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Design question for helium tank forge


JHCC

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On 11/6/2016 at 9:16 PM, Mikey98118 said:

Wayne likes insulating refractories over high alumina kiln shelves; If you cast it into a curved floor, it then is more desirable than kiln shelf in some forge designs, but with its positives comes a negative; it simply isn't as tough as the kin shelf. BUT, Supposing that you take advantage of its insulating superiority to place Perlite directly below below it, and use sodium silicate or more refractory to bond the Perlite into a monolithic? Now ya got something!

Okay, so are you saying that I could replace the kaowool in the bottom half of the forge with a monolithic made from one of the following: (A) a mixture of perlite and sodium silicate, (B) a mixture of perlite, sodium silicate, and ceramic fiber, or (C) a mixture of perlite and refractory? I think you're saying that would work with a floor made from refractory, but that I'd need an intervening layer of kaowool if I wanted to use high-alumina kiln shelf for a working floor -- is that right? 

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17 minutes ago, Mikey98118 said:

 

Do not replace the refractory blanket; but what you choose to do for a floor above that blanket is what is under discussion.

Okay, so I need the insulation of the kaowool all the way around the forge. Gotcha. I guess my question is, if I fill in that extra space with the perlite (or a combination of perlite, sodium silicate, and/or refractory), does that need to be inside the kaowool layer (Option 1 below) or can it fill in the space below that layer --that is, between the kaowool and the steel of the tank (Option 2)?

image.jpg

Where F = Floor, K = Kaowool, and P = Perlite. 

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  • 2 weeks later...
  • 2 weeks later...

I must say this thread has been super informative.  I've been kicking around the idea of doing a similar design with a 20# propane tank but feel like the 583 ci of Fire box Wayne quotes on his site  is quite demanding for needed output of burner/burners.  Besides being slightly bigger/longer than I would need, I do not have a 100# lp tank to feed the beast nor a truck to haul said 100# tank for refills.  FYI this would be my first forge and have reasons for wanting gas.

So I suppose my main question is, is a 20 pounder just too big for a general purpose forge or consume too much fuel for someone like me? I like the idea of a smaller helium tank, but also not sure if I can get one for cheap.

Follow up: pearlite filler is a great idea! is that mixed homegenously with refractory or is refractory layered over the top? I.e. Not pre mixed

I do realize it does depend on the type of burner I have in mind.  I originally thought gun/blown type but pricing fans was a HUGE turn off.  Then it was on to NA and the T, but recently just loved frostys work on a NARB. (2" x 6" I think?)

Im just trying to figure out exactly what I'm gonna do before collecting materials.  

Nice work planning so far JHCC, don't give up I'll take the plunge with ya!

Thanks!

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7 minutes ago, JA625 said:

So I suppose my main question is, is a 20 pounder just too big for a general purpose forge or consume too much fuel for someone like me? I like the idea of a smaller helium tank, but also not sure if I can get one for cheap.

Freon/R134 tanks are the same size, and are usually obtainable for free from HVAC folks and possibly even auto shops - pretty much any place that does a lot of air conditioner work.

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Jory: I agree, 580 cu/in is a darned large forge but the length isn't bad. How about putting another layer of Kaowool in the liner? That'll reduce the volume considerably. However you make the platform to form the floor you want the most insulation closest to the fire so if you're using perlite put it between the kaowool and the shell. 

Helium & freon tanks are easy scores, ask at a party or rental store or ask the folk at the transfer station to set one aside for you. Around here we have transfer stations rather than dumps, there is one landfill, it's open to the public but it's more expensive per load but it can be sort of an off road adventure getting to the trash face(?) Anyway the smaller more local transfer stations have a shed to put things like cans of oil, batteries, old pressure tanks: propane, freon, etc. The folk at the transfer station are friendly and if there's no line more than willing to talk. It doesn't take much of a bribe to get them to set things aside for you, not even a box of donuts does the trick for a long time.

Frosty The Lucky.

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Thanks jer, I did consider doing that with the lp tank.  Still am, I hate decisions when there's no obvious winner.  You reminded me that my area has a "bulk trash" day once a month that stuff has to go to similar relay point not just straight landfill.   I think I should have no problems coming up with a shell.

if the pearlite is just a filler per se does it need mixed with anything or does the layer/layers of blanket and castable above it make that moot?

 

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Non-refillable two gallon Freon cylinders are easily obtainable from HVAC contractors and repair shops, because they have to pay to get rid of them. I didn't know that there was even such a thing as party stores, but the two gallon helium cylinders are also non-refillable, and so they present the same disposal problem for them, and should be just as easy a source for free cylinders.

It seems that its been quite a while since anyone talked about properly venting "empty" cylinders before doing hot-work on them...

Perlite is usually "glued" together with sodium silicate as an outer insulating layer, or are used as an insulating ingreadiant in castable refractory, much the same way a sawdust used to be, before guys wised up.

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I'd probably use something to stabilize the perlite but if the ends are secured and the flame face, inner liner, is plastered with a hard refractory it probably isn't necessary.

My made the floor in my last cylindrical forge by putting a strip of Kaowool in the bottom, pealed the edges so it fit smoothly and plastered it all in, the ends too.

Mike just brought up venting pressure tanks before cutting and it's been quite a while since it was a topic here. Just open the valve and make sure there is NO pressure in non-flammable gas cylinders Helium, Freon, etc.

Propane can be a concern though, it really should be better than just empty. I cobbled an adapter together so I can blow compressed air into an empty cylinder and it flushes out in a couple applications. An empty propane cylinder is going to stink, Mercaptain is the oderant added to propane so you can smell a leak and it leaves a tarry layer in the tank. It's easy to remove though for a 20lb. cylinder add about 2 cups of chlorine bleach and fill it with water. Let it set overnight and rinse it out, no more smell.

Oh, about using compressed air to flush the tank, NO you don't put much pressure in the tank! Heck, the first time I did it I just wrapped a rag around the air chuck, opened the tank valve and blew some air in, removed the air chuck to let it exhale and repeated a few times. It still stinks at this point don't sweat it.

Cutting propane tanks is NOTHING like cutting fuel oil tanks and barrels the process and hazard are worlds different. Do NOT take a torch or welder to a fuel oil tank or barrel! EVER!

Frosty The Lucky.

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Also, unlike non-refillable two gallon Freon and helium  cylinders, propane cylinders all have a little fitting on the side of the main valve that can be unscrewed, leaving the valve open to outside air. I never do anything else on an "empty" fuel cylinder without taking off that screw completely; its kind of the same difference as thinking the gun is empty and doing the gun is empty:P

 

That should "   read knowing the gun is empty.:

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Great info gentlemen thank you!  I know drilling a hole for water displacement still makes me nervous on a manually discharged tank.  Good to know about air "rinsing" and the small fitting on the valve.  I'll pick up a smaller tank and do a side by side comparison and some math and make my decision. 

I figure a frosty t might be in order as a cast multi port might be too ambitious for a first timer.  

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  • 1 month later...

UPDATE: Given a bunch of factors (happiness with new JABOD, limited availability of funds, etc), I 've decided not to proceed with a gasser for the time being and have instead turned the He tank into a slack tub. I'll definitely be keeping this in mind for the future, though, so thanks to everyone who provided their advice and expertise.

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