The Stovebolt Site Forums The Shop Area Paint and Body Shop prime or not?

I replaced my cab corner today and have ground the welds pretty smooth. It needs some duraglas so should I prime the raw metal before the glass or go right on the raw steel? which primer would be best? I have rattle cans of self etching, grey sandable and red rust primer. I don't have access to a spraygun and the epoxy primer at this time.

I would still epoxy prime it as it seals it up much better. The others allow moisture under. You should be able to get a small can of 2 part epoxy. Depending on your results expectation you can brush/roll it if you like.

You can roll or brush epoxy primer. Use 2 coats. It sands and feathers quite well in my experience.
I would highly recommend epoxy primer over a welded area. Too many irregularities in final metal thickness and possible undetectable pin holes to risk using other primers.

SPI epoxy primer ships out of GA, If you ordered it when you made this post, you would have paint drying by now.

Anything out of a spray can is not going to seal out moisture as well as epoxy, and in some cases the spray can primers are not compatible with the solvents in Automotive paints. When quality paints and topcoats are running about 100 a quart on up (generally speaking), I'm not going to trust a $5 spray can to provide an adequate substrate for the money and effort involved to get to that point. ......Unless you're after a spray can finish, then by all means carry on. For a long term project (it won't be done in three days like most jobs in a body shop) epoxy will give the best protection from moisture intrusion to the steel. A single component spray can primer does not seal out moisture. No spray gun? Mix up the amount needed and either brush or roll it on. You'll be block sanding later so the imperfections won't be the end of the world.. But it will hands down be a better foundation for whatever you decide as a topcoat.

Thanks I will go by the paint store today. Didn't think of brushing epoxy.Here in Fla moisture is everywhere.

I encourage you to call and talk to Barry at SPI.
You won't regret it. Even if you choose a different supplier.

Yes, brushing it is handy. I have a small measuring spoon (maybe teaspoon or tablespoon) and mix 2 of those and 1 of activator and touch up small areas like where I drilled a hole. I got some small artist brushes from Home Depot for that.

Dennis

Well that turned out good. As I was heading to the store i looked in the barn and found a 1/3 can of epoxy primer and a small can of hardener. Mixed it 2 to 1 and brushed it on, sticky stuff but got in all the voids. Left it out in the sun to dry and looks nice tonight. Thanks for the good thoughts.Now on to the floor board.

Tell us more about duraglass kitty hair or any other fiberglass/resin absorbing moisture please...

Thats a new one to me.

CASO,
I think Fox was referring to "self etching, grey sandable and red rust primer" as the "others allow moisture under".

I never thought of rolling or brushing the epoxy primer. That's great, because I didn't have mush luck getting a good finish on my parts spraying, and ended up sanding a lot. A lot less clean up with brush or roller. Thanks for the info.!

Something else to then.
The best attribute of epoxy is the bond and barrier it creates between the metal and what ever comes next.
Two coats are the recommended thickness. Three is bomb proof (more or less)
But what happens when you start sanding down filler or high build?
You hit high spots and start sanding on epoxy.
Now it's not 2 coats thick anymore.
My solution was by black and white epoxy (from spi) and use one as my first 2 coats then mix the rest as needed/desired to my needs.
If I lay a third coat over the white/black I know to stop sanding as soon as I see that color shows up.
that 3rd coat can go on down the road, all the epoxy will need is a good scuff with a red scotch pad (320g).