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desertbob
04-24-2010, 10:39 AM
The question I have is about sandblasting. I got a sandblaster from Harbor Freight. Yes I know.:mad: It looks like a paint sprayer on the end of an air hose. Plastic bottle about the size of a large peanut butter jar and it has a pistol type handle and a plastic tube going down inside it. I (attempt) use it outside with a breathing filter and goggles. It never works very well. In fact it very seldom works and then only for a few seconds. Ive gone through all the directions and Im doing everything the way it says to do it. My question for this group is: Is there some web site or someone here that can pass on some tips for things to look for when sandblasting with this type of device? Ive often thought that if someone who really knew sandblasting were to watch me trying to sandblast theyd chortle and say well here youre not doing . Ive got a box of about 30 rusty C clamps (Adjustable, Brink and Cotton, Armstrong, Williams and Malleable Iron) that are quite serviceable but are rusty. I paid $10 at an auction for the lot. Some need feet too which Ill make after I get them cleaned up. Many thanks for any light you can shed on this. Bob

Bill Pace
04-24-2010, 11:19 AM
I havent used the 'spray gun' type, but have read of a couple others that wernt impressed with it.

For years I have used this kit with very good results ---

http://cgi.ebay.com/Air-sand-blast-sandblasting-sandblaster-Kit-8pc-/290424536644?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item439ea6be44

I go to TSC (Tractor Service Supply) and get a 50# bag of "Black Diamond" blast media (Garnet), about $10. Get a 5 gal bucket and fill about 2/3 full, stick the siphon tube in and blast away!

One major factor in any blasting is a compressor that will make the particular device youre using work -- it takes a lot of air to make it work properly. One of those little 'pancake' compressors (or similar) might give a short burst of air sufficient to function but you can get any real use out of a small compressor.

deltaenterprizes
04-24-2010, 11:59 AM
Bill thanks for the info about the blast media at TSC, I have been paying double that for blasting sand.
The type of sand and the moisture content is an important factor. I tried using "play sand " from Home Depot and it did not work well. I have elevated the sand bucket to get a gravity feed and that helps.

Guido
04-24-2010, 12:08 PM
The pistol type thingy (hard to say 'sand blaster') can be made to work, considering sufficient air volume/pressure, blast media, weather, patience, and not to mention target, are all equally involved. If only one is missing, 'yo in deepdodo.

Steep learning curves------accept the challenge, or give to a non-profit which will provide a receipt. Then, next April 15 deduct four or five times the costs of your experience.

Try the battery charger, soda ash dunk------perfectly quiet operation,-----and put the HF pistol type paint sprayer at the VERY bottom of your longest list.

--G

JoeLee
04-24-2010, 12:36 PM
Bill thanks for the info about the blast media at TSC, I have been paying double that for blasting sand.
The type of sand and the moisture content is an important factor. I tried using "play sand " from Home Depot and it did not work well. I have elevated the sand bucket to get a gravity feed and that helps.

The crap play sand from Home Despot is almost like a mixture sheet rock dust and cracked clam shells. The dust does nothing and the cracked shells clog up the nozzel. They do that purposly so people don't use it for blasting. A lot of laws in some states have changed as to what type of media you can now use for blasting. Glass beads and white sand for blasting is now very expensive and most automotive stores that once sold it do not any more. The alternative is the Black Beauty, vulcanic slag stuff but it doesn't work as well as sand..... breaks down too fast and when your done you look like you worked in a coal mine. I use glass beads in my blast cabinet but they recycle. IN my preassure blaster I use white sand, you might try a masonry supply store for that. If I can't find the white I use the clean brown sand, works as well as the white...... almost, but it's cheap. Just make sure it's dry and you have no moisture in your lines.

JL......................

krutch
04-24-2010, 02:18 PM
If you get media from any source not designated for blasting, it will need some prep. to use. You will need to screen the media with a fine mesh screen and dry it with a 100 watt or better bulb. Spread the media to dry or bake it.
I have a screw-on type 'blaster' from Sears, I think, which I have used to blast and spray liquids. It will do the job, but the blast cabinet is better than exposing your self to the back blast. Then again the 'portable' does come in handy at times.
BTW, you can reuse the media more than once if you screen it to remove debris. But there will come a time when it will only be powder and of no use.
Just my experiance!
Krutch

metalmagpie
04-24-2010, 02:32 PM
Sandblasting?

rule 1: you need about 10 times the CFM of air you thought you would
rule 2: your air needs to be DRY
rule 3: siphon type blasters suck .. well, more accurately, they don't!
rule 4: pressure type blasters clog up UNLESS ..
rule 5: you always use new sand from an industrial source OR ..
rule 6: you diligently sift and/or dry your used sand

I am currently tooling up to sandblast a big BBQ smoker, trailer-mounted, that I'm building. I'm going to use an 18hp gas-powered Quincy pump which puts out 26 cfm in parallel with a 5hp electric-powered Quincy pump which puts out 18 cfm, hoping for something north of 40 cfm. I also set up a 10x20' canopy to keep the mess out of the gardens and to keep my neighbors from open revolt. In addition, I bought a commercial air hood with its own compressor, which I intend to resell after I'm done. I bought 200 pounds of Black Magic 16/30 copper slag blasting media for a total of $27.38 from United Western Supply in South Seattle, as industrial a supplier as there is anywhere. I am using 3/4" hose with Chicago-type fittings everywhere, so as to not impede the air flow. I am going to try using the dirt-cheap 40lb HF pressure pot, but if that doesn't work out, I'll try to borrow a real one.

To me, that is the *minimal* setup for home sandblasting. Better would be a rented 180 cfm air compressor, and a 250 pound sand pot. But the budget doesn't stretch that far.

For some old C-clamps I'd either learn about electrolytic derusting, buy two or three gallons of Evapo-Rust (http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=96431), or find a buddy with a bead blasting setup and borrow it. None of those methods work on a workpiece 24x70", though, that's why I'm doing what I am.

MM

portlandRon
04-24-2010, 03:03 PM
Here is an easy, cheap and does not make a mess way to clean the clamps.
Buy a gallon of plan house hold White Vineger. Find a plastic or glass container that you can lay the clamps in and allows you to cover the clamp with Vineger. Depending on how deep the rust is and will take from a few hours to over night. From time to time remove clamp and us a brush under running water to scrub off the rust that has now turned black. Dry and oil.

Black_Moons
04-24-2010, 04:42 PM
Princess auto and other places also sell 'crushed glass' that seems to work well, about $10 for 50lbs, pertty cheap..

And while glass seems nasty, the particles are too small to cut a person, and feel much more like annoying sand when they get into your socks and such.

as for the gun type kit.. low mosisture in the sand is critical.. And well, don't use sand.. lol.

Farbmeister
04-25-2010, 03:25 AM
If you are having trouble with Black Beauty you are doing something wrong. Sand is the worst on heavy paint/rust.... to fine. 40/80 grit BB at anything over 60PSI (at the nozzle) can 'burn' through metal if held long enough. If you want to get it done fast (and have the CFM) 20/40 grit.

I have one of those plastic ones, as well as a siphon and pressure pot. With enough CFM (20@ 90psi) it WILL eat whatever you point at it (skin, metal, rust, paint). As for dust, you need a shop vac to remove it or do it outside.

If you are doing thin metal it really helps to have backing... the thin stuff can vibrate and you lose some blast power as well as the possibility of deforming the metal.

Poor sandblasting results are most commonly (90%+ of the time) the result of not enough CFM. Then moisture.. its pretty easy to see when moisture is the problem.. it spits out the nozzle wet.

datsun280zxt
04-25-2010, 08:17 AM
It's too bad you don't list your location, I'm sure someone out there may be close by and would let you use their blast cabinet.

desertbob
04-25-2010, 05:49 PM
To all of you that took the time to respond, I thank you. I'll print these answers up and keep them in my three hole binders. I live in the Mojave Desert just north of the Joshua Tree National Park. I'm going to start with the easiest (the vinegar) and work up to the more complicated, although I'll stop when the clamps are clean. Again Thanks , Bob:)

Black_Moons
04-25-2010, 06:11 PM
Yea even a small gun style sandblaster will pertty much use 18cfm+ with its smallest nossel.
So expect about 20~30% duty cycle for about 30~ seconds or less at a time with your standard 1.5~2hp 6cfm 10 gallon shop compressor before pressure runs out.

I really would'nt advise sandblasting unless you have a 5HP 18CFM compressor.. and I would'nt advise buying such a compressor for sandblasting.

Around where I live, theres lots of 'U-blast' places, you go in, buy some time/abrasives, and they provide all the equipment and air.

You can basicly NOT do open blasting indoors without the entire room filling with sand (ie speciality room needed).. and need like a 40'+ open area to do it outdoors.. (I do it on a tarp outdoors to recollect 1/2~ the sand or so..)

Even at 18CFM mind you, sandblasting large flat surfaces is SLLLLOOWWWWW
Your way better off belt/jitterbug sanding or wire brushing on an angle grinder any flat surface you can unless you have like a 50CFM compressor and a recirculation system for the blast sand.

Where sandblasting shines, is detailed surfaces and inside corners where a wire brush would never even reach, low but detailed/hard to reach surface area. Does it instantly where a wire brush would never reach.

Also, for the frosted surface it leaves behind, can be desireable for clearcoating afterwards, or for very high paint aheadsion.

RichardG
04-25-2010, 10:27 PM
Have you tried the battery charger and washing soda thing gust hang them in a bucket and next morning rust is gone. did a lot of old block and tackle stuff worked great and no nasty mess.
Richard

buns
04-27-2010, 01:47 AM
Princess auto and other places also sell 'crushed glass' that seems to work well, about $10 for 50lbs, pertty cheap..




I used the crushed glass to blast a car frame. Worked quite well and at that price is "disposable'. The only problem I had was that they don't remove the labels from the glass jars before they crush them, so the paper 'fluff' would clog the nozzle. A simple pass thru a screen solved that problem.

I used to use silica sand but have switched to aluminum oxide for serious blasting. It is not cheap, but I use it in my blast cabinet so it can be recycled.

A side note about silica sand. It doesn't seem to be available in my area anymore and I hope that no one is still using it. About 10 years ago I contacted a commercial supplier of sandblasting equipment and they included this little tidbit of information with their brochure:


From The Workers Compensation Board Of B.C.


"A variety of materials may be used in many of the same applications as silica sand in abrasive blasting. Employers are expected to switch to these products when practicable. "When practicable" means when an alternative product is available which can be used to perform the job. If an employer decides to continue to use silica sand, then the employer must demonstrate why an alternative is not practicable. An example may be on a job bid before April 15,1998, but not started until April 15,1998, and silica sand was specified in the bid.
The use of crystalline silica was prohibited in Great Britain in 1950 and in other European countries in 1966. Since 1974 the National Institute of Occupational Safety and Health (NIOSH) in the United States has recommended that silica sand be prohibited as an abrasive blasting material.
Workers' exposure to crystalline silica must be kept as low as reasonably achievable (ALARA) below the exposure limits in Table 5-4 in the Occupational Health and Safety Regulation (page 5-35).
Abrasive Blasting Operations "




Oy Vay! The use of crystaline silica was prohibited in Great Britain in 1950!! Yet 40 years later I was still free to inhale it when blasting. So, the government doesn't give a rats azz if I die from silicosis, but will fine me $167.00 for not wearing my seat belt. Oops, I wen't off topic. First post blunder.

KIMFAB
04-27-2010, 02:20 PM
The silica sand thing is interesting.
I live north of Vegas in the desert and a couple of miles from a silica sand mine. When we have our sand storms I have never seen a wonderful, caring gummint agent come by and give me a respirator.

Because of this I have always felt free to go to the sand mine and gather amounts of silica sand which works well for sandblasting.

The key here is to have lots of dry air. I took a 6" piece of 3" dia. sched 80 pipe w/ fittings to make it fit inline with the hose and stuffed it full of Tampaxes for a dryer.
I would use a respirator no matter what you use for the media and do it outside or in a cabinet.

Forestgnome
04-27-2010, 04:24 PM
Definitely make sure your air is dry as close to the blaster as possible. Moisture causes clogging.

ligito
04-29-2010, 10:52 AM
You could also tumble them, in a rock, or shell tumbler.
Probably be a whole lot cheaper, too.