[SixOfOne]

I'm looking for opinions more then answers, this could be done a handful of ways I guess..

OK what I am going for is like the attached picture I found. I already have the first layer of 3/4" MDF bolted down & T-Tracks screwed down. I am getting ready to start making the second layer strips of 3/4" MDF to go between the tracks.

My question is.. Should I remove the T-Tracks and surface the lower MDF layer or glue down my second / top layer of MDF and surface only that?

[justindewoody]

My opinion is unless you are going for super precision (something like .001 or less), it's pointless to surface the lower MDF. Just put everything together and surface the top layer. You will still end up with a very flat top surface. Only the t-tracks might be out of flat by a few thousands, but that shouldn't matter. I really like this idea for a spoil board. I might end up doing it myself. Where did you buy the t-tracks? I got mine from Orange Aluminum (Aluminum T-Track).

Justin

[jcarpenter2]

I'ld just do plane the top board. If you do the bottom one, you'll still have to do the top one so why waste the time. Like justindewoody said, your track may have a slight variation but i dont see where that really will matter.

[SixOfOne]

I got mine from Orange also, I told the wife what I needed and she actually found them. Price wasn't bad at all, hope that they work well. I didn't have any 1/4-20 bolts on hand that were clean enough to use, also 1/4 hex heads seemed a little loose in the track to me. I do have a large assortment of unused 5/16 carriage bolts from another project. I ground the heads flat on the sides to get them to fit but haven't tested them clamping anything yet. Seems like they will work, I hope.

I'll just surface the top layer and then seal it with something. I didn't want to remove the tracks anyways Thanks guys

[plcamp]

Your spoilboard is quite similar to mine. One primary difference is that mine is mounted to a wooden base with a 3/4" Baltic Birch top. I screwed 1/2" MDF to the plywood and then screwed 3/4" MDF to the top to create the actual throw-away spoilboard. This created a very solid and stable surface which was then surfaced (top side only) and sealed with 2 coats of shellac thinned with Denatured Alcohol at a 1-to-1 ratio. The seal helps with moisture control and makes clean up a snap. My all wood machine is now 2 years old and exhibits the surface scars of many projects which have not been resealed, however, I will re- surface and seal again before the Indiana summer and moisture arrive. My machine when new yielded .003" and over the 2 years of service has only degraded .002" over the entire 38" x 32" usable work surface.

[discojon]

I did mine very similarly also. I took a 3/4" MDF sheet, pocketed it and bolted it to the 80/20 rails. Then pocketed and cut planks out of another 3/4"mdf sheet. The planks bolt through the bottom board and help with rigidity and they are easily replaceable. When I redo them, I plan to undercut the bottoms so they encase the t-slot for added clamping support.