In an article published in Fine Woodworking by Thomas Schrunk provides a plan for silencing your shop vac. I drew up modifications of his plan for my Rigid 5hp shop vac and realized that I was creating a behemoth (>36h,30w,36d) when you add on a dust separator. For that size I might as well just save up and buy a legitimate two stage dust collector. I decided to forgo the baffle design for a simple box that will sit on top of my shop vac and ride on the shop vac’s casters.
That way it will still be able to tuck away under my table saw or workbench. I figured I could do this smaller version from scrap on hand, minus the acoustic padding.
Schrunk talks about the possibility of using ceiling tiles instead of acoustic padding. And since I’m trying to do this on a rock bottom budget I thought I would give that option a try. I bought five 2'x2' Armstrong 935 celing tiles for ~$2.50/each. I would have spent over $50 on acoustic padding. I considered buying a sheet of homasote (NRC=.4) but the ceiling tiles were cheaper and better (NRC=.55). However now that I have them home and started working with them I realize that they are very brittle and produce a dust similar to drywall. I posted a question in the forum regarding whether or not to use them.
I went with the ceiling tiles and while not a total fail….I would strongly advise against using them. If you don’t have enough money for legitimate sound proofing, just use the plywood box until you save enough money. Or go with the homasote option. The ceiling tiles are not at all durable and required an entire tube of caulk to salvage the project.
The edges were so ragged and the resultant dust so toxic and itchy, that I donned some nitrile gloves and layered on the caulk like it were icing on a cake.
In addition to the edges and seams I also applied a layer of caulk to the area that will be fielding the exhaust from the shop vac. With the box design there will be some wear and tear on the ceiling tiles where they come into contact with the perimeter of the shop vac. I’ll give an update on their wear when appropriate. I’ve got my fingers crossed that I don’t have to rip them out in six months and replace with homasote.
In the meantime the box is completed and functional, bringing the decibles from 104 to 82…which is still not quiet, but its a lot quieter and for me does not require ear protection.
-- J Azuma