Shot blasting

[prodrivewales]

Hi everybody,
We've just opened a new car bodyshop and I know want to include shot blasting on the premises, partly to help my preppers get parts ready for the sprayers and partly as another bolt on to the business. I came across a topic on the subject on this site and thought it may be worth using as part of my research. I am particularly keen to understand the relevant media to use in relation to the material being blasted. Any advice would be gratefully received.

[tresi]

As far shot blasting on body work expect the results to be much like taking a 12 ga shotgun to the car at about 25 with a load of #8 birdshot. You might want to take a look at soda blasting ,as in baking soda. Plastic media blasting is another option.

[papabear]

What tresi said, and also consider the fact that blasting done by an inexperienced individual that doesn't know the effects, or at too high of a pressure, can cause stretching of the surface being blasted, especially on thin stuff like body panels. No one likes to feel obligated to "wave back" to a passing car. In the right hands though, it could definitely be a valuable tool to have in your arsenal.

[stockcar92]

yea the soda blasting isnt really cost effective. once the soda is shot it cant be recaimed and used again. The term shot blasting is really not the term you want to use in the cleaning of automtive body parts. if you were to use shot to blast clean sheetmetal you would end up with some really nice scrap metal. shot blasting is a process that uses steel balls much like what is in a shotgun shell. in the right application it does clean real well but is used more as a case hardening process. anyhow i think the beter term would be media blasting and i think but im not sure the last time i checked the auto guys were using a crushed plastic blasting media for the process you are talking about.

Also a really usefull tool for this would be the car rotiserie.

[tresi]

Even blasting with a medium grit sand will warp body panels.

[haroldmulder]

When I was involved with a Spitfire aircraft restoration project we used what was called Glass beading for cleaning up the old metal. It worked great on the aluminium and did not damage it. Here is a link to a company http://www.tptools.com/p/349,183_Gla...-Abrasive.html

[papabear]

Glass beading is about the same as sand blasting. The media has a "life limit" and as already said, can warp, distort, stretch the surface. Glass does leave a nice "polished" looking finish though (especially on aluminum).

[prodrivewales]

Thanks for this guys, I'm probably looking more at chassis/axle/towbar/alloy and steel wheels more than body panels though as we're not into restoration on vehicles although I do have a good market for agricultural in this area. I hear that aluminium fragments are good for the heavier stuff and have a longer life

[stockcar92]

If what your trying to clean is the hevier components then sand is the way to go. I like to use the silica sand as it works the best in my opinion. Im not worried about the silica dust as i have the space suit helmet when i blast. I would not recomend blasting without one no matter what media you use. anyhow they will not sell you silica sand anymore if they know your blasting with it. I get mine at a pottery supplier of all places. i never tell them what im doing with it. if you dont get the silica sand then there gona sell you what they call black beuty. it is ground up coal dust and in my opinion dosent cut worth a darn as it is kind of cubish and has large dull flat sides rather than triangular and nice sharp corners like the silica sand. anyhow your gona need one hell of an aircompressor lol.

[Ian-MetalSmith]

Check out Eastwood.com and look for media under abrasive blasting or just do an internat search for blasting media. All kinds of stuff is used. At work we have a plastic media cabinet for removing paint from aluminum parts and a separate cabinet with course glass for rust and anything else. We are strick on only putting aluminum parts in the plastic cabinet and they need to be clean first also.

Like someone else pointed out, blasting with glass beads or sand can set loose free silica that will get in your lungs and cause silicosis.

Like stockcar said, you need a big compressor. take what you will think you need and double it.

[stockcar92]

Yea the air compressor i use has a four cylinder caterpillar engine. it has a 5 and 3/4 inch bore with an 8 inch stroke. that 5.75 X 5.75 X .7854 = 25.96 25.96 X 8 = 207.73
207.73 X 4 = 830 cubic inch displacement engine. it has a gardener denver 6 cylinder compressor. the engine has 500 rpm max and will hold 80 psi at quarter throttle on a full open hose.