Puffer lids

How many are running puffer lids, in case of a back draft or low fuel burn out?

I planned on screen door springs around the top like Wayne did, is 6 springs enough?


Hello Dave, Carl and David,

I use 8 springs on mine and they have done well. I try to arrange the springs with a little more tension on the front side of the drum. If the gasifier burps it will spit back in the bed and not on my cab.


Wayne, Cool !! I have a mid 1800’s carriage spring on the current trailer lid. I found it buried in my neighbor’s back yard years ago. I adjust the tension by adjusting the lengths of the 2 lengths of electric fence wire holding it down … ML

Hi Dave,
I was going to use a larger lid on top of the 100# propane tank with door type springs, but I got this wild hair thing and ended up with the following design, which is specific to my tanks but the concept could be expanded if you want something a little more complex, OHV puffer lid! lol. The bolt studs are drilled through the flange and welded airtight underneath. The double gasket is to keep gas and air separated in case of leak, which I did have. See pic of bad weld. I saw wisps of smoke escaping from around the bolt holes in the cover on my first fire and found the bad weld. Make sure to grease the underneath of the cap before assembly.
My feed lid is held down by 10 swing arms that tighten onto a flange so it’s a bit tedious to open, but once every couple of hours doesn’t seem too much trouble. I’m looking for a cam lock lever design to replace them.
The last pic shows cup retainers for the spring sections I removed from a screen door closure and cut to length. Use caution when open up the door closure, it’s under tension and will whack you. The double nuts for adjusting closing pressure and locking setting. If you put your palms on the top of the lid and grasp the cap flange you can pull it up to test the sealing pressure. If you build one like this make sure your bolt studs are long enough so you don’t run out of travel when you tighten them down and make yourself a bomb!! OK, now set the exhaust valves to .012", lol.

Thanks Guys
It seems that I use a similar one to Wayne’s. I have four brake springs for hold downs and a gasket between the hopper and the lid. It works very good.

On my basic systems I use just the lid for flash back and I use these simple spring loaded pull latches. I get the spring stock from a local vender for very cheap. I think the lengths are 12" and I can get them for just under a buck.

The systems with more options I have room to add additional flash backs. Those of you that were in the service may remember how there gas mask worked. These flash backs work axcactly the same way and work very well. If you only ever pull a vacuum you dont need a whole lot of presure on them. The vacuum will create the seal. I use some 1/8" thick rubber and use a backing plate to hold it down.that is spring loaded in the center. Under neath are four 3/4 inch holes drilled in an aray that the rubber seals againts. I use this system on my mixxers too.

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I currently am just running a flat plate over a ground flat hole and usually the goo will seal it up. I did this to get the lid condensate to flow back to the gutter. It was puffing quite a bit a few weeks ago so I took the plate off last week and hammered it flat again and put it back in the lid upside down and it is now sealing better. I have found that there is no easy way to seal things and have them blow as well. A little bit of air getting in the lid is no big deal unless there are problems down below or you run out of wood of course. That’s how my hopper just got toasted as there was no wood to distill above the charcoal and absorb the heat so it just radiated to the walls. Stuff on the walls puffed up a bit. This is normal … http://www.intergate.com/~mlarosa/images/woodgas/hopper-inspection-8-8-12.jpg … ML

Matt your flash back setup is the same as the ones on the fire box on my 150 hp gas fired Dutton steam boiler at work.Very nice setup. For the people that want to skip the puffer a 55 gallon will burst at about
15 psi.

I like to use cooking pot lids, because these are cheap and fit tight. Seal is made by high temp red silicone in several layers (it shrinks when drying) by using a piece of sheet metal as a mold to smoothen the surface of the silicone. Filters get a flat piece of sheet metal with silicone baking mats as a seal. Bolt/spring connection. Do not forget the O-ring between bolt and filter housing inside. Bit of grease or vaseline between seal and filter housing to prevent sticking.

One way valves, like well pumps have, make good ready to go back-fire reliefs. Or a rubber flap with central bolt, sealing the end of a pipe.


Beautiful detail DJ. I use fiberglass cord up in the groove of the barrel lid and glue it in with hopper tar then grease the whole thing. The tar and the grease caramelize to form to the contour of the barrel rim. It stays sealed and gently puffs if I close the lid too soon before enough smoke builds up. I have the pivot for my hinge out over the hopper opening just a little bit so when I open the lid the goo just runs into the hopper. Things stay pretty clean that way. Thanks for the photo.

Hello all,

I have received several requests to keep things from veering off topic. One of the advantages of this format over a mailing list is that we can avoid topics drifting. I intend to do that when necessary.

I have gone through this thread and cleaned up or deleted several off-topic posts. Please don’t take offense if I deleted your post, this is a moderators job. Old computers are fine to talk about, but in a different thread. Let’s keep this focused on puff lids.

Thanks for your understanding!