# What did I do wrong? Face gluing



## ChiefDJ (Nov 17, 2015)

So Im trying to glue a 5.5" x 12" 1/4" thick piece of maple to the same size piece of purpleheart face to face - resulting in a 1/2" thick piece.

I jointed and planed the faces and they dry fit together nicely. I used a generous amount (but didnt feel it was too much) of tightbond 3. I used clamps plus cinder blocks over 3/4 plywood to keep flat. Left for 30 hours.

The result was a nightmare. I wish I had taken pictures, but in no way were the boards flat. Despite the weight holding it down, the maple seemed to have warped and there were big 1/8" gaps between the boards in places.

Where did I go wrong?


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## DBDesigns (May 29, 2018)

This is pure speculation but it sounds like maybe you used too much glue. I think it might be possible that before the glue bonded, the water content in the Tight Bond warped the maple and made it move differently than the purple heart. Was it soft maple? Was it completely dried before you glued it?

Maybe you should try hide glue next time since veneer gluing commonly uses it. Gorilla Glue might work as well but it requires that you moisten the surfaces so that might be counterproductive.

Also, I am interested in what project you are working on that requires this combination of materials.
Good luck.
Best,
Tim


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## EarlS (Dec 21, 2011)

My 2 cents worth - you didn't have enough clamping pressure on the boards and/or there were openings between the clamps. When I glue thin boards together I clamp the entire surface as tightly as I can manage with clamps. I use HDMW spacers between the clamps and boards to make things easier to get apart after the glue is dried/cured. I would probably use a dozen or more Bessey Revo clamps on a board that is this size.


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## johnstoneb (Jun 14, 2012)

I think your clamping method failed. Pictures would help.


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## JADobson (Aug 14, 2012)

It's a pity this doesn't happen every time someone tries to glue maple to purpleheart!


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## Bill_Steele (Aug 29, 2013)

It sounds like you did everything right-the result is baffling. Did the grain in both pieces run the same direction? How do you get clamps and cinder blocks on such a small glue up? If you're going to do it again-I would suggest polyurethane glue and before applying it I would clean both surfaces to be glued with Acetone OR sand both.


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## John Smith_inFL (Dec 15, 2017)

I don't see how you can get clamps plus cinder blocks over the 3/4" plywood 
on a piece of *5.5" x 12" 1/2"* thick piece - - - unless the plywood was much larger
than the glue-up piece then the blocks were put on top of the plywood ?
and the clamps holding the edge of the plywood down too ?
I am thinking you may have somehow forced the glue into the center and trapped it there
when you sealed the edges with the clamps. sort of like a wet pocket in the middle
that did not dry completely. total mystery without some drawings, sketches or photos.
I'm with Johnstone.


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## bondogaposis (Dec 18, 2011)

I think the failure was due to too much glue and not enough *even* clamping pressure.You have to distribute the pressure evenly through out the surface. I don't see how cinder blocks would be effective with clamps on such a small piece. A picture of your arrangement would be helpful.


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## wormil (Nov 19, 2011)

Too much moisture/glue, insufficient clamping. Try using a glue that isn't Water-based. Contact cement or polyurethane.



> It s a pity this doesn t happen every time someone tries to glue maple to purpleheart!
> 
> - JADobson


Lol, truly.


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## RichT (Oct 14, 2016)

Purpleheart is among the tropical woods that are troublesome to glue up. A couple of tips that are often suggested are to sand the surface to roughen it and to wipe it down with a solvent like mineral spirits, naphtha or acetone to remove the excess oil that occurs naturally in the wood.

The previous posts that mentioned proper clamping are good suggestions to eliminate the warping it sounds like occurred.


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## ChiefDJ (Nov 17, 2015)

Here is what I'm trying to accomplish:

Maple + purpleheart are joined together and will be cut into right triangle strips with half maple / half purpleheart. These will be cut into little 1/8" tiles and put together in one of a number of neat patterns, which will go on top of a box I'm building.
The reason we're using purpleheart is because that's what she wanted and she gets what she wants. 

The picture below is the pattern I'm trying to accomplish. 
Sorry it's sideways:










And something like this is what Im ultimately working towards:


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## ChiefDJ (Nov 17, 2015)

> I don t see how you can get clamps plus cinder blocks over the 3/4" plywood
> on a piece of *5.5" x 12" 1/2"* thick piece - - - unless the plywood was much larger
> than the glue-up piece then the blocks were put on top of the plywood ?
> and the clamps holding the edge of the plywood down too ?
> ...


Sorry I didn't make this clear.

I used plywood underneath and on top of the piece I was gluing together just to have a flat surface on both sides. I'm short on clamps so used the cinder block as weight over as much area as it would cover and clamped the rest down to the bench.

In hindsight the clamping wasn't the best but it sure seemed to me there was a moisture issue. I just had never heard of others experiencing warping from the glue before.


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## woodbutcherbynight (Oct 21, 2011)

Get more clamps, do not cheat on this portion of the project. Weight alone is not going to be sufficient. HF clamps are good enough to use, and cheap enough to not hurt the budget.


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## joey502 (Mar 30, 2014)

I have noticed warping caused by what I though was the glue on thin pieces before. In my case they warped the entire piece warped, I did not have any issues at the glue line.

Since you have access to a jointer and planer I would suggest milling each piece thicker than 1/4', gluing them up and then re mill both sides flat. Wait a couple days after the glue has dried before your final milling to allow the excess moisture get out of the wood. Offset the boards just enough to get an accurate measurement as you final mill. This will allow you to ensure each layer is of equal thickness maintaining the look you are going for.

When clamping pieces that thin I would use at least 2 layers of plywood on each side of the glue up to even out the clamping pressure. The plywood would ideally match the size of the parts being glued, maybe a little over sized. I keep scrap plywood around for this type of thing.


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## 000 (Dec 9, 2015)




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## Kazooman (Jan 20, 2013)

Those pieces you are trying to make were more likely made as a long glue up that was then sliced into thin tiles.

Your comment "cut into little 1/8" tiles and then put together" sounds like a real challenge.


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