sandblasting

[midwstfarm]

What do the numbers on blasting sand stand for? I know they are the size of the sand, but they have numbers like 20/40. What does that mean, which size is smaller?

Also I payed $7 for 50 lbs of black beauty which seems kind of high. This is on a water blaster, so would river sand work or would it be too coarse? Also flash rust formed on alot of parts, is there anyway to prevent this or is it even an issue? Any advice appreciated. Thanks

 

[Robert v]

Where did you get your water blaster.Would like to have one I think .How do you like yours?

 

[midwstfarm]

got it from northern tool, it was around $60. Ideally I think a regular blaster would be best but our compressor isn't nearlly big enough to get much done. It's probably safer; no dust. Seems to take rust off just about as quick as air blasting. The biggest problem I think is the flash rust.

 

[NC Wayne]

The blasting sand I typically use I get from a local concrete block/supply yard. The only two grades I"ve ever used are BX12 and BX30. Not sure what the letters and numbers stand for but the BX12 is a course sand that"s great for removing alot of heavy material fast. The downfall to that is it tends to leave a fairely rough surface texture on the material you blast so it takes more work to get a slick finish for painting. The BX30 is a finer material that still removes the paint, etc fairely well but doesn"t leave a course texture. I"ll use it if someone asks me to blast a vehicle or something that they want to put a nice paint job on. As far as using plain river sand just make sure it has no impuritues, like clay, in it. Did a set of fenders for a guy once, over a weekend. The paint was alot thicker and better bonded than I had anticipated and I ran out of sand half way through. I made the mistake of going to HD and getting some play sand to finish up with. I wound up having to redo both fenders with the good stuff before I could even prime them because of the impurities in the sane left little "piles" of material all over the surface. Not a good thing. Good luck with your new toy.

 

[Anonymous-0]

Thats the one I've got . Works good , I think I run #30 sand also........

 

[RobMD]

REGULAR SAND HAS CRYSTALLINE SILICA- USE RESPIRATOR WHILE BLASTING WITH THESE NON-GLASS MATERIALS.

All caps for a reason- your health.

 

[Anonymous-0]

Try an acid rinse of phosphoric acid , or metal prep after the water blasting and you will be ready for painting, it would be easy to do since it's wet allready

 

[JerryCPP(WA)]

Out my way the local sand/gravel/concrete supplier has everything from 12 to 120. The 12 is huge grains, used on concrete. I use the #70 or #90, much finer for rust and paint removal. I suspect the dual numbers just mean they didn't screen it very well, and it has both sizes.

 

[Mike M]

I never could figure out that concept of water blasting of metal.Water and metal don't mix ! It is good on brick, stone.

 

[ohio]

And don't get caught! (It's also illegal in some areas, and around here they won't sell it to you if you tell them you're going to blast with it.)

 

[midwstfarm]

Is there still a danger of sillicossis when used in a waterblaster? I would think there is no way the dust can get in the air.

 

[midwstfarm]

where would one find phosphoric acid? I think we've got some muratic acid, would that work? It is some sort of rust converter, or does it actually eat away the rust. I would assume you spray it on and wash it off?

Thanks

 

[Wardner]

It's been awhile since I have bought Black Beauty. I used to get bulk trailer loads containing 24+ tons. The delivery trailers had pneumatic unloaders that pumped into my silos. I'll bet I still have 30-40 tons of sand on hand even though I've been retired for 10 years. Are you near eastern MA?

The grades, that Reed Minerals (Black Beauty) are based on, are US standard screen size. If the grit can pass through a #20 screen but not a #40 screen, it is 20-40.

Reed Minerals (may have a different name by now) used to have around twenty plants across the country. Each plant had its own product selection. I presume that was due to variables in the waste from the local electric utility plant that was always next door. My local plant sold Utility, 12-20, 20-40, 50, and dust. The dust used to be landfilled but they were able to find a market for it.

I am not sure about current security standards, but anyone used to be able to buy direct and take delivery from the processing plant. The savings are considerable; particularly if you buy over 20 tons.

Flash rust is not a problem. It can be painted over after a light sanding. The sanding is required for automotive type painting. No sanding required for castings, structural steel, etc.

Search on "US screen", "Reed Minerals", "Black Beauty" for more info.

$14 per CWT. I remember when it was $1. And I'll bet Reed Minerals charges the electric company a tipping charge.

 

[Wardner]

Screw the respirator.

Get an air fed helmet for ANY blasting media.

 

[ohio]

probably not as great, but some will still become airborne in the process.

 

[midwstfarm]

Thanks for the info Wardner, if you were only closer. It turns out reed minerals has a plant not too far away, so I'll see if I can buy direct from them.