[outoftouch]

I am chem stripping some fenders and after I get them cleaned up I want to prime with something temporarily....... while I do some body work.

My question is I am not sure what primer to use because I am not sure who will be painting the car..... is there a generic primer that I can use that can be applied over when the body/paint guys goes to do his thing ?

Obviously, it would be wise for me to have the painters primer of choice but I am so far away from that stage that I just want to get at the metal work...?

[Countilaw]

After you strip, clean with a good detergent and water. Blow dry and get all the water off.

Apply a good coat of Epoxy Primer (on both sides of the metal, if possible). As soon as it cures, which should take about 45 minutes, shoot everything a with 2 or 3 coats of good 2K primer.

You can get good products from either Smartshopper.com or SPI.com.

If you need it really fast like the next day, you can get good products from your local paint supplier. But expect to pay more for it there.

With the 2K primer, it doesn't matter you paints the car. Any paint will go on it.

Frank Cox
Cox Custom Cars

[outoftouch]

Count,

If my fenders are carrying 45 year old undercoating would you scrape off what you could and re apply, its rock hard........or strip the old off and hit with epoxy then hit with undercoat ?

What normally is the procedure ?

This will not be a show car because of $$ but will be doing my best to make it the best car that I can..

thanks

[TucsonJay]

Two rules to remember:

If you use a chemical stripper, scrub it with soap and water using a stiff brush or scotchbrite. This neutralizes the chemical stripper residue. Not doing this can cause blistering later.

Whenever you go to bare metal....ALWAYS use either metal prep....or self etch primer.

Metal can start rusting at a microscopic level, even if you can't see it. Even the moisture in the air can be enough to get it started. Why take a chance? Metalprep is really cheap, and takes very little time. Would you rather pay to strip off your entire new paint job and start over?

I don't always recommend epoxy primer, but it is watertight, so it will protect it from moisture long-term.

[jeremyb]

Do a search on metal prep on this site and see where that gets you. First of all, you don't need to be touching any sort of metal prep. Once it is clean and you have neutralized the chem strip (as stated above), sand with 80 grit or 180 grit and go straight to a good quality epoxy primer. I'm sorry but any sort of self etching primer or metal prep on a body is the way of the past. Doesn't matter whether you are doing a $100k show car or a regular daily driver, epoxy is your best and safest bet.

[Rag top bird]

I blast everything but hoods and I chemical strip them after stripping I scuff with a red scotch brite using metal prep mixed with water then sand with 180 grit after that I prime with epoxy primer then you can do your body work at any time

[outoftouch]

Why is a metal prep needed ? Does a good epoxy not just stick to the sanded metal good enough ? What benefit does metal prep have ? It seems like another step but if it is necessary....... Ahhhhh confusing.......

One uses it one does not......ahhhhhh...

[TucsonJay]

If it is freshly, and thoroughly sanded.... (I would not wait overnight, but it also would depend on humidity) .....you will probably get away with it.... unless you have pitting or seams that the rust can hide in.

Metal prep contains phosphoric acid. What metal prep does is to change rust, or "iron oxide", into "iron phosphate". The difference is that, once it starts, rust is an ongoing process. Iron phosphate is dead, and just lays there forever, never getting worse.

I use R-M 801, which has alcohol in it and does not require rinsing. I mix it with water, per the instructions, in a spray bottle.

Here is how hard it is to use...



spray an area on the surface, letting it stay wet for a couple minutes.

wipe it dry.

If there is too much residue, spray it and then wipe it off immediately.

wait 30 minutes and start painting.



How hard was that? You now have "insurance" that any rusting that might have started...even so small you can't see it....is gone!

I take these steps because I hate fixing my work a few years later, and I also guarantee my jobs against abnormal failure for as long as you own it. BTW, I sleep very well at night by using this approach.

Over the years I have done hundreds of custom paint jobs, and never had one job have rust reoccur.... unless it was underlying work done by someone else.

The self etching primers do the same thing.....if you want to spend a couple hundred dollars more.

Use one or the other, but not both, as that can create problems.

[shine]

if using spi no metal prep is needed or recommended. just sand with 80 grit and your good. slight surface rust is nothing to be alarmed by. epoxy will seal it . i wash cars after blasting with soap and water blow dry and epoxy.

[Hwyhogg]

Shine, once down to bare metal, hit the bare with 80 grit?

[TucsonJay]

Shine, You are right. The SPI epoxy will stop "flash rust", but no heavy stuff.

I doubt this is true of all epoxies.... but I haven't tried 'em all yet. :-)

[shine]

yep 80 grit.
spi is the best epoxy i have found. where ppg/dupont fail it performs great. it is the only thing i put on the early vettes i do.

[Hwyhogg]

SHINE,
I was reading an older thread and I came across some good advice you offered. It was simple, obvious and seemingly overlooked by many of us. The advice was simply to follow the products' manufacturer's instructions to the letter. It became apparent to me that of course the maker of a product wants,(needs), it to work well, so their advice will be the best....FOR THEIR product. Even if they do recommend another product that they sell to enhance another one, it will take away the ability to blame a product used outside of their recommendations. Then if enough people actually have unsatisfactory results after following the exact steps, we can look at calling it an inferior product. Thanks for stating so simply what I was beginning to forget. Product recommendations from us users should still lead back to talking to the company MAKING it.....Thanks again to this forum... we can learn how to learn if we listen.

[Rag top bird]

Originally Posted by outoftouch

Why is a metal prep needed ? Does a good epoxy not just stick to the sanded metal good enough ? What benefit does metal prep have ? It seems like another step but if it is necessary....... Ahhhhh confusing.......

One uses it one does not......ahhhhhh...

I know when you clean a panel with metal prep you can see the difference between that panel and the others that has not been cleaned I just dont trust priming over rust

[shine]

when i came to this site in 04 there were many professional painters here offering a wealth of knowledge and help. i have watched them leave one by one after tiring of arguments with unprofessional wanab's and a few of the moderators that were here. when you do this day in day out for a living you learn what works and what doesn't . posers who have only done a few cars , hack work or none at all think arguing with other professionals makes them something they are not or will never be. there is absolutely nothing wrong with doing your own on a budget. but cutting corners or taking unnecessary risk is just foolish. follow tech sheets to the letter. don't think for a moment you are smarter than the chemist who makes the product. every paint mfg has a tech line to call. i always suggest getting your tech advice from them , not some google warrior on the internet. verify claims before taking advice. before i agree to take a car the customer must call the references i supply. if he does not then i pass on the job. i do not work with fools.

the first thing i learned in business marketing is " it doesn't have to work. it just has to sell " sadly many of the snake oils sold today are just that.