jlc84cam350

ok, after everything is all smoothed out sanded and everything, is their anything different you have to do to the bumpers than to the rest of the car, i didn't take off the old pain, i just sanded everything down nice and even so everything looks perfectly flush, still a thew small scraches any idea on what i should use to fill them?, Is their any special primer i should use on the places where i went threw the paint, should i prime the whole thing. Sry if i am not making anysence its just i heard you had to use somekind of flex primer or something on the bumpers or else the paint won't stick very good and eventually peel off. I know it did that on my sunfire after about 6 months and i don't want to run into the same problems as on my camaro thanks.

slow_90firebird

Auto body places sell a flex additive that you can mix into the paint to keep it flexible longer, but that will eventually cure.

Personally I have never used them, but depending on how deep the scratches are, you can get special body filler made for bumpers that applies and sands out like bondo, but remains flexible enough to not crack off if the bumper moves a bit. I think people find spot putty works for small scratches too.

Before you paint any part of the car, you should lay a thick coat or two of primer, then block it out with a sanding block to get the surface completely level. That way, the primer acts as a final layer of filler, that when you sand it out, you can prime over again. Also by blocking it out, you can see where you might need more filler if the sandpaper doesent touch a certain area.

89importeater

also alot of paint lines now have a felx inhibitor (sp?) already in the paint. as most of todays cars have plastic bumpers. where ever you go to buy your paint from ask them they should know about the brands they sell.

327_TPI_77_Maro

iTrader: (8)

Flex additives basically help you assemble the car without cracking the paint. They wear off quickly. A lot of pro painters don't ever use flex.

I would personally strip to bare plastic, then put a coat of adhesion promoter (bull dog, this is what you were referring to as "flex primer", yes you should use it but only over bare urethane, not over paint) and then a few coats of 2k primer. 2k has some flex to it and has held up great in the past on urethane covers for me. Some people like to use epoxy primer first to deter rock chips but I have also heard it does not flex as well as 2k.

The more film thickness you have on plastic, the more likely it is to crack. So I would strip it. Stripping bumpers SUCKS. I use a DA w/ 80 grit at first and am super careful.

jlc84cam350

that 2k primer, is it more expensive than any other type of primer or pretty much the same price, if its about the same maybe i could use it on the rest of the car where i need it?, what do you guys think. By spot putty do you mean glaze i believe its called?

327_TPI_77_Maro

iTrader: (8)

You have to spray it from a gun (then again if you are priming a whole car you should be using a gun...). 2k is your modern refinish filler primer. It is chemically hardened to be durable, and it is sandable to fill surface imperfections.

If you are sanding old paint, you can spray 2k directly over it. If you are spraying over bare metal, you use either epoxy or etch first (most people use epoxy nowadays), then your 2k to sand and level, then some people prefer a sealer, then topcoat.

I would recommend checking out autobody101.com/forums if you are not familiar with paint terms and techniques. I didn't know what I was doing when I started out and the guys there helped me get on track.

jlc84cam350

ok, yha i am doing this with a gun, its just i wanted to know if that 2k is good on metal too, its filler primer you say?, ive used filler primer before but in a spray can form. I already got some self etching primer for the bare metal, but you say this stuff wouldn't be good for a final primer coat. I wasn't planning on priming the whole car but am starting to think i might have to its black and going red, i was just gonna sand all the clear off, patch places that need to be patched and shoot the paint over the old paint, would it be better off i primed the whole car before shooting the paint? I am not doing a show car here as long as it lasts me a couple years without starting to look like crap ill be happy. thanks

327_TPI_77_Maro

iTrader: (8)

You can't shoot any primer to metal unless it is specifcally DTM (direct to metal), it will say so in the product data sheets.

Most automotive epoxies are DTM, and etch is DTM. 2k is definitely not okay to spray over metal only. Yes I would spray several coats of 2k over everything, including the repairs and sanded OEM paint, because then you will have enough thickness to sand out surface imperfections.

So you can use your self etch over metal. You can not spray it over paint (you can overlap it from bare metal to paint a small amount). Etch primer is lacquer with a mild acid in it. So you definitely do not want that over a large painted area. Etch also is not intended to be a filling or sanding primer.

So you will need some sanding (2k) primer to do the job right. I would buy a gallon and put 3 full coats over the entire car, then block that 220/400/600, then topcoat. You don't need to seal over the 2k, but some people do. For a garage job you don't need to.

jlc84cam350

sry about that, didn't phrase my words right, i didn't mean directly metal, i just meant like over bondo or you know, places that have had work done to them. I know etching is meant just for metal protection, just one last question, is that 2k stuff good as your final coat before you paint, or should i use something else before paint too. thanks

327_TPI_77_Maro

iTrader: (8)

Yes, 2k is good to paint right over. Yes you can use it right over bondo. If you have no bare metal, then you have no need for that etch primer. That's for bare metal, only.

jlc84cam350

ok thanks alot man, that cleared a lot of stuff out for me. how many coat of this stuff can you put on?

2fast4u92z

I was realy scared about my paint on the plastic parts. My body guys all said to sand them down to the plastic, and to make sure all oils and such where out. Sounded like a pain in the ***. So I just bought all new GFX, and all GM NOS. With a expensive paint job it is not worth risking! And I got a killer deal around $500 for all of it!

I know he said he uses a primer that eats into the plastic. THan a flex in the paint. We have twisted and bent GFX it is what would happen and didn't even get stress lines!

327_TPI_77_Maro

iTrader: (8)

I think old (like 20 years ago) protocol was to use etching primer on the plastic. I don't think anyone does that anymore.

jay_d

just prime the **** out of it with high build and block and wet sand, ive done that on countless bumpers and never had anybody come back becuase their paint come off

JRods Firebird

Well I got a question also. I ran into a dam garbage can going like 4mph and chipped the paint and a small dent in my 91's front bumper but really looks like a crap load of primer and paint but still a small dent. Could I use a reg body filler and add a different type of hardner that will allow it to flex. I figure we are talking bumpers so why not ask a question. thanks

327_TPI_77_Maro

iTrader: (8)

There are specific types of body filler for plastic. You might be able to get away w/ regular bondo if it is in an area of the cover that does not flex much, but I wouldn't chance it.

JRods Firebird

No if thats the case then I wont use reg bondo. ILL try a part store and see whats the best for my application.

327_TPI_77_Maro

iTrader: (8)

You need a paint store. Almost no auto parts store will have plastic body filler (not good stuff at least). The only places I have seen it are occasionally higher end stores like Napa. but you'd be better served just going to an auto paint store and knowing you'll find it in one trip.

2fast4u92z

I would never use bondo! There is a product by 3M(I think) that is a two part glue. Looks crazy and has a special gun to load it in to. And it is the strongest body shop product i have ever seen. And hammer can't even touch it. Have to file it down. Same stuff we used on molded in body kits. We a plastic panel has stress lines or dents sanding down and prime and block is the RIGHT way to go.

As far as using etching primer. Ferrari and My friends shop(BMW) still both do this. They even have different kinds. ie metal,plastic,ect... If it is good on $300,000 cars it is good for me!

I understand people trying to do it "cheap and easy" but I haven't seen good turnouts this way. The many issue it paint curing right. Like the paint being hard. Like stock paint is hard to chip. But a cheap aftermarket paint job can get a million chips in no time!

JRods Firebird

I forgot whats it called but I got that stuff in the garage but im at work. You have to use a special 2 level caulking gun and it smell bad but its as tuff as steel once it hardens up. Expensive stuff. I used it on my 68 charger when installing a new trunk floor and drivers side floor. Im not sure if I would use it on my bumper.

jay_d

put rage body filler in it, it flexes the most of all the fillers ive ever encountered, you cant miss it its in a pinkish purple gallon can with RAGE wrote down the side