RUST & PAINT...how much rust do you have to remove??

[911 tweaks]

I am about to start the prep work on a 73' that will be repainted its original color...#80 Silver the coa says...
Anyway, as you can see from the attached picture, the tub has different degrees of surface and sub surface rust. According to the body guy, he will not warranty any of the work unless he takes ALL of the metal down to shinny silver metal.

My question to those who really know this area of car work, do we have to sand down that far OR can we use some type of a high build primer that will smooth out these areas & seal them from oxygen which I am told will prevent any further progression of rust. As you can imagine, if I don't stop the progression of rust, 1-3 yrs down the road I will have paint bubbles and a mess on my hands!!!

Please be specific and honest with what has worked for you as this is a $10k question I seek experienced help with. I am doing my best here to prevent a body job night mare which would waste $10k of my money and really piss me off...

Thanks for your help and experiences here!!
Bob

[Jim75911S]

I took mine down to bare metal, removed all the rust, replaced any bad metal, the whole front clip in my case, expoxy primer before even thinking about paint.

[Ernesto 911]

911 Tweeks...

Assume you are now in bare metal respray territory.
Review Freddie's invaluable "101" link...

I'm dealing with surface rust similar to yours on my project.
The body is in the preservation/reconstruction stage.
Some areas have pits that will require high build surfacer to level after the epoxy primer.

I start by sandblasting a panel with a pressure pot sandblaster,
hitting any badly pitted areas several times as to get as much of the micro rust out as possible,
while taking my time working in stages as to not warp the metal.
After cleaning up the medium mess, I etch the surface with metal cleaner and follow with metal conditioner.
If the pitted metal is especially bad...Or in an area that will be hidden (like underneath the windshield seal)
I use a metal encapsulant like "Chassis Saver" or POR15 to treat the raw steel.
Once dry, I follow up with the best epoxy primer I can get...Some have added corrosion inhibitors.
Repeat the process on the next panel/area.
Any defects in the suface will be handled in the bodywork stage.

Best Regards,
-Ernie

[911 tweaks]

thanks guys... So I guess I really do need to take it down to bare shinny silver metal and get every little spec of rust off... man that is going to be a TON of time & $$ won't it ??

How do I find freddies 101 link... maybe I will search by his name... I usually strike out when searching but will have a look...

Any other tips you can share or "to do's" and any "NOT TO DO's" ??

Thanks again!
Bob

[Classic]

Here you go Bob,

http://forums.pelicanparts.com/paint-bodywork-discussion-forum/381243-links-freddie-hernandez-101-series.html

I've had great success with Picklex Picklex-20 Click Here for Options: Autobody Store

Kills any micro rust, and leaves a nice coating on the metal. I live within 300M of the ocean, and i've found that metal treated with Picklex stays nice and shinny for about 3 months.

I'm a little bit slow, as work keeps on dragging me away for the car, and i find that some times it will be a week before i can get it finished with epoxy primer.

I'm not saying that this is some sort of magic potion that will make your rust go away, you'll still need to blast it, but i will give you time and extra insurance for any micro rust that may have been missed.

I friend also went this route when he had his car soda blasted, as you need to flush the panel with water, as the soda process can leave a residue on the panel which can effect the adhesion of the primer.

Hope that helps

Tony

[shabac]

You sand off what you can and they make some stuff that you brush or spray on the rust that changes it chemically. rustoleum and purple power both have one any parts store I have used it and if the rest of the prep is fine it lasts a long time. also to get rid of the bumbs you have to use frosting its really thin set bondo to smooth out the panels.

[962porsche]

if that car came to my shop the only way i would repair it is take the rest of it apart and send it out to have it blasted .

[Augustus]

Originally Posted by 962porsche

if that car came to my shop the only way i would repair it is take the rest of it apart and send it out to have it blasted .

...or dipped....

[962porsche]

ya or dipped . the only down side to dipping is cost but one big plus is dipping will get into the seams that sand blasting will not .