toying around with the idea of a gasser

[FieryFurnace]

I have a store that currently wants 200 round metal "TUIT's."
A "TUIT" is a round disk about 3/8-inch thick and 1 1/4-inch in diamter and is forged from a 1-inch long piece of 1-inch round stock.

Nevermind the particulars of what a "TUIT" is, I would just like some basic recomendations from which to begin my research.
A gasser that could hold a dozen of these at a time would speed up production. (So perhaps 4-inches square 6-8-inches long.)

So, my current requirements would be something that could hold a dozen of these pieces of metal.

Would that be a single or double burner sized forge?
Side burner, top burner, bottom burner? What would be the proper configuration?
Frosty.....would your burners be suitable for this?
Should I use a steel circular frame and line it with K-wool? (I can get 6-inch 1/4-inch wall pipe in short lengths for 35 cents per pound.)
What about just a firebrick box with an angle iron frame?
I've been told that the small gas grill propane tanks are not suitable for providing fuel to a propane forge. Is this correct?
If so, where would I obtain a proper source for fuel?
If I can use a gas grill propane tank, what is the burn time?

Those are all the questions I know to ask right now. I'd appreciate any help. I looked around on the first couple of pages of posts but didn't find anything that helped much besides Phil's post on Frosty's burners.

Feel free to answer any unasked questions that you may think it suitable to point out.

Thanks!




Oh yea.......has anyone ever used wood-gas in place of propane?

Edited November 11, 2011 by FieryFurnace

[doc]

Dave,
The small size of forge you'd like to build should be quite reasonably made from soft fire brick and angle iron frame. Almost any simple pipe burner (made from plumbing fittings) of about 1/2" or 3/4" pipe should be sufficient.A grill sized tank probably wouldn't give you too much trouble with this size burner/forge combination but you could either manifold two 25lbs. together or get yourself a 60lber.This would alleviate freezing up. You might want to use a hard brick on top of soft for the floor to resist wear.

Hope this helps

[pkrankow]

Stove pipe will work fine for a shell. If you can get a freon or expired propane tank that might be better. 1/4 inch wall thickness would have the advantage of being easier to weld stuff to, the other shell options I mentioned can be fastened with self-drilling sheet metal screws. Since you are an accomplished welder the differences are minor.

My forge is a single burner built around a single common stove firebrick, 2 inches of ceramic wool insulation, top entry, but with a top entry you have a horrible hot-spot on the bottom. Side or bottom entry probably are much better choices in this respect. I am using Frosty's burner, and the only complaint I have is it does not like wind (I work outside)

I wish for a few things on my forge, a larger "porch" , proper doors, and a slot down the side for wider items.

Don't forget there are square TUITs too.

Phil

[FieryFurnace]

I've heard that term "freezing up" before. What does that mean? (Other than to describe what happens to a guy that stays in the cold too long. )

Does the use of a firebrick box eliminate the use of K-wool? It sounds like it doesn't the way you're talking Phil.

If that is the case, it would be more advantagous for me to use the small 1/4-inch wall pipe that I already have, line it in K-wool, and stick a single piece of firebrick in the bottom to allow me to stack the steel on.

If I used a 6-inch diameter piece of 1/4-inch wall pipe then how much K-wool would I need? would an inch all around be sufficient?

I keep saying K-wool like I know what I'm talking about.........I hope that is the right term. :D

[Ramsberg]

Hey Dave,

Propane as a liquid has a very low boiling point and just like every other liquid out there is has a latent heat of vaporization, the exact btu per lb depends on the pressure of the liquid and its temperature.

The latent heat of vaporization is the heat energy required to convert a liquid to a gas or a gas back to a liquid. With water at atmospheric pressure (14.7 psi it requires 970 btu per lb and must reach a temperature of 212 deg F to boil. A btu is short for "British Thermal Unit" a single btu is the heat required to raise one pound of water one degree F. If water is held at 150 psi then it must reach 358 deg F to boil and the latent heat is 864 btu per lb, at 1,500 psi it must be 596 deg F and the latent heat is 556 btu lb.

Propane is the same way, the higher the pressure the higher the liquid temperature must be and the less the laten heat is.

With a boiler one uses fire to give the water the energy required for it to evaporate and maintain the temperature required at that pressure.

Propane absorbs the heat from the atmosphere, here are two links to two charts giving the latent heat at different temperatures and the temperature required at different pressures for propane.

http://www.engineeringtoolbox.com/latent-heat-vaporization-propane-d_1203.html

http://www.engineeringtoolbox.com/propane-vapor-pressure-d_1020.html

If one used a 25 lb tank in 15 hours that would be 1.67 lbs per hour, with roughly 155 btu lb that would be 258.85 btu per hour that the propane would absorb to maintain its temperature. If it is supplied with less heat then that it will drop in temperature and as the temperature lowers the pressure lowers and the latent heat required rises!

Propane has a specific heat of .576, so to raise its liquid one degree F it requires .576 btu per lb. This is also how much heat it will give up for one degree F drop.

So if you have 25 lbs of propane liquid at 70 deg F and it drops to 50 deg F then 20 deg F times 25 lbs times .576 then that is 288 btu that would be released. This is making it simple though, because as you draw off propane not only does it require heat to vaporize it but it also takes its heat energy along with it. Put another way if you have 60 lbs propane and you took 288 btu away from it, initial temperature being 70 deg F it would drop to 61.67 deg F. If you had 6 lbs and took away 288 btu then it would drop from 70 to -13 deg F! Which would only give about 15 psi, I don't know if that chart is in absolute or gauge in regards to pressure, absolute is considering the atmosphere and gauge is zero at atmospheric pressure, probably it is absolute.

As you can see from the temperature/pressure chart that I linked to, the lower the temp the lower the pressure and from the other chart the lower the pressure the higher the latent heat. So it is a double down situation, especially with just a little left in a small tank, then any significant draw of gas from it will drop the temperature so much that the pressure will be too low to do anything.

The freezing deal is from the tank walls becoming so cold that they not only condense moisture on them, but they freeze moisture on them.

The simple solution is to place the tank in a bunch of water, that way it can absorb the heat from the water instead of trying to absorb the heat from just the air around it, there is a LOT more heat in water. So in effect you can get the operational aspects of a big tank from a small one sitting in a bit of water.

However as Doc put it a small forge doesn't use as much gas and in turn the tank doesn't cool down as fast so for what you are doing it is probably a mute point.

Caleb Ramsby

[Ramsberg]

Hey Dave,

Don't know if you have checked it out yet, but Ron Reils website is in my opinion the best out there for designing and building your own propane forge of any size.

http://ronreil.abana.org/Forge1.shtml

Caleb Ramsby

[pkrankow]

You really want 2 inches of ceramic wool. This will keep the outside "cool" (it will still get hot), and save fuel in the long run.

Phil

[doc]

HI Dave,
Lets keep it simple OK . You want and need a small gasser to do a small job inexpensively and efficiently. You could get Kao-wool it works fine but you'd have to by a minimum amount that is more than you need for what you'r building. Then in order for the wool to last anytime and to protect your lungs from the bits of fiber that will be strewn in the air every time you fire it up and every time you pass stock in & out of it you need to coat it with rigidizer. Then if you want it to really last and give you more heat for your buck you'll need to coat it with ITC-100 or some equivalent.

BOTTOM LINE all this is going to cost you more in materials and labor than you'r going to make from the job it's for.

Get yourself some soft reflective fire brick, some angle iron build a forge box one brick high one wide and maybe two deep.The area you'r heating is less than one cubic foot, any losses thru the brick will be minimal compared to the heat in side and will get your job done fast and efficiently.
After you've completed your job you will have gained some understanding of how a gasser works and is built. If you think you'd like a larger one for other stuff you'r in a better place for building one and maybe can justify the expense. The small brick one will out last any equivalent wool forge at less cost.

Caleb's explanation on freezing and link to Ron Reils' burners are something I should have added to my first post........ Thanks Caleb

If this all sounds wrong to you then you can just disregard

Doc

[FieryFurnace]

HI Dave, Lets keep it simple OK . You want and need a small gasser to do a small job inexpensively and efficiently. You could get Kao-wool it works fine but you'd have to by a minimum amount that is more than you need for what you'r building. Then in order for the wool to last anytime and to protect your lungs from the bits of fiber that will be strewn in the air every time you fire it up and every time you pass stock in & out of it you need to coat it with rigidizer. Then if you want it to really last and give you more heat for your buck you'll need to coat it with ITC-100 or some equivalent. BOTTOM LINE all this is going to cost you more in materials and labor than you'r going to make from the job it's for. Get yourself some soft reflective fire brick, some angle iron build a forge box one brick high one wide and maybe two deep.The area you'r heating is less than one cubic foot, any losses thru the brick will be minimal compared to the heat in side and will get your job done fast and efficiently. After you've completed your job you will have gained some understanding of how a gasser works and is built. If you think you'd like a larger one for other stuff you'r in a better place for building one and maybe can justify the expense. The small brick one will out last any equivalent wool forge at less cost. Caleb's explanation on freezing and link to Ron Reils' burners are something I should have added to my first post........ Thanks Caleb If this all sounds wrong to you then you can just disregard Doc

I am certainly a supporter of KISS......KEEP IT SIMPLE STUPID.....in this situation. I'm not looking to weld, I'm not needing to heat 3 feet of 2-inch round bar at once, and I don't need to heat treat. The operation I would like a gasser for presently requires a single, comparitively low forging heat. In the coal forge I can heat at most 3-4 before I start losing them in the fire. I'd like a gasser I can park next to the PH and then just sit there and pull them out and pound them down. However, if I spend two days building a gasser and a hundred bucks in material, I've lost way more than I've gained.

I appreciate the detailed explination of "freezing up." Kind of clears things up for me so I know what I'm dealing with!

[pkrankow]

While I respect the opinion of Doc and Sam, the big cost of this is the regulator, hose, burner, and tank. The forge body is comparably cheap almost any way you make it.

This also means that if you find that the first forge body is unsuitable it is inexpensive to build something else.

Phil