sealing overtop of polyester primer
- This topic has 47 replies, 11 voices, and was last updated 11 years, 2 months ago by .
- Posts
questions about spray filler; whenever I have used it before I had always Put urethane primer overtop of the poly primer before sealing/painting..
For a restoration of a fiberglass body, the body is in pretty decent shape for a car of its age, doesnt need much mudwork, so my first thought was spray fill the whole car with slicksand , block everything down nicely, finish everything in 4-500, seal the entire car and go base or SS. After thinking this over maybe that sealer wont hold up as well as if I were to reprime the whole vehicle again with a 2k urethane. Has anyone sealed overtop of poly primer and if so, how did it look down the road…
thanksThis is a good question, I to have always urethane primed over my spray filler. But I know people are sealing it and then shooting there base and clear. I have seen this process lots on (T.V.) restoration shows . To me I feel you get better flow and gloss retention if you skip the sealing process all together. I guess if you were going to cut and polish the job then it wouldent matter, but for off the gun aperance I wouldent do it.
I haven’t used as much poly primer as you guys, but I’ve always used urethane primer overtop. If you did just seal over it, I would wonder if using waterbourne base rather than solvent base would make any difference, and affect durability.
If you do just seal over it, I would definitely suggest using a high quality sealer.
[quote=”jim” post=32297]This is a good question, I to have always urethane primed over my spray filler. But I know people are sealing it and then shooting there base and clear. I have seen this process lots on (T.V.) restoration shows . To me I feel you get better flow and gloss retention if you skip the sealing process all together. I guess if you were going to cut and polish the job then it wouldent matter, but for off the gun aperance I wouldent do it.[/quote]
yeah I agree with you for sure on going right to base and 95% of the time on a restoration or any complete I will reprime any burn thrus, finish everything nice in 6 or 800 and go right to base. This guy however really wants the poly on his car, and it will add a lot more time for me having to prime twice rather than once…
i dont trust poly it realy is bitch for moisture retention and to be honest with todays two part stoppers and high build primers i realy fail to see the need for the stuff ,as for using waterbased near it then again beware as it realy doese suck up water and the danger of microblistering is always worrying with poly hence why i avoid it
I’ve sprayed Slicksand w sealer and topcoated with Onyx. I didn’t notice much of a difference when spraying. One job came back in about 2 months later, repeat customer, and it looked as good as when it left. I also sprayed the engine cover from my outboard engine with Slicksand, Glasurit 289-49, Onyx, and Dc5335. It looked great until it got smashed up against a pole in hurricane Sandy. I was surprised to see how well it adhered though.
We base right on the Slick Sand. No troubles so far.
Thats pushing it, wouldent that be like just spraying over bodyfiller :S
[quote=”gtome” post=33336]We base right on the Slick Sand. No troubles so far.[/quote]
Sometimes it can take years for trouble to show up,just because you haven’t seen or heard of any problems doesn’t mean that its not happening.I sure hope you aren’t wetsanding your poly before you base over it :SI don’t see the point of using slicksand all the way thru on a resto,seems counter productive to me.I can see using it on a rough body,blocking it with 120 and repriming with 2k.
[quote=”gtome” post=33336]We base right on the Slick Sand. No troubles so far.[/quote]
Uhh..what base system are you using that recommends going over a polyester substrate?
Very true. I believe they have been doing it that way for 3+ years though. And im not saying its right or wrong. Just what we do. And the tech sheet says to finish it with 400-600 grit paper wet or dry and that it doesn’t require a sealer prior to top coats. And we are using PPG.
I usually strip the car, epoxy/bodywork, then 3 coats of slick sand and block with 120, spray 2 more coats, block with 220 then 400-600 depending on metallics or not.I still don’t see the point,I mean why not use urethane 2k after slicksand?I’m sure its counter productive to use slicksand for your second round of primer,I can’t imagine how painful and slow it would be to wet block with 400-600.Just think of the time you could save wetsanding a nice urethane 2k primer with 400,sealing and painting,but to each there own.By the way 220 -400/600 is a pretty big jump…..I am well aware of no time frame on a resto but why in the hell would you want to work harder than you have too :unsure:
You dont have to tell me man! I have no idea why they do it? I dont know about anyone else here, but Ive have never been able to get slick sand to lay out nice. Not even close to how 2k sprays. But I will say that it seems that the slick sand makes a nice candy shell and holds down really really well. These cars are stunning when they are done and there never any problems at all.
After the 220 I blow it off real well, wipe with wax and grease remover, and then guide coat it to be sure I get all the scratches out. Really isnt too bad to do. But it is real hard mentally to sand the whole car flat after the slick sand knowing your going to just spray more of the super orange peely slick sand back on again. Wanna have some real fun, spray slick sand on the inner part of the front fender of these old cars and sand that back out. Or on the cowl and firewall. Super fun. Hours and hours of finger banging all the crevaces. Obviously I dont do it by choice, but they wont budge on how its done.The main advantage of the polyester is shrinkage. I have a 1″ thick piece of it that was leftover from May 2012 that’s been sitting on my window sill and its exactly the same size as when I left it there. I also have a piece of DP26 primer that was from the same day, same thickness and its shrunk down and split into pieces. That’s a good enough reason for me. I don’t use it on everyday jobs, I just bought it do use on my own projects. I have a $30 Titan 2.2 gun and it lays it on as smooth as our 3M Accuspray lays down DP226.
Spray poly absolutely has its advantages,especially on restos or panels that are really rough.I would not use it for my second round of primer,too much work.
- You must be logged in to reply to this topic.