Sandblasters

[afroman006]

Ok, I have one of these infurnal things. Its one of the pressurized vessel ones where the sand is stored in a heavy metal pot that is filled with compressed air. I think its a 10 pounder or so, I got it from northern tool. Anyway, my compressor is not adequit for it, so I can only blast for a few seconds at a time before I run out of usable pressure. The damn thing keep clogging up with sand and it pissed me off enough that I used a grinder and flap disk instead of the blaster to clean a 24" diameter barbeque pit. I dont know if I am allowing too much sand into the hose, or if my sand might have abosorbed some moisture, as it has been sitting for about a year. So basically, what is the right way to use this bastard?

 

[rdn2blazer]

are you actually using sand? you dont want to use sand, sand is for pressure blasting houses before paint. for basic steel parts that are not too thin the best thing to use is Aluminum Oxide grit. we have 14 "Grit Blasters" at my shop. we dont call them sand blasters cause there used with grit. we have from 24X36 units to a 9X9X20 walk in unit with a helment and upper body cover that has pumped in fresh air, and every size in between. we use alot of Aluminum Oxide in all different grades (corseness of grit). we also use glass bead and carbide grits. there is certain applications where one is the optimum choice then 2nd, and 3rd choice.

a pressure pot unit does not require near as much air pressure as a syphon suction feed unit. our pressure pot units run as little as 30 to 60 psi. 90 to 120 psi which is what your average good compressor will put out is just not necessary. a suction feed unit will take every bit of that and then some. our pressure pot units have a second foot pedal that will over ride the regulated pressure and put max pressure to the unit if necessary. that for only a dificult area you are trying to clean.

keeping your grit dry is very important. Aluminum Oxide Grit goes through drying processes to eliminate any moisture. your compressor will put moisture into the grit if you dont have a good air dryer unit to dry the air first. those can be VERY expensive. we just bought a industrial air dryer unit for an auxillery compressor that was only about 500 bucks. thats cheap as dryers go but this if for compressors with 120 gal max tank size. I will be buying one for home when I can. its about the size of a 175 welder.

sounds like your main problem is moisture in your media which can cause it to kinda pack together and is not loose. and not enough pressure probably. what are you running your air pressure at?

you dont want to blast as hard as you can, only as hard as you need to. the harder you blast the faster the media will wear out. hope this helps. you will clean a part fast at max pressure but you will change you media 3 or 4 times faster then if you regulate it down to a reasonable rate and clean just a little slower and save the media life. media aint cheap for good stuff.

hope this helps.

 

[afroman006]

Cool thanks for the details. The media I'm using is a combo between steel grit and aluminum oxide. Ghetto, yes I know but I cant exactly remember when or how they got mixed and it was all I had. Thanks for the pressure tip. I have just been running it full tilt on 120 PSI but I'll regulate it down to 60 or so.

I think my biggest problem is the moisture thing. Down here on the coast it is usually at least 80% humidity with 90-95% not uncommon. I really need to invest in a good dehumidifier but I am half-ass saving for a new compressor first.

 

[grimjaw]

Minor hijack -

Is Aluminum Oxide grit ok to remove paint and rust from body panels? If not what is better? I was thinking of using Black Diamond Blasting Abrasive from Northern Tool.

 

[rdn2blazer]

Minor hijack -

Is Aluminum Oxide grit ok to remove paint and rust from body panels? If not what is better? I was thinking of using Black Diamond Blasting Abrasive from Northern Tool.

Aluminum Oxide can be used in a fine grit but there is better media then AO to use for that like crushed walnut shells or there are mixtures that professional grit blast shop that do car bodies all day long have come up with that work best for them. we do machined parts so its a different application. I do know with Alum. Ox. if its too corse and there is too much pressure you can very easily warp a body panel. you can feel the temp change on a part if grit blasted with corse grit with alot of pressure. it defenantly gets warmer.

 

[diesel4me]

Ghettoblaster!...

We had a home built copy of a "real" ALC pressurized sandblaster we had at the junkyard for restoration work..my co-worker made it from a 100lb propane tank,and we often used nothing more than the sand we could shovel off the side of the street ,sifted through a window screen over a 5 gallon pail,and dried by "baking" it in a metal bucket on an old wood stove!..now THATS ghetto!..

But it worked just as good as the ALC "factory" one that costed 350 bucks..we also used "Play Sand" you can get at home depot or discount stores with decent results..we found "Black Beauty" sand was too coarse and harsh on body panels,and was hard to dispose of,it made a black mess everywhere,sand would simply blend it with the other dirt...

I think keeping the sand 100% dry is the key,after sifting it thouroghly to remove pebbles and other trash....we have high humidity here a lot too,and sand will get enough moisture overnight to clog up in the blaster the next day....so we often had to fire up the woodstove to dry out the sand,so it wouldn't clog the tips up constantly..

Keep in mind this was at a boneyard,and we used it mostly for chassis work,not so much on body panels..we did use it a lot,and we could use it on sheet metal if we were careful,and used fine sand that had been used already..beats the hell out of grinding and sanding,and its much more effective at getting ALL the rust out and delaying its return as long as possible...

Adding a bigger tank to the compressor will help keep it from running out of air so quiclky...we had 2 tractor trailer tires and rims coupled together into our air compressor tank for extra "volume"..(we drilled and tapped the rims for 1/4" npt fittings!--and set the air pressure blow off valve at 125 psi)..crude,but effective!..

 

[botboy]

on a related note, home depot sells a product called "damp rid" that uses crystals to suck the moisture out of the air. My parents use their hanging ones in our closets to keep moisture at bay on clothes that aren't worn often and I use them in my ammo boxes to keep both ammo and powdercoating powder dry for whenever I need to use it. I would assume it would work great for drying out your pot blaster.