[Snufbudget]

In Modern wood burning heating Stoves a catalytic converter is in place to permit a more complete combustion allowing for “cleaner” emissions and compliance with EPA guidelines. The temperature of the flue gas passing through these converters can approach 2000 deg f. I am researching a problem with a Particular application in which the stove converter is made of stainless steel. Very fine wood ash in the flue has is Apparently migrating into the area of the converter and creating a bond or coating of the ash substance onto the stainless steel. I say “bond” as the material forms a smooth coating on the surface which is very difficult to remove. I have tried to soak the metal in a low PH solution of 50% white vinegar and50% water but it does not help to remove the material from the surface. Since the surface is the shape of a honeycomb with small openings mechanical removal is not an option. I would like to know if there would be a chemical solution which would dissolve or loosen the ash bond coating from the metal as the coating does stop the converter from performing in a good manner. Thank you

[Borek]

Just speculating here, but this is tricky. Converter was probably not designed to be in contact with water and its catalytic properties can be lost during washing (they are definitely lost when it is covered with dust, as it is contact surface that matters).

Have you tried to contact the manufacturer?

[Snufbudget]

Thanks, yes the manufacturer says to clean with a 50% vinegar solution however at least in some situations this does not touch the “scale” or deposits. Thinking about trying a stronger vinegar solution or maybe another chemical. I understand there is a risk of damaging the converter

[Enthalpy]

1100°C? Stainless steel oxidises in air at this temperature. Unless maybe perhaps you have a very special stainless composition. But if it's 18-10 or 17-12, it has oxidised due to the heat, and the new oxide layer incorporates ash. Good luck with your vinegar.