I removed everything from the boiler and scuffed the surface lightly and evenly with 800
grit paper. Wiped it down with denatured alcohol, plugged the holes with corks and sprayed
it VHT Black paint. Once it dried I removed the corks and bake it in the oven at 250 degrees
for an hour. To me it looks good but I can always swap it out for nicer nickel one down the
road.
The directions on VHT,(Very High Temperature), Paint says to heat it to 250, cool it, heat it to
400, cool it, and finally heat it to 600, all in half hour increments.
I only went to 250 for an hour and have not had any problems.
As far as boiler jackets on Wilesco engines, I think they only had them on the D24,28,and32.
If you choose to paint and bake, I would remove the flange, sight glass, and all gaskets first.
Don't just mask it off with tape when painting, then remove the tape and bake with them assembled.