Paint Bodywork Question

[268RTs4ME]

Need some info, new at this, I have my fender blasted to bare metal, do i need to etch prime them first, and then do some bondo work or do work first and etch prime?

 

[greenmonsta79]

There are guys that do it either way, I like to use self-etching primer first then block sand it to find high/low spots then do your bodywork, but I prime it first
that way if something comes up and I have to quit working on it the piece won't start rusting (because it will quickly the second the steel is exposed to the air!) Good luck with you project!

 

[1badgtx]

self etch first...
Petty Blue 67 GTX

 

[268RTs4ME]

priming

Thanks everyone appreciate the info.

 

[66_B_Body4ever]

Yikes! don't apply body filler over etch primer! If you need to prime (a good idea) sand the blasted metal first, and apply Epoxy primer. Once cured, the epoxy just needs to be scuffed with 80-120 before applying body filler. The acids in the etch primer will cause de-lamination problems with the filler, and were designed to work with primers, surfacers/paints.
I don't mean to step on anyone's toes here, its just not the right way of doing the job!

 

[moparpoor]

Yikes! don't apply body filler over etch primer! If you need to prime (a good idea) sand the blasted metal first, and apply Epoxy primer. Once cured, the epoxy just needs to be scuffed with 80-120 before applying body filler. The acids in the etch primer will cause de-lamination problems with the filler, and were designed to work with primers, surfacers/paints.
I don't mean to step on anyone's toes here, its just not the right way of doing the job!

He is right you don't put fillers over etch prime.Use a epoxy primer surfacer if you want to prime and block for low spots.Epoxy is the way to go.Etch prime is becoming the thing of the past.Sand the blasted metal with 80 grit or 120,make sure to wear rubber gloves.The acid from your hands will cause corrosion quicker than water.Once every thing is sanded clean with some wax and grease remover and prime.A few steps towards a quality finish.

 

[northerndave]

I agree. Epoxy is the way to go, that's the way I do it anyways.

With exception to maybe pressing in some metal 2 metal filler at weld seam areas to fill any pin holes I may have, I typically epoxy first, then scuff and lay filler in where needed over the epoxy.

 

[RGAZ]

Weird, I thought I was being lazy by just using epoxy prime and it appears I was doing it right all these years! I rarely etch prime jsut because I don't have it as handy. I always have epoxy prime around.

Good to know.

Randy

 

[66_B_Body4ever]

Epoxy is the best undercoat primer going. It combines a durable tough resin,(epoxy), etch capabilities (unless tinted white) and anti-corrosion properties (zinc). It is tougher than our topcoats (generally urethane). It is considered a non-sandable product which means it doesn't sand well and is not generally used as a surfacer although there are some surfacers out there that combine epoxy in the formulation eg: RM's Polyeuroxy which was a great product but very expensive. At the end of the day, Epoxy is the closest thing the layman can use to match factory e-coat, and in some cases better!

 

[dinney]

Hey guys I need a help. I have a BMW M3 Convertible which was scratched last week while parking it at garage. Then I gave it for painting at the part where the scratch was made, but the painting on that part has made my ride look ugly. So, wanted to change the color and paint whole body of the car. But when I saw a Nissan car wrap last night I changed my mind and decided to wrap my BMW. So, I wanted to ask which one is better wrapping a vehicle or painting? Is anyone here who have their car wrapped, if yes then can you say the good and bad part of wrapping a vehicles.

 

[66_B_Body4ever]

What the heck is a wrap? Don't wanna click on that link...

 

[darkhorse]

There are garages in Nepal?? wow learning something new all the time. this is great.

 

[northerndave]

wrap is just a big decal.

used comonly on semi trucks and trailers for business advertising logos, they can slather a whole 18 wheeler with cool designs and or logos, photo quality images or what ever you like.

I've never thought to consider it for a car.

It's just printed vinyl sheeting, peel and stick.

Sorry but I have to believe Mr dinney is a single post ad spammer.

 

[Cranky]

Hey guys I need a help. I have a BMW M3 Convertible which was scratched last week while parking it at garage. Then I gave it for painting at the part where the scratch was made, but the painting on that part has made my ride look ugly. So, wanted to change the color and paint whole body of the car. But when I saw a Nissan car wrap last night I changed my mind and decided to wrap my BMW. So, I wanted to ask which one is better wrapping a vehicle or painting? Is anyone here who have their car wrapped, if yes then can you say the good and bad part of wrapping a vehicles.

This is a typical post of a spammer.....

 

[Cranky]

And do ya need to etch blasted sheet metal? I've never done it. I don't do a lot of painting but that's how I've painted it. How much 'tooth' is needed? Clean off any dust and go for it....blasting is going to give you all the etching you need.

 

[66_B_Body4ever]

And do ya need to etch blasted sheet metal? I've never done it. I don't do a lot of painting but that's how I've painted it. How much 'tooth' is needed? Clean off any dust and go for it....blasting is going to give you all the etching you need.

It's true that sand blasted steel is rough enough for materials to bite into, the bigger problem here is that the sand or media impregnates itself into the steel and needs to be cleaned from the surface (by sanding prior to etch/epoxy). I have painted industrial stuff right after sandblasting, but with an appropriate paint system like Imron or Endura. the less material left on the surface that doesn't belong there the better the adhesion to the undercoat.

 

[66_B_Body4ever]

wrap is just a big decal.

used comonly on semi trucks and trailers for business advertising logos, they can slather a whole 18 wheeler with cool designs and or logos, photo quality images or what ever you like.

I've never thought to consider it for a car.

It's just printed vinyl sheeting, peel and stick.

Sorry but I have to believe Mr dinney is a single post ad spammer.

Ya, seen a million of them, just pulled a brain fart. We have a ton of that crap rolling around here...lol

 

[northerndave]

it seems "etch" is the new buzz word, I've been in the finishing industry for nearly 20 yrs and I haven't heard etch prime boasted anywhere as strongly as here at this site.

There are all kinds of specs for different surface prep prior to paint. Many of which are to do with the physical surface properties in the way of scratches or grit blast specs. Mechanical "tooth" as cranky states. (and you can’t beat it in my opinion) Sanding scratches are great for this as they give random direction edges for the primer to flow into and around prior to curing.

Epoxy is the way to go over scuffed/clean metal.

It wasn't too long ago that metal prep washes were the buzz. This actually makes sense because when done correctly metal prep wash processes actually attach or "grow" a very thin coating on the surface, usually iron phosphate . The PH of a phosphate treatment is acidic which allows the iron phosphate to attach creating a layer that bonds nicely to the steel, plus the later is inert. So, picture your clean bare steel with a micro layer of iron phosphate on it, then your typical epoxy prime plus whatever multiple coatings stages over the top on up to the clear coat.

Between your metal and your epoxy is that iron phosphate, what's it good for? Well it does help adhesion when it's done correctly, but the big deal is that fact that it's inert. So, a scratch or a tiny rock chip in your paint down to the bare steel is less likely to "creep" meaning the rust can't travel wild under the paint skin creeping a big blister.

Is it much better than just epoxy over sanded and clean steel? Maybe on something that you use and abuse and leave out in the weather 24-7, but not likely noticeable on garage queens.


I don’t know about all this etch prime business.

I guess I’ve always been a big fan of scuffed, degreased, dry clean steel with a nice coat of 2k epoxy over it as a foundation for any paint job.

 

[66_B_Body4ever]

Hey Northerndave, I agree with your statement about epoxy. Etch primers are more commonly used in production body shops for their speed. they have been around for many years, 1960's it was used primarily for it's ability to provide adhesion directly to clean unsanded steel parts. Epoxy never came on the scene until much later on. Etch is a blend of phosphoric acid, solvents, and sometimes zinc and vinyl polymers as in vinyl wash primer. They still have their use because of the speed but many of the new primer-surfacers are DTM (direct-to-metal) and do not require a pre-coat (primer). I personally have used them (etch primers) since I got into the industry (1981).
Today's paint technologies (water borne) will see the demise of the old school etch primers as we know them. They don't work with the new basecoats if exposed to the acidic nature of the etch primer. Up here in Canada we are all using waterborne basecoats and I have seen some waterborne clears recently come onto the market. Surfacers are said to be just down the pipe.
I have found that you can't blink in this paint industry these days or you missed something. It will make it tougher for the hobbyist in the future when more waterborne technologies are in place...