10 February 2013

Blasting Cabinet Project.

Well it's been too long since I've updated this blog, so I've got some playing catch up to do.  And so long as we remove the chronological parameters of this thing we'll be OK I guess.

I've been wanting a blasting cabinet for years, something to blast auto parts, firearm parts, and/or just about anything else in need of moderate to heavy duty cleaning and surface prep for coatings such as paint.  As with all new projects I take to the .com world to do my research on all of the forums seeking recommendations, tips, ideas, and such.  I decided to go with a blasting cabinet from Harbor Freights (HF), and if you know anything about the products from HF you would know it's usually mediocre to poor quality stuff from China.  There are certain things I would NEVER waste my money on from HF but some things can come in handy when used with moderation or modified.  And modified is the road I would be taking with this project.  I'd found quite a few ideas on the internet from various folks on automotive, firearms, and machinist boards describing their complaints, modifications, and successes with this product.  So with a list of supplies needed I was off into the Great Blizzard of 2013 to HF, Lowes, Sears, and the local metal supply shop. As I knew it would the parts and pieces purchased to modify the blast cabinet came out to more than the cost of the cabinet itself but the end product should be or at least I was hoping would be just as good as higher dollar cabinets at a fraction of the cost.

Here we go, the Harbor Freight cabinet at $119.


Back home and in the shop it's like an igloo in there, with the morning outside temperature of -5, and an indoor shop temperature of +20 I began by stoking the wood burning stove and plugging in a little portable heater.  Then I plugged my ipod into the speakers and put on a real good book to listen to while fabricating.


Next I pulled out some 2X4's and plywood to build a stand for the cabinet.  The hole in the middle of the stand would be for draining the media out of the cabinet at a later date if need be.


Some of my planned modifications included adding a shop vacuum to reduce the amount of dust inside the cabinet causing poor visibility and some light to increase visibility. And instead of having to reach under the table to hit the power button on the little 2.5 gallon Craftsman shop vac and plugging in the light strip, an LED under the kitchen counter variant, I decided to wire up a switch on the front of the cabinet that would give convenient and quick access supplying power to the receptacle that I would plug the vac and light into on the back.  BUT.  I consider myself a jack of all trades but I hate electrical work, and in giving credit where credit is due I phoned Marc for some guidance as he is far better with the volts, amps, or whatever.




I did add some paint to the metal switch cover to look nice above, and below you can see I added an air connection and washers to a hole where the original setup intended for one to just stick their air hose through a hole to supply the blasting gun with air.


Next came the abrasive media pickup tube.  A tube placed down into the lower part of the hopper to draw the media up into a connected rubber hose and siphon feed into the spray gun.  Most guys on the Internet spoke poorly about the supplied pickup tube so I began to create a venturi style pickup tube to sort of create a jet effect to assist the media in flow.

Below you can see the HF supplied pickup tube and the metal tubes I would replace it with.  You can also see that I drilled a 5/16th inch hole in each tube which when positioned together will help to produce the "jet" effect.


If the Marshall Tucker Band had been on the radio at this time I suppose I would of tried to play the flute with one of the tubes.
 Below I created a 5/16 alignment pin from a cut down bolt.


Then I welded the two tubes together,


removed the alignment pin, sealed the area around where the two holes met, and then pinched off the end of the one tube.


Then off to installing the pickup tube into the cabinet and securing it.  If you had no idea what I just did Google would probably explain the venturi better than I can


 Now for figuring out how to attach the vacuum system.



The hole provided was too large for the tube to my vac so I had to put together some PVC parts.


With all the piecing together I still couldn't get the pieces of PVC and the vacuum tube to fit snug so a piece of  rubber bicycle tube mended the connection quite nice.


Now this next upgrade was something I hadn't seen on the Internet but I felt the original mesh working surface was flimsy and the openings which allow the abrasive media to fall below into the hopper were just too large which could lead to small firearm parts like pins and such to fall right through.


So from my local steel distributor I picked up this piece of perforated sheet metal.


Cutting the sheet metal to size with the plasma cutter.


Damn nice!!



For lighting I purchased a couple of 18 inch under the kitchen counter LED lights and formed some brackets to hold it in place.  At this time I have only emplaced one of the lights at the top and plan to place the other light near the front of the box facing to the rear in the future.  One of the neat things about these lights is they are provided with an attachment plug that allows them to be hooked up in parallel removing the inconvenience of an additional external power cord.



Now for the almost finished project!



So off to give it a test drive.  Does the pickup tube even pick up?  No air leaks so far in the hoses, the plugs and wiring work and no sparks or fires thanks to Marc.  I then added the blasting media, 70 grit aluminum oxide that I also picked up at HF in a 44 pound container.  


The next thing to do is try it out on something.  So here is an old ball peen hammer head with a bit of rust on it in need of refinishing.


And presto!



Now to a rifle part.  I wanted to refinish one of my AR15's so I pulled this La Rue Tactical hand guard to blast first.  It was painted once before but I wanted to do it again.


Now she's ready for some paint, but actually Norrell's Moly Resin.  A baked on coating with excellent qualities but that stuffs only as good as the prepped surface, that's the biggest reason for the blasting cabinet. Now below you will see the hand guard is almost ready for coating after some cleansing in detergent.  The problem I have right now though with painting is it's too damn cold in the shop to paint, not because I'm a pansy when it comes to the cold but because liquids don't fare too well in the current temperature range of my shop.  I think I'll be constructing a small 2X4 and plastic painting booth that I can heat and paint in.


Now to finish things up, after using the cabinet for the first time I have found a few leaks that the media has found its way out of the cabinet so I will have to figure out a way to do a little better sealing off.


In the next couple of pictures you will see a bit of black blasting media on the wooden stand that has seeped out of the door and plug hole.  



Some of the other things I added and/or replaced was the internal air hose, I used a 2.5 foot yellow hose with a swivel end, I calked many of the seals but it seems I need to caulk some more, and I guess that's about all for now.  Take care...

1 comment:

  1. Very nice! You are a fabricating genius...and a pretty darn good photographer.

    ReplyDelete