Rust preventive coating: remove or touch-up
12-07-2008, 04:04 PM
#1
Skippy
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Rust preventive coating: remove or touch-up
First of all I have no idea if these cars, an 86 in my case, came with factory underbody anti-corrosion coating or if mine was done after purchase.
Fact is that the coating is dissappearing in some areas (rear wheel well). Question is now, do I remove everything or do i just pressure wash (?) and apply some new coating ? What is the golden standard for this ?
Fact is that the coating is dissappearing in some areas (rear wheel well). Question is now, do I remove everything or do i just pressure wash (?) and apply some new coating ? What is the golden standard for this ?
12-07-2008, 06:42 PM
#2
Drifting
Do you have pictures of this? The undercoating is quite thick, I think maybe it is just one of the multiple layers coming off or, as you put it, it is someone else's coating that is coming off.
Personally, I would just wash and then coat it with gravel guard or something. I would not try to remove the factory undercoating.
Maybe others with more experience can provide a more informed opinion.
-matt
Personally, I would just wash and then coat it with gravel guard or something. I would not try to remove the factory undercoating.
Maybe others with more experience can provide a more informed opinion.
-matt
12-07-2008, 09:42 PM
#3
1st Gear
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Kris,
Most of my experience with undercoating is from 356 ownership. An 86 911 should be much less prone to rusting and should not require the extreme measures taken to protect a 356 in a case like this.
My only concern would be if cracks and bubbles were developing in the coating that would actually allow moisture to be trapped between the coating and the metal bodywork. In that case you would probably want to remove the bad section of undercoating, clean that section and reapply a high quality coating.
Is it possible that someone applied an aftermarket coating over the factory rustproofing at some point, and that is now coming off?
Don
Most of my experience with undercoating is from 356 ownership. An 86 911 should be much less prone to rusting and should not require the extreme measures taken to protect a 356 in a case like this.
My only concern would be if cracks and bubbles were developing in the coating that would actually allow moisture to be trapped between the coating and the metal bodywork. In that case you would probably want to remove the bad section of undercoating, clean that section and reapply a high quality coating.
Is it possible that someone applied an aftermarket coating over the factory rustproofing at some point, and that is now coming off?
Don
12-08-2008, 03:59 AM
#4
Skippy
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Tx guys, I'll give it a good inspection after having cleaned the dirt. I'll just leave in place whatever is still holding-on well.
12-10-2008, 05:28 AM
#5
Burning Brakes
It is possible to obtain the same material and patch. Important to remove ALL material that is not bonding to the metal. Patching is part science and part art - a good Porsche restorer (not an official bodyshop) would be my suggestion. Had my '76 floor 'refinished' - guy steam cleaned floorpan, removed all the loose stuff, feathered back the edges, treated metal to ensure no rust was left underneath, patched and then skimmed whole floor. Looks so good I wish I could drive it upsidedown!
PJC
PJC
12-10-2008, 05:53 PM
#6
pressure wash - shooting from different directions to remove loose material - and apply some new coating
3M and Eastwood have it in spray cans - no idea which is best
or use Wurth if real ****
checking and cleaning grit, crud etc. from the underbody should be done every year
remove tail light housings and clean this poorly engineered grit trap too
too many people are waxing & re-wqaxing "their baby" and not doing the important stuff
3M and Eastwood have it in spray cans - no idea which is best
or use Wurth if real ****
checking and cleaning grit, crud etc. from the underbody should be done every year
remove tail light housings and clean this poorly engineered grit trap too
too many people are waxing & re-wqaxing "their baby" and not doing the important stuff
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12-10-2008, 06:06 PM
#8
Skippy
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Thread Starter
pressure wash - shooting from different directions to remove loose material - and apply some new coating
3M and Eastwood have it in spray cans - no idea which is best
or use Wurth if real ****
checking and cleaning grit, crud etc. from the underbody should be done every year
remove tail light housings and clean this poorly engineered grit trap too
too many people are waxing & re-wqaxing "their baby" and not doing the important stuff
3M and Eastwood have it in spray cans - no idea which is best
or use Wurth if real ****
checking and cleaning grit, crud etc. from the underbody should be done every year
remove tail light housings and clean this poorly engineered grit trap too
too many people are waxing & re-wqaxing "their baby" and not doing the important stuff