Wild idea for vacuum

(Carl Hilinski) #1

Years ago, I used to do some veneering and have a vacuum press. The vacuum motor (the one sold by Woodcraft under the Woodriver brand) has been lying around in the attic above the garage for years. So, of course, I’ve started to wonder if it might be put to use as a vacuum holdown table for the S03. I watched a ton of videos about people building their own vacuum tables and (as expected) I wasn’t fond of their designs. So I came up with this idea. Get a chunk of 12 x 12 3/4 inch MDF or plywood (big enough table to test) and rout a spiral groove into it 1/4 inch wide and 1/4 in deep (just because the vacuum pump comes with a 1/4 inch line).Then glue over that another 1/2 inch or so top with 1/4 inch holes drilled so they are along the spiral. Feed the vacuum into the center so it is drawing from the outside to the middle. Now, when you put a piece to be held down by the vacuum, you could just put in a rubber plug (or something) to block the suction at a point outside of your stock. A drawing is below. So tell me, what am I missing that should say “This will never work.”

(Jim Amos) #2

Sounds like an online project to me… inquiring minds want to know.

(Jude Marleau) #3

Looks cool, no problems here, I’m thinking up this tree also and now I’m considering a rectangular spiral because I always seem to have mostly rectangular pieces left over. Great idea, what will you do for a valve or shutoff switch, I wonder if a rotary switch would work? I like the idea of a plug in the next inline hole past the work piece. Great stuff, keep working on it and good luck. Jude

(Carl Hilinski) #4

The veneer pump is a single and it’s designed to run constantly. I’d need a lot of help with putting in shutoff switch, etc. At this point, I wanted to run it by some people as a “concept” thing so I wouldn’t spend a lot of time trying to engineer a certain failure because I don’t understand the principles behind stuff like this.

(Jerry Gray) #5

I believe it might work. Especially for square parts, but narrow rectangles might not get enough surface area.
Have you considered this design?

(Jude Marleau) #6

This is getting popular, seems like it’ll be my source when I’m ready, mac-valve etc. I have an a/c vacuum pump already so I’m close but not close enough to ready lay out a plan. Check it out, Jude

(William T Stokes) #7

I’d jump right into that if I hadn’t already committed to a clear acrylic back lit dance floo-er, vacuum infused waisteboard…

(Carl Hilinski) #8

That design has a lot to offer since you could use the sealer gasket to form around whatever type of stock you have. I’d have to figure out something to use for that gasket that was readily available and cheap. And I’d have to do the board in wood because I don’t yet work in metal. But I should build the spiral any way just to find out if it works.

(Carl Hilinski) #9

Here’s an update on the spiral vacuum table using a vacuum pump from a veneer press.

It doesn’t work. At all. Not even close.

I couldn’t feel any suck at all. I think it’s the 1/4 inch tubing from the pump to the table. When I just put the end of the suck tube on a small piece of 1/2 inch plywood (about 3 x 5 inches), there wasn’t enough suction to lift the plywood off the table. I then attached a shopvac to it, and I was able to get some suck. But my spiral grooves were only 1/4 inch wide and deep and I think that, too, is too small.

So we can label this:

(Jerry Gray) #10

Hey, thanks for updating.
Gotta break some eggs to make an omelet,

(Jude Marleau) #11

I tried a couple ideas also, I had a 30 yo vacuum pump, and made a mdf vacuum board, small 6x6, the mdf bled so much the pump never slowed down, packing taped all surfaces of mdf, made only 16 inches vacuum, pump needs cleaning and new oil, no grip until i line the area w/rubber weather stripping, foam weather stripping failed completely. Had success using a quick release coupler like air hoses, no leaks (was surprised), wrapped all fittings w/ plastic wrap looking for leaks, none.
Now to figure out HOW I want to use a vacuum table…The 16 inches of vacuum was enough for me to pick up the whole contraption by the board being vacuumed, so some success…but will be rebuilding the pump next week and new vacuum oil. I had looked in my junk drawer and I thought I could see a vacuum table, and it was there, surprise surprise…Jude

(Carl Hilinski) #12

Because I obsess about building tools, I simply cannot walk away from this. So tonight I sent an email to a local company that is a dealer for Gast vacuum pumps in my area, asking them if the pump I have would be considered too underpowered and therefore inappropriate for this application. I didn’t think about the MDF leaking. I have a chunk of 1/2 inch HDPE that I bought for another project that I may try. . As a side note, I’m thinking that the stretch elastic bands you can buy as exercise equipment might find some application here for blocking exposed holes on the table.

(Stacy Boncheff) #13

You may be able to seal the MDF with shellac etc. Some have used HDF but it is hard to find in my area. I would try sealing it first on both sides and see if that helps before going the more expensive route.

(Jerry Gray) #14

That Quick Seal spray rubber, worked wonders for me after I used it, and rubed it in good. It soaked in mostly, and seals good, but Make sure to cover everything from the overspray.
I forgot :frowning: , and it took forever to scrape all of it off the extrusions. It stuck good!

(Eddie Garmon) #15

So, from a lot of my first hand experience:

  • You need to find a better way to seal MDF. I have not found a good way that leaves it flat once it is milled into a plenum or a holder. I have switched to using HDPE myself.

  • You need to design a good plenum to spread out your vacuum across your mounting surface.

  • You should design a custom fixture for each job to mate between the plenum and the job, looking to create the most surface area as possible for the vacuum to ‘hold’ the piece.

(Carl Hilinski) #16

I think if I continue experimenting, I will switch to a smaller box and make it out of HDPE, which I have. Custom fixtures for repetitive jobs was a consideration because I already have those using screw-down clamps. The spiral design came out of a thought about being able to have one table and to customize the areas open for vacuum hold-down. One video I watched showed someone who made battens to lay over the uncovered holes. I think there are two issues. First, the pump I have may not be strong enough, though it can pull a veneer bag to 24/-.8 (it should draw a closed system to that but it might take a while). Second is that plenum design thing. My spiral design is like ductwork and that may not be as efficient for intake as an open plenum such as is often used in commercial office buildings. I am not an engineer, so I just don’t know this stuff.

(Jude Marleau) #17

The tests I did the other day, I sealed the mdf with spray shellac, 3 coats, and it held a vacuum, my pump is old and not used in years so I suspect the seals are dried out and need replacing as I could only get 16 inches vacuum. I can’t afford the hdpe so I will use mdf and I’m gonna paint them with kilz oil based paint (cause I have it) and see if that seals better than the shellac. It’ll probably wear better than shellac. As Eddie says I’ll make separate vacuum plates for each job with alignment pins so switching cuttings will be easier… With 1 inch thick mdf, I want to do a pattern on each side connected to the one vacuum port, than I hope the down sided pattern will hold the vacuum plate in place while the up pattern hold the panel to be cut. Big plans, we’ll see how it goes…

(Phil Thien) #18

In the world of loudspeaker building, besides shellac we often seal MDF with a mix of PVA glue diluted with water.

PVA glue is just the Elmer’s Glue-All (the white stuff we used when we were kids, not the “School Glue.”)

The stuff is cheap, easy to clean-up, and is absorbed into the MDF like water into a sponge.

Maybe give that a shot, too?

(Jerry Gray) #19

Here’s a table, I recently saw on Facebook.
T tracks, and Vacuum.

It appears you could use the rubber strips, and make several small vacuum pockets for bigger stuff, or use for smaller stuff.
Anyway, best of both worlds here?

(Jude Marleau) #20

Thanks Phil, I’ll give it a go. I also want to contact cement a piece of rubber (shower pan liner) to both sides of the vacuum table so it will hold itself down to the original waste board and hold the panel to be cut on top of it. I will have many vac tables as I will make one for each panel of toy parts. My main goal is to make this system as productive as possible and switching vac table “inserts” without clamps should do that for me. The shellac seemed to work but I wasn’t convinced if it soaked in very well but the watered glue should soak in great. Jude

Well the shower pan liner didn’t work, no surface flex, it is pvc after all. So rubber weather stripping is my only option as of now. 2 ( 1/2") thick cutting boards glued w/contact cement hold together to make a 1" thick plastic vacuum board. I’d love to find some live rubber like on the old drafting boards, but it may cost too much…For now I’ll be using mdf w/ tempered hard board (becuz I have it) contact cemented to each side and than sealed w/the watered white glue for the vacuum boards.