If you use, or have used a shop vac for hold down, I want to hear from you

[ed_lang]

Last Monday I cut 1/4 of my spoilboard so I could experiment with a shop vac I had on hand. I am impressed with the holding power of this Sears 5.5hp peak vac. I am not pulling thru MDF but rather placing my material I am testing with directly on the cut spoilboard.
Pictures here http://kc4ylx.smugmug.com/gallery/1440799
My next step will be to cut the skin from both sides of 3/4" MDF and try to hold a part laying on top of this MDF while laying on the spoilboard.

I would like to hear from those of you who are using shop vacs of any brand to hold parts and how you set your system up. Pictures are great if you have them! If you had tried a shop vac and then moved to a larger vac system, I would also like to hear from you as well.

I have used and still do use a low volume high vacuum pump for holding some items with dedicated jigs. I find this works great but am trying to explore another avenue with this thread.

In my tests so far I have NOT sealed any of the MDF so I am getting a lot less holding power than I expect to get with a sealed system.

The bottom line is I am trying to not spend $5K on a vac pump at this time.

If for any reason you would rather not post a response here, please email me directly or PM me.

Ed

[paco]

Hi Ed!

Impressing isn't it?!

If you like it and plan on keep it that way for a moment, I strongly suggest you to get a Fein (II or III) or at least a two stage motor/pump to avoid burning up your current Shop-Vac (yes, I notice the motor fan of this vacuum but still...). Plus you'll gain some pull and volume... and lower the noise level too!

I made the change some weeks ago and it SUCK (read pull A-L-O-T)!

I like you grid... but I wonder how easy it'll be to clean on rush production. If the slots are wide (3/8" to 1/2") and not to deep I believe it'll be OK... anyway, you'll discover this aspect soon.

Keep us post.

[ed_lang]

Thanks for the input Paco.

Here is what I have found out with a little guidance from an email or two since I posted.

More info at least.


Shop Vac Quiet Deluxe Series, 6.6hp 64" water 185CFM

Fein Turbo III 90" water 126CFM


The fein has more "suck" the Shop Vac has more volume.

[richards]

Ed,
I think that the figures should be 64" water OR 185CFM for the Shop Vac and 90" water OR 126CFM for the Fein. As soon as you start leaking air, the inches of water will decrease until you basically have no vacuum pull.

I have two Fein III vacuums connected in parallel to my Alpha 120-60 4-zone table. They work pretty good on larger pieces as long as I don't try to cut things in one pass. Smaller pieces require my GAST pump, Al*Star gaskets, etc. (Smaller depends on what gremlins are active at any particular momment.)

[ed_lang]

Mike,
Thanks for making my post more clear. Yes, you just cannot get both with this vacuum!

Since you are running two in parallel, you must feel you need the extra CFM. Are you using the 4 zone Shopbot provided layout? How do you plumb the underside of the table? Got any pictures?

I too have a high vacuum pump and use AllStar gaskets..... great stuff.

[larry_r]

Ed,
Am I correct to assume that you are not using any gasketing on the spoil board?

[ed_lang]

Hi Larry,
At this time I am using screws, clamps or high vacuum with jigs with AllStar gasketing. I am looking for the ability to put sheets and maybe even glued up panels on the machine and cut parts. I had not thought of using gasketing on the spoil board with the Fein vacuum and the zones.

[richards]

Ed,
Sorry, no pictures available. I am using a four zone platten, very similar to the one Shopbot provides. I changed it to fit my needs, but it does exactly what their's does. Basically, I have each zone connected to its own shutoff valve and all of the shutoff valves connected to a common manifold. One end of the manifold connects to one Fein and the other end of the manifold connects to the other Fein. All PVC pipe is 2-inch, schedule 40. My platten is a standard 49 X 97 sheet of 1-1/4 inch MDF with shelf-paper stuck on the underside to inhibit air flow. The top side is cut for the four zones and then coated several times with shellac to help channel the air flow. A 1/2-inch MDF spoilboard sits on top of the platten. The spoil board has had both sides surfaced to increase air flow. At the present time, the spoil board just sits on top of the platten without any sealant. To restrict air flow through the edges of the spoil board, I wrap the edge of the platten and the adge of the spoil board with duct tape (don't laugh, it works). The reason that I don't silicone seal the spoil board to the platten is that I often have to remove the spoil board so that I can use other vacuum masks for better hold down on smaller pieces.

Even with two Fein vacuums pulling together, there is not nearly enough vacuum to do some of the things that I want to do - and I'm talking about simple things like cutting a 21x24 cabinet top in one pass. Altitude may play a big factor here in the Salt Lake area, which is at least 4,000 feet above sea level.

After learning the limitations of my system, I've adjusted cut files to compensate. It's not ideal, but it pretty well meets my needs.

[ed_lang]

Picked up a Turbo III Fein last night. Quite! Seems to have quite a bit of power. More testing later today and this weekend.

[rcnewcomb]

We use a Sears shop vac for some cutting. I put a photo of our spoil board with gasketing on our blog (http://222artisans.blogspot.com/2006/03/more-about-our-vacuum-hold-downs_16.html)

[mklafehn]

Ed,

How did the Fein Work out?

What are the size of your grids as well as the space between them? I want to experiment with a similar design. Could you upload attachment used to make your grid?

THX

Mike

[ed_lang]

Hi Mike,
Sorry I had not updated this thread sooner.
I am still trying different things but here is what I have so far.
My machine is an Alpha96 running a PC7518. I mounted a 3/4" ply base to the Shopbot table then glued another 3/4" ply to it. I used the Shopbot 4 zone vac grid provided by Shopbot. I then brushed a heavy coat of poly on the grid. After it dried I sanded lightly with 220 on my ROS. I then marked the dead space between the zones on the edge of the ply. I used 2" PVC pipe from Lowes to plumb the vacuum. I used metal flanges and pipe thread to pvc adapters between the flanges and the rest of the plumbing. I did caulk the flanges when they were installed and screwed to the ply. I used 2" ball valves and 2" for the manifold. I might should have used something larger for the manifold but the Fein is only 2" so I stayed with that. Next I put a sheet of MDF on the grid and sucked it down. I surfaced the sheet and then turned it over. I used silicon caulking in the dead areas between the zones and the outside of the grid. I then placed the MDF on the grid and turned on all four zones. I then counter sunk screws in the dead zones and let the vac run for several hours. I then surfaced the MDF. Next I used the rest of the silicon to seal the edges of the MDF and the small half-inch overhang all around the ply grid. This is as far as I have gotten on the building process. Now it is time to experiment... I turned on the Fein and opened one zone. I used a 1/8" plexi sheet and started sliding it over the zone. In the first 2" or so I could feel the resistance. In the next 2 to 3" I could no longer slide the sheet! It is easy to pickup but you cannot slide it. I have also found that something as small as the zzero plate will "stick" to the MDF whith the Fein. I would not try to cut something that small without a mask around it but it does have resistance. I cut last weekend cabinet parts for another shop. One sheet of ply from them had a bow in it and I could not hold it flat with what I have now. I could almost hold it with vacuum after I pushed it down. I'll be adding a second Fein shortly.

I have a lot of questions unanswered like did I need the plumbing? Should I just put a Fein at each zone and turn them on and off as needed?

My thinking is/was to hook the two Feins together in a wye so I get twice the CFM with the same vac. I think this will be better and the plumbing is the best way I know of to do this.

Bottom line is, everyone who has seen this setup thinks I am crazy for even trying it until I turn it on, throw a scrap on the table, ask them to push it around, then open a valve and ask them to push it around again! They learn real quick this will work.

I am a little better in posting pictures to this place so take a look around and ask any questions you like.

http://kc4ylx.smugmug.com/Woodworking

I didn't measure the grids but it was designed for a 1/2" bit.

[mklafehn]

Ed,

Thanks so much for your quick response. Pics look great. My experimentation will take place this summer.

Mike

[larry_r]

Ed,
Thanks for taking the time to share your experience. I am thinking of doing the same thing with my Fein Vacuum. Right now it is a dust collector. Those pics really help. Again, great job!

Larry

[evan]

Ed,
I've added a second Fein T3 to a setup similar to yours (although I must say your plumbing is neater than mine) and the added CFM helped tremendously. I wish I had done it sooner. I really helps on those warped sheets. Once again looks great.