Sandblasting questions?

qbass187

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Hey guys,
I picked up a sandblasting cabinet for restoring arcade parts and stuff but I'm not familiar with the blasting media types.
Do any of you guys know a general guideline to use when choosing the media?
Any help would be greatly appreciated.

Thanks!

ERIC
 
I just got the harbor freight cabinet (link) for christmas. I use the glass bead media (link) which works great for removing paint, and I have seen no evidence that it damages the metal. I've read that some people use walnut shell if they want something less aggressive, but I've never tried it.

As you know -- DO NOT USE PLAYSAND. Even though they call it a "sand" blast cabinet, sand contains silica which will scar your lungs and kill you.
 
for those of you who sandblast at home, what kind of air compressor are you using?
 
I've got a craftsman 20 gal that I got off craigslist used for about $100. It's dual 110/220 but as it turns out, there is basically no advantage to running it on 220v. Maybe it runs the motor a little cooler? But it definitely does not generate any more air at 220v.

My compressor keeps-up fine. I've seen tutorials that recommend modifying the harbor freight cabinet to use a pressure pot (link) but I see no need with the compressor I have. At most I'll give it a second to catch-up, or give it a break after several minutes of continuous operation to cool down.

Thing is -- if you blast a coin door, or marquee bracket, or something on rare occasion... you're not putting it through the same workload as somebody who is doing old car parts all day long.
 
I use the black stuff; Blackblast .25mm Industrial Quartz. It lasts quite a long time before you have to change it out.

I have a Sanborn 7HP, 60 gallon compressor. 230v, 125-155 working psi. Got it on sale at Menards about 10 years ago. Never had a problem with it, very tough unit. And I've blasted a shit-ton of parts. Mostly car parts, but plenty of arcade related stuff as well.
 
theres several types of blast media out there to pick from.

the most popular are good old silica sand and crushed walnuts.

walnuts work ok but take forever. the plus side is they wont make the metal as hot so less chance of warpage and they arent as agressive. Think of it as fine grade sandpaper.

good glass beads work great. Really quick, aggressive, but if you get the nozzle too close or take too long in one section, you can accidentally warp, deform, or pit the part youre trying to clean up.. Think of it as midgrade/coarse sandpaper.

aluminum oxide also works well. thats the krap other people might call black sand or black diamond. Its SUPER AGGRESSIVE and can really fuck stuff up if youre not careful. However with care, it can be the most awesome because its so aggressive, you blast quicker. think of it as like 40-60 grit sandpaper. SUper aggressive.

pros and cons to each. Ideally youll want something all purpose but keep in mind if you plan to blast something delicate youll want to use a finer media with less pressure.
 
the most popular are good old silica sand and crushed walnuts.
Not sure I want to be "that guy" on the forum but FOLLOWING YOUR COMMENT MAY F'ING KILL SOMEBODY. DO NOT USE ORDINARY SILICA SAND.

http://www.cdc.gov/niosh/docs/92-102/
http://en.wikipedia.org/wiki/Silicosis
http://www.lawyershop.com/practice-areas/asbestos-mesothelioma/lung-cancer/types/silicosis

Said best on one page I ran across "if you're not familiar with this word [silicosis], you have no business 'sand blasting'". I don't know a lot about it. I'm no expert. But the very first thing you'll read says NEVER NEVER NEVER use good old silica sand unless you have a death wish. It seems irresponsible to even make such a comment.
 
AWESOME!
Thanks for all the info guys. That really helps.
I bought the cabinet from Harbor Freight, it was the big one with the built in stand.
I was going to try the glass bead media they had but was a little scared about damage.

I'll check all the links and make a decision.

You guys are a great!!!
 
I use the 80 grit glass media from harbor freight all the time. It works great at removing rust, grime and other stuff. Test on softer metals and adjust air pressure so as to limit etching the surface. You might want to look into a airline dryer as too much moisture will clog up the nozzle. The harbor freight cabinet works pretty well but needs a vacuum hooked up to remove the dust from inside the cabinet. You can buy the kit or make on from an old shopvac and some pvc. **Always wear a respirator or at least a dust mask.**
 
Looking at the product page for that blasting cabinet, it says:

"Requires a 5 HP compressor with minimum 12 CFM at 40-80 PSI"

Now, looking at your typical $200-300 20 gallon air compressor, these things are only around 1.5 hp and 5.1 scfm @ 40psi, 3.8 @ 90psi. To get something with 5HP and putting out that kind of CFM, you are getting up over $1k...so those of you that have this cabinet (or similar) what do you REALLY need in order to do some occasional sandblasting?

I've just got a little 6 gallon pancake compressor that's .8 hp, 3.7/2.6 scfm @ 40/90 psi. I have no problem upgrading to a 20-27 gallon compressor, but wanna be sure it would handle this.
 
Maybe check craigslist for something used? I am using a craftsman 919.165200 that I picked up for $100 locally. I don't have the original manual so I don't know how many SCFM. Of course I wish that I had something bigger, but I am able to blast with the compressor running continuously.

My biggest problem right now seems to be moisture -- the siphon gun clogs. I'm planning to add a cheap air filter / moisture trap to see if that improves things.
 
I've had my eye on this compressor for quite some time, it goes on sale around the holidays ect... but you need a 220v outlet to run it. it's a beast


Kobalt 3.7 HP 60-Gallon 155 PSI Electric Air Compressor: $499.00 (non sale price)

-Cast iron, twin cylinder, oil-lubricated pump features one-piece cast iron crankcase, thermally stable cast iron cylinder body, aluminum head and machined cast iron valve plate, automotive style ball bearings, and durable stainless steel reed valves
-Heavy duty induction motor for maximum performance and efficiency, 208-240 volt
-Large capacity, 60-gallon ASME vertical tank provides more air for longer tool run times on air tools such as ratchets, impacts, spray guns, hammers, etc
-155 PSI max pressure, 13.4 SCFM @ 40 PSI, 11.5 SCFM @ 90 PSI , 3.7 running HP

846212001660xl.jpg


http://www.lowes.com/pd_221565-1498...p_product_qty_sales_dollar|1&facetInfo=Kobalt

tho reading the reviews gives me mixed thoughts on this unit, it looks nice in person; guess it's a gamble once you get it home :(


Btw sorry not trying to jack the OP's thread, i'd be using this for blasting, and spraying mainly and the occasional automotive repair. Wish the blast cabinet from harbor freight wasn't as expensive >.<

I also planned on using what ever media HF had and mainly to do lots of small parts with the occasional coin door/autopart.
 
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Your pancake compressor will not cut it. It does not have enough volume in the tank. I use a cheaper 2hp 150psi 30gal craftsman air compressor. It does not have enough volume to blast continually but will go 5-7minutes and you'll have to wait a couple of minutes for the compressor to catch up. Eventually I'll buy a bigger compressor but got this one on trade for something else and it works ok.
 
I use aluminum oxide and glass beads. Both work fine.A.O is alot more abrasive ut good for remving paint from coin doors. I have a Dewalt 1.1hp 4 gallon (D55146) 200 psi dual hose portable. Works great.
 
Your pancake compressor will not cut it. It does not have enough volume in the tank. I use a cheaper 2hp 150psi 30gal craftsman air compressor. It does not have enough volume to blast continually but will go 5-7minutes and you'll have to wait a couple of minutes for the compressor to catch up. Eventually I'll buy a bigger compressor but got this one on trade for something else and it works ok.

Add to that, the sound of that pancake compressor constantly running is deafening.

I have the little Porter Cable pancake compressor and for anything other than nail and staple guns, it's useless. You can't run a paint gun or media blaster with it. If you don't want to spend a lot, check Craigslist for used compressors. Beware though, you might have to fix what you buy. I kinda got ripped, although really..it still turned out to be an ok deal.

I bought a 40gal horizontal tank Craftsman compressor thru Craigslist. I got to the house, in the bad part of the town. The seller wasn't home, but his wife came to the door in barely a t-shirt/gown. Wasn't half bad, except she looked like a druggie. They had these massive dogs that she had to put inside before I went into the backyard. The compressor was in a dark shed, she took me back there, etc.. I got weirded out for sure, and the husband/owner came home, came back there, then pulled the compressor out of the mess of a shed. As he's pulling it out, he slips on the wooden ramp, landing right on his back in a split second. It was like something out of a cartoon, except creepy. Plugged it in, heard it run, paid the low price, got the heck outta there.

Next day, started messing with it, and found it wouldn't pump any air. I took it apart and found that the cylinder sleeve was badly worn and the piston was worn out around the edges so that there was NO compression. I had to order $50/parts from Sears online, but after replacing the sleeve, piston/ring thing, O-rings, a brass fitting, then put a better valve on the bottom, it was still a good deal. I just didn't plan on fixing the thing. I did get a really nice/long hose that I don't think they planned on selling with it, so that sweetened the deal a bit in the end.
 
Time for a sandblast update... my setup stinks. My compressor struggles to keep-up, the siphon style gun constantly clogs, and it does not strip very well. So I modified my cabinet to use a pressure pot (link) like I've seen online:

- Start with the blast cabinet (HF #93608)

- Purchase a 110lb pressure blaster (HF #95014). Notice this version comes with the deadman valve and holds the most media.

- The pressure pot has a 1/4" male air input. I used a 1/4" female plug (HF #68181). Use a long hose so any water vapor has time to cool, condense, and get trapped by the filter. I didn't like the cotter pins provided for wheels/legs and instead used hitch pins (HF #67557)

- Modify the blast cabinet's 1/4" air fitting to accept the 3/8" output from the pressure pot. Ream the hole with a step bit (HF #44460) and replace the hardware with a 3/8" male barb (HF #68213), 3/8" F-F coupling (HF #68203), and a short 3/8" hose to the gun (HF #91295). You'll also need some thin washers.

- Purchase a dust deputy (link). This traps "most" of the media for reuse and prevents the shopvac filter from clogging every 15 mins. You should still filter the media to remove the paint chips, rust, and crud before reuse. I tried window screen but that's too coarse. I tried a funnel/filter (link) but it's too fine. Haven't found a good solution yet.

- All of this equipment is unbelievably loud so use hearing protection.

The deadman valve is heavy and awkward to use. The pot has been rather difficult to adjust and did clog a few times. Filling the pot is messy and leaves a huge plume of dust. But given that I can't justify a high-CFM compressor for home use, this setup is working a lot more effectively. I'm pretty happy so far.
 
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