cooking exaust manifolds

[knuck]

got them sandblasted. got por15 and metal mask. heard tell it's best to heat up the manifolds to get excess liquid residues out from the pits of the metal. quite sure this is the way to go,:thumbsup: yet before I fire up taters amana. any one know about what temp would be the best to complete this task it's not like I'm power coating. so I think I'll still be getin meals around here.

 

[heidigirl]

a number of years ago, i threw a freshly bead blasted intake manifold into my oven to do what you appear to be doing. the manifold picked up so much moisture from the heating process, i had to bead blast it again. my suggestion to you would be to wash down your pieces with laquer thinner or acetone and apply the por 15. i did my exhaust manifolds with the por 15 aluminized paint about 9-10 years ago and it has held up very well. its aged but there has been no chipping or discoloration in all that time. engine heat will cure the paint, the first time you run the engine.

 

[Fryguy]

I know this post is over 7 months old but I figured I'd throw my 2 cents in just in case anyone reads through the old archives.

In regards to heating up the cast parts before using any dress up material. I highly recommend that you cook the part, lets take a cast iron manifold for instance, before you do anything to it even bead blasting. I do powdercoating and I always cook the cast iron before I coat it or even blast it. This is to get all of the old oil, grease and grime that has become part of the piece over the ages. Lots of fluids tend to get on engine parts as we all know. We never clean them, we just assume that the manifolds will burn it all off. It does burn off most of it but the rest just gets heated and reheated over and over again.

This is what I recommend. Take your cast iron piece, preheat your oven to 420 degrees. Then place it in the oven. It will usually take a good 20 to 30 minutes to bleed all of the grime out of the manifold. Let your piece cool slowly. I recommend turning off the oven and leave the piece in there for an hour or so. Cast takes a while to cool. Do not take the cast piece out of a hot oven and put it directly in cold unless you like cracks

Once the piece cools, take some acetone and thoroughly clean the piece. Then I would have it blasted and then treated with your favorite coating -por15, powdercoat, jethot, etc. This will give you the best results and save you from having to reblast, etc.

Hope this helps somebody, sometime . . .

Fryguy