Need recommendation for new metal primer

[RedDirt]

I'm looking for a tough and durable equipment primer paint. What new metal primer do you use on your implement fabs?

Over the years I have used many different primers and frankly I'm not pleased with any of them. Adhesion to the metal is my normal problem even though I consider I do a a very good job in material preparation. Just a little scrape or abuse and I'll get a scratch down to bare metal.

Does anyone have a particularly good primer product to recommend and/or a paint preparation procedure that consistently gives you good results?

 

[dex3361]

Sand blasting first before priming. I have had good results with rustoleum. On rusty mental I used a zinc chromate primer and it held up very well for years of use(difficult to clean up though).

 

[Willl]

I'll get a scratch down to bare metal.

Until you get into powered type coatings, you're stuck with that.

 

[Gary Fowler]

A good inorganic zinc primer will self heal to some extent when scratched to help prevent rust and they are easy to apply. You need to abrasive blast the surface to get a good anchor profile to allow the paint/primer to adhere when using any primer or paint. Power brushing is next best thing if you use a very coarse bristle wire brush. You want the surface as rough as possible to give the paint more surface area to hold to. Zinc Chromate primer is used a lot on aluminum as a primer for painting aircraft and it works well for that and is usually yellow or green in color. Just be careful when spraying any zinc to use the correct respirator especially with the zinc chromate. Both the zinc and the chromium are pretty bad for the body if inhaled, ingested or absorbed thru the skin. Check the MSDS sheet on any chemical prior to use to see what the recommended protection measures are. MSDS sheets are available via internet for just about any material. If using the inorganic zinc, dont apply it too thick or it will crack on you as it dries, 2-4 mils is plenty. If spraying, it needs to be agitated constantly if using large quantity as it is 98% zinc powder and will settle out and stop up your spray tip. Most brands can be rolled, brushed or sprayed.

 

[JB4310]

Don't know if it would hold up to your demands, but Sherwin Williams has an industrial coatings line that is decent. Easy to use and dries in minutes, Rustoleum use to sell "Hardhat" spray paint, that stuff was great, but they dumbed it down, probably due to enviro concerns.

JB.

 

[glc24]

SEM makes a really good self etching primer,but its expensive.


Greg

 

[aviationben]

skip the primer, go for a por-15. very durable.

 

[Scotty370]

Thanks AB! Never heard of it! Gotta do some reading.........~Scotty

POR15, Inc. - Stop Rust Permanently - Repair Gas & Fuel Tanks

 

[Egon]

Put some phosphoric acid on it before painting.

 

[SPIKER]

Put some phosphoric acid on it before painting.

I second the phosphoric material, any and I do mean ANY paint manufacture will tell you you cant paint steel or aluminum you paint Phosphates that are bonded to the base material. (ever heard the term zinc phosphate?) well same thing only there are new coatings that mix with water when applied to a base metal, (you get Iron Phosphate when applied to steel) as it bonds with the steel leaches some of the iron out of the steel surface and forms iron phosphate crystals on the surface of the steel which are chemically bonded to the base steel.

this surface is then very rough at a microscopic level and at the right size to bond the paint to the steel.

Same process with a slightly different result on aluminum. the surface with have a multiple color hue to it when the process is done like oil on water in sunlight it will appear different colors as the different surfaces of the phosphate reflects different wave lengths of light based on the angle you are looking at them at

the Zinc primers are also great and will help but not as good as the pre-treatment of the base material.

Sandblasting is great too as long as it is not beach or play sand, it must be non-silicon sand. (black beauty brand is made from crushed granite.) and is expensive...

then you can top coat with just about any good paint, I like the stuff at TSC for 20 bucks a gallon and 7 or 8 bucks to add the hardener/chemical boning agent that forms a very durable finish. It has lasted on my dump trailer for good number of years.. that is dumping sand & gravel in/out of it...
Mark m