Advice..Opinions..Direction for 4x8 table

[mrgadget]

Been reading through the threads about vacuum tables, t-track, etc... My shop is not sealed very well and these very humid days in Georgia have me concerned about using any kind of plywood for the support layer (even Baltic Birch). I can get a sheet of PVC 1" thick and was thinking of using this for my support layer and cutting the plenum and t-track slots into the top of this sheet of PVC. I plan to add a universal vacuum sometime just not now. I want to use the t-tracks to hold a sacrificial table(s) that I can attach whatever I need to cut. If I need to cut a full sheet, which will be sooner than later, I'll go ahead and get the vacuum system hooked up, but for now I want to get started cutting. Does this sound feasible to you guys?

[beacon14]

How much thickness will remain where you rout out for the T-track, and how well will you be able to secure the T-track to that remaining thickness? I'm not real familiar with 1" PVC but those would be my main concerns.

One other thing to consider, PVC changes dimensions not with humidity but with temperature. You'll probably want to use slots instead of holes to secure it to the table. Not sure I'd want the table to be able to move that much.

Personally a well-sealed sheet of Baltic Birch plywood appeals to me more, with a second layer of the same material or MDF for the T-track and eventually the plenum.

Just my opinion, I'm sure you will hear others as well. I'm pretty close to you and my shop has a constant stream of outside air being pulled through all year long. My sealed BB Ply/MDF table stays nice and flat.

[mrgadget]

Thanks David. I guess I was trying to reinvent the wheel with the PVC. Seems like Brady has been there done that with it and it doesn't work too well, at least with what I was trying to accomplish and for the same reasons you stated above. I went ahead and ordered some MDO, Medex, and ULMDF and will put it all together and see how it comes out. I was going to go the Baltic birch route, but the MDO was almost half the price of the BB and it should work as well as the BB. Guess I'll see when I get it together. I have high hopes, though!

[beacon14]

Good luck, let us know how it turns out. Where did you end up finding ULMDF? I'm still working on getting Trupan sent in. Wurth Wood Group (aka Worthless Wood) has it in Charlotte, never heard back with a freight quote but will try to follow up next week.

[mrgadget]

Found some at Hardwoods Inc. in Mableton. It's Sierra Pine I believe and it has Masisa stamped on the edges. Don't know how it will work out, but willing to give it a try. I've yet to get my vacuum motors so I may end up just cutting it getting started if you're able to get some Trupan! I echo your sentiments about Wurth(less). Never had any luck dealing with them either.

[beacon14]

I tried a couple of sheets of the Sierra Pine a few years ago. I worked OK but I like the Trupan better. The Sierra Pine seemed to like to curl a little more as it was surfaced thinner and it didn't hold tape on it's edges as well as the Trupan. But if it's all you can find it does the job. I'll post about the Trupan once I hear something. Right now I still have one sheet left so it's not at the top of my list - yet!