kbog54

Hey, I was just wondering, i know that you have to add a flexing agent to the primer and paint when doing the gfx, does it matter if you add the flex to the whole batch and do the whole car? Or should you mix 2 batches and do the plastic and metal separately?

thanks.

87roc_t56

I am on my sixth third gen now and after hearing every story there is on what needs to be done I now know what to do to make the paint last and not crack or show bubbles on the plastic parts the first time the sun hits it.

The front and rear bumper covers and lower front spoiler/air dam are the only parts of the car that need flex agent. This is required in the primer and the paint/clear. Basecoat does not require flex agent. However ALL plastic and fiberglass components need a VERY thorough process to achieve proper paint adhesion. GM themselves screwed this process up in 88 to 92 or so. It goes as follows;

1. Wash everything with soap and water thoroughly.

2. clean all plastic/urethane/fiberglass with a plastic friendly chemical cleaner to remove any mold release agent residue.

3. You must then spray all plastic parts with an adhesion promoter/ sealer

4. then prime and paint in conventional methods being sure to use a 2k primer not a laquer primer adding flex to the nose and tail pieces only.

You should spray the urethane pieces seperate from the car as this will give you the best quality. Good luck.

kbog54

Ok, thanks for the reply. So i have to mix 2 seperate batches of primer?

For the adhesion promoter, is that just the stuff that you can get in a spray can?

Also, i'm repainting my fiberglass hood, but i just scotch padded it, and left the original paint on it. So i dont need to use flex on this?

thanks

87roc_t56

No you do not have to add flex to the fiberglass but it must be clean. I cannot stress how important the cleaning prep is on the plastic and fiberglass pieces. I use RM products and they have a plastic pre cleaner ( sorry can't remember the name here at the office ) and it works great. Follow the application instructions carefully. I also recomend sticking with one complete system from start to finish. What I mean by that is if you have a paint selected ( RM, Dupont, Sikkens etc. )then stick with their primer etc. If you mix and match be sure to ask your suplier if he will ensure compatability. I use RM stuff and find that their clear is the best for shine and durability but its also cause I am used to it. Different manufacturers products vary quite a bit in their nature such as sanding grits, drying times, color hold out et.

On the last job I did I removed all parts from the car and prepped and primed them individually adding flex to only the nose and tail pcs. I painted the body color and clear underneeth where all the skirts go on and then reinstalled all the GFX and all body pieces that get painted. I did this because I added pearl to the top coat and its very difficult to paint pearl on pieces independantly and get them to match perfectly. So I did exactly what you are thinking and flexed the whole car but its not the best thing to do. It really made the clear weaker than normal although the paint looked great I would have tried it individually if I could do it over agian and flex only the nose and tail.

Back to prep when you add flex to primer it is very "sticky" to sand and must be wet sanded or the paper clogs too fast. Yes the adhesion promoter comes in a large spary bomb can and it sprays with the consistency of WD40 so BE CAREFUL the crap runs as easily as panty hose on a fat chick.

One more thought here. If any of your flexible parts has any cracks in the paint you must sand them COMPLETELY out or they will show in a few months time after you paint. Its a bugger of a job to sand them out but if you want a proper job it must be done. If the paint cracks are old it will likely have migrated into the actual urethane a little as well but use 180 grit paper and they will come out. Elbow grease is the key to a successful paint job because the prep is what truly separates the men from the boys. These cars are particularilly difficult to paint because there are so many pieces and different materials to deal with so don't rush if you want it nice. Like I said before I have learned most of this the hard way. Good luck!

kbog54

Yeah, I have been prepping and removing rust for the past 4 months its a pain, but it will be well worth it.

For the paint, i wont be using clear coat, and it isnt anything fancy, just the stock white color w/o the gold stripes and gfx's.

But in your opinion, i should mix 2 batches of primer and primer sealer for the plastic pieces? would it hurt anything if I added the flex to all of the primer and primer sealer?

Also, with the paint, it should be ok to add flex to the entire coat as long as I dont clear coat it?

Thanks for the replies

87roc_t56

You can add flex to the whole job but be careful going hog wild with the flex in the primer. Perhaps you could spray a little carefully around the bumpers to avoid getting too much flex on the steel and before it dries spray the steel partrs without flex. Try to sand primer with flex and you will see why I caution you here. Flex makes the primer awful to sand.

If you are going with a single stage paint ( no clear ) then I would recomend using single stage urethane instead of acrylic enamel. Its superior in shine and it is far more flexible. You can just paint the flexible pieces without adding flex agent and it will look just as good but it will crack if you bump something. It does take a decent whack though... I have done this in the past and as long as you don't bump another car or a curb it lasts quite well. Of course adding flex to the whole job is fine but it does drive the cost up too.

I am a little confused about this statement;

"Also, with the paint, it should be ok to add flex to the entire coat as long as I dont clear coat it?"

You can add flex to clear as well. Adding it to the whole job will not cause any harm but when flex is added to anything it gives up some of the paints overall hardness in favour of flexibility so it will chip a little easier.

kbog54

ok, thanks for your help

Cool ZR

Some good information here.

I was wondering if you have used paint stripper to cut through previous paint jobs. How do you get that stuff cleaned up to make sure the new epoxy primer will adhere properly to the metal surfaces? How do you clean out the roof drip mouldings to make sure the stripper is all out and the paint won't bubble back up?

Thanks
Cool ZR

IROC-T

Use lots of water and a nutrilizer.

kbog54

just make sure you wipe it down thouroughly with degreaser right before you prime or paint it, also, if you are worried about the remnants of stripper, just let it dry a few days

Cool ZR

I was actually told to use brake cleaner to remove the remaining stripper. It seems kinda odd to wash down a bare metal panel with soap and water, but I guess it won't be on long enough to cause any corrosion before you seal it up with epoxy primer.

Anyone ever use that metal prep stuff?? Good or bad?

Thanks
Cool ZR

87roc_t56

Yeah I've used stripper before... its real messy so I tend to stay away from it. LOTS of water and a day in the sun cleans it up pretty well. Media blasting is the best way to strip but its costly. If your car has no body damage and you are only looking to repaint due to fade etc and your car still has the original paint on it then I would NOT recomend stripping the paint off as its really unecessary. Most cars from the mid 80's and newer have been "e" coated which is far and away the best corosion protection you can have so stripping it off would be a shame. If your ride has been resprayed its more common to find lower quality paint and then it would be a waste to spray new over junk so stripping is wise in this case.

I cannot stress enough how important it is to CLEAN all surfaces with the proper cleaner prior to each step of the job. The best way to ensure a high quality job is to pick a reputable maufacturer and stick with their of products start to finish. Most suppliers will only be too happy to provide you with literature that should spell out the recomended prep products and sanding grits required for each step along the way.

Patience is your best friend when it comes to body work. Good luck!

Cool ZR

I am hoping that cleaning it up with the water, and then thinner and then degreaser will do the trick. I am actually working on a 65 pickup an it has a lot of curved detail work on the cab and a ton of old paint and bondo that I wanted to get rid of..... it was 2" thick in some areas, unreal.....

Thanks for the help

Cool ZR

87roc_t56

One more tip if your body is not very straight. You can buy a spray on putty coat now that goes on thick as undercoating and ironically has a similar texture when its done. Anyway this stuff sands amazingly smooth and with only one apllication you can apply 3 mil thick and block sand out darn near any waves or imperfections in the body. One catch though is you need a special gun to apply it. That is with the RM stuff at least. I am unfamiliar with other manufacturers spray putty coats as it is quite new technology but it is amazing product. Cuts prep time down by many hours considering the "old" way of priming/sanding/priming/sanding/etc. This stuff gets you 90% of the way there in one coat. Good luck

Cool ZR

Wow that sounds like a great product. Does it go bare metal or after the epoxy?

This truck is a basket case and has had patches everywhere. The metal is all there, just looks like used it as target practice before bondoing it up. I'd rather have replaced the sides on the box but only some of it is available. Since its not available, southern stuff is like $1000 a side!!! The truck is going to be driven and used, so theres no way we're paying that. We had a buddy help us out with fixing the sides and shrinking them to get rid of some tin can.... It's good enough for a substantially smaller skim on the bondo

You say that stuff is an RM thing, I am going to look into that, that would really help me out as they must've used like 20 grit on the truck before....

Thanks
Cool ZR