Any special prep required after sandblasting?

[ericher69]

I was wondering if any special prep/work are required after sand blasting and before priming?

In the past priming/painting after blasting has led to rust within a year!

Am I missing a step?

Any advice from pro painters would be appreciated!

Thanks

 

[strum456]

I spray my blasted parts with southern polyurethanes wax and grease remover and wipe them off with a rag. Then i use scotch brite in one hand and an air hose in the oher to blow off the rag fuzzies. Then i spray 2 coats of southern polyurethanes epoxy primer. This holds up very well from my experience.

 

[moored4]

When I bead blast something I take it immediately out using CLEAN gloves and spray it with primer. Clean metal will start rusting the second it's blasted!

 

[strum456]

That flash rust isnt much of an issue. I also try not to let part sit around for a long time but i know a very accomplished restorer that washes his blasted parts with dawn dish soap and water. As soon as everything is dry he sprays epoxy. Of course he gets some rust after doing this and he says it hurts nothing. This guy does very expensive cars that are usually concourse judged.

 

[Gary Fowler]

You just have to remove all the grit from the steel. How you do that is either by washing it with water like a pressure washer or just a water hose or you could blow it off with compressed air but that usually stirs up the dust again. Washing with water is best but then you need to get it dry and immediately prime it. If you are getting rust in a year, I would change paint systems. A good inorganic zinc primer is good as it self heals if scratched and helps prevent rust in light scratches followed by an acrylic enamel top coat should work for you. It could be that you are not covering the sharp edges properly to get proper mils of paint. That is usually a problem with novice painters. I would suggest that you spray all the sharp edges first then overspray them when coating the othe flat surfaces and most of the time this will give you good millage on the corners. See your local paint dealer like Sherwin williams, Dupont or Pittsburg paint suppliers. They usually have a knowledgeable paint person that can recommend a good coating system that will last for many years.

 

[EddieWalker]

You really get what you pay for in primer. I remodel homes for a living and I'm still surprised at how many people use Kilz and then wonder why the paint doesn't go on well, or looks terrible.

Same thing with painting metal. I really like Rustolium Premium paints. They go on better and last a long time without any issues.

As for preping the metal before priming, I just blow off the dust and residue with my air hose and then prime right away.

Eddie

 

[Ductape]

You really get what you pay for in primer. I remodel homes for a living and I'm still surprised at how many people use Kilz and then wonder why the paint doesn't go on well, or looks terrible.

Same thing with painting metal. I really like Rustolium Premium paints. They go on better and last a long time without any issues.



Eddie

Eddie, what do you use when priming woodwork, interior and exterior ? Now that so much has gone water based...... hard to know what works best.

 

[Just Bill]

Look up zinc phosphate metal prep.
Its used for bare metal prep

 

[EddieWalker]

Eddie, what do you use when priming woodwork, interior and exterior ? Now that so much has gone water based...... hard to know what works best.

Zinsser is what I buy. Their 123 primer is great for latex paints and new sheetrock. It's on the shelf right next to the other primers at Home Depot and Lowes. For staines or problem areas, their oil based BIN primer works great, but it's misserable stuff. Sticky, runny, and very strong smelling.

Sherwin Williams brand primers are also very good. They have specialty primers that are just as good, so if I'm at one of their stores, I'll buy their product, but if I'm at the box store, I go for Zinsser.

Eddie

 

[3930dave]

I'm not a pro, so keep that in mind.

For easy to find in Canada, I use Tremclad Red Oxide (oil based) primer. I figure if red oxide is good enough for structural steel.....

Tremclad is an old Canadian label, but I think it is now owned by Rustoleum.

A trick I learned from a bodyman was to use fiberglass resin on problematic seams or weld areas. He'd clean up the area really well, then selectively use the resin to seal these problem areas. The resin will block water from migrating back into the problem spots.

I'm trying a variation of that approach with the steel wheels I just refinished on my trailer. I primed with Tremclad Red Oxide after sandblasting, painted with wheel paint (colour coats, then 2 clear coats). Once it was all dry (next day), I ran a bead of clear silicon around the seam between the inner section and the outer wheel rim, both front side and back. I'll see how this silicon approach stands up over time, as the seams are usually where rust re-starts from.

Rgds, D.