On Saturday, May 21, 2016 at 10:27:27 AM UTC-5, G. Ross wrote:
> Just my (ignorant) opinion.
>
Not ignorant at all.
If you clamp the slab, to close the crack even a little, you are very likely to crack the other side, somewhere. Those transverse cut slabs just don't cooperate with clamps. I've tried closing lots of cracks, that way, mostly with cypress and ER cedar, but they seem to always crack on a back side.
You can try clamping a little, but listen to the wood closely. If you hear any sign of minute cracking, then stop.
If you stick that slab in the hot sunlight, the heat will cause it to expand and you'll hear similar minute cracking sounds. ER cedar actually makes popping sounds, more so than small cracking sounds.... I suspect because of its volume (and type?) of resin, as compared to other woods.
I wouldn't use the wood chips or sawdust. If you had very large areas of, say, decay holes on the underside, then filling those, with a sawdust mix, would work out okay. The sawdust and chips mix would trap air and the bubbles would rise to the surface and look unsightly, on the upper topside surface.
Not only air bubbles showed, but it'll be rough... hard to sand and impossible to sand as smooth as you would want your table top to be, i.e., pretty and nice looking surface.
Link is pics of a sawdust mix filling (and use of boards/slats) on the underside of a cedar table top, with decay holes/defects.....
And the topside filling with red colored epoxy, only... no sawdust. The bar clamp was used to pinch the crack closed, slightly (1/32"), before installing the dutchman. *I used too much red dye for this project. The filling was/is too red, i.e., mismatching the color of the wood.
https://www.flickr.com/photos/43836144@N04/?
Sonny