[Tony B]

Unless this was a typo, it sounds like although you finish both sides, almost all pieces you have seen were NOT both finished. Soooo, doesnt that mean it is, in fact, more myth? Im confused because some comments after your seemed to say finish both sides. Sounds like one of those issues where there seems to be little agreement? At the very least I dont see the harm in finishing both sides.

@kindanewbie
Not necessarily myth. I am not sure what factors are at play. Could have something to do with age or maybe construction methods or wood drying methods. Maybe has something to do with the interior environment. Dont know. Was just making a statement about my observations that are contrary to popular belief.
I was raised in a 'finish both sides' world and from habit, I finish both sides of a table top. One, because it makes more sense and two, because I spray lacquer and it only takes seconds to spray the other side and only minutes to dry.
If I am building a dresser or chest, I only finish the outside. I also dont finish the drawers either. Only the drawer fronts. I make the box and the fronts are 'add-ons'.
Next time you pass an antique shop, stop and go in and check it out for yourself.

 

[kindanewbie]

Clearly, not finishing both sides is far more common. Not a single piece of furniture or cabinet in my house has unseen, finished sides. And nothing has any kind of [detectable] warp. On top of the many pieces you (and we all) have seen elsewhere. I think that secures a spot for the finish both sides method in the "why not, do it just in case" category.

So, a long thread and a lot of responses help something that is actually very simple finally sink into my thick skull:

• Thoroughly dried wood, kept in a stable environment, will have some limited expansion/contraction, but shouldnt cup
• Good technique (paying attention to grain, finishing, edging) add addition strength

 

[Rebelwork]

Clearly, not finishing both sides is far more common. Not a single piece of furniture or cabinet in my house has unseen, finished sides. And nothing has any kind of [detectable] warp. On top of the many pieces you (and we all) have seen elsewhere. I think that secures a spot for the finish both sides method in the "why not, do it just in case" category.

So, a long thread and a lot of responses help something that is actually very simple finally sink into my thick skull:

• Thoroughly dried wood, kept in a stable environment, will have some limited expansion/contraction, but shouldnt cup
• Good technique (paying attention to grain, finishing, edging) add addition strength

Cabinets are finished on the seen parts and inside. Furniture You made or bought?

 

[kindanewbie]

Cabinets are finished on the seen parts and inside. Furniture You made or bought?

I mean for my kitchen cabinets from a cabinet maker.
All seen parts are finished but not the unseen. So five sides to each cabinet: left, right, top, bottom, back. The left, right, and bottom are finished on both surfaces. But the surface on the back side that is against the wall, and the top facing the ceiling are not done. Althought that is plywood with formica. I still would think that the cover both sides would apply if relevant as i have seen plenty of plywood warp.

 

[Tony B]

Exactly my point.

 

[Rebelwork]

Cabinets installed unfinished will have unfinished parts. This is not unusual..

 

[Tony B]

................... i have seen plenty of plywood warp.

Probably because it came from Home Depot. LOL
Seriously though, If I am using Formica on a large surface, I will use what is called a 'backing sheet'. It looks like the brown backside of Formica but on both sides. I havent built anything large enough to warrant it in a very, very long time.

................... But the surface on the back side that is against the wall, and the top facing the ceiling are not done.............

Two reasons, there is not any significant amount of air exchange and also, these pieces are glued/nailed/screwed/inset sufficiently to another part of the cabinet.

 

[Rebelwork]

We never use a backing sheet on residential counter tops, but we do on jobs like power plants, etc..

 

[Tony B]

I have only used it on large tables on particle board, MDF and plywood. One time I used it in my shop on a 4' X 8' MDF Assembly Table using a grid pattern inside (Cant recall the name for that) getting older is a bummer at times. I'm sure I will remember as soon as I press the enter button on mu laptop.

 

[Mud]

For what it's worth, my very first project involved a bench seat/coat rack organizer for my drop zone in my house.

I heavily glued a piece of 3/4" red oak to 3/4" birch plywood. Boards were about 18" wide, about 6.5 feet long.

I also screwed the oak down from underneath the plywood. I do not know why I did this much fixing, it was my first project and I didnt know any better. It was WAY over constrained, no consideration for growth direction.

Everything was fine until 4 to 6 weeks later when winter came. The red oak split down the outer third as if I had split it with a chisel.

There was no way to repair it that I could think of other than to rip it out and start over.

Gluing the crack didn't work. At this point there was no way to reclamp it.

Moral of the story is, be careful about gluing thick lumber to plywood. The wood always wins.

If I were doing your project, I'd consider laminating veneer squares onto the 3/4" plywood.

 

[Tony B]

@Mud
Generally not a good idea to glue solid wood to plywood except on edging kinda stuff. Solid wood expands and contracts and plywood dont. That's the problem.
If however, for whatever reason you want to affix a solid wood board to a plywood board more than 6" wide or so, Use screws. Instead of drilling a hole for the screw in the solid wood, make a slot. That way, when the board expands and contracts, the screw can ride along the slot back and forth.

 

[Mud]

@Mud
Generally not a good idea to glue solid wood to plywood except on edging kinda stuff. Solid wood expands and contracts and plywood dont. That's the problem.
If however, for whatever reason you want to affix a solid wood board to a plywood board more than 6" wide or so, Use screws. Instead of drilling a hole for the screw in the solid wood, make a slot. That way, when the board expands and contracts, the screw can ride along the slot back and forth.

Thanks. For the next bench I built, it was all birch plywood and MDF with simple construction, so lesson learned. Poplar lumber was used for simple face frames.

 

[Rebelwork]

Poplar is a good shop material..

 

[Mud]

Poplar is a good shop material..

I like poplar for anything I will paint. Generally not a fan of stained poplar, although I have stained poplar in my house (stair hand rails, mantles, benches) and it looks just fine, lol.

 

[Rebelwork]

It’s just a good solid wood to work with.. like I said, shop material..

 

[kindanewbie]

@Mud
Instead of drilling a hole for the screw in the solid wood, make a slot. That way, when the board expands and contracts, the screw can ride along the slot back and forth.

And just when I started to feel confident about glueing the squares to the substrate.

Ok, veneer isnt an option because Im doing this because of the wood I have, as opposed to buying wood because of the project I want to make. What i can do, I suppose, is cut the pieces thinner. Not down to veneer thickness but... 1/4, maybe 1/8? Would that have any impact?

So, the suggestion of screwing, with slots means no glue at all? Essentially as you would with a panel in a cabinet door? Are tables normally made that way? I guess part of the answer is that tables arent normally solid wood on top of ply/mdf.

So.... back to no knowing what to do as far as securing the chess board to its base.

And I was this close.

 

[kindanewbie]

@Mud
Generally not a good idea to glue solid wood to plywood except on edging kinda stuff. Solid wood expands and contracts and plywood dont.

No such thing as a stupid question, right?...
When gluing solid wood to ply as edging, should the solid wood be rings up or down because this way if the wood expands will expand into and away from the plywood. As opposed to rings facing to or away from the plywood where the wood would expand up/down. Or does the lack of thickness of the edging make this irrelevant?

 

[kindanewbie]

So, Im at a loss again.

I will make a chessboard 3/8 thick. It will be 16" of squares, then a thin inlay border (1/8") then another 4 or 5 inch edging To get to about 26 inch wide table. Seems a bit small so might do more border, if not all 4 sides maybe front and back for a more of a rectangle. In any case, the point is all of this will be solid wood, glued together.

Now to make it a table top. Do I:

• Glue the 3/8 to 3/4 ply?
• Screw the 3/8 to the ply from underneath, with slots, and no glue?

 

[B Coll]

Unless this was a typo, it sounds like although you finish both sides, almost all pieces you have seen were NOT both finished. Soooo, doesnt that mean it is, in fact, more myth? Im confused because some comments after your seemed to say finish both sides. Sounds like one of those issues where there seems to be little agreement? At the very least I dont see the harm in finishing both sides.

It is not a myth. Any door manufacturer warranty explicitly states that all surfaces of the door must be sealed. I recall having a rep. from Morgan Door at one of my job sites over door failures. The first thing he did was put a mirror under the door, look at the top edge, and even pulled the door handles off to make sure all surfaces were sealed or the warranty is a no-go. Last week I was at one of our jobs and the subs failed to seal all surfaces of a $6k Simpson entry door set. A door style has 1/2" of bow in a door style. I have no doubt Simpson will reject our warranty claim.

 

[Tony B]

..................
So.... back to no knowing what to do as far as securing the chess board to its base.

I use "Z Clips" almost exclusively for table and furniture tops. They can be purchased from any woodworking store and also Amazon. They are relatively inexpensive.
They are very easy to install if you haven't made your Apron (frame) yet because you can use your table saw to make the slot before assembly. The slot is just what it implies.
If your apron is already made you can use the Figure 8 clips in the lower half of the sketch. I have never used the Figure 8's but I think @Rebelwork has.
Either way, it is a piece of cake to do. BTW: NO GLUE