OK I have talked to many pro's that say your waisting time and money to use a sealer before you base coat if you have used a 2K surfacer,

SO if I have used filler on a area do I need to seal it before I lay down the hi build surfacer(as I have read some people do)? Or is this unnecissary as well? :confused:

Zach,
am one of those that think sealing over sanded primer surfacer is a waste. Yes I will say sometimes its a good idea to seal over surfacer but when you have an ENTIRE panel sprayed with surfacer, I see NO NEED what so ever to spray a sealer.

I mean sealer is meant to provide a uniform coat for topcoats, provide adhesion and provide a barrier agaisnt imcompatible products.

Will you have no BETTER base for adhesion to spray any topcoat then sanded primer surfacer. If the panel is entirely surfacer no need for a uniform coat as its already one color. And if you are spraying a recommended topcoat over that surfacer what are you trying to hold back?

I really suggest sealing over surfacer when the topcoat is very transparnet. You use a tintable sealer to lay down a color that closely matches the topcoat color. One color that I do this on is GM's indigo blue, that color doesnt cover at all.

Sealing is just one more step to mess up, more products to buy and more ORANGE PEEL in your final finish.

On areas that have body filler all you need to do is just prime the area with your primer surfacer, DONT SEAL IT.

Dont get me wrong am not saying that sealer is a total waste of time period. Am just saying on primer surfacer it is. Thats just my opinion

Just what I wanted to hear. smile.gif I didn't want to have to go in and tell the jobber that I needed K-36 after I just convinced him to keep some K-38 on hand! The jobber is weird around here, they only stock 2002, 2021, and 2042 for high end PPG clear. But hey they don't salt the roads so there are many 40 year old cars around with no rust at all! :D

Most sealers also provide a solvent barrier for painting over substrates that absorb solvents easily. Some surfacers absorb topcoat solvents like a sponge later releasing them through the topcoats destroying the gloss. In my experience the softer, easier sanding surfacers seem to be more suseptable. Years ago the sealers helped greatly when spraying over laquer primer which was a very soluable product. Nowadays most urethane and epoxy based surfacers are not as susceptible to solvent absorbtion (sp?). with K36 and K38 primers there is no need for sealer in my opinion. graemlins/beers.gif

Did find out once on that the base sealer needed to be white? Don't know why, but it was the only way paint would match.