# Will Wood Glue stick when bonding to a stained/poly surface?



## wilschroter (Dec 17, 2016)

I'm building a closet with some pre-finished stained/poly'd poplar and need to glue some of the components together.

In your experience, does wood glue "hold" when trying to glue a piece that has a light poly coat on it? I'm using Titebond II … if there is a better answer for this type of application would love to hear it.


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## BlueRidgeDog (Jan 2, 2019)

No. You can use epoxy, but that will only bond to the poly and the joint will only be as strong as the poly to wood bond. Typically you mask off areas that will be glued when pre-finishing.


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## HokieKen (Apr 14, 2015)

I wouldn't trust it. Poly is a film finish which means it's on top of the wood. So, even if the glue bonds well with the poly, it's really not bonded to the wood. You essentially have 2 thin films of poly glued together and wood hanging onto the poly.

Is there any load on the pieces that need to be joined? Can you use dowels to join them? Sand away the poly only in the glue joint areas?


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## jonah (May 15, 2009)

Definitely not. I can scrape dried wood glue off my workbench (which has finish on it) with a piece of plastic.


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## wilschroter (Dec 17, 2016)

@HokieKen I was trying to avoid puncturing the surface in any meaningful way (since it's a cabinet-style finish in the closet) but that may not be an option.

These aren't *heavy* load bearning shelves - they may hold 6 pairs of jeans - but I also don't want to worry that some weird pressure will make them fall off either.










You can see in this image (it's a Sketchup render) where I'm using 1" tall by 1/2" thick poplar to hold the shelves. I'm trying to think of how to attach those brackets in a way that avoids using any fasteners from the face into the 3/4" wood behind it.


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## HokieKen (Apr 14, 2015)

What about pocket screws? If you join those supports with pocket screws from the back then the screws wouldn't be visible and wouldn't go into the back either.


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## wilschroter (Dec 17, 2016)

@HokieKen What do you think about using dowels? I can actaully drill directly through the back of the side frames into the 1/2" poplar. I'm just thinknig that maybe 1/2" poplar doesn't leave me a ton of depth for the dowel but it may not matter if ultimately it prevents the shelf from moving downward.


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## HokieKen (Apr 14, 2015)

I think dowels will form a perfectly solid joint. I'd use the fluted ones to make sure you utilize as much surface area as possible for the glue joint. One at each corner and one in the center should be sufficient IMO.


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## Jeff28078 (Aug 27, 2009)

With a narrow sanding block you could scuff up the surface behind the poplar giving the glue something to hold on to.


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## BlueRidgeDog (Jan 2, 2019)

Why not just put in shelf pins, so they are adjustable and free to move, but supported?


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## wilschroter (Dec 17, 2016)

@blueridgedog - I don't like the look of shelf pins. Have done those in some other closets and for this particular installation really like the idea of very solid-feeling fixed shelves.

Otherwise that would definitely be the way to go.


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## BlueRidgeDog (Jan 2, 2019)

In that case just use epoxy and move on. Will hold for what your use will be and if it ever lets go you can put dowels in.


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## Snipes (Apr 3, 2012)

I don't know why they need to be fastened together in the corner there, but I think your making to much work of it. use some finish nails a little filler and you'll never see them. They will have clothes on and never be seen.. Otherwise a clear polyurethane caulk would work for glue.


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## wilschroter (Dec 17, 2016)

Presumably any perpindicular "pin" - dowel, finish nail, et al - will prevent the shelf from moving up and down right? I know that finish nails aren't terribly sturdy, but I'm wondering how the shelf would move if it has nowhere to go but up and down (and there is a "pin" by virtue of a nail).

Someone earlier in the thread suggested a finish nail won't hold.


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## HokieKen (Apr 14, 2015)

I don't see any issue with a finish nail, depending on the load on the shelf. But, if it's just some clothes, I think a few nails will do the job.


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## Snipes (Apr 3, 2012)

I've done quite a few closets and I use finish nails all the time and never had an issue. Not sure how your doing yours. complete cabinets or sides and shelves against your existing walls? If i'm putting cleats to prefinished wood as you have shown I use few dabs of polyurethane caulk(generally OSI) and a couple 18 gauge nails. if the back cleat is going through rock into studs 16 gauge nail be plenty. If your doing prebuilt cabinets then I would build similar to kitchen cabinet.


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## RichT (Oct 14, 2016)

No one can answer this question authoritatively due to the many factors involved. What I would recommend is taking two pieces of the pre-finished wood you're working with and gluing them together to see for yourself what load they can handle.


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