Some of you have said that you rinse off the HDU with water before priming. Why? How much water do you use? How long do you let it dry before painting with Primer ( I use signfoam brand primer or Jay Cook's). Won't using the compressor to blow the dust off work as well?
Diane Balch
[ October 20, 2003, 12:54 PM: Message edited by: DianeBalch ]
Posted by Dave Sherby (Member # 698) on :
A few years ago when everyone was complaining about primer lifting off the HDU, I tried an experiment. I blew as much dust as I could at 110 psi. Then I put a hand nozzle on my garden hose. While hitting the HDU with a hard stream of water, I was amazed to see a river of HDU dust coming off the board and running down the driveway.
Since doing this I never have had paint lift off the HDU. Now, I let it dry, then stick my high tack Anchor sandblast resist on the raw HDU and blast away. If you still want to paint primer before blasting, let it set till its dry. You can tell.
I haven't tried cleaning the new SignFoam 3 with just the blow gun. The new stuff is suppose to be much more static free than the old stuff was. Oh, by the way, that was the reason. Static!!!
Posted by Laura Butler (Member # 1830) on :
I just got 3 sheets of SignFoam 3 for a sign and was really amazed to see how smooth it was. It isn't taking much sanding at all to get it ready to prime.
Posted by DianeBalch (Member # 1301) on :
I have been vaccuuming it with the shop vac, then blow it with the compressor then tack cloth. So far, in 7 years the only paint lifting problem I had was the one shot lifting off the 2 part urethane auto primer, on one spot- both sides of the sign, when I peeled the paint mask. I may have hd some oil on my fingers when handling the sign.
Thanks for the info.
Diane Balch
Posted by Mark Rogan (Member # 3678) on :
BLAST it with a garden hose before you prime and again, after you sand, then sand it again while it's wet with 600 or 800 grit wet/dry paper and give it one more blast with the garden hose. Those microscopic pieces of grit ain't coming off any other way.
Posted by Wayne Webb (Member # 1124) on :
Diane, I've been using Everwood HDU and I don't have to spray it with water. I did with SignfoamII.
Also, when sanding primer before topcoating( I'm using FSC88WB primer), I wet-sand with 400 and 600 grit wet/dry paper. It sands MUCH faster and very smooth that way and I'm using far less sandpaper too.
Posted by Steve Purcell (Member # 1140) on :
I've been using SignFoam since the '80's. Never washed it with a hose. Never had a lifting problem.
