Thread: Media blasting question

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I have never media blasted any parts or a vehicle before so I have a question. The guy who is going to be media blasting my 1930 Brookville roadster to remove Brookville's lovely red oxide primer says he uses crushed glass. He strictly uses crushed glass on car bodies because supposedly the crushed glass has less friction which curbs warping issues & leaves a painter friendly finish. So I'm trying to get an idea if this is the right or wrong type of media to use? Thanks

I had my truck done with crushed walnut shells which is the other choice,both of those media glass or walnuts are a good choice.Media blasting is a lot more common now and a lot less abrasive than sand blasting.

Brookville must only use that primer on certain stuff. The Model A bed we got and the deuce grille shell are bare metal. Maybe just the bodies get it?

I've heard of glass media blasting but have never heard one way or the other how well it works. I do know that most media (plastic, walnut shells, etc) will remove paint but not rust. Sand is the only one I know of to do that. But since you don't have any rust you should be ok, as long as he is a reputable blaster.

Don

Best advice is to have it done by someone that specializes in car bodies. I'm sure they all use different media mixes depending on the car and what needs to be removed.

One place in So. Cal. that is highly regarded and in the business for many years is Orange County Sandblasting in Orange.

I was just wondering why you want to have the primer removed?
Ken

Ken I purchased this 1930 Brookville roadster from a man who bought it in 2002, stored it in his garage on a rolling chassis, never drilled one hole in it or did anything with the build. He found a very rare 3 window Plymouth & decided to build it first. Anyway having no idea if moisture got a toe hold under that red oxide primer (porous & can draw moisture allowing rust to hide under there) of Brookville I thought it would be wise (better to be safe than sorry) to media blast the roadster first. I didn't want to put a high end paint job with custom air brushing over the oxide only later to have rust issues. IC2 has a 1931 Brookville and he removed his red oxide only to find many quality control issues and I want my body work to be done right & my paint to last awhile with no hidden surprises!

acrylic will remove paint. i use dupont starblast to remove rust and leave an anchor pattern. warpage is caused by peening the metal , not heat. any media hard enough to leave an anchor pattern will warp. even the starblast will if your not carefull.

Thanks, I understand why now. I have never had a Brookville body, and wasn't aware of those potential problems.
Ken

Never use sand!!!!!
There are different grades of most medias from fine to coarse.
Make sure who ever does this is experience with bodies. You can easily RUIN a good thing.
Make sure you have your paint ready or what ever you are going to use to protect the metal after blasting. You need to protect it as soon as its done. Like even the same day would be ideal.

Try a search their was a couple good threads.

SANDblasting can warp sheetmetal on some cars, however those built 50 years ago and longer have stout enough metal that sand should not warp it.

i have warped 12 gauge with sand at low pressure with a single pass just to prove how easy it is to a friend. never use sand as there are much better products without the health hazards.

Since I've seen my name in print above, this is some of what I found on my '31.

The primer is a cheap Western Paints acryllic primer. On my car I found it to be in excess of 1/32" thick in places, covering a mulltitude of dings, dents and poorly formed areas. Since it is almost impossible to "get behind" the door and trunk panels without potentially doing more damage, Rage Gold, Icing and poly primer worked their miracles. Additionally, when I contacted Brookville, they stated that the primer should be totally stripped.

Note to Don, Brookville '32 grille shells are supplied without primer - but they have enough other quality problems without the primer

Shown - trunk lid, top of rear quarter and dash with a pile of swept up primer on my bench from ONLY the dash.

Note - most of this was done by hand with 60/80 and some 'intervention' with my DA and a lot of 100 grit

i would hand sand the body down by hand and a D.A sander at low speed with alot of fresh paper on it if have seen were a D.A can screw things up to in the wrong hands start with 80 grit and work up to 120 sand out the low spots with 80 grit you do not want to have loss of hook up on the new paint and you would not want to put any filler over air dry acrylic primer . with all the money you spent on that body i would be very worried that it would come back a lot more screwed up hard to warp it all up by hand sanding

Originally Posted by pat mccarthy

i would hand sand the body down by hand and a D.A sander at low speed with alot of fresh paper on it if have seen were a D.A can screw things up to in the wrong hands start with 80 grit and work up to 120 sand out the low spots with 80 grit you do not want to have loss of hook up on the new paint and you would not want to put any filler over air dry acrylic primer . with all the money you spent on that body i would be very worried that it would come back a lot more screwed up hard to warp it all up by hand sanding

AS a note to Pat's post - the Brookville bodies are built from an extremely soft draw quailty steel to save their dies from excessive wear - which are made from an engineering plastic. About the only places that I found the DA useable was the slab sided rear quarters. When I hand sanded the doors and trunk lid, I used my 10 and 17 inch flat boards, other area, I used whatever worked. Most of the rest of the body has too many raised details to risk damaging with an out of control DA. The only way to fully and sucessfully clean off the primer is to totally disassemble the car to its lowest common denominator in bits and pieces - I even took the door hinges apart. I did NOT remove the Brookville primer on the inside of the doors, the trunk lid nor any other areas that are covered and upholstered.

Since we've gotten around to do it yourself with abrasives here's an alternative product for removing the primer around the body lines:http://www.redhillsupply.com/MMM7526.htm

I like this one as it doesn't build up a lot of heat, it gets in the "corners", and you don't run the risk of gouging the metal as might happen with a hamburger wheel or abrasive disc. I did about a 4 sq. inch area where the reveals meet just behind the B pillar in about 1 minute but can't find the pic.