JeffC

I am building a new aluminum trailer and i want to paint it. Can i use an acid etch primer and then paint. I dont want to sand blast it. Any info on precedure and type of paint..Thanks

James

Many primers are slightly acidic by nature, other advertize the fact as something special - If you are not going to blast prepare the surface be sure to degres and lightly sand the surfaces to remove soil and oxidation - apply vinly wash primer ( guess what it is acidic) polyamide epoxy intermediate and aliphatic polyurethane top coat - Your local marine supply store will have these materials on the shelf, or for 1/2 the price you can go to a large chain store such as sherwin williams - ask to look in the industrial or marine catalog and get the paint that industry uses at industry prices -

Automotive paint store will have similar however the automotive eposy is lower in solids and often has fillers than keep the cost down , make it easy to sand but will hydrate moisture - top coat would be what is sometimes call "single stage" such as Dupon Imron for a trade name

offthefront

Jeff keep this thread alive and post your progress ... ever consider Powder Coat ? Finding a PC with a 40' oven could be a problem ....m

James

Powder can be an option for a low risk/ fresh water trailer, however a typical exterior powder is aliphatic polyester, DuPont Imron for instance is aliphatic arcylic, very similar materials for color and gloss retention, and taber abrasion. Both materials will perfom similarly. What should be considered is the fabrication details - stitch welded areas, areas of overlapped metal, surfaces prebolted with nylock nuts. If any of the conditions exist then a conventional wet paint will perform better. With wet paint you can force material into cracks and crevices, whereas powder has a farraday cage effect and is repelled in tight spaces. A properly prepeared aluminum surface with a 1 mil profile by sanding or blasting and top coated using a polyamide epoxy and aliphatic polyurethane ( again I will use Imron because the name is popular) with a total dry film thickness of 4-5 mils will have an ASTM patti adhesion pull test of 1,000 + psi, A polyester powder coat applied to the same surface @ 2.5 - 3.5 mils DFT will have adhesion of 1,000 + psi. One component of performance is adhesion, many other factors should be considered including color and gloss retention.

So what does 1,000 psi adhesion mean ?
Latex paint on your house sticks @ 150 psi
Rustoleum brand alkyd paint @ 2-3 mils DFT 300 psi
Paint on the hood of a 2007 Lexus 700 psi
Paint on the side of an army truck 1,000 psi
Paint on the hull of a Navy ship 1,200 psi
Concrete side walk to sperate concrete (pull) 350 psi
Grip of a stripper on a brass pole (that's measured in $$)

Powder can be fast process for overall turn around and will work well on many shapes but is not a fix all - By the sq/ft Consider the shape, weight and complexity of the part before choosing paint or powder -

Boostable

Good information James. I have asked these question before myself and I appreciate the detailed response.

excalibur32

Well James learned alot with his cougar and Cuv aluminum race boats didn't you!!!!! Rivited just beautiful.

Chris Sunkin

Use Rustoleum 9100 epoxy with the water immersion activator. It covers over untreated, unprimed bare metal.

Powder doesn't chemically bond to the substrate. That's why when you get a scratch, the corrosion wicks and the powder peels off in sheets.

James

Thank you for the kind words with regards to the boat Riveted, however if I was smart or learned anything I would have quit boating a long time ago and spent my time improving my beer drinking skills -

excalibur32

James it ain't too late!!!!!!! I alway's supported the local favorite then you moved.

JeffC

Thanks James for the info.. This is a brand new c channel trailer that im building.. I was inspired by Jim Kirkland that built his own myclone trailer. I am going to custommize mine alittle bit diffrently thought..

Do these expoxys com in a variety of colors?