Fastenening the spoilboard down maybe I goofed?

[knight_toolworks]

I did not want to have to mow off the old spoilboard on my newly setup vacuum table so I used double sided foam vacuum tape to seal it and hold it in place.
But the downside to this is if the vacuum is not on the table is not flat. I found this out when I used another zone for the zero when cutting through a part and I could not get a full depth cut.
I thought the top had settled a bit since the setup was only a few days old. So I flattened the top only to have my two feins shut off from tripped breaker then a powerstrip trip. The flattening was far deeper in the middle without the vacuums running. So I ended up taking off extra.
But reading more do I need to remove the first spoilboard? Will the vacuum be affected going through two layers?

[dray]

I dont have a vacuum setup yet but having a completely flat surface is critical!!.

If I were you I would pull up that top sheet, if the spoilboard is over .50" I would just machine it flat then use that.

The more you have to suck through , yeah you are going to lose vacuum.

[knight_toolworks]

it's flat when the vacuum is on. but only on the zones that have it turned on.

[dray]

Take that foam out!!

Hey steve ,I need a small plane that will easily fit into my tool bags with a blade about an inch wide for cleaning up edges of sheet goods. I want to be able to take off around 1/64 to 1/32" per pass easily. What do you suggest in your line up?

[knight_toolworks]

I should be able to wait till I screw up the top enough. I did some full sheet cuts today and the depth was right on.
but now to fasten it on but be able to remove it with planing the whole top?
the pocket plane is the tool for what you want.
I only have one sheet of ultra light mdf left so I can't waste it.

[thewoodcrafter]

Steve,
I am still on my first spoil board so I have not been doing this long.

I fastened down the spoil board by recessing washer headed screws. I have 4 down each long side and 3 on the short sides.

I have 4 zones. I edgebanded the spoil board and ran packaging tape around that edge to the vacuum plenum.

When I replace this spoil board I plan on dadoing a groove for a gasket all around the table and in between the zones and a few out in the middle of each zone to support the spoil board so it does not suck down. I think with the right depth dado and the right gasket material it should lay flat anyway.

If you can get your spoil board off, try placing a few pieces of tape out in the middle of the zones.

[bleeth]

Steve: You should take your spoilboard up and make sure there is adhesive (or whatever you use for holddown-I've been using screws for years) balanced through the interior as well as around the edges. If not well secured the board will definately cup if large areas are not secured.

The best way is to glue it down.

[knight_toolworks]

I htink what I will do is route a channel on the main board for soem foam one sided tape. so there will be a seal but nto enoug hthickness to cause lift then I will drill holes in the board for threaded inserts and use that same hole pattern to drill the spoilboard. then the holes will always be in the same place and screws won't wear out the bottom board.

[joelschuman]

I go thru a spoilboard about every 6 weeks. I have tried both screws and tape, but now I use Phenoseal adhesive in a very shallow (.040") channel. Screws mean replacing the spoilboard before it has been completely used up, and I was never able to get the spoilboard to stay put with tape. I tried several woodworking glues, but they all let go prematurely.

When I replace the old board it is so thin I can tear it off with my bare hands, but that makes a mess. Instead, I use a part file that cuts thru the remaining spoilboard and the old Phenoseal, which is in a 1-1/2" band around each vacuum zone. Then I squirt a fat bead of Phenoseal, spread it in the channel with a plastic squeegee, lay down the new spoilboard, turn on the vacuum, and clamp the ends with curved cauls, since the end is where a board breaks loose when it wants to curl.

Using the Bot to get rid of the old glue saves a lot of time, compared to peeling it up with a putty knife (or removing a zillion screws). The ease and speed of replacement means that I don't think twice about resurfacing the spoilboard, especially since I got a 2-1/2" HerSaf insert cutter. < 10 minutes to resurface (including bit change), about half hour to replace spoilboard.