ive searched the forum, but theres soooo much information that i cant find the answer im looking for. i plan on stripping my body bare using a da. since i know this will take a while btwn sanding, oil and grease remover, taping etc, im afraid i might get flash rust. how long do you guys leave your bodies completely bare (hours, a couple days etc....). is there something that i can wipe it with prior that is used for this purpose? ive seen cars in magazines sitting in shops in bare metal. what do they do to make it work?

by the way, ive seen lots of how to paint steps, but what about the prep work(not after primer, but before)... sanding, blasting, stripping, taping, cleaning etc. what to do when and what to use please... thanks, Tim

Use metal prep on it before you spray epoxy primer on it. Metal prep will eat off any surface rust and give the epoxy a little more bite. Phosphoric acid will do the same thing. You can buy it at places like Home Depot or Lowes for about $6.00 a quart in the paint department. It can go by different names. Look for the green stuff in a clear bottle.

You better know what brand of epoxy you are spraying before you metal prep it with chemicals. Not all epoxies are the same and NOT all epoxies require metal prep.

Strip a part at a time, no need to strip an entire car body at once. Strip the part and if you use a good quality epoxy primer you dont need metal prep or etch primers just a 80 grit tooth on the metal.

Any cars I do like this I do sections each day (front cap one day, doors one day, quarters one day, etc.) and I prime the areas each day before I leave with Krylon hot rod black primer in the spray can. This keeps from having to worry about rust and also buys you time if you're not on a hurry-up schedule. When you complete the whole car like this you can 400 grit the entire car and reprime the car completely with a gun-shot primer before the final finish is applied.

Around here, you can leave a car in bare metal a long time outside. Once the water gets on it is when the rust starts. I have had a car in bare metal that had JASCO metal prep from Lowes rained on and it did not even phase it. If you leave it long enough you can get more surface rust on it, just come back and put on more metal prep. I have used a few different brands of epoxy primer over the metal prep and have had zero problems of any kind. No adhesion problems. I have a car sitting outside right now that has had epoxy primer on it over metal prep and it has been out there for a few years now. With hobby cars you can't always get back to work on them right away.

Klean Strip is another one of the brands they sell. You don't need it on clean metal to use epoxy primer on it. As anyone who has a hobby car knows, they can sit a long time before they are worked on again.

i guess pieces wouldnt be a bad idea, but id like to do it all at once. im going to shoot spi, so ill call barry and see what he recommends. i have been working a few areas that are bare now, but i do spray bomb them when im done for the day. the initial strip would take a long time, but 220 after the fact would be fast. would hitting it with 220 on a da get rid of it, or would it still stay in the pores.

sevt chevelle... i know you shoot spi. have you ever used a metal prep to get rid of the surface rust? will the epoxy "eat" very light surface rust. im going to get my frame blasted, and depending on the time of day i get it back, it may be a couple of days before it sees primer. this is one of my main concerns.

thanks, Tim

sevt chevelle... i know you shoot spi. have you ever used a metal prep to get rid of the surface rust? will the epoxy "eat" very light surface rust. im going to get my frame blasted, and depending on the time of day i get it back, it may be a couple of days before it sees primer. this is one of my main concerns.

thanks, Tim

Barry will tell you to get rid of that metal prep. SPI, valspar and a few others state in the tech sheets NO metal prep or etch primers.

Now yes you can use phospic acid(navel jelly) to remove surface rust, I use it. But once its done removing the rust remove it, da sand it off with 80 grit. Navel jelly is a great way to remove surface rust but not something I want for my foundation of a paint job.

220 grit for epoxy is too fine, you need to go down to 80 grit. For that frame the texture left behind from the sand is perfect for epoxy no need to da sand it...Eric

so i guess my plan is going to be to do the doors, fenders, hood and deck lid together, and do the body seperate. if i sand down the parts with 80, fix any pinholes of rust with naval jelly (not much original sheet metal left), and then shoot, i should be able to get each done in a day. sand, tape and prep in the morning, shoot in the afternoon.

thanks, tim

This is a touchy subject for me.

Eric is right, a lot companys don't say to use metal prep before spraying Epoxy. Barry at SPI is one of them. Barry also says NOT to use his Epoxy over a soda blasted car. Why? Because Epoxy is very sensitive to less than perfectly clean metal.

I am uncomfortable NOT preping the surface with metal prep even though it is a pain in the butt.

If you don't metal prep at least make sure the car is wiped down with a damp cloth (water only) a small place at time and drying quickly.

I get into the pinholes after phos acid with a wire wheel. Be careful when using the acid because i have seen rust bubble after a month or so in the pinholes.
use a wire wheel on a grinder and watch the heat.

I just used metal prep on my roof,after it was dry I went over it with 80 on the da before epoxy.Now I'm concerned,is there a way to tell if I'm gonna have problems?

Don't worry about it, you won't have any problems. It mightl leave a white residue. You can wipe it down with lacquer thinner or just go over it with epoxy. You might see some white residue in the epoxy. PPG sells metal prep also. You will need high build primer over the epoxy primer anyway. Water will neutralize phoshoric acid. I wash the car down before the epoxy goes on. If you wash the car, there is not enough time for surface rust to start before the primer goes on. The etch primer they sell has acid in it and it needs to be nuetrilized, that is where some of the problems start. This cuts out a step. Believe me, that epoxy primer is on there.

Believe me, that epoxy primer is on there.

I hope so,but is there any signs that I can look for to know if I'm gonna have any problems before I go farther?

I hope so,but is there any signs that I can look for to know if I'm gonna have any problems before I go farther?

What brand of epoxy are you using? As I mentioned before NOT all epoxy primers require metal treatments, some will react in a negative way.

The only sign that I know is try and sand the epoxy off. I don't think you have much to worry about. You can scuff up the epoxy primer and shoot some more over the top, It is not going to hurt anything but you might be doing it for nothing. The instructions on the label even says it can be used before applying body filler. If you had scale and used metal prep, it won't help you. If it was good metal, you should be good to go. Paint jobs all involve a lot of sanding.

I have some Klean Strip brand in front of me. This is what the label says, Phosphoric Prep & Etch. Removes rust from metal surfaces & inhibits flash rusting. Helps insure good paint adhesion.

I'm using epoxy made by starlite.The tech sheet does say not to apply over etch primer.I didn't realize metal prep would be similar to etch primer.I suppose I'll wait a couple days and sand the epoxy to see if it's holding.

On my 72 buick (which is the only one i have so far that is getting ready for paint), i previously sanded it all the way down to metal about 4 months ago, sprayed some primer i got from sherwin williams, left it outside since then due to moving to a new home, had some surface rust that went through the primer, sprayed some of that phosphoric acid ontop of it without touching it, and removed it instantly, i did spray about 3 coats to get rid of it for sure, this green liquid thing works great, car restorers best friend, now im scratching my head on finding tricks or tips that will solve my problem of getting a straight as a ruller body lines, and panels...need to find out what are the best tools to use for sanding body filler or putty, also what is recomended for small dings and waivy panels... other than that, good luck, oh, yea, what i do is i spray the phosphoric acid as soon as it gets rid of it, i spray some soapy water to get rid of it, then get a towl with phos. acid and clean it again, if you leave the acid inthere for a long time after it eats all the rust, and bare metal shows up, you will get a white salty look where the rust was, make sure you either wipe it again with phos. acid..any tips and trick for body working would be greatly appreciated.

Some of the best $6.00 you could spend on your car. I use it on frames and anything else that might have surface rust on it. I pour it in a jar and use a paint brush to apply it. I put it right over old paint before I even start. If there is any loose paint, it will flake up after you put metal prep on it. I think the white residue is what scares people.

Etch primer is not the same thing as metal prep.

Yes, the white residue i guess is all of the rust dissolved, it just doesnt look good to others. So you wipe it off to get rid of it...

I think the white is phosphate.

69chevelleX2, i wouldnt leave anything primed outside, i always thought primer was porous, and water would absorb. you should use a sealer, or even a base coat. Its really common to see rusty primer on touch ups that are driven around or outside.

Can someone confirm that regular primer is porous?

ak

Lacquer primer is porous. That's old school primer. People still use it and they still sell it. I think epoxy has chromates in it that help prevent it from rusting as easy. Lacquer primer does not use a hardner like epoxy and 2K primer. Epoxy primer does not have high build like 2K primer does, it does have better adhesion.

I'm using epoxy made by starlite.The tech sheet does say not to apply over etch primer.I didn't realize metal prep would be similar to etch primer.I suppose I'll wait a couple days and sand the epoxy to see if it's holding.

Never used nor heard of that brand but good chance if the tech sheet says no to etch sheet then it will also follow through with metal prep.

The ONLY primer or sealer that wont be affected by the weather is epoxy. Urethane primer will soak up water.

Epoxy can have high build all depends on the brand.

I have pictures from start to finish. This site is not set up to let me post them or I don't know the trick to post the pictures. I can show you what it looks like using metal prep.

I have pictures from start to finish. This site is not set up to let me post them or I don't know the trick to post the pictures. I can show you what it looks like using metal prep.


I appreciate the offer but pics aren't needed.What's done is done.I know this primer takes about week to fully cure so I'll wait that long and see how it acts when sanded.

Does it look like there is a problem with the primer lifting? If there was going to be a problem I think it would have happened already. Epoxy can stay gummy for awhile when you sand it. I have done more than one car using the metal prep. Even if you wait 2 weeks before you sand epoxy, chances are it will gum up the sand paper unless you wet sand it. There are some brands of epoxy primer that some people claim can be sanded.

Why not call/email the manufactor instead of getting a bunch of what if's and could be's?

You dont need to see lifting to get paint problems.

I want to see the picture posted here.

Why not call/email the manufactor instead of getting a bunch of what if's and could be's?



Great idea I'll do that when I get a chance.Thanks

Ken,this primer once cured about a week sands nice does not gum the sandpaper at all.I've blocked some areas and the top surface will lighten leaving any low areas dark,it's like a built in guide coat.I'm doing the whole car this way,so I'll find all the areas that need attention.

Like I said the first time, don't worry about it. The problem with tech sheets is they are not doing the work. Some of them are written to cover their butts in case something happens. Pictures are worth a thousand words. Someone could come on here and say they did one thing and then find out it was nothing like was described. I'm not saying you did that. If you got a gun that did not put the paint on right, do you think the paint manufacturer would cover the cost of the paint? Some of the paint suppliers are paint salesman and nothing more.