Insulation for boiler question

[Badhabit]

I am modifying my coal fired boiler and want to reinsulate the outside. It is 24" in diameter and 8' tall. I have had the fiberglass pink insulation wrapped around it and covered with sheet metal but am thinking about using spray foam instead. I was at Lowes today and just got confused about all the different types and was wondering if spray foam would even stick to the metal. Any suggestions as to brand? I plan on sandblasting the outside just to make sure it is clean and to give the foam some "tooth" to stick to. Has anyone used those kits that are at Lowes. They come in a cardboard box and not sure what is involved in using them. Customer service was about normal there so didn't get to ask any questions. Help

H

 

[BillK]

How hot is the metal surface going to be ?? I would think that foam would melt at the temperature of a boiler.

 

[Badhabit]

The water jacket runs about 165F. The firebox I was thinking of rockwool as it runs about 500F

H

 

[BD1]

Contact a pipe insulating contract and get the preformed pipe insulation. Yes, they do have 24'' x 2 '' or even 3'' thick .