Trouble gluing miter joints

[jim gossage]

I am having problems gluing up my miter joints on picture frames. During the test fit using a band clamp, the miters are perfectly closed, and with pretty strong clamp pressure there is no frame deformation or twisting. For the glue up I use tite bond III and rub a thin layer of glue on each miter edge with my finger and this takes about 2 minutes to get them all 8 edges done. Then I add the band clamp and carefully pull the joints together, about another 1-2 minutes. In the end, there is a very slight gap in some of the joints, I assume due to glue film. The gap is uniform so the problem does not seem to be with miters that are 0.1 degrees off one way or the other. What is the preferred way to glue these joints? A different glue? Just coat one side of each joint? Glue 1 or 2 joint first and dry fit the others during clamping, then come back and glue them?

[Mel Fulks]

I would use Tite bond 2, it cures faster than Tite bond 3 , and I use a sharp knife to shave of a bit of wood in the center of one piece
in each corner since the cut pieces often have a ‘high spot’.

After all corners are glued and dried ,I drill holes in the joints and push in a tight nail using a small nail-set.

[glenn bradley]

Titebond III has the highest viscosity of the three Titebond "wood" glues and will therefor require a greater clamping pressure or reduced glue application to achieve a similar glue joint "gap". I use Titebond III for just about everything for ease of supply management. However, I clamp miters like so:
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which allows a very focused clamping pressure to override the high viscosity glue and I routinely get pretty decent results.
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For boxes I use these type of clamps for the same reason:
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and again get pretty decent joint results.
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If you want to use band clamps and a high viscosity glue you may consider changing to something like a Merle clamp (https://www.amazon.com/MLCS-9012-Woodworking-Exclusive-Multi-Corner/dp/B000FNKXIG/ref=pd_lpo_1?pd_rd_w=fHb2u&content-id=amzn1.sym.116f529c-aa4d-4763-b2b6-4d614ec7dc00&pf_rd_p=116f529c-aa4d-4763-b2b6-4d614ec7dc00&pf_rd_r=J04ZSE9QZBF4MZ5DGA2M&pd_rd_wg=RxA5s&pd_rd_r=f8cae9fc-c11f-43dd-90dd-ede0911ee467&pd_rd_i=B000FNKXIG&psc=1). These allow a crushing pressure for a small band clamp. I would prefer to use an adhesive with a lower viscosity like Titebond II and / or a more focused clamping method. We all find our preferred way of doing things. Once you find yours you will be able to repeat your results with confidence.

[Lee Schierer]

You are essentially gluing end grain, so you want a good amount of glue. I've made dozens of picture frames ranging in size out of various woods. I use Tite Bond II. I also use a picture frame clamp (https://www.woodsmith.com/article/woodworking-tip-shop-made-frame-clamp/) similar to this, except mine are commercially produced and made of aluminum.
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[Mel Fulks]

Glenn, you sure got some great grain match there , or is that “contact paper” ?

[John TenEyck]

A bit of a tangent, Glenn, but I just couldn't believe TB III has the highest viscosity of the three yellow Titebonds, but it does per TB's data. That's sure not the way they behave for me though. The behave exactly the opposite. TB III flows very easily while TB Original is much slower to pour, doesn't run as easily, etc. I wonder how TB measures the viscosity? Different methods give different results.

John

[Maurice Mcmurry]

III is also brown which I like for dark wood. For your lovely Maple maybe try Extend, I, or II.

[Jim Becker]

III is also brown which I like for dark wood. For your lovely Maple maybe try Extend, I, or II.
They make a "dark" version of the Type II product...but I have not found it locally to-date.

[glenn bradley]

Glenn, you sure got some great grain match there , or is that “contact paper” ?

I will take that as a serious compliment :). It is solid walnut outer frame with a 1/2" wide birdseye inlay about 1/8" thick and the inner frame is solid birdseye maple about 3/8" thick. Picture frames can be very basic things and be very attractive as such. Many times you do NOT want the frame to distract from the art. I think that for snapshots it is fun to push the picture frame format a bit and add a bit of razz-ma-tazz.

[glenn bradley]

A bit of a tangent, Glenn, but I just couldn't believe TB III has the highest viscosity of the three yellow Titebonds, but it does per TB's data. That's sure not the way they behave for me though. The behave exactly the opposite. TB III flows very easily while TB Original is much slower to pour, doesn't run as easily, etc. I wonder how TB measures the viscosity? Different methods give different results.

John

I agree. In use TB-III seems to be just about the right balance for me. I guess it would have been smart for me to ask what his material was. Any of us who have had a starved joint can relate to how important this might become. Whether due to not enough glue or not pre-wetting (or sizing) a surface for glue up on an absorptive material like oak, a crushing clamp pressure can starve the joint. I tend to wet the end grain of both surfaces with glue, let it soak in for a minute or so, then apply a "normal" film of glue to one side, and clamp as shown.

[jim gossage]

Glen,
Nice miters, really nice baby!

I didn't know about the viscosity issue. Might have to try TBII. Does anyone use cyanoacrylate with longer open time?

Any recommendation on whether to put glue on both faces of each miter or just one?

Thanks, Jim

[mike calabrese]

Tb II I use this to glue up hundres of joints in segmented bowl rings. I also believe most segment boul turners use TBII.
as far as the joints go you might look into a 45 degree sled for your table saw.
Here are some YouTube links that can give you some methods used by other folks.
https://www.youtube.com/results?search_query=perfect+miter+joints
https://www.youtube.com/watch?v=_KEw83c8T98
Again for bowl segments there is a sled called a wedgie sled example https://www.youtube.com/watch?v=_KEw83c8T98
This is an example of a wide 45 cut made on a DIY wedgie sled.
The other picture FYI is a 12 segment 24 piece segment ring with spacer pieces again cut on a wedgie sled and built with TBII. The ring is a left over from a bowl job that I turned into a moisture test piece but you get the idea on the angle cut quality all due to the DIY sled.
calabrese55
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[Derek Cohen]

I am having problems gluing up my miter joints on picture frames. During the test fit using a band clamp, the miters are perfectly closed, and with pretty strong clamp pressure there is no frame deformation or twisting. For the glue up I use tite bond III and rub a thin layer of glue on each miter edge with my finger and this takes about 2 minutes to get them all 8 edges done. Then I add the band clamp and carefully pull the joints together, about another 1-2 minutes. In the end, there is a very slight gap in some of the joints, I assume due to glue film. The gap is uniform so the problem does not seem to be with miters that are 0.1 degrees off one way or the other. What is the preferred way to glue these joints? A different glue? Just coat one side of each joint? Glue 1 or 2 joint first and dry fit the others during clamping, then come back and glue them?

Jim, I suspect that the problem lies with your clamping method (the band clamp), and that it places pressure at the outside of each joint, and not across the joint, itself. Lee's clamp is a better design.

Regards from Perth

Derek

[Alan Lightstone]

You are essentially gluing end grain, so you want a good amount of glue. I've made dozens of picture frames ranging in size out of various woods. I use Tite Bond II. I also use a picture frame clamp (https://www.woodsmith.com/article/woodworking-tip-shop-made-frame-clamp/) similar to this, except mine are commercially produced and made of aluminum.
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Lee:

Interesting. I've always used band clamps, but I agree this design looks better.

Which commercially produced clamp are you using? Glenn looks like he is using one too.

[Stan Calow]

. . . Does anyone use cyanoacrylate with longer open time?

Any recommendation on whether to put glue on both faces of each miter or just one?

Jim I wouldn't use CA glue for this. CA is strong in tension, but has no shear strength. So a sharp rap, like falling on a corner, can more easily break the thin plastic layer that CA forms.

I use whichever bottle of TB I have open. I put on both faces - and always use reinforcement, even just the V nails for small frames. And I use the same 4- corner clamp thing that Lee shows. Maybe from Lee Valley, but Ive seen similar from the usual suspects.

[Kevin Jenness]

Glenn's clamping ears (post #3) allow for directing pressure at 90* to the joint surfaces, which is what you want. These can be made up to suit the job, whether boxes or frames, and can be temporarily attached with hot melt or a paper joint. If using a band clamp, make up corner blocks that will put the force where it is needed.

It is pretty much impossible to get a starved joint using pva glue unless there is insufficient glue applied in the first place. Pvas work best with minimal gluelines. Miters may need a double application due to absorption into the partial end grain surface. Fat joints indicate insufficient or mis-directed pressure, old thick glue or the glue setting up before pressure is applied.

[Michael Burnside]

You are essentially gluing end grain, so you want a good amount of glue. I've made dozens of picture frames ranging in size out of various woods. I use Tite Bond II. I also use a picture frame clamp (https://www.woodsmith.com/article/woodworking-tip-shop-made-frame-clamp/) similar to this, except mine are commercially produced and made of aluminum.
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I prefer TB original for most things, including frames, but wow this threaded rod clamp for frames is genius! Thanks for sharing.

[Carl Beckett]

I am having problems gluing up my miter joints on picture frames. During the test fit using a band clamp, the miters are perfectly closed, and with pretty strong clamp pressure there is no frame deformation or twisting. For the glue up I use tite bond III and rub a thin layer of glue on each miter edge with my finger and this takes about 2 minutes to get them all 8 edges done. Then I add the band clamp and carefully pull the joints together, about another 1-2 minutes. In the end, there is a very slight gap in some of the joints, I assume due to glue film. The gap is uniform so the problem does not seem to be with miters that are 0.1 degrees off one way or the other. What is the preferred way to glue these joints? A different glue? Just coat one side of each joint? Glue 1 or 2 joint first and dry fit the others during clamping, then come back and glue them?

Can you describe what type of gap gets created when gluing? Since you test fit with the clamp first - it is not obvious to me why adding glue would change the fit/gap. (possibly something slides easier with glue - or doesnt slide - vs dry clamping). Maybe if the glue dries out before the clamp pressure is applied? Use more glue to allow squeeze out, or switch to a slower drying glue?

I always try to reinforce mitered frames with a spline or even a small domino if possible. The domino can 'help' alignment (or fight it if the domino isnt in the right location). Often I can use regular clamps if a domino since the joint isnt sliding around during clamp pressure.

[jim gossage]

Can you describe what type of gap gets created when gluing? Since you test fit with the clamp first - it is not obvious to me why adding glue would change the fit/gap. (possibly something slides easier with glue - or doesnt slide - vs dry clamping). Maybe if the glue dries out before the clamp pressure is applied? Use more glue to allow squeeze out, or switch to a slower drying glue?

Its a pretty narrow gap (maybe 0.005") across the length of the joint from inside to outside corners when looking down on it. The wood is curly maple. Its still lined up properly so I don't think sliding was the problem. It just looks like there is an invisible shim in the joint, which makes me think the glue dried a little before clamping and left a bit of a film that couldn't be squeezed out. I haven't tried to break it but the glue up seems very solid. I'm probably making much ado about nothing - I'm one of those woodworkers who aims for machinist tolerances! It was a gift so I don't have it available to take pictures anymore.

[Patty Hann]

Glenn, what are those clamps called that you used on the box, and where did you get them? Thanks

[Grant Wilkinson]

I frame for 2 local artists, most in poplar, oak or maple. I tend to use whatever glue bottle is closest. Here is the clamp that I use. I have bought longer lengths of 1/4-20 threaded rod for larger frames. To reinforce the joint, I used wide crown, thin staples. So far, so good.

https://www.leevalley.com/en-ca/shop/tools/hand-tools/clamps/31162-veritas-4-way-speed-clamp

[glenn bradley]

Glenn, what are those clamps called that you used on the box, and where did you get them? Thanks

Grant has a link in post #21. I have one of the Lee Valley and one of the Woodcraft versions. The Lee Valley are quite a bit nicer. I have a few lengths of all-thread to make them more versatile.

[Stan Calow]

That's the one I have. My tip is to add wing nuts on the end of those long threaded rods. When I'm handling them, you can whip the clamp around, and those brass knurled knobs can fly off into distant corners of the shop, never to be found again.

[Carl Beckett]

I have the same threaded rod clamps. They work.

But - if it is glue drying out before clamping it might not be a clamp issue...

Since it is already 'partially' end grain (as a 45 miter), I would have concerns on strength since the joint didnt pull tight. As mentioned, I have had some come loose after a few years so now put a spline or some other reinforcement in everything.

[Patty Hann]

Grant has a link in post #21. I have one of the Lee Valley and one of the Woodcraft versions. The Lee Valley are quite a bit nicer. I have a few lengths of all-thread to make them more versatile.

Thanks... (thanks to Grant too)

[Charles Lent]

Two things cause problems with gaps in miter joints.

1. The miter cuts aren't EXACTLY 45 DEG.

2. The boards for top and bottom or the two sides aren't EXACTLY EQUAL LENGTH.

When cutting the miters not only make certain that you are cutting at exactly 45 degrees, but also cut both opposite at the same time using a stop and clamp to prevent any movement during the cuts.

I use my standard Delta Unisaw Miter Gauge with a length stop and clamp added, but also set the miter gauge to the exact 45 deg angle using a MiterSet gauge, and get perfect mitered box and picture frame joints every time. The MiterSet gauge can be set to any angle in 1/2 degree increments and is the most accurate gauge that I have in my shop. It will work with any miter gauge that has an accurate 3/4 X 3/8 standard bar and saw with the miter slots of this size.

I have no connection to the MiterSet manufacturer, but love the gauges that they make.

Charley

[Tom Blank]

Deleted, question already answered.