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How do you clamp things that are not square?

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Forum topic by Mary Anne posted 07-14-2010 03:53 PM 1962 views 2 times favorited 25 replies Add to Favorites Watch
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Mary Anne

1057 posts in 1925 days


07-14-2010 03:53 PM

Topic tags/keywords: clamping help

When I made my Cubicle cutting boards, the hardest part was clamping for the glue up. I tried making various jigs, making the boards in sections, even tried rub joints, but no matter what, everything did a lot of slip-sliding when I applied pressure to the clamps on the final glue up. I have some similar designs I want to do, but would really like the gluing process to go easier and hold things more exactly in place. So, how would you clamp something like this?

Click for details

Thank you!!


25 replies so far

View Kate's profile

Kate

397 posts in 2591 days


#1 posted 07-14-2010 04:00 PM

Have you tried clamping just a few sections at a time using masking tape instead of clamps? If you use regular masking tape (not blue painters tape) you can stretch it and it makes a good clamp. I use it on a lot of small (and some not so small) projects.

Love the boards by the way.

-- Kate, http://www.wooden-box-maker.com

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Mary Anne

1057 posts in 1925 days


#2 posted 07-14-2010 04:06 PM

No, I didn’t think to try tape, but I’ll give it a go on the next one.
Thanks, Kate!

View Rick  Dennington's profile

Rick Dennington

3550 posts in 1911 days


#3 posted 07-14-2010 04:17 PM

Greetings Mary Anne,

Kate has a real good suggestion for using masking tape to use as clamps. Years ago when I built guitars, I would use masking tape to hold the binding on around the edges of the body until the glue dried.
One suggestion I would make, and that is to use a band clamp. I’ve used that to glue up irregular shapes. I have a couple of different ones, but I like the ratchet types, where you can apply the right amount of pressure…. Another thing I would suggest is that you wait a couple of minutes before trying to glue the parts together…. let them get a little “tacky”, and when you put them together, they won’t slip and slide on you as bad..just don’t wait too long, or you’ll have to re-glue…... lol. Stellar job on the boards…. beautiful work…. They are too pretty to use…... lol…... Good luck…. Rick.

-- " I started with nothing, and I've still got most of it left".......

View CampD's profile

CampD

1209 posts in 2203 days


#4 posted 07-14-2010 04:18 PM

Left-handed-un-square clamps, available at you local 7-11.
:)

Umm, Tape works good and doing small sections at a time.

-- Doug...

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Rick Dennington

3550 posts in 1911 days


#5 posted 07-14-2010 04:19 PM

I was a little late…... Barry beat me to the same suggestions… I type too slow, I guess…....

-- " I started with nothing, and I've still got most of it left".......

View sras's profile

sras

3902 posts in 1846 days


#6 posted 07-14-2010 04:20 PM

In addition to those listed above, I can add a few more:

Fingers – use a fast setting glue and just hold them tight for 3 or 4 minutes

Small bungee cords – I have found these at Home Depot in packages of 10 or 20. They are about 8-10 inches long. I just wrap them one after the other. The advantage over a rachet clamp is I can adjust each successive one to apply the forces over a range of directions.

Wedges or levers – depends on the situation, but sometimes I will be able to wedge or pry the pieces together

-- Steve - Impatience is Expensive

View BritBoxmaker's profile

BritBoxmaker

4419 posts in 1753 days


#7 posted 07-14-2010 04:30 PM

Mary Anne could I suggest the windlass Clamp as in this blog of mine, here, as a low cost option.
You would obviously have to alter the internal angle of the softwood blocks to suit your design. I suggest two tensioners on opposite sides.

Softwood blocks also get rid of any marking problems with band clamps, as they crush before the hardwood you’re using would.

Either of those or build yourself a clamp with three fixed cauls (one side of the hexagon) and three floating ones that you clamp the pattern tight against these with.

-- Martyn -- Boxologist, Pattern Juggler and Candyman of the visually challenging. http://www.theartofboxes.com

View antmjr's profile

antmjr

262 posts in 1900 days


#8 posted 07-14-2010 04:40 PM

Mary Anne, some years ago I built a boat, and the most difficult things to clamp in a boat are the laps near the stem (see here on picasa if you like): obviously things get far harder if one is so idiot (as I was) to round and smooth the stem before having completed the planking: in this case the clamps slide continuously and it’s hard to clench them. A nightmare.

So my suggestion is to think how to clamp your staff before cutting the boards in sections: if the pieces on the edge were, say, triangular, it would be easier to clamp the row (you can cut them later when the glue has set). Moreover a jig may be useful; I’d fix two pieces of wood on a panel, this way \..... and I’d put your work inside, clamping all together (maybe on a sheet of nylon :-) )
—-
edited to correct the jig: probably it would be better this way /.... , I mean: with an acute angle

-- Antonio

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patron

13140 posts in 2058 days


#9 posted 07-14-2010 04:51 PM

here ,
you can make wedges from rectangular pieces ,
just band-saw diagonal , leaving a blunt end (for removal) ,
reverse the
mark them with numbers , as they want to be used with their partner .
make as many as you like ,
the ‘push board’ wants to have the lower corner relieved ,
so it doesn’t stick to the work , and you can wax it too ,
or cut it off later .
tap them against a fixed stop on a backer board ,
with wax paper or plastic , on the surface of the backer board .
keep tapping (and releasing any that are to tight) ,
until you get them all where you like them .
then just go around and tap them all tighter .

-- david - only thru kindness can this world be whole . If we don't succeed we run the risk of failure. Dan Quayle

View Mary Anne's profile

Mary Anne

1057 posts in 1925 days


#10 posted 07-14-2010 04:55 PM

Is this site great or what? A great group of people!

Lots of great ideas. I did try using a ratcheting strap, but everything still slid off. Maybe because the sides are not equal? I’ll try that one again, or maybe Martyn’s windlass, with some blocks on the corners. Also tried the fixed cauls and floating cauls combo. That worked best for doing halves, but there was still a small amount of slippage. Not a lot, but enough to bug me. Maybe use small wedges would fine tune it.

Barry,
How do you use the hot melt or super glue for clamping? I can’t picture that.

View Mary Anne's profile

Mary Anne

1057 posts in 1925 days


#11 posted 07-14-2010 05:04 PM

antmjr,
I think I could only build a leaky boat at best! :) It also occurred to me to leave long edges that I could square up and cut off later. But like you, everything was already cut and fitted before I thought of it.

David,
Ah, I see. The same thing should work on a shape with more sides. Using pairs of wedges to keep the straight line makes sense, too.

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patron

13140 posts in 2058 days


#12 posted 07-14-2010 05:14 PM

however many sides you like .

-- david - only thru kindness can this world be whole . If we don't succeed we run the risk of failure. Dan Quayle

View TopamaxSurvivor's profile

TopamaxSurvivor

14991 posts in 2392 days


#13 posted 07-14-2010 06:37 PM

I haven’t done this, but if I needed to clap a very odd shape, I would use a bunch of little sandbags to fill the voids; then, use a band clamp, cauls or what ever it took to put the pressure on.

-- "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

View TopamaxSurvivor's profile

TopamaxSurvivor

14991 posts in 2392 days


#14 posted 07-14-2010 06:38 PM

OOps, forgot, with those boards, I would have cut some scrap wedges to make it square for clamping.

-- "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

View SPalm's profile

SPalm

4889 posts in 2598 days


#15 posted 07-14-2010 07:42 PM

Mary Anne,
As you see, there are lots of options. I have done a few of this kind of thing recently, and I found out that a good fit really makes things easier (sounds like a Duh). Place a full sheet of 220 grit sandpaper on the bench and sand all the parts very lightly. Try to get a ‘piston fit’. Of course, this requires accurate cutting too.

Using a sponge roller to apply the glue helped me a lot. I was able to get a smooth and consistent film. Also this was quick and not messy. Then slide the mating pieces back and forth a little and they will stick together almost by themselves.

I have not used a lot of pressure. David’s wedges or Brit’s device with the separate adjusters seems like the right amount. Blue tape comes in real handy, and I use it for the pre-assembly of the miters.

Sub-assemblies helped me. I was also able to trim them to fit into the other subassembly better. This allowed a more controlled and fun-filled environment.

Steve

-- -- I'm no rocket surgeon

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