clamping issues

[Marcjwebb]

hi all ,

this must be a rellly easy for some on here, but myself, never really needed clamps til now, as only just started with joinery.

anywho, when i clamp 2 panels at 90deg, it seems to want to bow in and unless i am pulling back on the clamps, wont sit at 90 whilst the glue dries,

it must be something silly i know, but not an issue i have had before.

Regards

Marc

 

[Mike.S]

Any chance of a picture/drawing of what set-up you're using, as I can't quite understand it from your description.

 

[Marcjwebb]

I shall get something drawn so you can see how I'm doing it. What's the best way to upload an image on here. Not done that yet

 

[Alexam]

picture-posting-guide-t63716.html

 

[Marcjwebb]

this is how i mean when im clamping the panels it seems to want to bow out for some reason, opening up the inside of the joint slightly and not sure why, whereas the outside seem of the joint is perfect

 

[rdesign]

If you make right angle triangles out of scrap wood and cut the corner away so no squesse out will stick to them then screw on two pieces of scrap to the edges so u can put an f clamp holding the piece at 90 degrees then use your bar clamps as u have illustrated to apply the clamping pressure. 4 cheap f clamps with the triangle 4 bracing will keep it at 90 degrees

 

[Benchwayze]

Marc.

Use three clamps if you have them. One across the centre of course.

In case, pressure is the trouble, don't throttle the life out of the clamps. Just enough pressure to close the joint. Clean off the squeeze out while the glue is wet.

Edit. Something just occurred to me:

Not wishing to teach egg-sucking, but you are using some kind of mechanical jointing? (Screws, nails, pocket holes, dowels, or some kind of rebated joint.)
With larger panels I'm sure you know, but you can't just rely on a glued butt-joint.

HTH.
John

 

[Marcjwebb]

using biscuits just very odd that it seems to lean, have tried three clamps i do tend to clamp down hard and then clean the squeeze out,

 

[Benchwayze]

Marc.

What are the panels made from? Ply. MDF? Some plywood sheets can have a bow in them. Difficult to remedy.
I would position the clamps across the end panel, with the clamp bar at 90 deg to the surface of the panel and not in the same plane, as your drawing suggests.

Difficult to explain, but the pressure is applied in a slightly different way, and there's more surface area of the clamp-head working for you. The clamps won't slip off so easily either!
Try that?

HTH.
John

 

[Marcjwebb]

its melamine chip that im using for cabinets, is it worth me doing that clamping as that whole cabinet rather than just an end then and end then a top then the back?

 

[Benchwayze]

Marc.

Ah.. I see. You are clamping two 'L's and then clamping those up together. Best to clamp the whole carcass in one; although it seems you might want some help, unless you want a bit of a fiddle. I trained the Missus, to assist when I was just starting. A bit of 'the blind leading the blind', but it worked. if it's a job that isn't going to show when completed, stick a few screws in as well as the biscuits. That should hold things steady while you clamp. With the added screws you might not need to clamp, but I usually do. I would join both ends to one longer side first, with the boards on edge. The three sides will stand up for themselves. as long as you don't wait too long! Then I would put the other long side on. The biscuits should hold it in place while you fit the clamps, and that's where you will need the help to position the clamps. Don't forget to measure the diagonals, so you know it's all squared up. The main thing is have everything you need to hand, and ignore the phone until you are done. Then you should be golden. I'm not sure the glue will stick to the melamine faces, so you'll be relying on just the biscuits to hold things together. Maybe the screws would be a good idea left in, as a back-up.

If you were local, I'd come over. As it is, I can only wish you the best of luck. Hope it goes okay.

John

 

[bugbear]

I saw this, long ago (long enough that I had to use the Wayback machine to get it)

https://web.archive.org/web/20060203235 ... /clamp.htm

BugBear

 

[SteveF]

out of stock but i sure other suppliers

http://www.rutlands.co.uk/sp+woodworkin ... es+m_29190

the posh version

http://woodworkersworkshop.co.uk/Woodpe ... uares-Pair

or these

http://www.ebay.co.uk/itm/4-x-4-100mm-R ... 1019750163

Steve

 

[Benchwayze]

Looks like you'll be buying two sets of four 'mitre-clamps' then Marc!
Drapers used to make a decent example.



If all else fails, the Spanish Windlass might come in handy, instead of buying a band-clamp. :lol: :lol: :lol:

Steve.
I think I'll break out the tools and make a few of those corner thingies, that Rutlands sell!

 

[SteveF]

Looks like you'll be buying two sets of four 'mitre-clamps' then Marc!
Drapers used to make a decent example.



If all else fails, the Spanish Windlass might come in handy, instead of buying a band-clamp. :lol: :lol: :lol:

Steve.
I think I'll break out the tools and make a few of those corner thingies, that Rutlands sell!

those rutland ones are really handy
I use them as a spare pair hands on dry assembly as well as glue up
also when trying to clamp to fit pocket screws

Steve