Vacuum table in progress finally

[fleinbach]

I have thought (procrastinated) about how I was going to make my vacuum table and layout for the past two years. I do all types of cutting with the shopbot and wanted the flexibility to control cutting everything from full 5 x 12 sheet material down to smaller pieces, plus the ability to hold long boards. My final decision was to use 13 zones. I tried to lay them out to fit most any situation. The enclosed picture depicts how they are laid out. Of course there will still be times I will need to mask off a small area. The total cost for all plumbing was just under $300.00.

I started my layout with four sections 5 1/2 inches wide. This area was created to hold down long boards. The breaking up into four sections was to help align with the second row. The second row starts with 2 foot wide sections, expanding to the width of a 48 inch sheet. Combined with some sections from the first row. I can hold down portions of four by eight sheets in 2' x 4' increments. The remainder is broken into sections so that I can hold 5' x 8', 5' x 10', or 5' x 12' sheets.

So far, yesterday, I cut the Plenum into a 5 x 12 x 1 inch sheet of MDF. Today I will be putting on some epoxy paint as my sealant. I chose epoxy paint for two reasons. The first reason is I happen to have 2 gallons of it sitting on my shelf for the past six years. The second reason is, after testing it on a piece of MDF, I found that it seals far better than anything I've used in the past.


After reading other people's solutions on this forum I decided to start with a Fein vacuum. I purchased a Fein Turbo Vac IV on eBay for $350.00. Depending on my results I may purchase a second Fein, or if need be I will move up to a blower. I can certainly afford the blower, but I chose the Fein for its better noise control. I might add that you do not realize what people are talking about when they describe the power of the Fein. When I plugged it in yesterday for the first time and felt the power of it I was blown away. I have four other shop vacs here, some costing twice what the Fein cost, but the Fein is far more powerful than any of them.

I will update as I progress.


169

See larger picture here http://www.theaterrooms.com/vacuum.htm



170

[fleinbach]

Well due to the rain today. I got a chance to put a finish on my top. Here's what it looks like with one coat of epoxy on it.

Larger picture http://www.theaterrooms.com/vacuum.htm



171

[harryball]

I don't think I can get 13 shop vac heads under my 4x8 table :-) LOL Looks great Frank, I'm jealous!

[fleinbach]

I was realy hoping I wouldn't need 13 shop vac heads!

[fleinbach]

Well I got around to installing my plumbing today. This is what it looks like with 13 zones.


172



173

I do have a question. What thickness of a bleader board is everyone using? I thought someone just recently, like in the past two weeks said they were able to hold down parts through a 3/4" bleader board. Well, in one of my smallest zones, which is only 6" x 24" I put down a gasket, and it will hold a board down extremely well. So I plane down a piece of MDF on both sides to one half of an inch, and it holds this down very well also. But if I try to put a board on top of it it doesn't hold at all.

[btk]

Frank,

Are you using Regular MDF or Trupan?
Trupan(i.e. light-weight MDF) really makes a difference.
I use a 1" thick piece of trupan that gives me plenty of thickness to surface several times before having to change. Once it gets below 1/2" it starts to curl and needs to be changed.

Brian

[harryball]

Frank,

That sounds like it may have been me. I'm using the 4 shopvac heads. I cut 1/2" plywood for bat houses and one of the common parts is 6" x 20" and it holds it so long as I don't break the vac anywhere.

I let it suck the entire sheet down, then do my cutting with a down spiral in a single pass at 6 ips. I've never had it slip yet. I do not take a 6 x 20 and put it on the table and try to carve it or anything. I can place the part on the table and it seems to be stuck very well if I close the rest of the zone off with 1/4" hard board. But I've never tried carving or cutting that way.

For plaques, I have a template that the plaque fits inside of. I place the entire thing on the table and let the vac hold it. Works well but I've recently discovered I need to make a "snugging" feature in my template for small plaques.

As for boards, I've had NO luck getting any board to stick to the table. None whatsoever. I have 200 bdft of flat 1x8x8 coffee stain pine that will not stick to the table. I figure it's just too porous under the board to create a vac. I always create a holddown pass to mark screw holes and secure it that way.

Robert

[fleinbach]

BTK

What kind of vacuum systems are you using? I am using lightweight, MDF as a spoil Board. If you noticed in my pictures above I do not have the spoil board installed as yet. If you look at the lower right corner, you can see I have masked off a 6" x 24" area, which is one zone. I found a piece of light weight MDF and placed it on the masked area after planing both sides with my thickness planner. All other zones are shut off to give maximum pressure on this one small area. This is sucked down extremely well. It takes enormous pressure to pull it off of the table. Since this is simulating a spoil board. I place a piece of 0.75" x 8" x 30" MDF on top and it's as if there is no vacuum at all coming through the spoil board.

Robert,

If I understand you correctly, you do not have a spoil board at all. There is no doubt that my setup will work very well if I do not use a spoil board but I am hoping that is not the case.

[harryball]

I DO use a spoil board, 3/4" MDF. I recently replaced it, surfaced both sides, sealed the edges with shellac and sealed the seam between the spoil board and vac board with tape.

I use several pieces of 1/4" hard board on the table when I'm not cutting sheets that cover an entire zone. I use them to help create the vac over the entire zone.

Robert

[btk]

Frank,
I use a standard 4 Zone Vacuum table with a Fein Vacuum. As my plenum, I use 3/4" Cellular PVC (Azek, FYPON, etc). I beleive that I used the shopbot supplied file to cut my plenum.
On top of my plenum, I Silicone in place a sheet of Trupan which has had skin surfaced off of each side.

My setup looks similiar to yours, however I think that my holes cut in plenum (where connects to PVC pipe below) are larger than the ones that you have.

I also do not rely on my vacuum system to hold down such small parts and instead use either clamps or a specialized jig. My zones are 2'x 4' and work very well to hold down that size or up to full 4'x 8'.

Brian

[btk]

Frank,

Actually, looking closer at your photo, what I perceived to be the holes, are actually bolts that you have screwed into your plenum to hold down to the steel table.
I have a 3/4" base of marine grade plywood that is bolted to SB steel table, and my PVC Plenum is siliconed and screwed to this base from below.
I have no bolt holes in my plenum (however I have no idea if this makes a difference).

Brian

[fleinbach]

I am sure the bolt holes will make no difference as they are totally sealed. The Plenum is eproxy and in my test holds down a piece of three quarter-inch MDF with tremendous force. If I did not use a spoil board I would have no problem holding down my material. But for some reason I cannot draw air through the spoil board material I tried. Since it appears from what you have said, you are able to draw air with a Fein Turbo Vac threw a piece of surfaced MDF I will need to experiment further.

The really strange thing to me is that I know you can draw tremendous vacuum through MDF even without surfacing it. I learned this when I picked up a gast vacuum pump from a flea market about two years ago. I made a 12 inch diameter vacuum puck and attached it to a hoist so that I could pick up my MDF sheets to move them to the Shopbot. I placed the puck on a stack of half-inch MDF to try it out for the first time. I was totally shocked when it picked up six sheets. Yes, there was enough vacuum that it was able to pull through six sheets of half-inch MDF.

Well it appears I will need to do some experimenting today. I will let you know how I make out.

[bleeth]

Frank-I wonder if with a zone and bleeder as small as 6 x 24 you may be losing a lot of surface vacuum through the edges of the spoil board? Maybe sealing those edges will help.

Dave

[fleinbach]

Dave,

Yes, I did think of that and intend to try it also today. I did intend to seal the edges of my actual bleaderboard when I do put it on.

[beacon14]

Frank,

Some MDF board is much more porous than others - You may have to try to find a different brand or grade.

[fleinbach]

Okay, I had a few minutes so I taped the edge of the board. That did not help at all. I have to leave now for a while, but when I get back. I will try some more of the boards I have here. I probably have at least five or six different brands of MDF. I'll report back at the end of today.

[richards]

Frank,

Have you installed a vacuum guage in your system?

With the current brand of MDF that I am using as a spoil board, and with either one or two Fein vacuums turned on, my system pulls about 5-inches of mercury with all valves closed. With all four zones open, and only the spoil board (nothing being held down), I get about 2-inches of mercury. With all zones open and Melamine coated particle board on the table, I get about 5-inches of mercury, which you would expect, since the melamine is not going to leak vacuum. All of the brands of MDF that are locally available in Salt Lake City have been porous enough to work with my Fein vacuums. Other users have reported that certain brands of MDF haven't worked at all for them.

[fleinbach]

Mike,

No, but I will try as soon as I find it.

Mike and David, what brand MDF are you using?

I have about a half a dozen different brands in my shop purchased from four different sources.
So far I have tried three of them with no luck.

[richards]

Frank,
Plum Creek is one of the brands that works well for me. It's usually available from Lowes and sometimes from Home Depot.

[harryball]

I just tried some MDF from HD and Lowes here in Atlanta, I'm on my way to Atlanta Wood Products to pickup some ultralight MDF.

I have the opportunity for a stark comparison as the exact sheet I want to hold down, that the other two MDF's can not, is still sitting here.

Robert

[fleinbach]

Robert, I'll be waiting to hear how you make out.

I just called my distributor to find out what brand they are carrying. This is what they told me. It is called Panfibre and their website is http://www.Uniboard.com

They carry these three types standard, excel, and ultra-lightweight. I have tried the ultra-lightweight so far from scraps I have in my shop. I am not certain of the origin of the other two scraps I tried so far.

[fleinbach]

Okay Mike,

I found my vacuum gauge and installed it in the system. I am still testing in an 8" x 2' area and I am getting 6 inches with the valve closed. When I open the valve I get a minute deflection of the needle, then it returns to 6 inches. So it appears there is no loss of vacuum through the bleader material. I would equate that to no suction through the material. The slight deflection is probably due to vacuum loss just before the seal grabs.

I suppose this means I need to find some new source of MDF for a bleaderboard.

[btk]

Frank,

If you can get your hands on some Trupan (which is a different formulation than regular MDF), I know that it makes a big difference.
www.trupan.com (http://www.trupan.com)

Good luck,
Brian

[harryball]

OK, there is no need to buy any other MDF than an Ultralight MDF or Trupan. I purchased a sheet of 3/4" from Atlanta Wood Products and noticed the different immediately.

Even unsurfaced my Z plate stuck to the board nice and firm. Once surfaced the suction increased. I then flipped the board over and secured it on the table and surfaced the top. I coated the edges with Shellac.

I placed a 12" x 12" blank of 1/2" MDF on top of the table with one zone on and everything open. Thwmmmp... it stuck quick. It sticks pretty good, I could work it loose with a fair amount of pressure but for vcarving I believe it would have held in place. With a section of hardboard closing the rest of the zone and after I tape the seams... I know it would stay in place... probably could be cut with a down spiral.

Get the ultralight mdf for your bleeder board, it's well worth it.

[paco]

Frank,

what pipe size reach the bed?

Are your ball valves B&K (Muller)? I'm looking for 1-1/2" to 2" plastic ball valves on the NET... is 1-1/2" large enough or should I go 2" ID?

You should get very much more than 1 inch with a "good" bleeder board; anything more than that, you're just holding the bleeder and not the material...


Ed Lang,

I've notice your ball valves and I'd like to know of which brand they are?... they look sturdy. Do they turn easily?

Any one have/know online supplier for plastic ball vavles are welcome to post here... for me.

Thanks!

Was a little "off" topic but got to ask...

[fleinbach]

Robert,

I'm glad to see you got something that works well. Above I mentioned that one of the types of MDF I used was ultra-lightweight and it did not work. I decided to do a search last night for Trupan and found an explanation of why I am having so much trouble with this. Here is a link to Brady's explanation about the difficulty of finding the elusive perfect bleader board material. http://www.talkshopbot.com/forum/show.cgi?tpc=312&post=36365#POST36365

I plan on making a trip today to Russell plywood in New Castle, Delaware to pick up some Trupan and hope it is from a good batch.

Paco,

I used inch and a half pipe and inch and a half ball valves. I purchased the Ball valves locally for $12.85 each, they are Legend. I did a search on the web and found them here http://www.dealtime.com/xDN-miscellaneous--accent_shopping_merch-brand_legend~PG-5
for $10.83 each. You have to scroll to page 85 through 105.

These valves work very smoothly. I originally purchased 12 of them a year ago and since I made 13 zones I had to purchase one more. Since I did it on a Sunday I ran down to the local hardware store to pick the last one up. It is twice as hard to turn it than the others.

[harryball]

Frank,

Make SURE you get the correct MDF when you pickup. The guys here at AWP had a tough time figuring out which was which. I can see it would be very easy for them to pull the incorrect board and sell it as ultralight.

I'm glad I found this too and it does work well. Hopefully the trupan you find will be in proper condition and work for you.

Robert

[billp]

Guys,
If it IS really Trupan it will have "Trupan" stamped on the side of each individual piece. Also Trupan is sold in metric sizes, so if you take a caliper and get 18mm (.7") you'll know it's truly the right stuff...

[Brady Watson]

174

[fleinbach]

Well guys, here it goes my trip to Russell Plywood was not in vain and it was very enlightening also. First for the good news. I purchased a couple of sheets of each of the three types of MDF that they carry. They are standard, double refined, and ultralight. As soon as I returned the first thing I did was lay a sheet of ultralight on my Plenum. I am still in the testing mode so I did not surface either side, and was amazed, I finally found a sheet of MDF I was able to draw air through. And I might add it held very well. First I tried holding a piece of MDF 12" x 20" and it required a significant amount of force to pull it off the table. Next, I put a 3 inch disk of MDF on, and though it was easier to move it still required a bit of forceto move it. I am very satisfied that I now will be able to apply my bleaderboard.

As for my vacuum gauge readings I now read 6 inches with the valve closed and 5 inches with it opened.

Now for the enlightening part. I have no idea who the manufacturer is because Russell plywood couldn't tell me who it was. First they no longer carry Trupan. I took a tour of their warehouse and was told they used to carry Trupan. As I looked around I noticed there were many variations of MDF including a stack of green MDF which I was told was waterproof. I asked about taking a sheet with me, but they said it was all for special order. I was told the reason there were so many variations was because they came from different manufacturers. But he really didn't know the names of any particular one. So even though I have something that works very well. I don't know what it is.

[billp]

Frank,
Doug/John Roughton down in Kitty Hawk ,NC are using that same green MDF for signs since the waterproof face solves one of the major concerns people have always had about using MDF outdoors. This way you can seal the edges with the "glop du jour" of your choice and have a sign blank that should cut easily, and hold up to the elements. It would be worthwhile to have someone follow up on that stuff and find out it's name...

[ed_lang]

Paco,
sorry I didn't get a chance to read posts till now.
My ball valves are 2" and I bought them at Lowes. They are made by America Valve. I liked these because they turn easy, seal great and come apart like a pipe union does.

Hope this helps.

[harryball]

Frank, the difference is amazing isn't it? I'm pleased with the performance. Does your Ultralight MDF have any edge marking with the brand name similar to the Trupan? Mine does not, but the banded pallet they cut open was labled.

I also found a "Plum Creek" sticker on one of my MDF panels I tried before, must have been the one from Lowes. It was the last board I tried and I admit it worked better than the first board I tried from Home Depot.

In the end... get an Ultralight or Trupan bleeder board.

Robert

[fleinbach]

Yes, Robert it's amazing.

Ok, I asked them to come up with the manufacturer and they finally told me it is Tafisa. Here is a link to their site. They are researching to find out where they got the water resistant MDF from. Bs soon as they get back to me I will let everyone know.

http://www.mdf-info.org/manufacturers/m2details.asp?RECORD_KEY%5Bmembers%5D=CustomerID&C ustomerID%5Bmembers%5D=332

[fleinbach]

Well, the manager called me back from Russell plywood and was not much help. First of all he informed me that the MDF I picked up is not Tafisa. So I asked him who was the manufacturer. He said he does not know but he will look into it and call me back.
Next I asked him about the water resistant MDF, again he did not know who the manufacturer was. They seem to have a very large operation doing a lot of business, but I have no idea how. Oh, but he did say that they will shortly be stocking the water resistant material.

If they ever give me a manufacturer I will post it here.

[fleinbach]

I spoke to the manager again up at Russell plywood. He apologized when he found out that the light weight MDF I picked up is Tafisa. He was mistaken when he said it wasn't. He will also be carrying a water resistant MDF within a few weeks.

For more info on this material I have created a new topic here

http://www.talkshopbot.com/forum/show.cgi?tpc=15719&post=42963#POST42963

[jwool]

Frank,

I want to cut a plenum similar to yours 49x97mdf (4x8). Do i use the 4x8 plenum file with the 1/2 inch V-bit that came with our SB, then change to a straight bit when boring the holes? if not, how & where do you find this design ?

excellent plenum !!!

Thanks

[fleinbach]

Jerry,

No, I did not use the 1/2" V bit to cut my Plenum. I chose a 1 inch core box bit and set the depth to 1/4". I'm sure either would work just as well. I just like the curved channel that the core box bit makes. To cut the holes I used a 1/2" by 4 inch straight cutter. The 4 inch straight cutter was necessary to cut through to the bottom of the Plenum board. You need to position the bit as low in the Chuck as possible and even then it just broke through the bottom of the board at the end of the Z plunge limit.

As for the design it was my own. I wanted more flexibility than the typical four zone tables provided limiting the necessity to use masking to get maximum holding power. I also decided on a narrow zone at the front edge of the table to hold longer boards rather than sheets.

Here is a DXF of the 4' x 8' portion of my Plenum. You may be able to use it with some minor modifications. The circular portions in the grid layout where to avoid hitting my bolt holddowns for the Plenum board. I could have avoided this if I had added a second board. Actually, if I had it to do over again, I believe I would have taken that route. I had actually considered BTK's method described above of using Azek for my Plenum board. Although I am sure my proxy probably holds air just as well it was a huge pain to apply to the grid.

I applied my bleaderboard yesterday and will post my test results in the next couple of days.




175 (12.9 k)

[fleinbach]

Yesterday I used my new vacuum table for the first time. I was making a wall plate for the lighting control in my latest theater room. It is 3/4" MDF 13" x 13" with two 3" x 4" 3-D relief areas. The 3-D areas were cut with a 1/8" Ball nose bit. The cut out areas were made with a quarter inch Whiteside up spiral. The cutting parameters were a .38 step down at 5 inches per second with a .003 cleaning path. I set the finished depth to .745 leaving a .005 skin. This worked very well. When I removed the piece from the table and turned it upside down I was able to remove the skin by simply pressing with my finger around the edges.

The piece was held down firmly with my Fein Turbo Vac IV using my smallest zone only. This zone is 5 1/2" x 24" I used Saran wrap for masking on the portion of the zone not covered by the work piece. Nearly half of the piece I was cutting had no vacuum under it at all. I could have turned on the second zone in that area, but I would have had to mask off more than three quarter of that zone. But by only using this small surface area (approximatly 99 square inches)for holding power I found out just how well the vacuum works.

Over the next several days I will be V-carving and profiling 5.5" x 18' Azek boards.


Here is a picture showing what was cut.


176

[fleinbach]

177