DC Salvage

[Jim Taylor]

Hi Guys,

Wanted to run something by you guys, and get opinions. So I have read through a significant portion of Bill Pentz's most excellent web site on DC:

http://cnets.net/~eclectic/woodwork...clone/index.cfm

And, am now convinced that I need to improve my DC system. Unfortunately, a cyclone is not in the cards at the moment... so I am trying to come up with a semi-low-cost solution to improve upon my 1200CFM 1.5HP Delta DC.

My first thought was to design a, large, long horizontal drop box with a cartridge filter vertically at the top, perhaps with vertical screens of varying permiability (sp) to disrupt the particles and create finer filtering as you travel through the chamber... and reduce the risk of clogging the cartridge. I now feel this approach is too messy, and have come up with, I think, a far simpler design.

Now I am considering a large vertical chamber (maybe 36"wx30"dx72"h). This chamber would physically enclose the top filter bag, and would need to be completely sealed to the top of the DC input ring, as well as being leak free. The top filter bag would be inside this chamber, and be used during operation. At the top of this sealed chamber would go the cartidge filter for exhaust back into the room. Chips and gravity challenged dust would dropped, and be contained in the botton bag of the DC tree, as in normal operation. The top filter bag would act as a first filter stage and prevent anything larger than 30 microns from entering the sealed chamber, and the cartridge filter would act as the second stage filter and prevent 99% of the fine particle dust from entering back into the workshop. This is basically how a HEPA filter vacuum works, stage 1 bag filter, stage 2 HEPA filter.

It seems possible that I may run into problems with resistance due to the 2 stages. This why the chamber is extra high. Each of my current, supposedly, 1 micron bag filters is about 30". I plan to sew the two together and make a single larger surface area for the top bag filter, and thus need greater than 60" height in the sealed chamber. Secondly, I may run into to much resistance by only having a single cartridge filter. Plan A is to try with a single cartridge and short bag, if things seem to be working, I could move to the large bag/second filter to create less resistance. Also, I will be moving to 6" input ducts to reduce the input resistance to the DC. Finally, if all fails, plan B is to convert the DC over to a cartridge filter as specified on Bill's site.

Lastly, I do have some ideas for sealing to the DC input ring of the bag tree and the chamber door. I am going to mount the ring directly to the chamber, and the chamber would be mounted directly to a wall. A piece of plywood with about a 2" hole, greater diameter than the ring would be placed over the top of the ring. Mounted top and bottom of this Ply would be two of my fome floor tiles, with hole diameters about 1" less than the ring diameter. The intent is to create a force fit gasket over the top of the ring. The monting hole on the ring would allow me to attach the ring to the Plywood, or a suport structure under the Ply. For a front door, I was considering a round hole just shy of a bycicle tires diameter. Then adhering a tire around this hole, partially inflate the tire, and this will act as a sealing gasket for the front door, bolted to the chamber around the outside of the tire.

Well this is the just of my salvage project. I am not married to the idea... so if anybody has tried this, or you know it will fail, I would be happy to hear that advice.... or any improvement suggestions... wife needs me back.... gotta run

-Jim

[Bart Leetch]

Why don't you save the time & effort & just get the top pleated filter from Jet or another manufacture to start with.

I have gone through the effort & made a sheet metal tube 20" diameter & tall enough to put 2 diesel truck air filters into that sits on top of the bag rim. It has a piece of material in the bottom of the tube with a solid center & pie shaped pieces cut out to let the exhaust come up around the outside of the filter cartridges & exit out the center at the top. It was a lot of work & isn't easy to clean but the CFM increase was amazing.

But I plan on getting a regular big pleated filter because they are easier to clean & not as tall so I can add a sheet metal spacer ring that will be fastened to the garbage can to make it about 15" taller then using the skirt available at Woodworkers Supply that fastens to the bottom of the bag rim & top of the garbage can that makes it easier to dump the garbage can.

After saying all the above my vote still goes for the jet filter. It just works better & is easier to clean. Then use a metal garbage can & the skirt from Woodworkers Supply.

Save your effort for something that will give you more return.

Been there done that.

[Charles McKinley]

I'll second Bart's suggestion. Either get the conversion kit from Jet or look on bill's site He has plans for a conversion to the filters.

[Jim Taylor]

Interesting design on the metal flu.

In reading Bill's site, I was under the impression that the Jet conversion did not include a fine enough cartridge filter (I think it was something like 5 micron) and that the top-o-the-ring mounted conversion (as on Bill's site) got clogged easily. These were the problems I was hoping to resolve.

I will probably still go forward with some type of conversion. I ordered the filter specified on Bill's page from Wynn Environmental (really nice people). I think I can build the rest for something like 30-40 bucks, so it won't break the bank. If I can get good CFM and good filtering (down to .5 micron), that is what I am all I'm looking for (not much, right :) )