The Stovebolt Site Forums The Shop Area Paint and Body Shop Sandblasting grits

I have borrowed a sandblaster and have access to a high CFM compressor. I also was told about a plant locally that sells "Black Beauty" coal slag pretty cheap in 100# bags. I will be blasting the frame of my 1949 3800 Chevy truck. I also plan to blast the seams/grooves/hard to sand places on the cab and smaller parts.

I have sandblasted before, but never had to make the decision on what grit to use, just to "have at it". My question would be what grits/media would be best to blast:
frame?
cab and other body components?
Would the Black Beauty work, or is it a waste of money for my application?

Thanks!

I haven't used BB but if I were, I'd probably save what I shot the frame with and use it to do the sheet metal. It will be smaller and less aggressive.
I believe an 80-120 grit would do what you want.
Remember to back off the pressure to 45-55 psi for the sheet metal and keep the angle of the 'jet' around 45* to minimize any warping.

Others here may advocate for silica play sand... but I'd rather use a safe blast media.

All the play sand that I have had experience with isn't a very pure sieve. Lots of pebbles and larger particles. I'd be afraid it would get a piece in the nozzle, clog, and blow up the hose.

I'll pick up some of the BB and try it out. May try the method of reuse and see how it works. After all, that's what my extra parts cab is for, experimentation.

How many pounds do you think I would need to do the complete frame? Haven't blasted anything in about a decade. So not exactly going to be the most efficient operator.

I get my sand in 5 gal buckets @ about 40 lbs ea. I think.
I'd guess a bag or two would get the frame done depending on how well you're able to reclaim what you shoot.

I sift the used sand through a window screen while blowing the shop vac across the 'stream of sand' as I dump it on the screen. It gets rid of a lot of the paint, dirt, etc that accumulates and makes a 'cloud of dust' the next time through.
Don't worry you'll get efficient before your 1/2 way through the frame... or take it to someone else!

That's exactly what I do, including a fan or stay up wind of dust while using my hands to sift. Of course I were a breather at all times and no humans down wind. Regular sand is in your soil and will be ok. Put a tarp under or shovel it up and dump in garbage can if you don't live rural like. It will NOT take off grease/road tar/gunk. You can blow off frame, pressure wash it, shake it on a paint mixer and you will still have sand somewhere in it, it hides and waits till you paint. With sand you don't feel like you have to "save" it like other media. Do it way outside away from house if you can. If you have an HOA, do it at night. But you are in Texas you probably have 8000 acres. BTW high CFM is good but what you also need is big tank, 80 gal and up for sandblasting.

Around here BB is about 8-19 bucks a bag and is pretty aggressive. After using one bag I still have the other leaning against the wall.

I go to my concrete mixing company and but silica sand that is SIZED so it don't clog up stuff. I bought some not long ago and it was about 4 bucks for a 50lb bag. It comes in Fine, Extra Fine and Medium. I like the Fine which on the bag is described as 45 grit.....I think. I use it but never pay attention to the writing anymore!

It will depend on how bad your frame is. It could take a couple hundred pounds and I have done them that took much more.

For what its worth, I sold my pressure blaster and promised myself I'd never use one again. If it don't go in the bead blasting cabinet it goes to someone else. Think about it.

I have migrated to adhere to Alvin's last paragraph.

I buy my cabinet abrasives locally from a professional blaster (I blend alumina beads with plastic beads - no distortion of surfaces).

Otherwise, I'd probably try to buy from Tractor Supply Company.

#1 Silica Sand is my answer for everything. I have done several whole trucks with it. At $5 for an 80 pound bag, you cant go wrong. This is NOT play sand. Play sand is way bigger and would destroy anything you are pointing it at. The stuff I am talking about is the consistency of fine sugar/almost flour. It wont warp your work at 110psi. If you are doing carbs or highly rusted zinc or cad plated parts, turn the pressure down to about 40psi. Other than that, I use it for everything. It gives you deadly Silicosis if you don't wear a good respirator, so just like when painting or doing anything else with airborne particulates, be safe. Once you try this stuff you will wonder why anyone would purchase all the rest of the media stuff they sell. You get it at the local lumber yard. The brand I buy is Quickcrete. Downside is speed. If you have really tough substrates, it will take longer. Since I have way more time than money, this isn't a factor for me, however if you want things done faster, go with something else.

If you are outside doing a frame and want to save money, get two 4x8 sheets of plywood and make a backstop (corner) and focus your blasting in that direction. Put a tarp on the ground, use a sifting screen, and re-use as much of the sand as you can trap.

He is basically talking about a frame, you can't warp a frame. Grooves and hard places don't warp. Small parts don't warp. Just my 2 cents on this particular OP to let him know. Not arguing warpage on flat panels/big areas with no features. But on a home blaster, it is still hard to warp anything. It's way too much trouble for me to take a frame somewhere for blasting, but I don't do show trucks. I rattle can the frame with Rustoleum gloss black.

Good stuff everyone. Yes, currently looking at sandblasting the frame. However, I do have some areas on the cab that will get some blasting. Not going to do the large sheet metal areas like the roof/back of cab/door skins. Mostly the areas that I can't thoroughly sand with paper or a wheel. The crimps, creases, and crevices. Places that rust like to hide and not rear its ugly head until years later. For the cab I think I have settled on using glass.

But for the frame sounds like there isn't a huge concern regarding the use of BB. However, BB would not be good for the cab.

Short story.. when I decided to sandblast the first time, I went to the local concrete company and they had a firehose/air compressor on a trailer/diesel engine setup that they rented out to people like me. They used sandbox sand.. here in Kansas its called gravel for the "gravel road" system. I suited up and went out there and started sandblasting, all happy we have such a service so close by. Well, if you point it at something, better do it quick or you will blast a hole in the FRAME! Its when I learned and appreciated pressure, metal properties, and what NOT to do. Doing the entire frame took about 3 hours. About 20% of the metal is lost in the process. A very bad idea.

Nowadays, using the Silica sand I am so happy with, it takes about 2 days, 12-14 80 pound bags of sand, and 0% loss of metal. Keep us posted on what you used, how long it took, and your satisfaction with the result. I made sure to have nothing but shiny bare metal left in ALL areas of the frame. This kept the substrate an even standard that paint will adhere to the same in all areas. Fun stuff no matter what you use!

I have a mobile wet abrasive blaster. I use crushed recycled bottle glass in a 40/70 fine. It looks like sand but doesn't have the silica to worry about breathing. Does great on frames and really great on sheet metal. Oh, and it's about $10 for a 50lb bag

other than the crushed glass being possibly less dusty, not sure where that idea of non-silica glass came from Splib, but you've been misinformed, glass is basically silica sand

Bill

What I think a good take-away from this is, anything that is dusty, ends up clogging your lungs and is a BAD thing. From bondo dust, to metal/welding dust, to urethane paint particulates, its all something that should mean RESPIRATOR to you. I don't look at one media blasting media as better for you than another. This is good practice. Be safe and be careful. Your loved ones will appreciate it.

But worry about breathing it anyway.

The seller's website you link is giving misleading, false and misinformed info. I.E. "It is non-hazardous, non-toxic...."

OSHA says: (excerpts)
Health Hazards
Abrasive blasting operations can create high levels of dust and noise. Abrasive material and the surface being blasted may contain toxic materials (e.g., lead paint, silica) that are hazardous to workers.

• Silica sand (crystalline) can cause silicosis, lung cancer, and breathing problems in exposed workers.
• Coal slag and garnet sand may cause lung damage similar to silica sand (based on preliminary animal testing).
• Copper slag, nickel slag, and glass (crushed or beads) also have the potential to cause lung damage.
• Steel grit and shot have less potential to cause lung damage.
• Slags can contain trace amounts of toxic metals such as arsenic, beryllium, and cadmium.

Alternative, less toxic blasting materials include:
• Dry ice
• Plastic bead media
• Sponge
• Sodium bicarbonate (baking soda)
• Ground walnut shells, ground corn cob and other biodegradable materials
• High pressure water

OSHA Document:
DSG FS-3697 11/2013 (5 mo's ago)

Google it

I stand corrected. It's good to learn something new everyday. Thanks guys. Good info in this thread.

Just always wear a good mask, keep kids, dogs, cats away. Off the subject a bit but Dogs, Cats, Horses, cows, sheep.... can receive eye damage when they look at welding. Does everyone know that? Hope so.

Bartamos.. thanks for inserting safety into these conversations.

Sometimes we get so focused on how to complete a short term goal we forget about the long term consequences. Having folks looking out for us, like you, is a big help.

Regardless of what we are using there are MSDS sheets available that clearly identify safety issues. If we could all look for those with the same vigor and enthusiasm that we research topics here it would ensure our own longevity.

I switched away from silica sand due to the health risks and now use "nickel slag", it still has risks, just not as bad as silica sand. That's discussed here, a previous media blasting Stovebolt thread: https://www.stovebolt.com/ubbthread...p;Words=media&Search=true#Post991886

Thanks for everyone's input and the safety messages. In my younger years I was invincible. Not so anymore. I won't pick up a tool anymore in the shop without the appropriate safety gear. Seen too many buddies have injuries/issues when a simple moment spent using the right PPE would have lessened or removed the impact of the action.

I'm still waffling on whether to do it myself or send it out. Part of me wants to do it myself, just for the sake of doing it myself. Another part is saying, just send it out, save yourself the effort of rounding up a blaster, large mobile air compressor, and media. May be a wash when it comes down to it factoring in time and diesel spent. So I'm not any further down the road in making a decision, but I'm at least a little more informed.

December 2013 Vintage Truck issue #21/No5 for a great article on sand blasting and your health.

FWIW...topic already beaten to death. I use play sand from HD that I run through a window screen to remove the pebbles. I wear a respirator and hearing protection while blasting. I collect the used sand, screen it again for re-use. But, only re-use one time as after two times through the blaster the sand is mostly powder and wasted effort to collect it again.

I tried using black beauty once, but it kept clogging the nozzle of my 80 lb pressure pot...too much trouble. I tossed the stuff.

If I were to use dedicated blasting sand, I would use #4 grit blasting sand.

In my blasting cabinet, I use aluminum oxide.