Removing Automobile Paint

     I have stripped 100's of cars paint and rust over the years. I can tell you that you can do much more harm than good in a very short amount of time without proper blasting technique.  I have worked on projects for Randy Grubb  www.blastolene.com  - Randy Lackey www.randysrodsinc.com and Paul Hulst http://www.hulstcustoms.com/. There is a strict "0" tolerance level for improper blasting at these boys shops as you can see by their pictures. You had better know what you are doing as many of the parts being blasted are not replaceable.

I have shot most blast medias and found out that you can actually use a few different types and get quality results on automobile metal, but you have know what your doing with the nozzle or you will most likely warp the flat metal.

Have you ever heard the saying, "you can't use sand to blast a car, it warps metal". Let me inform you, that it is not the sand that should ever be blamed for the wavy metal, you might want to check the trigger-man's  skill level, because he or she is lacking.

It takes a long time to get the feel for how metal moves when blasting so remember, if your not experienced never try to blast the paint from any flat metal on the car, you will save yourself much grief. These areas are most commonly the roof, hood and trunk lid.  These flat areas of the car are always easily stripped with chemicals anyway. Stick to blasting any surfaces on the car that are not flat and you will be OK.

Use Gorilla Tape to mask anything on the car, it is the only tape that has the adhesion and mil thickness that is needed for this process. Duct tape is simply a joke. Always make sure that the surface is extremely clean prior to taping, as you need it to stick like never before. Dense cardboard can be used to cover the glass, just use Gorilla tape to bond it.   http://www.gorillaglue.com/tapes.aspx

When it's time to start blasting, turn the air pressure down to about 90 psi and have the nozzle angled at  60° to 70°. Stand back 3 to 4  feet and keep the nozzle in constant motion. If nothing is coming off or it is extremely slow going, move in slightly or try turning the pressure up 5 psi. You want to work at the lowest pressure possible and furthest distance from the metal for best results. Remember, keep that nozzle in constant motion, never let the metal get hot. Remove 1 layer of paint at a time and be especially gentle when remove the final coat, or in most cases the primer.

I have shot cars with the following blast medias, commonly using a 1/2 inch "wide entry" nozzle.

Starblast Ultra by Dupont, shot from 90psi to 125 psi. Starblast Ultra is 70 grit and works great on both paint and rust removal. Leaves nice profile and is not dusty, would highly recommend.  http://www2.dupont.com/Titanium_Technologies/en_US/products/starblast_ultra/index.html

Tri-Vitro crushed glass 70 grit shot from 90 psi to 125 psi. Both paint and rust blast away efficiently. Leaves nice profile and is not dusty, would highly recommend.  http://www.trivitro.com/vitrogrit/vitrogrit.html

Plastic Media approximately 60 grit (it varies) shot at about 35 psi. leaves no profile. Not good for rust removal, but removes paint very well.  http://www.ustechnology.com/aboutus.htm

60 grit silica sand actually works just fine. It is much more dusty than the above medias, but when nothing else is available, it will get the job done. Works good at rust removal. Shot from 90 psi to 125 psi, leaves nice profile in metal. 30 grit is way too coarse, do not use it on a car unless removing undercoat from the bottom. I would not shoot this product without being hooked up to a fresh air supply helmet, due to silica content. 

Soda Bicarbonate is nice that it does not harm the glass but can be tortuous slow. Shot at 125 psi (or as high as your compressor will allow), soda leaves no profile in metal. It would not be my choice of blast media for a car unless the car were made from aluminum. This blast media works great on aluminum (see picture of helicopter at bottom of home page).  http://www.armex.com/

Green Diamond nickel slag has great cutting characteristics but the 30/50 grit simply leaves too much profile for a car. This product works best on tanks and machinery.  http://www.greendiamondsand.com/

Walnut Shells 35/60 grit.  I would not choose this media unless my car was made out of wood. This product works great at removing paint from wood. Walnut shells leave no profile on metal and does not work very well at rust removal.  http://www.kramerindustriesonline.com/blasting-media/walnut-shells.htm