Ha! Ha! Under the philosophy of putting your money where your mouth is:
I just bought 64 lineal feet of the woven fiberglass stove sealing rope that I’d recommended.
Sadly our north county hardware store was going out of business after 60 years. Killed off by Amazon and south county chain-stores the owner said in the newspaper.
So I cleaned off his one shelf for his retirement for him. Four different diameters. Meeco Mfg., Inc Seattle WA USA
Mine is the bronze 2000F sealer rope. Their white and black ropes are only rated to 1000F usages.
Again gasifer system sealing with this rope if done best is actually doing just as all modern no-leak anymore engine/transmission sealing is done.
The components to be sealed are mechanically hard surface to hard surface match up tightened down. The actual “sealer” component is 50% LIMITED compressed into channels in between these. No RTV or tacky “glue” is used on new installations anymore… Engine components resealing is most of the time possible. Heat stuck, then torn, on disassembly. THEN you use the goo-glue versus buying a new cover, or composite “gasket”. The composite “gaskets” are soft metals rimmed for compression limiting with a molded-on oil/fluids/coolant resistant inner elastomer thicker bead.
So using this rope-seal on a gasifier . . . make the grooved channel side on the upperside or cooler side component. Lower/opposing side can just be a flat surface. The inner rim/retainer of the can-be-an-open-sided square shaped channel does not have to be gastight! Can be skip spot welded. Channel Mus- be narrow enough to ~10-20% squeeze the rope. Assembly clamping to the opposite component then squeezing down the 50% rope standing up for final compression sealing.
And as it took me years to convince one particular hard-headed gasifer developer, IT WILL BE AIR/GASTIGHT for the low system pressures involved.
Gasifier metals temperatures vary in-use widely from one zone area to another. There WILL be materials heating expansion to deal with. Shut down gone cool - then contraction.
Making a hard welded flange exposed from the oxidization or intense charcoal glow zones across gas flow chambers to the system ambient temp outside is an seals failures experiences. Yeah. Yeah. Thicken the flange. Add more bolts. Upgrade the flange sealer to higher and higher high-tech!
Jeez-dude. Just move the joint up away from the most intense heat areas. Quit hard bolting rigid together, constrained. Successful rigid-jointing and you are then transferred stress’s than will flats warp/buckle and welds crack. Let things differential expanded and contract “float” on the rope seal.
Many/most modern vehicle engines cast iron exhaust, to downstream tube-steel exhaust pipe use actual spring loaded in-line heat-proof shouldered bolts to clamp with to allow for these systems movements.
Available at any North American auto parts stores. Salvage/Wrecking yards. Hint. Hint.
tree-farmer Steve unruh