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Need help with sandblasting

#1
I just got some doors from texas(ctc ranch) and they have surface rust on them that seems pretty bad. I have a blaster that I have never taken out of the box. I need to know what type of safety gear I need so I am not breathing the stuff. and some tech tips so I dont warp the doors would help the cause.

What type of blasting media should I be using?

I will have pics of the blaster when I get it together tonight
 
#2
try to find crushed recycled glass media. its extremely forgiving when it comes to warping sheetmetal. you'll need a blasting hood and a respirator for many medias. crushed glass you can get by with a good dust mask.
 
#4
I have a 7.5 horse 80 gallon air compressor and this blaster. Thanks Jim I will try crushed glass, do you think it will cut all that rust away?
 
#6
Be sure to use DRY media, DRY air supply, and not too coarse of a media otherwise that blaster will clog up at the bottom and at the nozzle which will result in you throwing stuff and kicking the dog, etc. I've blaster a little using a unit like that from Harbor Freight using sand, blackdiamond (fine) from Tractor supply, and Starblast. I think starblast is they best.
You may need to re-plumb the bottom where the media and air mix by installing 1/2" pipe 'T' instead of the machined fitting it comes with.
You have a lot to blast and the nozzles will wear out so plan on getting some replacements. That dead man is a cheaper version and make break sooner than later.
 
#7
The style you have is a pressure blaster, air pressurizes the tank, then more air feed the media along. The other type is a suction blaster where you just suck the media into the air stream. The warping you are worried about is due to blasting too close to the metal and at too high of pressure, which is why I like the suction blaster if I am worried about warping.. Its pretty simple, more air, faster results, so you need to balance your time with good results. If you use alot of air pressure, stay farther away and just get closer in areas where you know you will be replacing metal or filling for sure.
 
#8
30-40 PSI at the pot and angle blast like others have said.

Keep the tip back 18" or so and very slowly remove the rust using the large pattern that holding the nozzle away from the metal gives you. If you are close cleaning a dime size area to white metal you will make a mess of the door.
 
#9
you guys rock! I will keep the air dry and turn it down to 40 psi and keep the nozzle 18" back. I am also aware that 80 grit or finer is what I want to blast with and blast at an angle. Thanks for the quick responses. Your knowledge is invaluable
 
#10
I'll be pleasantly surprised if you get that blaster to work at 40 psi. You'll know pretty quick. If it doesn't work, turn up the pressure. I don't think I've ever come close to warping metal at 90 psi with my 5 HP 60 gal. setup. I think its the industrial size blasting setups that can potentially warp a panel because of excessive heat build up resulting from the media's friction with the blasting surface. Those setups run at higher (125psi+) pressure and CFM than what you could ever achieve with a stand-up compressor setup I think.
 
#11
starblast is about the best. air pressure has nothing to do with whether a blaster will work or not. my commercial rig runs at around 40 lbs. no need for more. the trick is to have a little more pressure in the tank than the hose. i can adjust mine to where no media will fall into the stream with it wide open . heat also has nothing to do with it. stay at an angle to avoid peening the surface .
 
#13
The $30 glass is garnet, the $24 is beads. Different shape, I think the garnet is more aggressive since its block shaped and not round like a bead.
I pulled this off the net: GARNET - Hardness: 7.5; Size Range - 5 sizes from 16 to 100 grit; Shape: Blocky particles. This natural mined material is fast cleaning and is an excellent alternative to sand and coal slag (black beauty). It is not as effective as Aluminum Oxide on difficult applications. Garnet is used widely in waterjet cutting and has a higher Iron content than Alox while sizing is on the "loose" side. Sold usually in bulk containers, but bags are available.
GLASS BEADS - Glass beads are formulated from chemically inert soda-lime glass to produce a metallurgically clean surface for parts and equipment. The beads are spheres of uniform size and hardness to impact the surface of the part. Metal Preparations glass beads meet OSHA standards for cleaning operations and release no free silica or toxins that may harm workers or the environment. Breakdown of glass beads is generally caused by fracture and does not contaminate workpieces. Another advantage of using glass beads is the disposability, spent glass is environmentally friendly as compared to chemical cleaning methods. Normally this simplifies the disposal which results in reduced cost and required paperwork. Glass beads are often used for stress relief. Metal Preparations has available mil-spec (MIL-G-9954A) glass beads at absolutely no extra charge.
 
#14
dont use black beauty on sheetmetal. you'll end up warping it. black beauty cuts very fast but its better for steel parts. perfect for a frame, etc. sheetmetal, not so much. my glass i use is fairly fine and has a mesh size of 40/70. thats basically a range of 40-70 grit. i can blast with that and it leaves a finish fine enough in steel where i can epoxy and go right to paint with no sanding. aluminum its a bit too coarse to do that but steel no problem. glass beads are entirely different than crushed glass. beads are more for a cabinet and not what you want.
 
#15
I start with the crushed glass and end up with glass dust that works like beads as it breaks down. The reason Glass is a little quicker is because it has the same effect as baking soda. When the baking soda hits the metal it explodes and gives that little extra cleaning for free. Glass also explodes with the impact until it turns into dust. When it is dust, yeay, its really dusty to spray. The sands dont really have that effect of breaking and exploding on the surface, they just beat themselves down til they are no longer sharp..

Any cheap sand you might find with metal in it is silica, the cheapest. Places like Menards have it in 50 pound bags for about 8 bucks.

You really need to see how low you can blast with that machine. It is a dance of pressure in the tank and pressure in the line to get them to work.I really hate my pressure blaster, it always stops bringing media, its like the air line pushes the media back in the tank instead of out. If you can get yours set up right, then you can see if you can go with a coarser media like black beauty coal slag with lower pressure. Its also alot bigger and if you do have moisture in the air it will plug up at the bottom fitting.
 
#16
just a note . the lower moh scale the safer you are. the more aggressive the media the more damage you can do. the starblast is 6.5 and fine mesh . it gets into tight spots really well and removes rust from pits . it is one of the most forgiving medias out there.
 
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