tm9-801.com

Since I am yet again taking paint and rust off metal I thought I would give some pointers:

The obvious: DON'T SKIMP ON A COMPRESSOR OR THE PLUMBING!!!! Google how they rate compressors... basically whatever the manufacturer tells you is not the right number. My pump is 15CFM@90PSI 5HP 220V 2 Stage 3 lungs, 60gal receiver, 3/4in black iron header all around the garage. The main regulator is only 3/8ths... but even this is not enough to keep up with the pressure pot.

Put a moisture separator at the sandblaster. Filters generally don't impede CFM.. so use two (one at the pump and one at the pot) to get rid of moisture that will condense in the lines.

You can 'cheat' the CFM if you use a smaller nozzle orifice... but getting media that fine can be an issue. Generally if your nozzle has worn to 2 or 3 16ths most garage compressors will not keep up with it. Keep the nozzle small and you will get more hood time. BUT you will have to use finer media, and also screen it more carefully so it does not clog.

Cabinets: BIGGER IS BETTER! Mine will EASILY fit a side panel and even a combat rim off a jeep.




That's an engine side panel off my Chevy. LOTS OF ROOM!

Last big tip: You really need a vacuum source to keep the dust down, and I also wear a paint filter to keep the dust out of me. I can use my cabinet for about 10 seconds without a vacuum due to the dust.... turn on the vacuum and I can go till the pot is empty. Even a small vacuum/shop vac will do.

Since I just got done with about 2 hours of media blasting goodness here's whats hot off the top of my head:

Clean the parts. Grease/oil will clump media and can smear over metal.. if not thoroughly cleaned off it will cause paint issues.

Tape off machined areas for seals or flanges used in assembly. Otherwise the seal may not hold back the fluid and you'll have to live with drips or try sealant. There is a product called 'Gorilla Tape' that is very thick and very sticky... it can take repeated accidental blasts and still protect. Its expense, but great stuff.

On one of the panels I just did the primer was so thick I was having to really bear down on it... instead of trying to blast if off, I took it out, put some paint stripper on it and it bubbled right off. Use the right tool for the job. Sure, I could have worked it with the media... but that means running the compressor and shooting media that I would have to screen/refill. Paint stripper took 2 minutes and I was back at the booth with it.

Use the right tool!!!! I was about to blast a crankcase ventilation housing but once I looked at it I saw that the cap, chain, and baffles, seal surfaces were all 'in the line of fire'. So I simply cleaned it first... and found out that the original finish is 90% in tact. I put it in molasses to eat the tiny bit of rust that was on the part. This will save the original finish and seal surfaces. Plus its less hood time.

After you blast, you have to clean the part to get the fine dust out of the metal. USE HOT WATER. I have not had a blasted part flash rust using hot water as you can see the water evaporate right off the panel. No you have a paint/oil/grease/dust free surface to paint... and primer just loves that kind of stuff.

Given the choice of siphon, pressure, or soda go for the pressure blaster.

Pressure pots give you the most pressure.. so even though the pot holds a finite amount of media, you get a LOT more done that with a siphon setup. The only caveat is that if you have the compressor (20+ ACTUAL CFM at 90psi.. not just stamped on the pump) you will get farther with a siphon setup. But most garage compressors are not rated anywhere near 20CFM.

Tyvek 'painters coveralls' are great to keep you clean if you blast outside. Wear 2-3 layers of clothes because you WILL SWEAT. Cotton will keep you comfy a little longer.. but at some point you are going to start filling up the booties with sweat.

Blaster gloves: HANDS DOWN BEST VALUE: Harbor Freight blaster gloves. PERIOD. Item#4468 $6.99

Blaster hoods are worth the $20-30. Media WILL find its way past any goggles/respirator unless you have an all encompassing hood. Throw away visor shields are also HIGHLY recommended.

When blasting, play with the distance, angle and rate or the media stream. Simply angling the stream a little can increase your cleaning rate.

When you sift the media for reuse, pick a proper mesh size... to fine and you waste time filtering items that won't cause an issue. To large and you clog the tip. Remember as you use the tip (unless you spend the $$$$ for carbide nozzles) the orifice will wear and get larger.... you can use that to increase the rate of sifting by using lower mesh count.

To clarify some of my tips:

Screening media is what you do to the grit to remove the large chunks of rust/paint chips/crud that can clog your nozzle. I use screen door mesh. Its cheap and you get a lot for like $5 at any hardware store plus there are many different 'mesh sizes'. Generally if the mesh is 'insect proof' or 'shade' type its going to be more than fine enough for 40/80 grit media. Don't get aluminum/stainless mesh.. get the plastic stuff. If you look at the screen the holes are the 'mesh' that allows the smaller bits through and keep the large bits out of the bucket. I cut a 2'x2' square and use either a 3 or 5 gallon bucket. Using a bungee cord around the top (buckets generally have a few ridges molded around the top) to hold the mesh over the top of the bucket, I also let it sag 1-2 inches so the media 'pools' and I can load up a lot. Once the media is on the mesh I simply shake the bucket back and forth to agitate the media and it drops down into the bucket. Placing a piece of wood under one corner makes shaking the bucket much easier. Unless i am outside I also rum my shop vac to suck up the dust it makes. Once all the media is screened, I vacuum off the chunks left behind, scoop on more 'dirty media an repeat' I can refill a 50lb pressure pot in less than 10 minutes with this method. Depending on how I set the air and media valves, this will last 10-20 minutes of blast time.

Unless you know you have rust, paint stripper to remove paint (only) is MUCH FASTER than media blasting. Use paint stripper from an auto paint store or a QUALITY auto store like NAPA. Autozone and Advance sell garbage with respect to paint supplies. Get some very cheap paint brushes as they are generally only useable once and follow the directions. Paint will bubble an lift off. You can also use heat on *SOME TYPES* of paint. Generally if the substrate is wood, you can heat the paint up and take it off and not have to use stripper. I use MAPP gas, but propane will work. Note: acetylene is WAY TO HOT

The best all around media is aluminum oxide. It will remove paint and rust but does not leave as significant a texture to the metal. If you don't have rust pits this is generally the best option as it won't tear up the metal significantly. If CAN erase stamped markings if you bear down on them. It also 'lasts' a long time before the media loses its abrasiveness and becomes more dust than media. AlOx is also the finest media. Its easily smaller than 80 mesh. This is critical if you have a small compressor and have to use a very small nozzle. This will allow small compressors to do some blasting work.

Garnet/coal slag/black beauty is more for rust than paint. It will remove paint, rust and skin, and leave a significant texture to the metal. This is EXCELLENT for primer adhesion, and generally the best if you have pitted rust. It WILL remove all but the most pronounced stamped/engraved markings. Black beauty lasts a long time.. it really doesn't turn to a dust like AlOx, but as the media fractures, it gets smaller and exposes more sharp edges to do more work. At some point it will reduce to dust, but it has the longest staying power before needing to be replaced. You need to run a larger nozzle because of the media size. At LEAST a 1/16th in orifice.. generally an 1/8th for best flow.

Walnut shells are really only for paint. Its much to soft to do anything to steel. It will not harm stampings/engravings unless in zinc or brass, and can frost glass (the two above will abrade glass away rapidly. If you ever saw a design 'frosted' onto glass its either walnut shells or a chemical etch. It also turns to dust/loses its edge the quickest. I would use paint stripper before walnut shells if given a choice. Walnut is available in various sizes. So you also need a fairly large nozzle orifice.

There are other much more exotic media. But way to expensive for anyone other than professional shops.

Last bit: light.. you will need lots of it. If outside you should be set, but once you get into a cabinet setup you only have a small window to work through. Halogen shop lights work the best, cheap to replace and the even if the glass get frosted (as it will) 500watt halogen diffused through a frosted glass still puts out a ton of light.

I was emailed about glass beads. Glass is between walnut and AlOx. Its not really for rust removal. Glass beads can take off paint and not affect metal but glass beads have a short life. And is also expensive. My view walnut and glass beads are really for cleaning more than rust removal. Yes, they will take off paint and will not affect the metal much (glass will live a satin finish) but for the cost if all you need to do is get rid of paint then use paint stripper. Faster, cheaper.

Bulk ordering is the cheapest. Generally everything is sold in 25/50lb bags at retail locations (Tractor Supply, Harbor Fright) so this is the most expensive way to get it. Once you get into the 1000lb+ orders you start to save money. But unless you can justify a couple tons of media (ie SPACE to store it in a dry location) most people are going to get 1-5 bags at about $10-$50 bag. I did a whole jeep with less than 5 bags of black beauty. The stuff just lasts. For the Chevy I bought 5 new bags because it was on sale at T.S.C.

Don't be afraid to throw out an entire pot of media if its not cutting. You'll save time with fresh media and your compressor/nozzle/hoses will thank you for that.

One thing that seems to change A LOT are the deadman nozzles for pressure pots. They seem to phase out every 2-4 years. The original deadman on my HF pressure pot is not sold any more, but they still sell nozzles for it(?). I have a second type deadman but the rubber stopper isn't sold anymore so it leaks and had abraded away. So now I have to buy the latest deadman that has parts, and also stock up on consumables less I have to buy ANOTHER deadman in a year or two.

And for all the HF haters, let me assure you that the stuff they sell is just as good as TSC and Eastwood.

This is what I wear when blasting outside (large panels, axles, fenders etc)



I can fill up a pair of boots with sweat in about 30 minutes in this. Since the goggles don't fit properly with a paint filter on I had to add some plastic taped on with electrical tape.

Add the $7 HF blasting gloves and you are all set for a day of removing paint, rust, and a few lbs of water weight.

LOL - Paul, that is SUCH an attractive look on you! You must have to beat the women off with a stick when you get dressed up like that!!

It looks ridiculous but works. Blowing chunks of black beauty out of your nose gets old QUICK.

I also wear ear plugs.... so its like being in your own little work.

Best part is I get out of all kinds of chores.. SWMBO knows that once I get into this I ain't getting out till I'm done... then I *look* so tired that I get to shower and sleep on the couch.... even though I am quite fine.