I am getting ready to sandblast some hdu and have used various techniques in the past. Usually I use fsc88 primer filler a couple coats, let dry thoroughly, then sand and paint with one shot. Then I apply hartco stencil. I wanted to know what some other techniques are out there and what works best. I am using 1.5" 15 lb and the signs are 3x5
Posted by Dave Sherby (Member # 698) on :
I was a BIG fan of prepainting redwood, but I have never been a fan of prepainting HDU. I do a quick sand of the surface, clean off the dust well with water, then apply a high tack resist and blast.
[ January 03, 2006, 11:57 AM: Message edited by: Dave Sherby ]
Posted by Bob Stephens (Member # 858) on :
I'm with Dave and use the same technique. Even with expensive automotive finishes, I wouldnt want to risk having the blast mask lift the pre finished paint work.
Posted by Wayne Webb (Member # 1124) on :
All these HDU signs below were done with the pre-paint method. The additional colors, of course, were brushed on after blasting but the main color was sprayed on prior to. I use fsc88WB primer and latex paint. Neither my paint nor primer lifts after blasting.
Clean clean clean Make sure your HDU is clean and dust-free(no matter which method you use). Roll on the first couple of coats of fsc88wb. Don't sand between coats. Spray on the last coat with an HVLP or airless gun. Let it dry overnight. Wet-sand it with 330 and 400 grit wet/dry paper(it sands MUCH faster this way) Rinse off thoroghly with the water hose. Let dry overnight or, better yet, 24hrs. Dust it off good with a soft tack rag. Use a dark one so you can see when it's clean. Spray on two or three thin coats of the topcoat paint. LET IT DRY FOR 5 TO 7 DAYS....Maybe a little less if the humidity is low enough. Mask with Anchor 153 stencil and blast at no more than 75 to 80 psi. Keep the nozzle moving. DO NOT LET IT LINGER IN ANY ONE PLACE...I GENERATES HEAT...KEEP IT MOVING. If the stencil is starting to turn brown, your pressure is too high and/or you are moving too slow.
[ January 03, 2006, 05:03 PM: Message edited by: Wayne Webb ]
Posted by John Meeks (Member # 5081) on :
Just my 2 cents... When working with HDU, it really depends on the surface you wish to have as to the paint and primer to use. If you want an ultra smooth surface use high build, sandable primers and possibly smooth, sprayable paints. Otherwise regular latex primers and paints will work fine and you can prime and paint in 2 to 3 days. Then use one shot paints on the rasied areas. I personnally do not recommend pre-painting or pre-priming your piece. Unless you're using a router table with a paint mask on the surface and are trying for a quick turnaround job (IE. SAND, PRIME, PAINT, PAINT MASK, ROUT, PRIME AND PAINT ROUTED AREAS, Strip mask and SHIP)then it's fine. I guess after painting redwood and cedar for 15 years, I got used to certain steps that I just transferred over to my HDU signs. Feel free to e-mail me or call if I can offer any more answers.(signmonster68@yahoo.com, 864-275-5140mbl) John Meeks
Posted by Wayne Webb (Member # 1124) on :
The signs below are redwood, primed with "FirstStep" primer and topcoated with latex. The FirstStep is real nasty stuff(contains toluene and xylene). Wear a respirator. Proceedure is also different except the waiting part. The latex topoat still needs to dry 5-7 days(maybe a little less dependinmg on humidity) and the blast pressure can be increased to about 90 to 100 psi. The Firststep does a good job, it's just bad to work with. One of the reasons I don't do many redwood signs anymore.
