Cyclone lid not working

[Ron Franssen]

Hi Phil,

I built the cyclone lid you designed after seeing a thread posted on sawmill creek.  Mine is not working nearly as well as yours does in the video.  I'd say only about half of the debris is collecting in the garbage can.  I'd like to describe the method and pieces I used to build it and then perhaps you could offer some suggestions as to improve the separation efficiency.

I'm using a 30 gallon metal trash can.  The first time I turned to shop vac on, it sucked the sides in, not totally, but a good bit.  I'm not talking about a deflection that was restored when the vacuum was turned off, I'm permanently disfiguring the trash can.

My lid is over sized by about an inch or so and I routed a 1/4" groove where the lid contacts the garbage can.  It is a very tight seal.  Secondly, just to the interior of the routed groove, I cut another circle that is pretty tight with the interior of the can.  The top is made of 3/4 mdf and the interior "seal" is made of 5/8 mdf (just stuff I had lying around).  I cut a hole in the exact center of the lid and installed a pipe that my shop vac connects to and sealed it with silicone.  My pipe extends below the interior of the lid by about 2" or so, I can get a better measurement if needed.  My input tube is also a spare piece of the vaccuum cleaner that I installed so it roughly resembles the pictures I have seen posted on your web site.  The bottom baffle is made of 5/8 mdf.  I missed my measurement when routing the smaller diameter cirecle (240 degree portion) so it is a tad bigger than the 1.125" specified, but only by a 1/4" or so.  Finally the baffle is mounted about 4.5" below the lid's interior seal.  I can take pictures and post them if that would help. 

I'm not suggesting that the design doesn't work, just that my implementation is not working for me.  Maybe you can offer some suggestions that will improve the use.  Maybe my shop vac is just too powerful? 

thanks for any insight.
Ron

[phil (admin)]

Very interesting.  First, I'm surprised that the can collapsed, is it possible that the inlet was blocked at the time of the collapse?

Also, now that the can has collapsed a little, are you sure the seal between the top and the can is still good?  If there are any leaks that opened up between the lid and the rim of the can, then your separation efficiency will drop substantially.

And maybe some pics would be helpful.  What kind of shop vac are you using, BTW?

[Ron Franssen]

Thanks for the reply. 

There were no blockages in the lid or in any of the fittings or connecting hoses.  I think the can collapsed because of the shear  vacuum from the shop vac.  I have "beat" the can back into shape, at least as much as I can, but the top of the can is relatively round, and since I have the 1/4" groove routed into the top, I can still force the can into a completely round shape, at least at the top.  I'm pretty sure that leaks are not what is causing the separation problem.

I'm using a craftsman 6 HP shop vac that has a 2 or 2 1/4 hose attached to it. I've had this vac for about 10 years and it was advertised with "hurricane force winds".  I've never been disappointed with its suction.

I'll try to take some pics tonight.
thanks

[phil (admin)]

Did you ever get a chance to take some photos?

[Ron Franssen]

I've been pretty busy this week.  I'll try to get some this weekend.

[Ron Franssen]

...wanted to provide an update.

Without having changed anything, I needed to plane some rough 2x4 (s) into "good lumber" for the workbench I'm building.  I hooked up the shop vac and the seperator and began to plane.  My planer is the dewalt with the built in blower, so that might account for some of the difference.  Anyway, I did not empty my shop vac before I started this process so I can't say with 100% certainty, but it appears that the seperator caught nearly all of the chips resulting from the planing process.  I didn't see evidence of the chips in the shop vac at all.  So the seperator was working pretty well, at least for the planer.  The two key differences I see here (between my last and first use of the seperator) are 1 - the addition of the blower on the planer and 2 - planing the wood (feed rate) versus vacuuming debris from the floor.  I'll keep you posted.