Thread: Mitre clamps + techniques for mitre joint cabinets

By peripheral clamp, do you mean one that has a band and corners that goes right around the cabinet? If so, that is probably about as good a clamp as you'll get. However, you can supplement them with ratchet tie-down straps.
To overcome the problem of slightly inaccurate mitres even with these, I lay the pieces out with insides down, and tape across the mitres with either masking tape for smaller jobs or duct tape for bigger ones. Pull the tape tight. then turn the whole lot over, apply glue and fold it up. (don't forget to put the back and/or front in as you do so -DAMHIKT.) Then make any minor adjustments before you apply the clamps.
I've glued old inner tube to my clamp faces so they don't bruise the timber. Also, before you do them up fully, adjust them to make sure the corners are pressin evenly on both sides, and check the diagonals are equal.

If you have a few additional F clamps, you can use mitre clamping blocks like this setup. For a carcass type glue up, you can use several blocks per mitre. Add in the band clamp/ratchet strap and you should have a fairly robust clamp-up. I've only had to do this once - otherwise for something thinner like picture frames, these 90 degree squares are great - either screw them onto a backer board and use them as a frame for the frame or clamp them to the frame.

Originally Posted by Alkahestic

If you have a few additional F clamps, you can use mitre clamping blocks like this setup.

That's a great way . I like doing such clamping , its the best way IMHO.

If its an important glue up though I'm not so keen on the use the paper .

The paper in between is for easy release and clean up but it can fail under to much pressure or moving around adjusting clamps to violently.

Imagine a block coming off in the middle of a glue up . How do you get around that ? Your Cooked! You've got to clean everything off and start again .

If you use a pine block to glue on with no paper (any wood would do but pine is a good splitter) You then split the softer pine block off close to the glue join after its job is done, then either plane it down or better , heat the thin remainder and the glue will release it . Hide glue would be ideal for release but most glues release under a decent heat . If its water based glue you can then use warm water to wash of the left over and dissolve it clean .

Originally Posted by auscab

That's a great way . I like doing such clamping , its the best way IMHO.

If its an important glue up though I'm not so keen on the use the paper .

The paper in between is for easy release and clean up but it can fail under to much pressure or moving around adjusting clamps to violently.

Imagine a block coming off in the middle of a glue up . How do you get around that ? Your Cooked! You've got to clean everything off and start again .

If you use a pine block to glue on with no paper (any wood would do but pine is a good splitter) You then split the softer pine block off close to the glue join after its job is done, then either plane it down or better , heat the thin remainder and the glue will release it . Hide glue would be ideal for release but most glues release under a decent heat . If its water based glue you can then use warm water to wash of the left over and dissolve it clean .

I hope this comes thru- havent replied before even tho I hve been a member for many yrs
No miracle cures it seems, but I pick out the following ideas
Good squareness and mitre to start
A peripheral mechanism, tape, clamo, to hold it together during assembly and apply pressure
So good so far....
Then a method to ensure alignment precisely
I note the glued stops- has anyone tried the Woodpeckers MCT? Same as wood blocks but not glued- but you need 16 blocks and 24 clamps to align both sides!!!!
video here- I hope-https://www.youtube.com/watch?v=0_UJwZF2QVc , or Google Woodpeckers MCT
Thanks again
More comments appreciated
I have a daughter who likes mitred birch ply cabinetry
Tnx
Bob

I use three different techniques, Bob; all work well.

Smaller work: I just tape across the corner joint to form a "gaffer hinge" , then glue the surfaces and fold the joint untill the surfaces join. Great for small boxes, etc.

Most work: I use angle cauls as suggested by Alkahestic making the cauls fro MDF, softwood or hardwood and gluing them either with hot glue (rough & ready) or with PVA and newspaper (more reliable). I am aware of the risks mentioned by Auscab, but so far have not had any failures.

Best Work: Use an angled spline. I cut the annngled mitre either as a continuous mitre on the sawbench or as a series of mitres with the domino. The splines make the mitred glue joint close as normal F-clamps are tightened.

Splined Mitre.jpg

(Those grey things are (very) stylized F-clamps.)

Originally Posted by Alkahestic

If you have a few additional F clamps, you can use mitre clamping blocks like this setup.

+1 for this. The blocks we have at my old work had an extension on them so you'd F clamp them to the work (instead of glue/paper), then clamp across them. The same thing can be applied to curved rails and anything else where you need to clamp over odd shapes.

We also had great success with simple masking tape joins, it's amazing how much clamping force you can get with a bit of tension in the tape. Lay it all out on a flat surface outside up, run strips of tape across the joins, flip it over, glue and fold. Not just small stuff either; waterfall benchtops and big dining table bases work just as well. You do need a lot of space and a few extra pairs of hands for the big stuff though.

Originally Posted by elanjacobs

+1 for this. The blocks we have at my old work had an extension on them so you'd F clamp them to the work (instead of glue/paper), then clamp across them. The same thing can be applied to curved rails and anything else where you need to clamp over odd shapes.

I've used this method successfully on a couple of quite complex glue-ups. I have a slight modification - I glued 1000 Wet & Dry to the extensions, which stops the blocks slipping when clamped.

Thanks all for your advice and experience
I hve made some prototype supprts with a triangle glued to a 150x 20 x 30 piece with abrasive glued on
Seems to work, will make some more
Tnx again, Rgrds Bob