Over 99% efficiency with MDF dust

[dharms]

Just finished my top hat, couldn't wait to paint it, had to try it out. This is a small unit sitting on a five gallon plastic pail, chamber size is 5" high x 10.5" diameter. The baffle is made of formica, and I'm running it in front of a 3hp ShopVac QSP with 2 1/2" hoses.

I had a full shop vac bag containing almost entirely MDF dust, which seemed like a good place to start testing. I ran a couple of 200g loads through, collecting anywhere from 197-200 g of dust - hard to be completely accurate since the precision of the scale is only 1g, plus some dust collected under the baffle which I didn't realize was happening until later.

Then I tried corroborating by volume. I cleaned out my shop vac, and with a HEPA  bag in place of the stock foam filter I vacuumed up over two gallons of dust. I ended up with a thin partial coating of fine MDF on the HEPA bag and a scant bit of dust inside the shop vac itself. I tried to collect that dust for measurement and while I couldn't get it all I estimate it was one or two tablespoons. Even allowing for five tablespoons of dust getting through (absolutely no way it was that much) that's still 99% efficiency. So I'd say it's more like 99.5%.

I am extremely impressed. Awesome design, Phil - many thanks for sharing it!

[Rudy81]

Excellent results. I hope my build will turn out as efficient.  I am in the final stages of putting my large Thien top hat together.  Glad you have had success with your build. 

Phil has certainly designed an outstanding system.

[dharms]

I have no doubt you'll be happy with it. When I started building mine I looked for info on small collectors and didn't see a lot of data, so I thought I'd post my results in case anyone else was curious.

One other thing I meant to post earlier. I made the wall out of some 1/4" acrylic I had sitting around. To lock it into the base I put a 45 degree bevel on the inside edge (before bending) and then routed a corresponding groove to receive that edge. The top of the wall is just a straight cut. On assembly I loaded the top and bottom grooves with silicone. After everything had set I trimmed the edge flush. The 1/4" was a pain to bend but I'm happy with the result.

[Rudy81]

I bet it was tough to bend 1/4" acrylic.  I had a tough time with 1/8" acrylic.  I suppose you had to heat while trying to bend.

[dharms]

Yes, I used a heat gun and after I had it roughly to shape I put it in the oven for a while to finish forming it.

Definitely a pain  :)