Blast Cabinet Tech....hopper design

[lbhsbz]

For years I've had a HF benchtop blast cabinet (the red one) and it has been mostly useless. I recently started a business where I need to blast lots of castings so I ordered the skat blast pick-up tube and gun, which works amazing, when there is abrasive over the end of the tube. It seems after 3 or 4 minutes, all the abrasive is piled up around the sides and the suction tube just draws mostly air. Growing tired of shoving my hand in there to rearrange the abrasive, (and growing tired of all the leaks, even though I sealed the hell out of it), I found a US made Kelco 24-24 benchtop cabinet for sale locally for $300. I figured it would be better, since it's made by a blast cabinet company....it is, but marginally.

It's constructed of 3/16" steel and has about is 6" deeper hopper with a greater slope on the sides than the HF cabinet, but still suffers from the same problem....about 3 minutes in and I'm out of abrasive and have to rearrange it.

I think the problem is twofold...
1: Inadequate slope on the sides of the hopper due to the contraints of a benchtop sized machine
2: Inadequate space between the grate and the top of the abrasive pile, causing the blasting action to blow the abrasive away under the grate where the gun is usually pointed (middle of the grate to the back of the cabinet) and pile up in the front corners and everywhere else other than where it should be.

What's my solution here? I currently have 50 lbs of aluminum oxide in it.

I don't need a benchtop machine, so I'm thinking making the hopper a foot or 2 deeper, which will increase the angle of the walls so abrasive won't pile up, and will likely allow me to have the same amount of abrasive (50lbs or so) in the machine with at least 1 or 2 feet between the grate and the top of the abrasive pile...reducing "blowout" (for lack of a better term) and also probably wasting less abrasive since it won't be getting blown around in into the dust collector. I'm thinking this will fix it, but there may be a simpler solution that I haven't thought of.

any ideas?

 

[cvairwerks]

Making the hopper deeper creates a hardship when you want to change abrasives. There are some pressure/siphon feeds that work better. Quick way to fix your current cabinet is build something to break the adherence to the walls. Could be a ******** or maybe an air blast pipe. Flat bottomed grain bins have the same problem, but use powered sweeps to drive the grain to the output augers.

 

[lbhsbz]

Air sweep idea sounds kinda neat…you think just a square “ring” of pipe right under the grate with 1/16” or so nozzles drilled every inch or two pointed down-ish would do it? I could put a little button valve inside the cabinet that I smack every few minutes.

I just dumped in another 10lbs or so out my other blaster and it seems to get me more time…my 80 gallon 5hp 2 stage ingersoll has no problem maintaining 150psi while blasting, but gets hot in about 10 minutes, so maybe I should just take a break and manually rearrange things until I can find a screw compressor.

 

[lbhsbz]

Update…dumped all the abrasive out to reassess and found the suction tube (TP tools) about 8” off the bottom of the hopper…the bracket had become bent somehow. I made a new bracket to keep it in place about 1/2” from the drain cap, and it’s running great now…I still need to give it a rest when my compressor tank gets too hot to touch…lol.

 

[ZRX61]

I had one of those bench top set ups from Horrible Fright. Being merely useless would have been an upgrade from how bad it was. I got so hacked off with it I sprung for a TP960 & gave the HF one away for free.

 

[lbhsbz]

...and the solution I came up with was to cut the grate in half...easier than rigging up whatever...when I run outta sand, I just pick up the grate and push stuff around. I'm back in action in less time than it takes it me to get my arms outta the gloves.

 

[e015475]

I spent many hours trying to make my HF blaster work. I had to bang on it constantly to keep the media flowing.

I often thought a steeper draft and a material ******** would solve the problem

Something like this -

https://www.grainger.com/product/DAYTON-Electric-********-1DYN5

In a fit of pique one day, I threw the HF blaster in the dumpster and bought a welded steel blast cabinet off CL.

It has about a 2 foot long tapered hopper and I thought that would be the solution, but not quite. Instead of hitting it continuously, the occasional kick with my knee will keep the media flowing (and contrary to what a previous poster said, changing media is a snap - there's a plate with a rubber seal, and its held in with a spring on the bottom of the hopper. A five gallon bucket sits under the hopper and you can change media in just a couple of minutes)

I've often thought a air assist tube to keep the media in a froth of air right at the suction tube would be a solution and a lot less expensive than a $200 ********

Another thing that helped is a 100 watt incandescent bulb to not only light the work, but it'll get hot enough to keep your media dry and avoid clumping. You'd think the environment in the cabinet would be pretty hostile, but I on my second bulb after about ten years of use.