Thread: Sandblaster

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I bought a "40 lb." pressurized sandblaster, and I am rather disappointed. Blame it on inexperience. It pumps though 5 gallons of sand in about 3 minutes, and it takes at least 5 minutes to stop and fill it back up again. As you can see, this quickly gets frustating.

I was thinking about maybe buying a "110 lb" one. That will get me up to about 8 minutes of blasting time, but I have other ideas.

I bought a siphoning unit for about $20, but I have not fully tested it yet. It doesn't appear to be very effective, though.

Has anyone ever made their own pressurized sandblaster? I was thinking about using a 25 gallon drum, but I don't know about the allowable pressures. I will have to do some studying on that. I think about 100 psi is required. I want to be safe.

Any ideas?

Hopefully you're not blasting your body sheetmetal with 100psi sand!

No, I haven't blasted any steetmetal yet. My blasting experience is limited to some greasy suspension parts. What is the recommended pressure for sheetmetal? I know it is a delicate procedure, but I haven't found anyone with significant experience. I got a couple of quotes from pro. sandblasters who say they have done a "few" bodies before, but I'm not comfortable turning my car over to someone if I haven't seen any of their work.

I won't do ANY sheetmetal with a sand blaster. Well, if you turn it down as low a pressure as you can and still get some action, you could get away with doing the floor, and some of the higher rigidity areas like door jambs and such. But when in comes to exterior surfaces, especially the broad "flat" ones like doors, quarters, and roof...........................no way Jose'. Unless you want to have your car look like a potato chip ad.

You're smart to avoid commercial blasters who don't have a gang of experience. Personally, I'd do derusting with chemical agents, and I don't mean full immersion. You don't want any of that material in the nooks and crannies, it will bleed out later. Especially bad if it does it after paint. Then follow up the chem action with a DA, preferably soft pad, and don't hold it in any one area very long. Better to go back and forth a bunch of times (less heat build up in the metal), than bear down in one area 'til it shines.

I've got a gallon of Picklex sitting on the shelf, but I haven't used any of it yet. I did a test spot, and it turned the rust black, but I'm not sure how to use it. Do you spray it, wipe it, brush it? When you are ready to prime, does it need to be sanded, removed, or just sprayed over?

What type of chemicals do you use and what is your process?

For the interior, I was thinking about just using Zero-rust. For the exterior, I'm going with an expoxy primer. I have been debating for some time now on what rust removal route to take.
Sanding disks and/or Scotchbrite discs, sandblasting, chemicals, etc.

Picklex-6 is recommended for Powder Coaters only. Other users please call 1-800-9POWDER or email for advice on the Picklex formulation best suited for your application.

http://www.ashjentech.com/picklex.htm

http://www.stoprust.net/ this stuff is called Rust Bullet, havent used it but it sure looks like good stuff, you may want to read it cause it might just help you if you trying to remove rust..........joe

I got Picklex 20. It's the good stuff (at $55 a gal.)

I'll check out that rust bullet stuff.

Bulldog, When it turns it black that usually means it has neutralized the rust. I have a bottle of some stuff that I used for my car that was buried for 60+ yeas and it worked great, you spray or brush it on, wait 2-4 hours then wipe it off with a damp rag and then dry it and its gone or neutralized. The stuff is called Burts rust remove or berts can't remember, there is a 1800 number to order it, I will post it when I get the bottle from the shop today. My dad got it at a flee market.
I would recommend brushing it on as with this chemical it was a killer on the lungs when sprayed, even with a mask the chemicals hung in the air for a long time to where you had to leave the shop when done spraying for almost an hour, Then again I had almost no ventilation in there at the time it was winter.
But I will post the # if anyone is interested in it, The bottle was like $20 and did almost my whole body. And its a 1920's touring car. So its probably smaller than your car.

Most rust "busters" I'm familiar with are the phosphoic acid type, which is what causes the black oxide you've observed. (also the same thing in Coca-Cola that will "eat" a nail if it's left in a cup of Coke). Another old line product that has been used in body repair business for years is Rust Mort, again, contains phosphoric acid. Whether you grind it off or not depends on how much deposition there is. I've found it best to "grind" off as much rust scale as possible, abrasive grit dependent on how rusty the surface, or the black fiber wheels, or "flapper" discs (supposedly helps with cooling). Then use the chemical. That way, the deposition is minimal, mostly down in pits, and won't cause you to have to build an inordinately thick film of primer/surfacer to overcome it. Always rough up the metal surface before primer/sealer so that it has what's called "tooth", in order to help the sealer bond to the metal (even though most are epoxy, mechanical bond is essential).

There may be other types of chemistry besides phosphoric acid, and I get the feeling some of the "magic potion" companies are trying to impart some mysticism to their product for sales purposes, but it can't hurt to check around. A couple months ago one of the rod mags had an article on using muratic acid (probably because it's so easily obtained), and they were happy with the results. It left the surface with a greenish/grey look.

Originally posted by bulldogcountry1
I bought a "40 lb." pressurized sandblaster, and I am rather disappointed. Blame it on inexperience. It pumps though 5 gallons of sand in about 3 minutes, and it takes at least 5 minutes to stop and fill it back up again. As you can see, this quickly gets frustating.

I was thinking about maybe buying a "110 lb" one. That will get me up to about 8 minutes of blasting time, but I have other ideas.

I bought a siphoning unit for about $20, but I have not fully tested it yet. It doesn't appear to be very effective, though.

Has anyone ever made their own pressurized sandblaster? I was thinking about using a 25 gallon drum, but I don't know about the allowable pressures. I will have to do some studying on that. I think about 100 psi is required. I want to be safe.

Any ideas?

bulldogcountry1
I made a quick drawing of my sandblaster (not home made!)

If you have a similar sandblaster, I think you have to shut more (?) valve 2 to adjust the air and sand mixture. The valve 1 should be always fully open unless the valve 2 gets stuffed up with sand.

About the acid dipping I use 3 kinds of methods.

1) Phosphoric acid (liquid) I mix wit water 2/1 and I use a paintbrush to spread it over a sandblasted surface to stop the rusting process. Once it's dryed you can sand and paint the surface.
Note! The Phosphoric acid is very dangerous to use so you have to use goggels, rubber glowes and not to breath the fumes.

2) Citric acid E330 (dry powder) is the same stuff you have in Coca Cola. It is not dangerous. A small spoon full of it in your washing macine will clean all the calsium from the pipes.
I use the Citric acid in a tank of warm water and it will remove all the rust from places where sandblaster cannot. For ex. Inside of the doors, gas tanks, engine blocks etc.

3) Baking soda is good if you need to remove rust from the small parts like bolts and nuts and you cannot use sand blaster.
You need a bucket of warm water, melt the baking soda in the water and put the parts in the bucket. Put stainless steel sheets around the parts in the water and then connect a 12V battery charger like this: The Positive (+) to the stainless steel and negative (-) to the rusted part. When you connect the power tho the battery charger you will see that rust will lift to the surface.
Note! don't touch anything when the power is on!


Jani

I built my own blaster about 15 years ago from an old water heater tank. It's ugly as sin, but as effective as any of the commercial unit's I've seen. The design is the same as Janiluo has shown, and it holds up to 200 Lbs of sand.

I think the tank was rated at about 300 psi new, and after I welded on wheels and legs and a 2" fill bung in the top, I pressure tested it to 200 psi.

It sounds like your running way too much sand through your unit, doing some rough calculations your using 5-7 times the amount I use. The sand is supposed to come out in a fine mist.

My working pressure on heavy parts (manifolds, brackets, hinges etc) is 100 psi. I've done a lot of sheetmetal with no problems, but I only run 75-80 psi and move rapidly so as to minimize heat buildup. I've even done hard plastic pieces such as arm rest bases, window garnish etc (65-70 psi about 18" away) to clean and rough the plastic up to take paint (this is not for the faint of heart or the beginer). I run an 80 gal 2 stage compressor and I run out of air pressure after about 20 Min ( I usually get well over an hour of actual blasting from 200 lbs of sand, depending on the air pressure and how much sand I'm actually running through).

Found it.

I got a $25 sand blaster at a parts a rama, it is essentially a 5 gasllon bucket with a funnel at teh bottom. A hose comes from there to a gun in your hand, and air attaches to that and siphons the sand/media from the balster. the top of the blaster is open to the air.

I bought a bag of silica sand ($9, 60# or more, heavy stuff) and hook it up to my 6Hp 90-120psi compressor. Away i blast!

I try hard not to breathe the silica sand...just an assumption it might no be good to do so.

Cleans up anything i have tried to do! I have done flat sheetmeta, all the way to metal under it (saw bubling paint, blasted to raw steel and worked my way back out to a new finish).

More power would always be useful, but this works just fine, total cost (includeing a cheap hood and 2 ceramic tips, sand...$35)

There are other media you can blast - walnut shells, glass beads, and the most recent is plastic.

I plan to build a bead blast cabinet using the same principal as soon as i can get another handheld gun piece.

I have done parts of 4 cars now, and still have over 1/2 bag of sand (parts being 6 wheel wells, 2 floor pans, varios suspensions pieces, 2 bodies in places, etc.)

Picures or band name available upon request.

Ya , Don't get in a "cloud"even with a mask & hood. It sticks in your lungs, And come back to bite you later. Have you tried the ceramic beads,? when you get a cabinet, try them out, not worth it unless you can reuse them. They're a little "to proud of them" for me to use ,no cabinet..