Introducing...the F16

[beacon14]

Well it's finally ready - in fact I've already cut the first two jobs on my new table and I am all smiles. It's an 8 zone, double manifold, 16 valve beauty with T-track to boot, powered by twin FEIN Turbo III's. Can you tell I'm a proud papa this Father's Day?


7577

The table is 3/4" Baltic Birch Plywood, with brown "backer" laminate glued to each face with yellow glue in a vacuum bag. A layer of 3/4" MDF was added with polyurethane glue using Brady's method of putting the grid side down while running the vacuum. Then I routed the grooves on the top side and epoxied and screwed in the T-Track.

I'm not sure if I'm going to glue a spoilboard down over the grids or leave it as is - for now it is working well with a piece of 1/4" MDF surfaced 1/16" off each side (1/8" current thickness - not much room for error). I'm getting some 3/8" MDF this week and hopefully some 1/2" Trupan to try out.

Each of the 8 zones can be opened to either or both vacs, or turned off. So I if want two 2' x 8' zones, or two 4' x 4' zones, or want all my power on a single 2' x 2' zone - no problem.


7578

I have been scouring this forum for the last 2 years specifically devouring any info on vacuum tables and this is what I have come up with. It's basically a culmination of all the ideas I have picked up here along the way. Thank you to all who have contributed. I'm looking forward to revving it up and seeing what it can do...

[pete]

David - outstanding job - a thing of beauty - you are not going to actually cut wood and mess it up are you - more pictures please - those look like quick disconnect type valves - I can only find glue up type - where do you get that type of valve. Thanks, Pete

[jay_p]

David,

The laminate backer seems like a great way to stabilize the table. That stuff is cheap and I often forget about it. Good looking table.
Jay

[sagreen83]

David,

That looks awesome! I am very interested in this thread... I am just putting my Alpha back together after a move across the country and wanted to try a vacuum table with my 2 brand new fein turbo IIIs.

Couple of questions..

1) Why didnt you go with a 10 valve system where instead of 2 valves per manifold, you would go with 1 per manifold, and have one on the input of each of the turbo IIIs?

2) I've never used the "Brown Backer Board" you are talking about... Where do you get it, and what is it?

3) So, on the 3/4 MDF, do you have the exact same grooves on the top, and the glued down side of the sheet? What are the depth of your grooves?

Would love to see more pictures of this beast! This is probably the nicest one I have seen yet!

[mnrite]

If you have grooves in the top of the sheet and the vacuum ports to them, what are the grooves on the bottom for? Also working on my new vacuum table.

Thanks
Mike

[drodda]

David,

I have been wanting to do this for some time but I have a problem with my table moving because of weather and humidity (Iowa). I have to constantly resurface my table to keep it flat. Is there anything that a person could do to get away from the problem of resurfacing and recutting the grid every week? Maybe using epoxy on the bottom of the whole table or something? I have been thinking about doing something like this in a more stable material ie corian or aluminum. But have yet to want to spend the money to do it.

[joe]

Dave,

I agree with you.

Perhaps you could use a sheet of Extira. It's cheap, won't swell and is pretty flat. I have sealed it off with epoxy to harden off the top surface.

J
www.normansignco.com (http://www.normansignco.com)

[beacon14]

Peter, the valves are solvent type from Home Depot (I tried a local plumbing supply house, he had to order them, they didn't fit the 2" pipe, back to HD)

Scott, each of the Fein vacs has it's own manifold, and each manifold is connected to all 8 zones. I often do repetitive work using 2 sections of the table, one on each vac, so I can turn one off and change the part while the machine works on the other section of the table. Whenever a manifold is in use its vac will be on, so no need for additional valves to isolate the vacs - if I upgrade to a real vacuum blower later I would need valves for each manifold to be able to operate separate zones as above.


7579

Here are the main PVC assemblies, less the center sections with the vac hookups and gauges. The valve handles are on opposite sides because I want to add wood extention handles and if the valves were all facing the same way the handles would interfere with each other.

The brown backer laminate is essentially the same thing as plastic laminate but without the decorative and protective top layers. It's used (sometimes) on the undersides of countertops and other concealed areas where there is a need to balance a panel which has veneer or laminate glued to the face. A well stocked laminate supplier should have it - I paid under $8/sheet. I'm hoping it will stiffen and stabilize the plywood substrate, but it also serves as an air barrier for the bottom of the MDF plenum.

Scott and Mike, I used the grooves in the bottom to glue the MDF tight to the laminated plywood table.


7580

I only wanted the minimum amount of grooves here so I used a 1/4" bit and routed 1/8" deep. These grooves were abandoned in the bottom of the platen once the platen was glued down. I wanted the grooves in the top of the platen so I could experiment with different spoilboard materials and thicknesses before committing. Notice the vacuum holes in the table are initially sized for the shopvac hose ends - since the plumbing was not in place yet I glued 1/4 of the platen at a time using the two vacs directly. The picture shows the 2nd quarter about to be glued down. In the background is a piece of melamine which I placed over the MDF to minimize airflow and maximize suction.

Dave, I'll have to let you know how well the table stays flat. I also glued hardwood blocks to the underside around the perimeter and sealed all the edges with 3 coats of polyurethane. With the exposed grooves it's a simple matter to slide a new spoilboard on or re-surface the old one and never have to re-cut the grooves. Even if the table moves a little re-surfacing the spoilboard will give me a flat surface - at 6ips with a 1.5" bit it only takes 10 minutes.

Thanks for the compliments everyone.

[sagreen83]

David,

I'm getting real close to getting my Shop finished and putting the bot back in action. So, I emagine that this thread will explode with questions when I get to that point
How is your new vac table working out? Did you settle on a spoilboard thickness?

Scott...

[beacon14]

Scott,

I'm very pleased so far. I have not had much chance to cut full panels - that's coming next week. But the system works and the flexibility of switching zones on and off and between the two vacs has been invaluable.

I've mostly been cutting partial sheets of melamine and MDF, and I can tell so far that with non-porous sheet material, not cutting all the way through, holding power is plenty, but as the material gets more porous or more flexible, or through-cuts affect the vacuum, or less than the entire zone is covered due to an irregular workpiece, the table and I are still getting used to what each other is capable of. So far I have not run into anything I can't hold down one way or another and I have not even been tempted to put any screws into the table. (I have screwed items from behind onto scraps of MDF which were then held down by the vacuum.) The shop-vacs (even the top-of-the-line Feins) are the weak link of the system, but with the proper approach it can be made to work very well for most of the work I do. I can upgrade the motors later without changing the plumbing or the table.

Right now I'm using 3/8" MDF surfaced both sides which seems to make a nice spoilboard. My limited experience is that thicker is not better with shop-vac type power plants. I have not had a need for the T-slots yet, but I'm sure I will.

So far I have not found anything I would do differently, but it's only been a few weeks, so there's still time!

[sagreen83]

David,

Purchased all of the plumbing parts that I think I need to build the system. Kinda expensive! I am going with 11 valves, and with all of the wood and plastic, I have about $500 invested in all of the schedule 40 PVC...

Question, did you glue all of your joints? If you were able to pull it apart to take these pictures, it would seem like you still have it loose... Are you leaking any vacuum?

Scott...

[beacon14]

Yes, unfortunately efficiency is not cheap. I had about $325 in the plumbing and around $550 total including the plywood, MDF, fasteners, etc.

The PVC is all glued - the pictures were taken during the assembly process. There are no leaks in the PVC that I know of.

[sagreen83]

David,

Is there any chance that you could send me your parts wizzard file for cutting the grooves in the top?

Scott...

[myxpykalix]

Look in your folder C:\SbParts\Vacuum (part of parts wizard) and you should see 5 or 6 different plenum cutting files for different size/config tables. If you don't have that email me.

[beacon14]

Scott,

You have mail

David

[geneb]

I'm in the process of building the vac table in this thread and I've got all the parts with the exception of the brown backer laminate. I've not been able to find it locally. Is this component required, or can I just glue the plenum quarter sections to the plywood table base with Tightbond III and not worry about vac leaks?

Thanks!

g.

[steve4460]

Hi Gene

I just used 3/4 2 sided white melamine 4x8 sheet to cut the zones in to it then sealed the cutts with some laquer put the 3/4 MDF spoilboard on top of that . I only have a 4 zone and I am making cabinet parts . They are staying in place nicely with just a 6.5 HP 20 Gal Shopvac .
Bot on

SV

[geneb]

My problem is that I've already got the 3/4" MDF material. I'd rather not go out and buy another sheet of material for this if I can avoid it.


tnx!

g.

[beacon14]

You can skip the brown backer if it's too much trouble - the exterior glue should do a decent job of sealing the plywood - you may end up having to seal the bottom of the plenum if you get too much leakage. Or you could try calling Atlanta Wood Products - they can send you a couple of sheets via UPS. 404-792-0910.

Thinking more about it I would want to glue something to the underside - if you only glue to one face of the plywood you are likely to get more movement (warping). At the very least I'd recommend thoroughly sealing the underside of the plywood if you skip the laminate.

[geneb]

I guess I've misunderstood how that table is built.

My understanding is that the layers go (from bottom to top), 3/4" plywood table base, laminate, 3/4" MDF plenum with T-Track, spoilboard.

Your reply seems to indicate that the plenum is also 3/4" plywood and not MDF. Is this correct?

My table base (as bolted to the 'bot frame) is a 7 layer plywood and I'd be astonished to find a that a pair of Fein IIIs could pull through it.

Thanks David!

g.

[steve4460]

Hi Gene

Use the 3/4 MDF as your spoil board on top of the plennum made from 3/4 Melamine Particle board that has the white stuff on both sides ,that is laying on top of a sheet of top of the line plywood I think they call that MDO about $60.00 per sheet around here. It has a plywood core and then they put a thin layer of what looks like MDF on both sides. Make shure you bolt that to your steel cross members good , and counter sink the bolds . So that your plenum 3/4 melamine will lay flat . then surface the plennum , then pin nail you 3/4 mdf to it .Just a couple of small pins around the edge to keep in place . Yes you can run the surfacing bit from shopbot right over these small pin nails and your ready to suck the sheets down tight

Bot on

[beacon14]

Gene,

You were correct before I confused the issue, with the exception that the 3/4" plywood table base has the brown backer on both top and bottom faces.

For those who have not seen it there is a more detailed explanation in the October installment of my column (http://65.36.212.143/notes_from_the_sandbox.htm) on the ShopBot web site.

[geneb]

Stephan:
I've already got my table base bolted down with all 25 or 30 bolts that came with the ShopBot.
I'll investigate the 3/4 Particle Board/Melamine panel though. It may be a good alternative to the missing brown backer laminate.

David:
Ahh, ok. I'm glad I didn't get it mostly wrong.


I did get some 1/16" (might be 1/32, memory is fuzzy on that) sealing tape from All*Star as well as some of the edge-sealing tape. I'm wondering if the sealing tape would work well underneath the plenum board...

tnx!

g.

[drodda]

David,
Could a person coat the Grid pattern with a shelac or something after cutting to seal it from leaking if they already have the MDF glued to the Plywood support board on an existing table top? I currently have 3/4" baltic attached to the supports and 3 layers of 3/4" mdf glued to the baltic with a layer of tightbond between each layer of MDF. This top is 3" thick. I would like to turn my table into a vac table but don't want to remove the MDF down to nothing. I was thinking about cutting the pattern that you are using into the existing MDF after surfacing the table. The spraying a sealer or clear coat over the entire table top and bottom and sides to try and get away from having to surface this top again. Then placing a spoil board over this to such through. I hope I expained myself well enough? Any advice would be greatly appreciated.

Thanks,

-D

[steve4460]

Hi Dave
That is exactly what I did with the one sheet of melamine after I cutt the groves in that way you get a much better vaccum.
Bot on

[fleinbach]

I used epoxy paint to seal mine. The epoxy paint sealed the MDF in only one application. My table can be seen here
Vacuum Table (http://www.talkshopbot.com/forum/show.cgi?tpc=28&post=42572#POST42572)
I had also made some test pieces and sealed them with polyurethane. To get an airtight seal I had to apply for coats with the polyurethane.

[drodda]

Frank,

Are you making a groove for the sealing tape to go in or is it just laying on top of your Plenum? If layed on top do you have to place the sealer tape everywhere to keep the spoil board level all over the table?

David,
What is the reasoning for the Aluminum T-strips under the spoil board? Or are you using the vac without a spoil board?

I cut mostly full sheets into table parts and drill holes through the sheets to connect them together. Will I loose all my holding power by having these holes through my material or willl there be enough holding with the rest of the non-drilled area to keep the parts from moving?

I have thought about using a different board for each table style to block off the areas where it will be cutting through.

Where do I find this epoxy paint like you used Frank?

Thanks for the information, I am very close to taking the plunge into a Vacuum table as I just placed new MDF on my table top and it is looking very nice without the 3 million screw holes in it that the old one had from my old hold down methods.

I am also looking into a vacuum table for laminating sheets. These plenums look like they might work good for this table also.

-D

[steve4460]

HI Dave

I cut 1/2" 4x8 Melamine on my setup all day long with a 6.5 Hp shopvac on the 4 zone setup and it works good until I cut about 10 sheets then I need to resurface . I cut the 1/2 with a 1/4" downspiral at 7 ips no chips with 1/4" stepdown .
after about 9-10 sheets sometime I lose vacume for smaller parts like 12x 42 upper cabinet sides . other then that it works good that way .
Melamine realy likes to slide around ,but if you cut unfinished plywood or mdf then that will stay put in smaller parts longer .
Bot on
SV

[fleinbach]

Dave,

To seal my spoil board to the Plenum I used a high grade latex caulk. I wanted to use a high-grade silicone, but they all seem to skin over too quickly not giving enough time to cover the whole plenum. I used two screws to hold the board in place so it would not slide. Next I placed a sheet of MDF on top of the spoil board and turned on the vacuum system. I left the vacuum on for 24 hours to be sure the caulk had cured. You do not need to worry about any discrepancies as they will be minor and removed when you surface the top.

My preferred method for cutting out parts is to leave a .01 skin to hold them in place and at the same time you lose very little vacuum. A Fein Turbo Turbo Vac IV works excellent for this. So far I have cut parts as small as 3 inches in diameter, and they remain in place fine. With MDF, a .01 skin is very easy to remove. With zone control and masking I have successfully cut individual MDF parts as small as 10" x 12" with a 1/4" bit at 5 inches per second .25 inches deep per pass.

You can purchase epoxy paint from Sherwin-Williams or Sears, but I'm sure there are many other places that carry it. Just make sure it is the two-part epoxy. I have been working with MDF for a long time and have always had a problem finding something that would seal it easily.
I have tried many primers and polys, but they all take three to four coats before you can apply a top coat easily. One coat of epoxy seal's better than the three or four coats of everything else I tried.

[geneb]

Frank, do you think the Epoxy Paint that places like Lowes sells would work? The stuff I'm referring to is typically used to paint concrete floors.

Here's an example:
http://www.lowes.com/lowes/lkn?action=productDetail&productId=16139-2174-922001&lpage=none

tnx!

[beacon14]

Gene, I think the glue lines between the laminate and the plywood add to the stiffness and stability of the assembly but I could not tell you how much. Even though it's a pain to remove and replace the table I'd consider doing it once and it should last the life of the machine. (No matter what happens short of natural disaster you can always surface down to the top of the plywood and build it back up)

If laminating the bottom is not an option then anything that blocks both air penetration and moisture exchange would be the next best thing. I guess the Allstar tape is a moisture barrier but I might be wrong - they could probably tell you.

Dave, I think your question has already been answered but yes what you describe is just what I would do in your case.

The T-track is an alternative to using the vacuum and is used without the spoilboard. For workpieces that do not get machined all the way around the edges The T-track is often all that is needed. For regular vacuum table work the spoilboard covers the T-track.

I have also been using the T-track to hold vacuum jigs or backer boards to the table to which I then secure the workpiece. This way I can turn off the vacuum between cuts and know that the jig will not move. This has proven to be the first unforeseen use of the T-track and I can see it coming in very handy.

[fleinbach]

Gene,

As long as it is a two-part epoxy it should work the same. The epoxy I used was for concrete floor.

[geneb]

Frank, the example shown is not a two part epoxy. The two part stuff is kinda steep.


I think between the tabbing feature in VCarve Pro and the T-Track system, I should be ok even with the regular concrete sealer paint.

Thanks for your input!

g.

[bill_lumley]

A simple question about table size for the base/plenum etc. Many of the sheet goods these days I will machine come in 49" X 97" . If the platen and base assembly are machined to 48" X 96" this means I will have an overlap of about 1/2" all around when holding peices in place with the vacuum . Is this something I should be concerned about or should I build the base out of larger material (5' X10') trimmed to say 50" X 98" to cover this situation .

Thanks Bill

[stockbub]

OK, let me see if I can put everything I have in words and as short as possible. My shopbot will be here in 2 weeks. My table is 5x9 so I will have cuts on all plywood. 3/4" bolted straight to table. Laminent on top of that. 3/4" mdf on top of that. Groved into that 3/4" mdf t-tracks and also groved design. Seal all edges. Take 1/2" or 3/8" MDF for spoilboard pined nailed on top of that. If spoiler board is on top of that, How do you get to t-tracks?Poiler board is sealed with caulk around the edges. Will I have to get or modify the grid pattern since I have the larger table? I will be using my bot to cut out cabinets and do some onlay cabinet carvings. I will have to cut all the way through. I was thinking of 2 fein units, but their was a post about fein and gast vacuum? Will the feins be enough for 3/4" plywood and 1/2"5x5 baltic birch? Cabinet parts will be nested on sheets of plywood. My total table height would be 2 1/4". I have heard others say their tables are 3" Just want to make sure I am looking at things correctly. Also, where are they putting gasket material?