Vacuum Grid/Plenum Question

[Austin Shafer]

Hello, we bought this used 144"x60" 2012 Alpha and the spoilboard was glued using some sort of silicone and was coming off. IMG_0889.JPGIMG_0888.JPGIMG_0887.JPG

So, if I resurface the grid a tad would I have to re-apply shellac? Also should I put more glue than what they had, they only put a small amount around the edges. What are your suggestions for getting this silicone off?

[ADAPT_Shop-Brady]

Running a table surfacing program from the SB software would remove the remaining silicone caulking but because the plenum is MDF, you would want to seal it again if you resurface it.
I just did our table surface and used silicone caulking to hold down the spoil board to the plenum. The caulk was placed around all the vac zones to help with zone isolation and also on roughly 10% of the "nubs" inside each zone.
Working for us.

[Kyle Stapleton]

We only seal the grid and glue the whole top down (all zones and all nubs).

[Austin Shafer]

We only seal the grid and glue the whole top down (all zones and all nubs).

I have seen this done and was hoping I would get an answer confirming that it works well.

[ByronConnDesign]

Works great, the better you can seal the edges of the grid to your bleeder the better your vacuum will be. An ultralight MDF works best as a bleeder and don't forget to surface the outer skin on both sides of your bleeder and seal the edges.

If you feel like upgrading using a rigid plastic for the vacuum grid is the way to go.

[Austin Shafer]

Works great, the better you can seal the edges of the grid to your bleeder the better your vacuum will be. An ultralight MDF works best as a bleeder and don't forget to surface the outer skin on both sides of your bleeder and seal the edges.

If you feel like upgrading using a rigid plastic for the vacuum grid is the way to go.

The previous owner did not surface the outer skin on both sides... I was wondering why they didn't.

[BoilermakerAndy]

I used wood glue to both seal the plenum AND glue the bleeder down. It's MUCH less expensive than Shellac. I also didn't know what would happen if I tried to glue a surface finished with shellac. But, wood glue is CHEAP.