A customer brought me a used sign board, which he coated out himself... more pics here
[ February 24, 2012, 11:27 PM: Message edited by: James Donahue ]
Posted by Sonny Franks (Member # 588) on :
Ouch........
Posted by bruce ward (Member # 1289) on :
you cannot paint latex over an oil based product THAT was the problem. I dont care if he would have cleaned it and then buffed it out it still would not have stuck...whan I first saw the pic I thought you were holding up and dirty yesllow rag
Posted by Dave Sherby (Member # 698) on :
Bruce, what do you mean? Professional painters use latex over oil primer all the time, in fact it is recommended. I'm with James. You can see the dirt in his pics. A good cleaning and scuffing would have worked.
Posted by Si Allen (Member # 420) on :
Dave ... if you clean then use a primer (Oil, laquer, or shellac) you can paint over oil base with latex.
Latex directly over oil base will fail, cleaned or dirty, doesn't matter.
Posted by Rodger MacMunn (Member # 4316) on :
I'm with Dave Sherby ....... as long as the oil-based finish is clean & has been scuffed up to give the acrylis some tooth, it will hold. It won't, however, stick well to a shiny surface. The water based does need to be 100% acrylic though..... no cheap stuff. I have signs that have been out there for 12 years or more & there has been no problem.
Posted by bruce ward (Member # 1289) on :
Dave do you see where the above sign had a oil based primer on it? I don't. I see a sign that was rolled on top with latex on oil painted sign...that aint gonna work....and if you think taking that sign and scuffing and cleaning would have sufficed latex to adhere to it, you keep right on thinking that
Pay attention kids
[ February 26, 2012, 08:07 AM: Message edited by: bruce ward ]
Posted by Rodger MacMunn (Member # 4316) on :
Bruce, I'm not going to sit here & argue with you but I've had no such bad experiences. I'm not talking about oil-based primers either. You do need to allow more drying time though. Using a primer in between will make a difference, granted, but isn't absolutely necessary. ClearStar products are waterbased ....& they stick fine to 3Shot.
Posted by James Donahue (Member # 3624) on :
Our land line has been down for a couple days, and our internet with it. If it were me, I would consider latex directly over oil a bit iffy. Definitely would scruff before the topcoat. The real point is that I've seen a number of outdoor re-coats, billboards in particular, fail because they weren't washed between coats. And those are all oil on oil. A hassle to be sure, but one can add a smaller amount of detergent to the water; which will then serve as wash and rinse.
Posted by bruce ward (Member # 1289) on :
First off neither topic is depictive of what the OP has posted...do you see any damn oil primer in the pic above? NO...Is there any mention of the product above being Clearstar..NO!
And rodger if you are placing latex over oil without primer more power to you I would have to see it to believe it
Posted by DianeBalch (Member # 1301) on :
How can you tell by looking if the primer is oil based or water based?
Diane
Posted by Checkers (Member # 63) on :
Actually gang, latex or oil doesn't matter because you can never believe what the client says or does.
IMHO, the best solution is to offer no warranty on client supplied substrates and the problem will be solved
Havin' fun,
Checkers
Posted by James Donahue (Member # 3624) on :
What Checkers said...especially measurements. I knew there was a problem as soon as I was loading the coated signs on my truck. I have a panel holder, a lot like the glass guys use. I drop a sign in, clamp it on with c-clamps, and drive away. This time however, it was a rainy day. I couldn't even clamp them down without the paint lifting. Then, window splash splash people will know what I'm talking about; the rain started running down between the old and new paint. Just like rain will do between latex and glass. You can actually watch a bubble form, run down, and leave a stretched out wrinkle in its wake. Strange but true. An oil based black outline will prevent this on window splash, provided you get it there before the rain starts. Back to this board, Bruce, it's true there was no primer, but if the board had been clean, it would have come off after a time delay, and in isolated pieces, not sheets. Ultimately though, you're right in that it's not something I would feel comfortable gambling with.