Problems with glass bead blasting

[DAVEN1256]

I am taking my first shot at glass bead blasting and running into some issues. Poor visibility inside the cabinet, dust escaping everywhere, and trouble getting a vacuum cleaner to help with the visibility.

My blast cabinet is a small table top model that loads from the top.

The cabinet instructions say it has a dust port. There is a hole in the right side of the cabinet ( no attachment for a vacuum cleaner though) with a cone shaped paper filter on the inside of it. Then there is a foam filter over the paper filter. I am assuming this is the dust port. I rigged a vacuum cleaner connection over the outside of this hole. Maybe that wasn't the right thing to do.

There is also a vent hole on the back of the cabinet with a dense, what appears to be, cloth or cotton filter.

When the lid is closed and I turn the vacuum cleaner on, gloves get sucked in and stand straight out like an inflated balloon. When you put your hands in them, they are too stiff to be useable. If you take the filter out from the vent hole on the back of the cabinet, it lets air in and you can use the gloves but they are still stiffer than if the vacuum wasn't running.

When the vacuum cleaner runs, there is no difference in the visiblity inside the cabinet..... It also seems like when the gun it is working, it is pressurizing the inside of the cabinet and can feel the air blowing through the seals of the door.

There is glass bead dust all around the area of the cabinet. Top, front, sides, and back. Is this normal? I know some gets out. I checked the cabinet to see if all the joints were sealed and they seemed to be. I put masking tape on the outside of all the joints and it actually seemed worse afterwards.

Did I set this up the right and what do I need to change to improve the visibility, keep the dust from escaping, and stop the gloves from blowing up?

Thanks,
Dave

[tmodel66]

I don't know what's wrong but I can definitely say you have something wrong. When my blast cabinet is closed and in use I get a little blow by around the door but not the way you a describing. Is your paper filter stopped up? Sounds like the whole cabinet is pressurized. 

[68rs327conv]

Sounds like a similar table top model I have, I rigged a a very small shop vac that I can hang on the wall next to the cabinet and I had too much suction, I placed a plastic cap over the vacuum nozzle and punched a few holes in it to reduce the suction.  Yes gloves stand out when on but have no trouble working.  You will still have some media escape but not much as the vacuum helps a lot.  My problem is lighting, as the light with the cabinet never worked correctly so I bought a cheap led lamp and hand in the cabinet inside a plastic bag.  Good thing I prefer the wire wheel to media blasting

Mike

[jeff68]

Sounds like I have the same cabinet as you.  I have only used Biasil sand and Black beauty in mine.  I use a small shop vac on the port with the cone filter.  The air intake on the back is open (no filter over it).  I have no issues with dust unless the filter in the shop vac clogs.  I actually run an old shop vac without a filter in it now.  I set the shop vac outside and run a long hose to the suction port - filter clogging problem solved.  The gloves get sucked straight in as you mention.  So, check to make sure the vacuum isn't plugging up with fine dust.

How much pressure are you running to the blast gun?  As already said, it seems like your compressor is overpowering your vac and pressurizing the cabinet.

2 other suggestions for this cabinet:
1)  Make shields for the inside light from the clear protector tubes sold at HD or Lowes
2)  Buy or make clear shields for the main window

[DAVEN1256]

Thanks guys for the advice and ideas.......In regards to the pressure I am using, it is 80 psi. The specification part of the instruction manual say the "working" pressure of the cabinet is 40 to 80 psi. In the operating instructions area, it says to set the regulator at 80 psi.......Should I go lower?

                   Dave

[Everett#2390]

You might try lower pressure and compare the results.
I had done PBM blasting on a couple alum wheels to remove brake dust embedded in the surface.
Cranked the pressure down to 30 PSI, and dust came right off and no deformation of the surface texture.

[Mike S]

I try to use the lowest pressure so it has steady media feed and performance. No need to use excessive pressure which will only pulverize the media faster.
With glass beading it is about 40 working pounds for my setup (Harbor Freight blaster and a shop vac for exhaust).

Mike