Sandblasting problems, need help

[Zegapain]

I'm new here and was wondering if some of you could help me with my current problem:


I purchased a 20 lb sand blaster from Harbor Freight (this one (http://www.harborfreight.com/20-lb-capacity-pressurized-abrasive-blaster-40925.html)), I also purchased a 25 lb sack of glass bead media (this stuff (http://www.harborfreight.com/25-lbs-80-grit-glass-bead-blast-media-46426.html)). My goal is to completely sandblast my Coolermaster HAF 932 so I can later paint it.

I followed this video here from youtube: YouTube- Case Mod: Paint Computer Chassis, www.mnpctech.com (http://www.youtube.com/watch?v=Q_YY83dGbEI)

I went about using the sand blaster just as they did. However, after using more than half of my 25 lb sack of glass bead media, I was barely able to get through 1 panel (1 side only). I don't know what I'm doing wrong. I have an idea my air compressor might not be adequate enough for this project. I have a 25 gallon Craftsman Professional air compressor, it pushes 8.6 SCFM @ 40 PSI, and 6.8 SCFM @ 90 PSI

I was shooting the media at around 85 PSI, primarily because the air filter I was using on the line said to not exceed 90 PSI.

I don't know if the media I'm using is coarse enough, or whether my PSI is too low. In the video, he uses an 80 grit media as well, however, fails to mention which type it is. I did notice the media was of brownish color, maybe it's walnut shells? I know it's not the same media I'm using because my media is white in color.

After he was done blasting, his panels were rough to the touch, mine were smooth......... not a good thing for a high build primer to try and stick to.

Could it be that my 20 lb blaster is too small? I notice most people get the 40 lb version, I was just trying to save some money being that the 20 lb blaster was on sale for $60 vs $100 for the 40 lb blaster.

All I know is that after completing 1 half of 1 side of a panel for my case, I've already blown through more than half of my 25 lb sack of glass media. I cannot afford to go through this much media, due to the fact it costs $25 per 25 lbs.

So I'm asking what you guys suggest I do?

I'd appreciate any help that can be provided.

*I'd also like to mention that this project was partly inspired by Nevergive7.

[Tiny]

well from what i remember the case is powder coated on the out side and that stuff is hard as hell to sand off or even sand blast. Your best bet might be to take it to a powder coating shop and see if they can burn it off for you. Most powder coating shops can do this. As for running out of the media you might try blasting it in to some kind of box or even a plastic tub so you can recover your media.

[uoislame]

If what I remember about sand blasting, is that using beads is softer on stuff than sand. I could be wrong, however.

[Tiny]

the beads keep it from pitting

[Zegapain]

Update:

I have since returned the 20lb sand blaster back to Harbor Freight and exchanged it for the 40lb model. Getting back to the blasting, results were initially good using the new blaster with Aluminum Oxide (70-grit). However the problems just never stop. What happens is for the first few seconds the medium is ejected from the nozzle with satisfactory results until about several seconds in the medium no longer ejects and I get nothing but air pressure. After pondering for a moment like Whinne the Pooh it hit me that the medium near the bottom of the tank may be getting clogged.

Now I know moisture is a consideration but the blaster comes with an air filter exactly for that problem. Also, I live in central California (the valley) which has a fairly dry climate. While blasting I have to constantly shake the sand blaster tank in order to "loosen up" the medium clogging near the bottom. Anybody know how to tackle this problem?

Thanks for everyone's support thus far.

[Snyxxx]

Update:

I have since returned the 20lb sand blaster back to Harbor Freight and exchanged it for the 40lb model. Getting back to the blasting, results were initially good using the new blaster with Aluminum Oxide (70-grit). However the problems just never stop. What happens is for the first few seconds the medium is ejected from the nozzle with satisfactory results until about several seconds in the medium no longer ejects and I get nothing but air pressure. After pondering for a moment like Whinne the Pooh it hit me that the medium near the bottom of the tank may be getting clogged.

Now I know moisture is a consideration but the blaster comes with an air filter exactly for that problem. Also, I live in central California (the valley) which has a fairly dry climate. While blasting I have to constantly shake the sand blaster tank in order to "loosen up" the medium clogging near the bottom. Anybody know how to tackle this problem?

Thanks for everyone's support thus far.

Keep us updated on this. I have always been interested in mini sandblasters. Good luck.

[NeverGive7]

Uh oh...... "I'd also like to mention that this project was partly inspired by Nevergive7"
Didn't anyone ever tell you NOT to do what that NeverGive7 guy does? :rofl:

Can you tell us what your pressure settings are and all of your valve positions?

Also how do you go about getting your blaster running?

What I did with mine is I would start with all the valves closed then open up the main air inlet one which would pressurize the tank, open the bypass valve right below that one, then open up the nozzle valve. At this point you have straight air running through, then I would slowly open the media feed nozzle on the bottom of the tank until it barely started shooting media out (you'll hear it more then see it)

As far as conserving media you might look into a blast cabinet as well. Of course I would get your blasting down pat first as their cabinets are $229 I think. Then you could reclaim/reuse your media a couple of time (depending on what media). You might also use a angle die grinder and some sanding disk to knock off as much as you can by hand and then blast all of the nooks and crannies.

[cheapskate]

Don't spend a fortune on a blasting cabinet. You are already using 70 grit, so why not go on the cheap and switch to sandbox sand?
The filter would be your biggest issue here. It's keeping you below the blaster's rated pressure. Filters are mostly to protect the moving parts of air tools, right? My blaster is rated at 80-90 PSI depending on the nozzle. If the pressure drops about 10PSI below that, it starts clogging, not etching, etc...