Sealing off unused spoilboard

[phealey]

Hi, I've got a question.

We have a 120'' x 60 '' shopbot system but never use it to cut anything more than 53'' wide. How would we go about sealing off the extra 7'' of the spoilboard to help improve vacuum suction on the rest of the board?

Thank you,

Pat

[supertigre]

I use a piece of Mylar to seal off any unused vacuum real-estate.

[bleeth]

You could also seal it with a couple coats of shellac. Another thought is to cut a narrow straight groove and then fill it with something that will still cut nicely when you need to re-surface, thus isolating it. A strip of HDPE comes to mind. Bondo would likely work as well although it is somewhat porous, but not nearly as porous as mdf.You could use 1/4"mdf with melamine on both sides if you do cabinets and have that laying around, or even a piece of pre-fin 1/4" birch/maple ply.

[dlcw]

I just use pieces of hardboard - shiny side down. I've got several pieces I can place around material to seal things off.

[bearcat]

We use 0.020" thick calendered vinyl sheeting to mask off open areas. It's cheap and flexible enough under vacuum to be pulled tight against the material/table.

Ed

[curtiss]

Have you tapped in a vacuum gauge into you vac table somewhere so you know what is happening ?

Pretty easy to do with a pipe thread tap and a few fittings and a $10 auto vac gauge.

[terryjones]

I use several different sizes of pond liner depending on the size of the project. Just lay them to finish closing the vacuum zone. A friend of mine uses some shower pan sheet material from Home Depot. Both work equally well.