Equal Finish On Both Sides

[Randall Frey]

Yes, it's me once again. On my dining table project I am wondering the extent to which the under side of the table should be finished or sealed from the elements. I want to prevent the top from warping and at present, I have the top and under side treated the same with stain and a 1lb cut of shellac. I will be applying RH varnish to the top. Does the under side need equal treatreatment of varnish as well? Or if the bottom needs more, can I just wipe on more shellac? Thanks All, Happy Holidays

[Jim Becker]

THe bottom doesn't need anything, although I typically will put a coat of shellac on the bottom just to keep it "clean". Finishes still let moisture through. Besides, if the top is installed correctly to be held flat with allowances for wood movement, it's not going to "warp".

If you were veneering, you would need to put a backer veneer on the bottom, however, to avoid warping due to shrinkage.

[peter slamp]

Excellent! I was just about to ask the same question! Thanks.

[Randall Frey]

Thanks Jim,
You answered my question. My thought was, since the RH varnish will be a thicker finish layer on the top than the thin shellac on under side, I might still have issues with the rate at which moisture will come and go therefore causing a warp. The table is a dual pedestal type so it won't be screwed to a solid frame. I did make a 3 1/2" apron that will be attached to the under side as well as the table slides to accomadate the leaves. All have been fashioned to compensate for movement and to help hold it flat but as we all know wood moves so I thought I would ask. Thanks

[Steve Schoene]

For a pedestal table, or other form that doesn't have a frame to maintain flatness, it is more beneficial to balance the top and bottom. But don't get carried away--since you are only scuff sanding between coats, you don't need as many coats as on the top, where the between coat sanding may also be leveling the finish.

[Randall Frey]

Thank you, I will build up the underside a bit to help keep things equal.