. There is an abundance of that. You can fuck around as much as you want as it's free.

>>1170960
Kek. I scaled ol grants shit up to a trailer mounted fire tornado and lava throwing machine. Never plaster at me or my son again

>>1171293
That a boy OP.

>>1171373
Yeah but deisle turns into gas when u get it that hot. I bout blew myself up with an open tank spill. I have fucking welded full deisle tanks right on the truck. Electric would be so nice and quite

>>1171373
And can confirm. Cans suck my ass.

Almost got a can bailer and grain bin hopper built tho.

>>1171497
Yes but the cancer

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So I've been trying to figure out how I want to lay out the furnace but I didn't take into account that most people use a 1-2kg crucible but I'm designing mine for a 6kg which is substantially Bigger of course. I should have gotten probably 4 or 5 more bricks to make it a more comfortable size like I wanted but I think I'll just make due with the 10 I have using some left over ceramic blanket. Another thing I discovered is that the alumina silicate bricks are "arch bricks" where they're not perfectly square along the width, but they wedge out about a 1/4 inch from 2.75 to 3" making it so j would have to cut or shave them all down to make them flush or use a bunch of filler to fill in the gaps. This could have been easily mitigated if the hard brick was arched too but they are square. Either way i have to square them to make the bracket hold them tightly. Now I'm just trying to figure out in my head how to make a little cutting jig for a hand saw to make them all as perfectly the same size as possible.
Everything's always gotta be a headache don't it... Sigh...

Why has no one mentioned an induction furnace?

Does nobody care about eddy or his currents?

>>1171373
I agree. That's what I did but I suppose you could pump it full of argon.

>>1172791
Eddys an expensive goy and his currents are massive

Maybe get the bucket of refractory from home despot or Lowe's? Form your own? Currently using 2 steel rims stacked with an old grill top as an ash catching/ blower intake area, and welded with a fucking Walmart Dutch oven as a crucible and shop vac blower. Losing a lot of heat out of the top without a lid, but that's in the near future. Wood for fuel for now though.
My plan is to use the motor oil and/ or gas, but I'm working on gathering supplies.
Try directing your heat better. You are using a fuck ton of fuel

I have an interest in this but need extra high temperature.

For this reason I have considered pre-heating the air going into the burner using the hot exhaust gases using some kind of simple (and tough) heat exchanger.

Any experiences/recommendations for such an idea? The primary need is high temperature, not necessarily saving propane. Oh and for complicated reasons I was planning to use coal fire.

>>1172791

Expensive to buy outright, difficult to build yourself. Less efficient than a well-insulated resistive furnace for aluminum.