Painting HDU before masking question

[RiXaX]

Is there an advantage to priming HDO before applying sandblast rubber ?

 

[JBurton]

I wouldn't think so, in fact it would probably just slow down the blasting, then you'd have to reprime the freshly blasted area before paint. Disclaimer: I don't sandblast.

 

[tbullo]

I apply it to the raw HDU. I have done it the other way and did a finish coat for the letters and border. But once you prime and paint the background and remove the mask, it leaves a edge sticking up on the letters that I don't like.

 

[RiXaX]

Thanks folks. I seldom use HDU. Most of our sound are redwood.

 

[Gino]

I wouldn't paint it first.

 

[TEN]

If there are small parts in the design the primer will give the mask a higher bond to the HDU. Sometimes small parts of the mask can get blown away. If care is taken when blasting it may not be an issue.

 

[John_Smith]

If you don't sandblast signs or work with HDU materials, then you shouldn't offer advice.
I used to prime and pre-paint HDU and sometimes had good results. 95% of the other times, it was more trouble than it was worth.
The steps that I endorse is to sand the HDU smooth, take it outside and spray with the water hose to get as much dust off as you can.
Then, do the rubber mask and blasting. After blasting, do the same water hose washing again.
Your shop = your methods.