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black sand

3K views 28 replies 9 participants last post by  Bee4Me 
#1 ·
I am media blasting using this black sand (black beauty?) medium grit. I am blasting with 90psi on a spot blaster and trying to get rust out of surface rusted but heavily pitted metal. I blast it but when I go and use picklex (rust converter) I can still see black marks deep inside the pits! What am I doing wrong? Is black beauty too big to get in there and remove rusted metal? What can I do?
 
#7 ·
90 PSI should be ok but since I am not sure what you are blasting and what equipment you have I would only be guessing. You said spot blaster so I assumed you were talking about small spots but if this is a large flat area and you are using a blaster, either suction or pressure, that covers large areas then the sand would be a bad idea because of the danger of warpage. How big an area are we talking about?
 
#11 ·
90 psi is gonna warp stuff pretty bad. i use starblast because it is very fine and will clean the pits out. leaves a good anchor pattern and it is very forgiving on warpage too. NEVER shoot 90 degrees at a panel or it's going to wave bye bye . blasting can be done with 40 psi with no problems. my rig runs at about 40 psi .

ps.......... playsand kills.
 
#12 · (Edited)
I use 90 PSI and higher with a pressure blaster all the time on seams such as that and warpage does not seem to be a problem, I don't think it would be on those parts in the pics either. I have had some serious warpage problems in the past but that was on flat surfaces and I have warned repeatedly about that. I have found aluminum oxide to work extremely well in removing rust from pits and in fact it works especially well on separated seams where the rust is usually quite deep.

ps play sand makes you miserable for a while and then it kills.
 
#13 ·
i agree red. it's flat panels where you get into trouble. door edges get folks in trouble. doing door jambs and hitting the edges a little will warp a 1/4 panel in a heartbeat. my rig is a little bigger. i have a 1 1/4 hose with a 3/8 nozzle. i have a 185 cfm compressor but only use around 40 psi. try the starblast sometime. it's very fine and has less the 5% silica. only 10 bucks a bag.
 
#14 ·
You just have to keep at it with the coal slag.
It will eventually clean it up and using it on areas other than panels is not a problem IMO. I'm using it myself on the current project and it actually cut's better after a couple cycles as it breaks down and gets into a smaller area.
The media as it first comes out is rather large and most of it bounces off and WAY out into the area so a tarp is necessary to recycle it. After it breaks down some it will be easier to contain and recycle.Just be sure to clean the greasy gunk off first as well as the seam sealer cause it can get recycled into the next blast and gum up the metal with the residue causing you a world of trouble later down the road with the paint.The blaster nozzle is another concern as some have a very large opening and put out a lot of material which is fine for lots of area fast but deep rust needs a smaller nozzle to concentrate the media to exactly where you need it. If the pitting is "that" bad,the metal needs replacing anyway. Here is the firewall/cowl seam which is "toast" in most of the seam area but still some good metal left on the firewall. I'm having to "cut & paste" as no replacement panel is to be found which is a shame cause most all these 80's trucks are wasted here.

Here I have blasted the firewall and sanded the cowl. Most of this will get replaced with new metal but I wanted it clean to SEE how bad it really is,which is coming to "light" after the blasting. :(

After cutting out the bad metal I made patchs using a stretcher tool and round pipe to form the repop part along with a little work with the hammer.
 
#15 ·
Bee, That warning about contaminating the sand/media with sealer, oil, grease and undercoating is one that is not mentioned enough. Some years ago I recycled some sand that I had used to blast the underside with after scraping as much old undercoating off as I could but the tar (or whatever that crap is) wound up embedded in the metal surface where it caused some real headaches. It is not as simple as wiping it down afterword because the rough surface makes it a bear to remove and if you don't get it ALL- :pain:
 
#18 ·
TSC play sand. $5.00 a bag and finer than Black Beauty and cheaper. I fought al day with a sandblaster that kept clogging up. New tips, the sand was coarse enough that it would lock up inside the tip after a few minutes. As far as contamination, a powder coating facility a few towns over does not like to do anything that an owner has prepped 100% due to contamination with the wrong sand, etc. All they use is aluminum oxide to blast parts.

Kevin
 
#19 ·
for those of you doing your blasting at home or in the yard. remember this , if you lived by me i would take you to court for endangering the lives of me and my family. play sand dust from blasting is a killer. think of your kids and others if not yourself. every time you recycle it the dust gets finner and more dangerous. i do blasting as a business and the industry as a whole is trying to get rid of sandblasting all together. there are much safer medias to use . i find it disturbing that people recommend this stuff without doing their research. the safe rule in the industry is 5% quartz or less. if 10 bucks a bag is too much you are in the wrong hobby. take care of your lungs....... their the only ones you got :D
 
#24 ·
Shine, After having worked around the mining industry I have seen far too much of what silica can do to a person and what is so shocking is how little it takes to do it! Even though I was a vendor I still had to sit through the safety training before I could work at some mines and some of the things we learned about silica was worrisome to say the least. When you consider that the dust they were dealing with contained only a fraction of the free silica that will be in blasting sand it really gets scary. I have used play sand quite a bit and I have recommended it to others (even in this thread :spank: ) but I took extra care to use the proper protection and always warned about the hazards. I think I am going to take a different stance from now on because the risks are too high and I know that too many people will use that stuff with improper or no protection but the biggest thing is what you said about the "collateral damage". Even dusting one's cloths off after working with sand can stir up dangerous amounts of silica and the area around the operation will be dangerous until the dust is gone, but I suppose you know all this already. I have heard the tired old arguments about some "old timer" who has done it for years with no protection and no problems but to those that think this is making too much out of the hazards better think again since even one heavy exposure can do damage that may not show up immediately.

As you have said repeatably, sand kills. I will not recommend it to anyone anymore.
 
#25 ·
it is scary red. i just pray that my stupidity of youth is not going to come back on me. i too have done it. but when setting up the blasting business i did my homework. what i found was terrifying. i know some of you guys get tired of my preaching every time this comes up but get use to it. if i can steer one person away from this crap it will be worth it. every time someone recommends this stuff i will hit the pulpit. there are approx 100 different medias available for blasting and sand ain't one of them .:D remember 5% quartz or less is the rule.
 
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