bash,
Be careful when using the media blaster. Keep the tip moving all the time. Don't try and clean all the way to bare metal by sitting in one spot. take it off in layers. There was a great thread here on BCF about media blasting. I'll try and find it and edit in a link for you.
Bash, can't find the link but here is the text of the post. Credit given to original poster. Not my work.
Only three months late coming into this thread, but I thought I'd throw in my few years (over twenty) experience at sandblasting..
I avoided the word "media blasting" because I have not used anything that would cut rust like sand does.. Word of note, one must use the finest sand available (I use #4 when I can get it, #3 the rest of the time.. It is available at professional builder supply stores --not Home Improvement stores)
I use two "types" of methods.. the first is a 100lb capasity pressure blaster (requires a minumum of a "real" Five HP Compressor (not a 5hp motor with three capasitors fitted to it). Plus, my compressor is a twin cylinder, Two Stage with an 80 gal tank and my pressure blaster will "work" that compressor.. but the compresor "stays ahead" of it.. That's the key to getting finished with your car and parts.
I blast the "hard parts" (frame, suspension parts, etc.) with the fresh, sharp sand.. as the sand wears into a finer grit, I start blasting the sheet-metal. I use 60lbs psi max input to the pressure blaster and ALWAYS use a "low angle" and NEVER hold the nozzle on one spot or area more that a few seconds as this is what causes panel warp! I "wave" the nozzle back and forth, allowing it to remove one layer of paint at a pass.. for stubborn paints or rust, keep "waving", eventually it will come off. Don't "rush" the job as that WILL warp a panel.
As that sand continues to be beaten down finer, I then move to the nuts, bolts, washers (yeah, I sandblast those as well! Especially the hard to get Whitworth) interior trim and garnish mouldings.. The sand is almost a powder by this time, it is a very dusty environment. but the powder produces a satin-like finish on the pieces, enough to give "tooth" for the paint to stick, but no scratches or pits are produced.
In order to "preserve" the sand for multiple uses, I simply bought some rolls (20'x100') of clear plastic sheeting and cordoned off a corner on my shop. I used 1x2's to tack the plastic to the ceiling and the two corner walls. The "open" area is attached at the ceiling.. Try to use one continous sheet for the perimeter walls then weight down the sheeting at the floor.. I found that "to be blasted" parts work rather well.. This way, the sand can be scooped up, strained, and reused about 3-4 times. Overlap the "opening" by at least ten feet. This helps reduce the dust "seeping" out into your garage or shop.. It isn't 100% effective, but better than nothing.
While some "dust" does escape, it is minimal (don't be doing any painting while sandblasting!!)
I usually buy ten 100lb sacks of sand at a time.. When doing the "hard parts" I only use "new" sand.. I scoop it up and place it into a 55 gal steel barrel that has a removable top. This allows me to then use the "beaten down" sand during the "next phase" of blasting.
It also goes without saying that proper protection be worn at all times, hood, resperator, rubber gloves and I order the full Tyvek suits, If I'm careful about taking the suits off, I can reuse them about a half-dozen times, at least... they help keep your clothes cleaner and the wife happier.. Sand isn't good for washing machines, either.
On the Cabinet Blaster, all come with a suction feed type blasting gun.. It's totally useless as it takes forever.. I simply cut a hole in the side of my cheepie plastic cabinet (bought new for less than $100 at Harbor Freight) and, after removing the nozzle and on/off valve from the end of the blast hose, I fed the hose from my pressure blaster into the cabinet, then replaced the nozzle and valve.
I also use my H-D Shop Vac.. it's about 80% effective except when using the "powder" sand.. then it's about 30% and requires more frequent cleanings of the filter.
Speaking of which, the most important thing about using your shop vac on your blast cabinet is to get a couple of (not cheap) optional paper filters that go over the vac's suction intake to the motor.. Failing to do this WILL result in sand eating your motor in short order. Plus, the paper filter MUST be cleaned frequently, least it clog up, losing it's suction, resulting in a contained dust cloud in the blast cabinet.
The replacable PVC (PCV?) "covers" that tape to the inside of the viewing window are a MUST as well. I don't trust the double-sided tape that comes with some covers, I add a strip of masking tape, overlapping at the corners, completely around the permiter of the "cover".. failing to do this will allow sand and dust between cover and window, resulting in poor visibility and additional scratches on the window... the pressure blaster will frost a "cover" in no time.. cheaper than replacing the viewing window.. not by much, but easier.
A resperator is a MUST even while using the blast cabinet as they aren't as "tight" as they are suppose to be.. and Silicosis is a permanent death..
Something you all should know, but, like me, probably forget.. Once your part is sandblaster, NEVER touch it with your sweaty, greasy hands, unless you like rust growing out from under your fresh paint. Go to your local pharmacy and buy a box of "Exam Gloves".. these aren't Latex.. Plus, get the "Unpowdered" type.. A little harder to put on your sweaty hands,but less residue to remove from your, now, "in-the-white" metal.. Blow off the parts with double filtered air (I rigged up a "clear type in-line" paint gun filter to a "Quick Disconnect".. works great..just keep an eye on the dessicant, once it turns color, dispose and replace). After the dust is blown off, wipe down the part with a product like PPG's "Cleaner/degreaser". I've tried the Eastwood "Pre-Prep" stuff with mixed results.. go with what works and doesn't cause you extra work.
Tack-off the part just prior to priming.. which needs to be done within 24 hours of sandblasting. Now, having said that, I have left parts "raw" for up to four months (in north central Texas) in the enclosed sand-blast area.. the sand acts as a dessicant and helps holds the humidity down.. The plastic walled enclosure helps keep the moist air out. Each regional area will vary.. best to prime the part quickly.
Sorry to be so windy, but, to be done correctly, one must look at sandblasting as an art like body-work, painting and quality mechanical repairs... all require careful attention to the details to "get it right"..
I hope this is a help and a benefit to those so interested.