I had some BIG letters cut from ½" thick Sintra plastic for an office wall installation. It was just CALC which overlap and are welded together for their logo. Pretty simple stuff.
So I planned on painting them with metallic silver spray paint. Krylon didn't have a FUSION silver at the hardware store so I bought the regular silver metallic (off brand). I thought this spray paint sticks to everything, right?
It took forever to dry. I left it to dry overnight. I went to check on it the next day and when I picked it up it was still tacky and left smudges and fingerprints!
All spray paint is not created equal. Fusion must have some special "magic" but this stuff didn't. I had cleaned it with denatured alcohol before painting but didn't prime it. I don't think that would have made a difference. I wanted a smooth sprayed-on look to resemble metal but ended up wiping most of it off. I covered the whole thing in silver metallic vinyl which looks really good.
Should I have looked around for a silver Krylon Fusion or would something else have worked better? This Sintra is great stuff, but I was going for a slick finish for my customer's office wall. What should I have done to get the look I was after?
Sign-cerely curious, Steve Posted by Sandy Baird (Member # 4773) on :
Steve,
I wanted pvc painted a colour that Krylon didn't make. What I did was paint a base coat with a Krylon colour, let it dry well, scuff sanded and primed over the krylon and then finished with the color and brand of paint I needed. The Krylon sticks well and make a good base to paint over. Others might have tricks that have worked for them.
Posted by Brad Ferguson (Member # 33) on :
Hi Steve,
Krylon Fusion has a very aggressive solvent system which helps it stick to PVC.
Would an adhesion-promoting plastic primer have made a difference underneath a less aggressive paint? I don't really know. Surely someone else has experience with this. I'm pretty sure you can buy adhesion promoter for plastic in spray cans at the autobody suppliers. Body shops paint PVC and ABS plastics all the time.
Our procedure for painting PVC: Thorough sanding first. I use 400 paper, but Scotchbrite works, too. Then, almost always, I spray with Matthews adhesion promoter for plastic. It's almost like glue, but thin. When it has flashed, I topcoat with polyurethane. On small stuff for interior application I have sometimes skipped the adhesion promoter, but never the sanding. Also, sanding introduces static, so just before spraying, I wipe with a plastic prep (Matthews) that removes static, then a final very light wipe with a tack cloth. So far I have had only one failure on PVC, and I had skipped the adhesion promoter that time. Most of the problems I have had painting PVC have been from dust rather than lack of adhesion.
When I have used Krylon on vinyl sheet, which is also PVC, the paint seems to bite very well. It acts like it melts into the vinyl.
Sounds like the job worked out for you in the end.
Brad
Posted by Patrick Whatley (Member # 2008) on :
If you used that Valspar paint for plastic from Lowe's you might want to look at having your letters redone. That stuff NEVER dries on vinyl or PVC.
Posted by Joe Sciury (Member # 4653) on :
Why not just regular Krylon? Have used it for years, before Fusion came out, with great results on the stuff the Fusion claims to stick to. I really haven't noticed any difference in the regular Multi-Purpose and Fusion except the higher price and the marketing hype.....IMO
edit:.....Looking at the MSDS specs of those two products it looks like Krylon changed the Multi-Purpose. It used to have (MIBK) Methyl Isobutyl Ketone which it no longer does but Fusion has it.
I always thought that was the solvent that really melted into vinyl and PVC so it looks like Krylon's new Fusion is the old formula and the regular multi-purpose has been changed/cheapened.
[ September 29, 2010, 07:36 AM: Message edited by: Joe Sciury ]
Posted by Mike Pipes (Member # 1573) on :
I add a bit of MEK to spray paints, it will make pretty much everything bite into any plastic you could want to paint. It's a really hot solvent and I'm actually kinda surprised you can get it at your average hardware store/home center.
When I was in shop class in high school, we bonded plastics together using MEK, just dipped the face in it then clamped it together. The MEK is so hot, it softens the surface enough to allow chemical cross linking between the two pieces.
I've also used it to make ABS plastic "body filler". It'll completely dissolve ABS shavings into a paste, which is handy for some of the more unusual projects I get myself into. Posted by Weston Pulley (Member # 10330) on :
I have used Duplicolor primers and paints with great success. These are automotive grade primers and paints which bond very well.
Posted by Ray Rheaume (Member # 3794) on :
"What should I have done to get the look I was after?"
On PVC materials, even with Fusion, I put down a coat of PPG One Choice plastic adhesion promoter and pretty much can spray anything over it once dry. But yes, there are different grades of aerosols out there.
If you really want that automotive color and finish, check out Napa Auto Parts. Many have a system where they can mix auto paints into aerosol cans for you in either base coat and single stage. Usually somewhere between 12-20 bucks/can depending on the color.
For a REALLY bright silver, I'd have sprayed it with an aluminum finish and cleared them. Since the letters are inside, I would expect they'd hold up pretty well over time.
Quick way out...wrap them in vinyl of choice.
I'd probably have leaned toward chrome or a mirror gold myself, but then, I have always been easily distracted by shiny objects. Rapid
Posted by Mike Pipes (Member # 1573) on :
"Fish love shiny things, but then again, don't we all!" - Phil Hartman, "The Anal Retentive Fisherman" SNL
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