Spoilboard Question

[frankwilliams]

I was sondering if anyone has tried glueing a new spoilboard sheet on to the (freshly machined) thin old one. This would save a lot of time removing whats left of the old one and to me the vacuum should work the same as long. If anyone has experience, ideas or speculations on the pros or pitfalls, I would be very interested to hear them. I searched the forum but couldn't find any direct references to this approach so I hope I'm not duplicating.

[harryball]

I machine down to about 1/4" then lay down a lot of glue around the edge, on each zone boundry and a few globs in the middle, then lay on the new sheet. I do not use the vac to hold it down, I pile stuff on top. The one time I used the vac it didn't stick... I think it pulled the glue down into the old board away from the new top was the only thing I could guess.

Robert

[bill.young]

Hey Frank,

I'd worry about the glue sealing the surface and restricting the vacuum "flow" if it covered the whole surface of the spoilboard, rather than Robert's "tack welding" method. I've got no experience or scientific data to back it up, though...just a hunch.

Bill

[harryball]

Covering the entire surface with glue would be the same as sealing the surface and it would restrict the airflow. I basically applied the glue in the same places I applied it during the original gluedown to the vac grid. I've not noticed any decrease in performance and my guage still reads about 1" or a tad more on an open table.

I think next time I may cover the table top with plastic then turn the vac on so I have vac but almost 0 airflow. The airflow is what I believe pulled my glue out of the upper board last time causing it to fail to adhere.

Robert

[frankwilliams]

Thank you for your input. I should have been more clear, I was only thinking of glueing as Robert suggested and glueing around the zones, not over the whole spoilboard. Now all I have to do is find a few hundred, (maybe thousand) pounds to weight it with (sorry about the fridge honey, ha ha ha).

Thanks Again

Frank

[daski]

1 sheet of melamine on top of the spoilboard and turn on the vac, works like a charm.

[ryan_slaback]

Frank,
Regarding the necessary weight...

Got a Mother-in-law?

[john_l]

"Got a Mother-in-law?"

I think Ryan means get her to help carry out the fridge.

[jhicks]

We have a 4 layer system made of 4 sheets of material.
(Base & plenum are MDF), (bleeder,spoil board are Ultra Light Trupan)

1 BASE Bottom is sealed with 2 coats of shellac on bottom side and edges then BOLTED to frame. One could surface this but that takes place on upper layers so not required.

2 PLENUM layer is attached to BASE with glue between them for permanent base/plenum/zone layer now 1,1/2" thick and screwed with 1,1/4" screws from bottom thru base into plenum selectively along edges while standing on it or applying as much weight as possible to hold down and allow glue to dry between MDF sheets. Just add a stack of plywood sheets etc to hold down and dry.
BE CAREFUL with screws as you will be machining plenum grid/zones into this next!

Do not forget to design this all in advance to position vac line holes and grids in proper positions and avoid base cross members etc.

When glue is dry follow A B C D E& F steps

A machine/surface top of unsealed plenum sheet #2 flat.

B Cut plenum zones into it with 1/2" or 3/4" core box/ball nose to create your grid design. (ball nose better than dado as it has no sharp inside corners to seal rather smooth radius air channels easy to seal.

C Border the perimeter of each zone with a 1/4" wide x.031 deep dado for perimeter gasketing to be applied after sealing. Offset outside plenum grid approximately 1/4" to 1/2" outside the zones

D Cut in vac pipe holes being careful to avoid any support steel or screws so design everything in advance to space properly!

E Then seal everwhere well with shellac on top and sides of plenum together with base edges again. Two coats over all surfaces and leave to dry.

F Apply AllStar adhesive 1/4" x .062" thick gasket tape in the .031" deep perimeter dados around the zone perimeters.
Plenum is now complete!

Set up vac plumbing into the zone holes and seal with any silicone or whatever you choose inside hole at pvc pipe/MDF base/plenum joint.

3 is BLEEDER BOARD Add the ultralight/trupan, turn on vac. Eureka it holds. Machine it/surface it flat, flip and surface side two. This breaks surfaces and improves air flow/suction while reducing thickness of bleeder down to approximately 5/8" or even 1/2"
Seal edges of this bleeder if you like but not absolutely necessary at all.

We never cut into this base/plenum/bleeder board 3 layer combo.

4 is SPOIL BOARD of another 3/4" ultra lite on top of bleeder. No mechanical attachment necessary from our perspective.
Lay sheet on top, turn on vac in all zones, and surface both sides.
DONE!

This 4 sheet combination has been in use for over 16 months but no reason to think the 3 base/plenum/bleeder layers will ever need replacing. Maybe resurfacing some day to thin the bleeder layer but not required. It might give us more holding power if we decide to do that though.

We surface the top spoil board repeatedly on alternating sides until its about 1/8" thick, then dump it and replace with a new one, surface both sides of the new sheet and start over.
The bleeder and top spoil board are held only by our two 5.5 hp rigid vacs and do a surprisingly good job with no screws, glue or any mechanical fastening.
Once vac is on, gaskets and suction hold everything together and away we go.

Happy New Year and no matter how you do it,we think a vacuum is an absolutely essential low cost addition. I can't believe we avoided it for two years with screws, clamps etc and it was like a miracle when we saw how easy and effective this simple addition was to sheet change over and holding the work. I think we spent $350.00 to implement plus 2 life time guaranteed Home depot Rigid shop vacs.
When we do run small or long soilds, we simply add another fixture sheet made from Melemine about 12" x 96", vacuum it down and screw or clamp the solid stock to it so as not to put any screws in the spoil board or deeper into the bleeder.

[john_l]

I do not mean to change the flow of the thread but.. Jerry, I am very new and still just trying to understand the various setup choices. If I may ask what's likely some elementary questions to you... Why the gasket material between the cut plenum grid sheet and the underside of the next sheet? Why the forth sheet at all? Couldn't the 3rd sheet (bleeder) just suit as the spoil board anyway?.. and wouldn't that save you another 3/4" under the spindle/gantry to leave out the last sheet?

Thanks!

[jhicks]

Hi John, good questions so here are my reasons. As always different strokes for different folks so I only provide what works for us and why we do it. Always more than one way to skin the cat so take what works and modify for your own purposes.
Gasket material ? Ok, the grid/plenum is in fact surfaced flat, then sealed with shellac so why gasketing?
Well the next layer is very porus ultralight and it is not sealed so it sits on top of the shellac plenum under its own weight (not very heavy) and we have 10 independant zones on our table each approximately 12" x 48". So when I want to use just one zone for a 12" x 48" area, how do I focus the vacuum as much as possible under/in that area?
My answer is gasket it around the perimeter, turn on the vac in that zone, and the primary vacuum will be restricted to that area/zone. The vac sucks down the bleeder that .031" created by the gasket rising above the plenum board and seals it as much as possible from leaking outside that zone. It does not prevent vacuum from moving through the material laterally inside the ultralite but it does concentrate in the zone well and wont leak between the plenum zones. Some may say it works fine with no gasketing but we found improvement and gasket tape is cheap and tight zones really increase the vacuum in the intended areas.

On top of that the Ultra lite will tend to cup after machining on only one side or even with age and humidity conditions so by using gaskets it adds an extra measure of sealing at each zone.

Finally the gaskets tend to prevent the bleeder from slipping and sliding on the plenum by adding resistance as they are kind of a spongy material rather than the smooth shellac surface on the plenum.

Why 4Th sheet SPOIL BOARD? Well its not an absolute on this either. One can certainly have their bleeder and spoil board in one BUT you will constantly be cutting away at it when surfacing and eventually it will distort as it gets thinner.

With the 2 layers the bleeder is pure and flat and never changed (make it thinner if you like but not too thin.You want it to be stable and FLAT)
And as the spoil board gets used and resurfaced it gets thinner and thinner until its gone. Again as this is done one does witness some cupping unless its flipped over and surfaced somewhat equally on both sides when recycled.
Of course you could use a 1/2" sheet or 1/8" spoil board but it wont last very long before needing replacement.
YES it does reduce your active Z Guess technically since the spoil board and bleeder are surfaced both sides before any use approx .062 so total is reduced by 1/4" making it only 1/2" more then surfaced as needed.
Hope this helps explain why we did it that way. Making it work for you is what counts so experiment away and post whatever you come up with as vacuum hold down is a key to every botter.

[john_l]

That all makes good sense.. Thanks Jerry

[gskinner]

Jerry,
I have just started a plenum and spoilboard setup like yours and have just a couple of questions.
How are the Rigid vacs holding up to the constant use?
Is the gasket the Allstar CR-06-25 and what length is on a roll?
Thanks

[jhicks]

George, the rigids are lifetime guaranteed so if you lose it, take it in to HD for replacement but I have had no failures after some fairly heavy use over 18+ months.
The gasket is the 062-25 and I think it comes in 100 ft rolls or maybe even larger. Need to contact them for specifics. They are always very helpful.

[gskinner]

Thanks Jerry

[claude12345]

JERRY COULD YOU POST A PICTURE OF YOUR PLENUM SO I CAN FIGUER OUT HOW TO ROUTER THE ZONES ON MINE IF THATS POSSIBLE THANKS

[claude12345]

JERRY jusy wantsd to thank you for the pictures great help

[john_l]

Where's the pictures. You guys not going to share?

[handh]

Yes, please post the pictures for John........and us too. Always want to see what others have to share.

[claude12345]

ill post mine as soon as i finish my machine wont arrive for another week as long as jerry doent mine it is his design . i hope i didnt put you on the spot

[jhicks]

Sorry John, This entire discussion was on the forum earlier and Claude e-mailed me so I sent them directly to him. Here is the top zone view and simple photos of under the table. Hope it helps.

6559
6560

[john_l]

NP Jerry. I was half joking anyway. I thought I had seen them all by searching the archives but I had not seen yours.

What I just bluntly realized... you actually mean Rigid shopvacs when you say shop vac discussing your system. I thought you were just referring to a Fein as a ShopVac.

It looks great, well done, there isn't much you can't hold with that setup. Sorry to cause the repost.

Thanks, John

[jhicks]

Hey John, YEP a real HD rigid vac does the trick. In fact right before Christmas thsy had them on sale for $29.00 so thats hard to beat.
as far as holding sheet goods its pretty versitile up to 5x10 sheets and most variants inbetween. As far as smaller pieces, we vac down another spoilboard in a 1' x 4' section then just screw or clamp the piece to it and that works well for the hardwood or plastics in smaller pieces

[gskinner]

Jerry,

Do you know how much vacuum your Rigid vac is pulling?
I have one of the best 6.5 hp that Home Depot sells and my vacuum gauge only shows 3" of vacuum, and that is with all the valves closed. I have also tried another vac that I have and get about the same results.
Before I get another vac to go with this one I want to be sure this will be enough vacuum to hold things down.
If this doesn't work I may try the 9-15 vacuum project and hopefully get at least 9".

If anyone else can chime in and let me know how many inches of vacuum are working for you that would be appreciated.

Thanks

[Brady Watson]

I started my vacuum endeavor with that exact vac...best it ever pulled was 3.5" Hg - not enough to bother with unless your parts are really big. Go for a Fein T3 or the 9-15.

-B

[gskinner]

Thanks Brady, Looks like the 9-15 for me.

[jhicks]

Hi George, Not sure and never measured on a gauge. All I know is it works for me with lots of cutting in 3/4" ply cabinet parts, signs in hdu and plastics. Not sure what Brady means by "unless your parts are really big" but we cut drawer faces 5" x 18" cabinet strechers 4" x 28" and acrylic circles 3.5" diameter in 1/4" acrylic.
Maybe thats big but I'll never try to convince you it will be your solution. More vacuum is definately better so get as much as you can. Either way the plenum system works well.
My friend with 2 feins thinks the rigids hold better just make more noise so to each their own.

[claude12345]

can anyone give me a hint on how and what program to use to resurface my spoilboard thanks in advance

[Brady Watson]

In the SB3 control software, goto: Tools-> Tabletop Surfacer or just type in the TU command into the box. Follow the instructions carefully & you'll be fine.

-B

[claude12345]

thanks jerry i got it done and it works perfect