Would like vac table recommendations for 96-60"table

[Plyoboxwarehouse]

Hey guys, I put in my order for a new PRSAlpha 96-60 and looking forward to getting it next month! I mostly do flat panel processing of 3/4" plywood for cabinet cases and MDF for doors. Once I get the machine I would like to add on a vacuum table. I would like to get some recommendations for laying out a plenum on a 60"x96" table. Most of my sheet goods are 48" width, so I don't need vacuum on the whole table most of the time. I'm considering getting a few lighthouse blowers at least initially until I can afford a larger industrial vac pump from Busch. Right now I'd like to plan ahead to get some sort of vacuum table set up so I don't have to rip out a table that doesn't have a plenum. I specifically would like to hear from you guys with the 60" width tables. Thanks!

[David Iannone]

This is my progress. I am in the middle of a Vac hold down table build. I have a 4x8 2001 PRT with 4g board. I have always used screw hold down until about next week hopefully.

Search this forum, you will find all the answers you need. I know nothing about the whole science behind vac hold down, but I am about 2 weeks into this build and I gotta tell ya I did some tests with my shopvac today and yesterday and am very impressed. The whole plan came from this forum. I am building a vac box with 2 lighthouse motors.

Dave

[dlcw]

I made a 7 zone plenum. The zones are sized in such a way for 4x8 sheets , 4x4 sheets, 5x8 sheets and 60x60 BB sheets without having to use extra material to form a vacuum. I also use a 4x4 sheet of MDO with T-track rails for holding down smaller stuff. The MDO covers the 4x4 zones.

I use a Black Box vaccum setup designed by Gary Campbell with 3" PVC piping and RV dump valves to turn zones on and off. At 2500' altitude, I can pull about 7.5".

I also use 1/8" MDF surfaced both sides as a sacrificial board when doing sheet work. This makes having to resurface the actual spoil board intervals much, much longer. I only resurface the spoil board when moisture levels change and I see the spoil board getting a little unlevel. The 1/8" sheets cost about $6 at my supplier. Well worth the price of not having to keep resurfacing the spoil board. Each 1/8" sheet lasts me about 10 to 16 sheets of actual plywood being milled. Of course for 60x60 material, that gets placed directly on the spoil board. But I seldom use 60x60 anymore. I use 4x8 applyply for drawar box parts now instead of BB.

[MogulTx]

I don't have mine turned on ( the vacuum pump) but the guy who owned it before me used thick rubbery/vinyl stock, like you would make a floor mat out of. He placed this around parts to prevent the vacuum from "leaking" on him. ( My table is 5' wide, and he was using this for a cabinet shop, too).

That way, he just flopped this material down next to his ply or MDF and turned the vacuum on.

What you need to do is to read all the different opinions, suggestions and general musings that will pop up here, and decide which one sounds like it will fit YOUR scenario the best... and proceed with that!

Monty