I have a fairly new diamond plate truck toolbox that I need to repaint to change the color. Being diamond plate it is difficult to scuff up before painting. Anybody have any suggestions as to how to do this? Do not want the paint peeling off in few months. Do I need a primer?

 

Is it steel or aluminum?

Steel, best bet is sandblasting. Aluminum, get yourself some scotch brite pads, or a scotch brite wheel for your drill, and go nuts. Same can be done for steel, but blasting is still better.

For a steel box, any dtm enamel paint will work. Leave the box and the paint in the sun to heat up, then brush or roll the paint on, for a smooth, thick, and incredibly tough finish.

For aluminum, use a high quality etching primer, 3m or the like, then paint, spray with multiple thin to medium coats, 20 minutes or so between.

You could do the roll/brush with the aluminum, but I'm not sure on adhesion over time.

 

if it is a thin coat on aluminum, a self etching primer can be used. do not use a latex base on aluminum. As Pind suggested: thin coat of enamel on warm metal, then nice bake in even sun..

I have used a very light coat ( only see light color) on an aluminum utility enclosed trailer. I reduced the viscosity and had good results for the second, third and final color coat. clear coat is generally not used. heat afterwards is key to long lasting paint.

if you are rattle can painting, put the cans in the sun, very light sweeping pressure on the first coat, no heavy color then. even coating for the third coat for color. a build up process. good luck and I will meet you at the cabana for fresh greens and a drink!

 

Thanks for the answers so far. It is aluminum, but a factory paint on it. Looks like powder coat. I am very familiar with painting bare aluminum, but that is not the problem here. If this was a flat plate, could just sand it to scuff it up, but how on earth do you sand diamond plate? Sand blasting is not an option.

Just came back from Auto Zone and noticed that they have a Truck Bed Coating in a rattle can. That gave me an idea. As this is only a small area, basically the top and rear of the box, why not use this product? I wanted a flat black finish anyway. The instructions say that no primer is required. Hmmm, almost too easy.

 

What he said!

The heck with that! 'Thin coat'... PFFFT! Get a big tub and dip the dang thing in it! This is for wimps!


Seriously, if it's aluminum, wipe it down with denatured alcohol before you start applying the paint, coating or whatever you decide to use. Do I hafta tell you to let the alcohol dry off before painting?

 

Isn't there some sort of a plastic media for blast cleaning aluminum?

 

Aircraft stripper. 'baby poop' is what we call it. Dab the mess on, watch the paint peel and curl up before your eyes. Washes off with water.

 

Self-etching primer.

I've used it for my train horns as they're sand cast aluminium and the only thing that will stick other than powder coating.





-Kris

 

I know all about that aircraft paint stripper as I have used many gallons of the stuff.

As this is only a toolbox, have decided not to get too fancy with doing the 'right' thing. Don't want to strip off the new paint that is on it as I know that it is well bonded to the aluminum, so am going to paint on top of it. Going to prep it as well as I can around all the diamond plate 'bumps' and then rattle can it with that truck bed coating I mentioned earlier. Did a test with it and that stuff sticks very well to bad surfaces. Even got some on my fingers and it just does not come off. If it peels off in time, then will strip everything and start from scratch.