Need Help Painting HDU foam...

Didn't know about the wood grain effect, so maybe one coat of primer.

The sanding applies to flat surface HDU panels which provides an even finish for the finish coats of paint. Sherwin-Williams and Benjamin Moore latex were our favorite brands.

 

The number one thing to remember about painting HDU/PVC is dry time and prep work.

If the can says dry for 6 hours, triple it. HDU and PVC do not absorb moisture. So all of the drying goes one direction. When you paint a wall or wood, it will absorb some of the moisture which makes the drying go much faster. So don't rush the paint.

HDU is also a material that needs to be really clean before painting. Sand it down to form a texture, blow it off, and then if you can, spray it with a garden hose. You want to get it clean as you can.

After that, it depends on what you're doing. If you're just painting it all free hand, paint choice is less of a big deal. Use really good exterior grade paints and you'll be fine. If you plan on using vinyl and masks, you need to be MUCH more careful. I recommend DTM paints. I've always used PPG but other brands work I'm sure. They're a mix between an enamel and a traditional latex paint. There are a bunch of HDU specific primers you can buy from your sign supplier. PPG Sure Grip also works well. There's another PPG fast drying paint that I haven't tried since I've been moving away from carved signs and that's Breakthrough. Dries way faster than typical latex paints.

But the #1 rule of painting HDU/PVC signs, above anything else, is let the sign really dry. You just can't rush it. Every time I have, I've regretted it.

 

This is the primer I use from Tubelite. I use SW latex paints, 2-3 coats for finishing. Be sure to lightly sand your flat spots and then rinse the sign with water and let thoroughly dry before priming/painting.

 

+1 for the PPG Breakthrough paint...awesome!

 

blow it off real good as far as primer you can use a high quality exterior flat and spray it on possibly 2 coats of this. We use nothing but BEHR paints, they hold up just fine and NEVER use oil based

 

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

 

Just an additional option to keep in mind: After years of painting HDU in many of the same helpful ways already suggested here, I actually developed a good working relationship with a local auto body shop. I've had him doing all my HDU painting now and its been completely worth it for me. His spray room is is much more dust free than any place I have to work, we get a full range of automotive colors to work with, his guys do a much better job of cleaning it than I ever could, and most importantly the signs get a high bond primer, followed by an evenly applied auto grade enamel finish. He likes to do the work because its very straight forward and quick and what he charges me is totally worth the time I save not having to fool with things especially if I end up getting a run and and having to sand and repaint. I return the favor by helping him out when he needs custom vinyl striping, or other vehicle graphics. I loved the satisfaction of doing everything myself, and still do all of the finish work and leafing myself, but sometimes time and profit margin just don't let me do it anymore. Just a thought - good luck!