Hi There,
Here is what I do when painting HDU with the simulated raised grains from my homemade “Grain Frame”.
After Sandblasting, I Blow Off the sign to get the dust out of the valleys. I get my blower as close as I can to the grains to make sure I’m getting all the dust.
Then I take a power washer and give it a good cleaning. Naturally, I do not get too close to the grains because they might break off. After the water bath, I sit the sign on end with the grains vertically. (Helps to drain the water) Again, I blow it off to get as much water off as possible. Then, I let it sit over-night.
I do not use any primer on my HDU, I go directly to the color I am planning to use. If you have ever painted a “grained” HDU sign before, you already know how much “fun” it is to get the paint down into the grain valleys…not to mention how long it takes.
By-the-way, I always paint the entire substrate before applying the Sandblast Stencil. (I use Porter Paints) The frame gets it color, the letters will be get their colors, etc. I make sure each coat is dry between coats. Then I apply my Stencil and weed the background.
After Blasting, and leaving the Stencil still in place, I use a Paint Sprayer. I spray a small section (about 2’ x 2’) of the grained area. Then, using a Stiff Bristle Brush. I “push” the paint into the valleys. I do this for each coat. I find this faster rather than dipping my brush into the paint can and applying it by brush only...takes too long.
Once that is finished, I remove the Stencil. The frame and letters already have their colors applied and the sign is finished.
This works for me.
Barry
) It can even be used to fill dings and gouges if you let it set up in a paper cup and use a putty knife. It smells EXACTLY like Bondo. I think you can top coat it with anything. You can get an almost glass-like finish using car paints, if that's what you want—I can make a slab of HDU look like real marble.
