Improving Fine Dust Collection - - - - - - - -

[Hobkirk]

I use a Craftsman shop vac in the shed outside the garage with my separator can inside. I do a lot of sanding. Most of the fine dust makes it into the vac. I want to almost eliminate the fine dust making it into the shop vac filter. [As an aside, I've seen reference to adding a bag to the vacuum to catch the dust but I don't comprehend - what type of bag, attached where/how?]

Relevant issues (?):

• I modified the cap on my separator with a thin sheet of black metal (anodized flashing from a roll) to create a "wall" to deter the fine dust going directly from the inlet to the outlet - it helped a little, but not nearly enough. I have extended it some since the picture was taken with no improvement. Some sawdust/chips can pack the outside of the "wall" without any discernible effect.
  
• my bottom baffle layer fits quite closely to the sides of the can
  
  • I must have an imperfect seal because the suction at the end is not as strong as at the end of the hose connected directly to the shop vac even though the wood dado in the top fits tight enough I can almost lift the can by lifting the top with no suction - I do not have any type of gasket or sealant [how would I do that on a tight fitting dado?]
    
  I DO NOT WANT TO BE FORCED TO BUY A DUST DEPUTY!
  
  Any suggestions? Would it help if I added a longer extension on the center outlet pipe? Thanks.

[phil (admin)]

If you're using a sander with a small hose, the problem may be that you aren't getting enough air to do a good job separating.  The more air, the better it works.  So on my PC orbital sander with 1" hose, I have a small relief hole in the blast gate of my network that allows a little extra air to leak in.

I don't know if they have bags for that particular vac.  The ones I use on my Ridgid (and my older Shop Vac brand) went INSIDE the bucket and attached to the inlet (from the inside).

Finally, if the vac is outside as yours is, and if the motor is sealed from the exit port, I'd be inclined to just remove the filter.  Let the small amount of fine dust just blow out the exit port.  If, OTOH, the debris passes through the motor on the way to the exit port, you probably need to leave the filter in place.

[Hobkirk]

How can I seal the can better? The fifth picture shows the dado pretty clearly. And it does fit quite tightly.

[phil (admin)]

Add some weatherstripping to the bottom of the dado?

[Fabian Valinskas]

It looks to me that the gap in the baffle might be larger then 1 1/8" wide?  Is this the case?  If I am correct, you shouldn't have it any wider, and that might be part of the problem.