Sandblasting 1971 Porsche 911 T

[Rawbert]

I am restoring a 1971 - 911T in Jamaica. I am contemplating using a local shop to Sandblast the body for paint stripping. I have encountered some articles that caution agains this. Can any one share their experience or any advise on the subject. Would be appreciated.

[charwood77]

you should check in the paint and body section of this forum. I will soon be embarking on this journey and have learned that sand blasting is not the ideal method for paint removal. Most suggest using aircraft stripper paint remover. Apply liberally and even cover it with plastic to allow it to really set in. after about 30 mins you can use a scraper and then a dual action sander to get what remains.

I think sand blasting can leave pitts that will have to be smoothed with filler... it can also cause excess heat which can warp the metal.

[ossiblue]

Sand blasting is definitely not the method to use on sheet metal unless the blaster is a master. As mentioned, warping due to excessive heat produced by the sand is a real problem. In addition, sand will be everywhere within the body cavities unless every hole/entry point is properly sealed.

Using a media other than sand, however, often produces excellent results without the danger of heat warping. Walnut shells and soda come to mind, for example. Given your situation and the impression that the shop you will use is not expert on auto bodies/sheet metal, I'd be looking for a different method or, at least, a media other than sand.

[HawgRyder]

Remember...as soon as the blasting is done...maybe even parts of the car at a time...PRIMER IT!!
I have seen too many cars that got properly blasted or stripped...and then left overnight before being primered.
My 69S was done this way before I got it...the miosture got to it...and it had tiny little rust spots all over the car...the PO just re-primered and then painted.
If I had not discovered the spots when stripping the car for new paint...I would have lost the car to rust.
Bob

[Algernon]

+1 on that, ossiblue! Walnut shells, soda or better still, dry ice for minimum damage. They may even be able to stop before removing the original passivated surface. I understand going right back to bare metal is not necessary or desirable. My $0.02

[Rawbert]

I appreciate all the responses. Very prompt and the guidance has been very useful. I now have a clear path for proceeding. Thanks again for taking the effort.

[911pcars]

Originally Posted by Algernon

+1 on that, ossiblue! Walnut shells, soda or better still, dry ice for minimum damage. They may even be able to stop before removing the original passivated surface. I understand going right back to bare metal is not necessary or desirable. My $0.02

911s didn't use galvanized body metal until 1976. Taken these years ('76-on) into account, preserving that protective layer is important. However, on earlier cars, it's preferable to remove as much as possible to avoid having excess paint. A good painter should advise you.

If possible, the thinnest coating thickness is preferable for longevity. Multiple layers that increase the coating thickness tend to crack and not last as long, so say some refinishing experts (Meguiars and paint manufacturers).

This is a good time to provide this link on a presentation about everything you want to know and more about automotive paint coatings
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=38&ved=0CFgQFjAHOB4&url=http%3A%2F%2Fprojects.nfstc.org%2Ftrace%2Fdocs %2Ffinal%2FThur_1000AM%2Fbrun_conti.pps&ei=4vMwUtT1NMOniQKpmICQCw&usg=AFQjCNEQYwlXfsKT5iY1G_gOpR3pPQ_Dpw&sig2=O_HMLHeL20uFvQiQ_wQB9A&bvm=bv.52109249,d.cGE

Sherwood