vacuum for blast cabinet?

I made a water trap for mine. Well, I made the entire sandblast cabinet out of a 55 gal drum, but with a little bit of host from Home Depot, some pipe clamps, caulk and an empty litter bucket, it wasn't hard. Just look at any bong and you'll see how easy it is. It's true that running a shop vac can be loud, but if the vac itself is outside, it's not too bad.

Another alternative, if you don't care about making a downstream mess with the grit, would be to build a "venturi blower".

Basically, you aim a tight plume of air from a high-velocity centrifugal blower into a larger pipe. The impetus of the incoming air is transferred to the larger column. It makes a good exhaust system for airborne particles that might damage (or be exploded by !) a motor in the air stream. The suction is not high, but total air motion can be tremendous.

Like I meant to say above, it won't vacuum up stuff off a surface, but it can move vast quantities of air and entrained dust without contaminating the blower or its motor. Such systems are often used in explosive dust environments where having even an explosion-proof motor isn't quite as safe as you'd like it to be. And since the motor is never in the particle stream, it improves the long-term maintenance characteristics of the system.

LLoyd

LLoyd

Can you vent to outdoors? If you can, then one technique for corrosive vapors and dust is to use a venturi. You put a nozzle inside a duct (like dryer vent) that blows toward the outlet. This creates a vacuum in the duct behind the nozzle and the bad stuff never gets near the blower. You want pretty good velocity, as from a shopvac set up to blow, or a leaf blower.

For CFM, figure the volume of your box. Say the box is 2 x 2 x 2 feet, that's 8 cu ft so 80 CFM would change the air in the box 10 times a minute. Most squirrelcage blowers don't deliver anywhere near rated volume if there is any backpressure, but a higher-velocity blower like a shopvac or leaf blower can do it.

I use a blower scrounged from on old downdraft range. It's very quiet and moves a lot of air, although not at high pressure. It will definitely vent straight outdoors if you have that option. I have my blower attached to the cabinet (acutally a 55gal drum)and it's all light enough to put outside when I use it. The exhaust of the blower has an A/C filter, rolled into a cylinder, with a can clamped to the bottom of it to pick up the heavier particles. The filter works better when dirty. I don't use it in the shop however because it lets dust loose occasionally. I don't think this type of blower provides enough pressure to overcome the restriction of a HEPA filter, though.

I too have used a Rigid vac in the past. It works fine, but sounds like the back end of a jet after a while.

Depends on the design. A venturi can pull a static vacuum of 28" Hg. There's a neat calculator online for estimating duct pressure drop.

drop.http://www.freecalc.com/ductloss.htm>

Thank you for the suggestion (and others) that suggested the venturi, I understand the principle (back pressure) but didn't know it is used the extraction. I might be building my own cabinet too and might be putting a vac gauge in there just for fun. Looks easy enough to rig up with plumbing Y or galvanized ducting junction.

I will probably be using the cabinet outside and the extractor will be definitely be outside, however I am trying to capture the grit since I am in an urban neighborhood, I don't really want the grit to land on my cars or people near by. I could still try the venturi venting to a DIY wood box with a furnace filter but I am not sure how well the dust collector handle back pressure. Well, we know it can blow up a

P.S. manual for this dust collector says 102-110dB @ 3 feet, is this considered very loud, but normally you would have a 4" hose at the inlet so it would muffle the sound a bit. But then a shop vac @ 3 feet is loud too.

Bear in mind that I live in the mountains and have no neighbors behind my shop. After my second shop-vac died, I took the handle off of an old Hoover vacuum cleaner, removed the belt and bush roller, blocked the intake so it sucks from straight down with the belt cover removed, went outside and stuck it over a hole in the wall that the shop vac hose fits into. I siliconed around the roughly triangular suction area and deck-screwed it to the outside wall. I even left the lights in it. It works great, and a little more dust in the forest won't hurt a thing. Replacements are cheap in if it ever burns out. I get a kick out of sand bags that warn of silicosis, then see CalTrans truck sanding our roads all winter. I guess people are not as important as protecting the trees from salt.

I've set up a blast cabinet & vacume sytem, have a look here-

The hamster was quite impressed,if a little PO'd.

I run a HEPA filter in the shop vac, nothing gets through it except air & its washable :).

H.

jeremy snipped-for-privacy@my-deja.com wrote: