J Dickison

Double lung bellows

18 posts in this topic

After trying many different sources of air for my forge I had the opportunity to work on a forge fired with a good set of double lung bellows and that was all it took. The air blast is superb and the control is infinite when set up using a weight bar to control the fall of the top board. I have since built several bellows for Smiths around the country and here is the latest set that is going to the blacksmith on the movie set of the WGN TV series Salem.

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That is a beautiful bellows. This one of the many things on my list to make. Got plans to start with a smaller one. Do you know when that series will start? You'll have to let us know when it will be on air.

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Very very nice.  From the photos, it appears that you used splines to join the boards, or am I mistaken?

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The originals I have investigated are set up so the bottom lung only feeds into the top lung through the flapper valve and the top lung is the only one that feeds the fire with a flapper valve on the outlet to keep back draw and bellows explosions to a minimum..  Is that how you are plumbing yours?

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The originals I have investigated are set up so the bottom lung only feeds into the top lung through the flapper valve and the top lung is the only one that feeds the fire with a flapper valve on the outlet to keep back draw and bellows explosions to a minimum..  Is that how you are plumbing yours?

​That's how continuous pressure is generated so it can blow steadily instead of huffing and puffing like a single bellows. One lung loads the other one; it can act like a receiver tank on a compressor.

Edited by HWooldridge

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TP, that looks like the center board. Nice way of dealing with the outlet air chanel with a menimum of carving. 

The first set I have built ended up with the valves two light, i have to tear them apart and re work the valves, not to self, door skin is way to light!

 

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First set I made was based on an original commercial set at the museum in the OKC fairgrounds.  Back in the early 1980's...

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Looks like I may need to take a trip up to the fairgrounds, thanks TP. I like bellows, one of my experimentals uses a manual double actionbed bed inflator. I realy enjoy using it. The ones that I'm having problems with is a 20" round with 6&12" chambers and a 3/4" out let 

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I used light metal flappers caged and bedded on felt.  Had intermediate "horseshoes" to keep the "leathers" from puffing out. it all came out of 2 4x8' pieces of high grade hardwood plywood.

I used it for 20 years and could pump it to welding heat with my pinkie.  My next ones were Y1K based off of Divers Arts and iconographic materials.  Not nearly as nice and you pretty much needed a bellows thrall though charcoal does take less ooomph.  I gave my original set on to a friend as the mover out west was already taking more that a semiload.

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I don't use bellows under normal circumstances but I've sure watched a lot of guys using them. The biggest mistake I've noted is folk make them too small. They mistakenly think half the size means half the output and end up with bellows that won't do the job. Bellows measurements are volumetric so 1/2 the size is 1/4 the volume.

Just saying.

Frosty The Lucky.

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Yes mine pretty well filled the back of my pickup when it was mounted on it's frame.  I had to load stuff around and under it to take a forge too.  As I mentioned it was based on a commercial set of blacksmith's bellows from back when.

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Just make sure that you have some heavy and airtight material. It need to be allmoust hard to flex.

Just like shoes  leather. If it is too thin, bellows won't inhale top chamber.Why yours valve is so near nozzle?

Edited by natkova

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Mr. Dickerson ,do you have a simple drawing for your bellows? And maybe a few more pics? I'm wondering about the thickness of the leather you used, and valve sizes as well as the overall size.

Hopiing to build a set for our summer demo, they really get the kids interested when they can pull / pump the bellows

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I used heavily treated canvas used for wind wings on oil drilling rigs in Oklahoma. Got the "scraps" for free.  Only lasted through 20 years or so of abuse and then needed some repairs.  Remember in a double lunged bellows there are 3 sets of boards: top, middle and bottom.  Only the middle and bottom have valves in them and the middle is stationary with the top and bottom sets hinged.  I have seen tops with a sealed access hole to allow you to work on the middle valve without taking the bellows apart---a great idea and I wish I had made mine that way!  Note that how you mount the pumping handle makes a big difference.  I could pump mine to forge welding temps with my pinkie while a friend used one at a "historic village" set up so poorly that he blew out his shoulder using it for 10 years!

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On 2015-06-11 at 3:52 AM, Frosty said:

I don't use bellows under normal circumstances but I've sure watched a lot of guys using them. The biggest mistake I've noted is folk make them too small. They mistakenly think half the size means half the output and end up with bellows that won't do the job. Bellows measurements are volumetric so 1/2 the size is 1/4 the volume.

Just saying.

Frosty The Lucky.

Do you not mean 1/8 or am I missing something?

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I normally use the bellows.  But do not have a preference.  The old crank blowers do quite well. I have used electric foot operated switch and that was fun.

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