Painting Fiberlgass hood

[Kyle]

I've got a FG hood I am about ready to paint. It will be painted with PPG DP primer, then HOK BC/CC

1st question: Who makes a good sand-free adhesion promoter that I can use on the under side of the hood so I won't have to sand it. The hood is raw, rough glass on the inside, so sanding it so the primer can gain some tooth is pretty much out of the question.

2nd question: The hood is basically a skin w/o supports underneath so it is pretty flexible. The PPG tech sheets say when you spray it over flexible plastic to reduce it (in addition to the hardner). Would that be a good idea in this case?

3rd question: I bought a quart of PPG DX 801 plastic adhesion promoter, again since the hood is quite flexible would a coat of this be a good idea?

Sorry about the long post, I just want to do this the best way I can!

 

[rex]

First prefit the hood to make sure you don't have to shave the edges to make gaps and to make sure it isn't so warped it actually follows the fender and nose lines.Underhood scuff it well with a red scotchbrite and clean it spotless with g&w remover-won't be fun but you need to.Mix the DP with the 401 hardner,not 402.As long as the surface is spotless this combo will stick whether sanded or not.When you get to the outside you can thin it down 2-1-1/2,the 1/2 being DTV 802 or the proper DT reducer for the temp for the sealer mix.Sanding with 320 or finer is fine dry or if you enjoy wetsanding keep it over 500.Give it about 15 minutes to flash and squirt it.Give back the 801,it's strictly for raw plastic,not glass or anything primed.

 

[nooshie]

Rex, would , DPLF 40 be a good solution to prime and seal an area a person might not want to sand? While we're talking about FG I also have a question. I looked at a paint job recenlty that is concept ppg, Black on an old corvette. There are so many pin holes and bubbles I could not believe my eyes. The owner of the car said he had it painted in a local shop and they will not fix it. He call the PPG rep and still didn't get ant help. My question is, what would cause this? Any idea's

I have used PPG on the very few cars that I have painted and I have been satisfied with the results. If I follow the directions.

Nooshie
Nooshie

 

[Kyle]

Thanks rex. I bought the 801 for the plastic bumpers, I was just wonering if it would help in this case. Time to get to work!

 

[rex]

Hey Nooshie,sorry about the delay.The DP will work great for that but if you are going over sandblasted steel I let it sit a few days and sand it,it shrinks in to the surface and the paint's teture will look sandblasted too.Another option is let the DP sit an hour or so and blow a few coats of surfacer primer on it,DP sands like crap if it doesn't sit a month or so.Hard to say about the Vette without seeing it.I take it it's a glass body when you say old so the first thing that comes to mind is there wasn't a solid foundation and solvent penetrated into the glass.These newer urethanes have gotten pretty hot solvent wise and I've seen them go nuts on glass,I think gelcoat can't seem to privide a strong enough barrier anymore.If it's real small bubbles and pinholes maybe a large solvent pop and some didn't pop?Either way I doubt any paint company will back it up.EZ's painted a few Vette's as I recall so he'd have more info on them.I try to avoid them at all costs.

 

[nooshie]

Thanks Rex, No problem on the delay. Things are a little crazy right now anyway. I've been told that the newer paints are difficult to paint on fiberglass because their sealer can't protect the gelcoat. That didn't make sense to me, but what you said about the solvents being hotter than earlier paints helps me understand better. The tiny pin holes in the paint job I'm talking about is listed on the ppg defects link. I just found it last night. This is really interesting stuff. By the way I've got the flames taped out on the lawn mower hood that I 've been working on. I hope to paint them sometime tomorrow.

Nooshie

 

[thimmesch1]

the pinholes you are seeing is most likely either poor quality fiberglass or pinholes in bondo that were not completly filled when primed???? just my 2 cents(seen it before)
:0

 

[rex]

Could very well be pinholes,I'd have to see it to tell if it's that or it popped.Singlestage Concept seems to pop a little easier than the clear if you don't use it much because it's reduced twice as much.Pounding it on sure doesn't help.

Kyle,I oopsed,600 wet is better than 500.Actually 2 coats of the thinned DP would be better but I usually don't and you have to wait an hour before baseing.Make sure your bumpers are raw urethane for the 801,not factory primed or anything else on them.

Nooshie,good luck on the hood.

 

[Kyle]

Kyle,I oopsed,600 wet is better than 500.Actually 2 coats of the thinned DP would be better but I usually don't and you have to wait an hour before baseing.Make sure your bumpers are raw urethane for the 801,not factory primed or anything else on them.

Nooshie,good luck on the hood.[/QB]

<font size="2" face="Arial, Verdana, Helvetica, sans-serif">Thanks agian, I plan on stripping the bumpers down to bare plastic before starting on them.

On the subject of bumpers, does anyone here use a flex adative on bumpers?