I have discovered there is such a thing as dual chamber bellows, and would like to try my hand at building one. While looking at diffrent designs that use leather and canvas I got to thinking if pleather/vinyl would be an alternative. The only negative I can think of would be lack of fire resistance. If the bellows was located a distance from the forge would there be any danger? I am not sure if heat would travel back thru the ducts etc? I have a huge quanity of vinly upholstery fabric that would work great if it would be safe.

Thanks for you input

Forge gas sinks, so the bellows have to be higher than the firepot to prevent a backfire. If you can get your hands on an old pleather or bonded leather couch to cut up you might be able to do this for free, and the springs in the couch are medium or high carbon leaving just the wood frame for firewood and the padding for disposal.

If you put a lining of a layer of cotton fabric, such as drop cloth, the cotton will have a short term fire resistance (till it chars). It can also be soaked in borax water and dried making it more fire resistant if you are still worried about it.

I have also considered using polyurethane under body and bed liner as a spray coating on drop cloth since the can is fairly inexpensive. I don't know how flexible it will remain, and while I have the materials I have not done a test.

Phil

I built a bellows years ago and used vinyl that looked like leather. It lasted several years, I heard it was later replaced. A coke gas explosion may blow things apart but it does not put a lot of heat into the bellows.

Just be aware synthetics don't like hot stuff, scale, sparks, cinders, etc. will stick and melt into it, maybe not deep enough to damage it but maybe. I like canvas, it's easy to make fire resistant with a soaking in a borax solution and tends to last a long time.

Frosty the Lucky.

So to summarize you could use: leather, fake leather, plain cotton canvas, heavy canvas tarp material, canvas coated with "tool dip", or rubber roofing material. You can also find a material called "bellows cloth" used in musical instruments, but it is very expensive.

When using a double lung / dual chamber bellows, always be sure you are pumping enough pressure to inflate the upper chamber, even if it's just a little bit. As long as there is air in the top, it will be blowing out.

I have seen folks get caught up in watching a piece come up to heat and just barrreeelllyyy pump the bellows so that they were simply squeezing air out of the bottom with no top chamber inflation. When they let off the lever, as the bellows reenflates, it sucks forge heat straight into the bellows... not a good thing.

As long as the bellows functions corrrectly, it should be blasting air out, never inhaling.

Frosty, what is the solution mix for canvass, I have a huge old bellows I been thinking of redoing.

Another thing to be aware of, ... is that burning vinyl emits some very TOXIC fumes.

roung here the local Deer processer will give hides to anyone that ask for them in bulk so i can get 15 to 30 at a time . way cool

I am going to rethink the Vinyl, just not worth the risk. I dont handle fumes well at all anyways,

Back to the drawing board,

thanks guys

Frosty, what is the solution mix for canvass, I have a huge old bellows I been thinking of redoing.

A saturated solution of borax in water but that's a rule of thumb as I recall it. I don't think you need to boil the water to get as much in solution as possible, just mix it till it wont take any more. I don't think there's a "right" solution unless it's a public safety issue, say a big top or such.

Frosty The Lucky.

Check yardsales for old tents. Most are fire retardent material. Also, check out army surplus stores for old tents or shelter halfs. You might ask as they could have some with rips or holes they'd sell real cheap since you just need the material. I was going to make a great bellows until I lucked into a blower and that was my plan.

my first set of bellows I used leather coat. but down here in Florida leather just dose not hold up. If I were to do it again I would use canvas drop cloth with the white rubberized roofing paint if you do not want white you can have pigment added to make it a different color.