cone

[leewaytoo]

some barrels come with a removable top.
why not cut the bottom off.
then weld a cone on the inside of the lid to direct
the gas/heat inside the barrel?
the lids are pretty much secure as they have to keep
liquids inside. one could use a small amount of oakum
as a seal?

[Donkey]

It could be tried, though I'm not sure how it would help.
It would mean you would have to raise the barrel to allow for proper gap up top..

Oakum will burn out (assuming we agree on what oakum is), how about stove gasket?

[leewaytoo]

would the cone simply create a venturi effect as well as directing everything equally and avoiding a concentrated
heat point in the center of the barrell?
also.
as to raising the height.... as long as the heat risers is the
same distance as is normal ... the center cone would not matter?

just thinking that "if" the cone creates a venturi effect then
the velocity of the gas and heat increases downstream.

the pressure increases in the heat riser and gas might
have longer time to combust???

just asking questions to understand where i am wrong or even
if i may be right...

[peterberg]

leewaytoo,
Don't try to concentrate on the heat riser for combustion to take place. 90% of things are happening in the burn tunnel, the riser is definitely not the spot where it all happens.

Directing the gases in a smooth way down the barrel could help to minimize friction, yes.

[leewaytoo]

lead melts about 5-600 f so oakum will probably not work..
also..

when placing the "secondary air input" it would be well below the bottom of the riser??
not directly at the bottom of the riser's opening into the burn tunnel?
tks

[Donkey]

Umm.. I'm not sold on secondary air for the J-tube design.
I AM (already) sold on the Peter Channel, which IS technically secondary air. (Isn't it?) Seems like the best injection point is just downwind from the pyrolysis zone, which is where the Peter Channel is.

[thewongs]

If I wanted to seal a barrel top on, I would simply use car exhaust repair paste. Most of the large barrels with removable lids also have a clamp around them to hold the lid securely. You could spread the paste on this clamp before fitting. This would also allow for it to be removed without too much trouble later..

[Donkey]

Odd.. My folks were boat people.. Oakum, since forever back, was tarred hemp fiber, used between planking in boats (and ships).
The term "devil to pay" comes from calking the seam at the waterline which was known as "the devil". It was reserved as a punishment, sailors were lowered on a rope and had to do the work at sea, half submerged in freezing ocean, shoved against a barnacle crusted hull by waves.. Crappy job.

[bud]

I think the term oakum also applies to hemp (sometimes oiled) used as "backer rod" by plumbers for leading cast iron waste stack joints. I would think most of it burned off when the molten lead hit it, but it kept the lead where it was needed until it set up.

[leewaytoo]

i used oakum to repair a broken cast iron toilet "flange"? you stuff the oakum in and then
melt the lead in a cast iron ladle, then pour in. the oakum didn't burn up, and the lead
sealed the joint. still, the temp to melt lead is 621f. so oakum might burn up with the greater
temps at the top of the barrel?

yesterday i viewed a video where the couple had a removable top on their barrel.
it was easy to remove by hand and was hand hammered back on? didn't see one nor was there any mention of a gasket.

[Donkey]

Right.. That's the video of Ernie and Erica over at Permies.com. They use stove-gasket.