Caul for glueing with CA glue

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Sven

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I wish this was either a hypothetical question, or one I'd had the sense to ask yesterday!

I was inlaying a pattern of MOP into a small ebony disc, which in turn was going into a mahogany headstock. The MOP went well, I was impressed with myself as I'm working at the limit of my abilities when it comes to inlay.

This morning before work I routed and gouged out the recess in the headstock, and what do you know; it also went perfect. In fact I was ready so I poured some medium CA in and pressed in the ebony disc. Glue came out, I wiped and reached for a clamp and a caul...


So. What are the options for caul material? I'd like one that doesn't stick to CA glue, form an inseparable bond to the different inlaid materials, and that does not require chiseling off said materials, in parts.


If I'd published any pics or the wurds that came out of my twisted face, this forum would be shut down permanently.

But..! With a fair bit of violence and will power I managed to save it, minus a few ebony chips. And the circular disc went in the wrong way, but the MOP pattern is sort of symmetrical.

Fanx / Sven
 
I think PVC electrical insulation tape will work. Have just glued up a test piece - will report back later.
 
ProfChris said:
I think PVC electrical insulation tape will work. Have just glued up a test piece - will report back later.
Click to expand...

Seems to work. The tape peels off the caul and is then stuck (lightly) to the wood - most of it peels off, and any remaining scraps can easily be scraped off.
 
Thanks! I used clear acrylic plastic just because when I tried to glue two pieces of that with ca they came apart as if they'd never seen glue. The imagined advantage was of course that it's transparent.
 
Just buy a roll of Bakers waxed paper, that you use in the oven.

I fold it to double layer it and use whatever flat thing is nearest, usually a scrap of ply

Good for epoxy too
 
Beau Hannam Ukuleles said:
Just buy a roll of Bakers waxed paper, that you use in the oven.

I fold it to double layer it and use whatever flat thing is nearest, usually a scrap of ply

Good for epoxy too
Click to expand...

I don't think this is readily available in UK shops - replaced by silicone bakeware, I suspect. It's a constant surprise how many "ordinary" things in my country are not in shops abroad; no ibuprofen (analgesic tablets, like aspirin or paracetamol/tylenol) in Hong Kong, for example.
 
ProfChris,
Over here is the equivalent greaseproof paper?
Alternatively if may be 'baking parchment' iirc used to line cake tins etc.
H
 
Buy a sheet of silicone "oven liner". It is a very thin fabric covered with silicone. It can be cut to whatever sizes you want, and reused over and over. I would lay it over the inlay, than apply the caul. It's heat resistent too. Anne Flynn
 
I have a box of clamping cauls made from off cuts of plywood and such. Every one of them gets wrapped in a layer of clear packing tape. The cellophane type. Nothing sticks to it.
 
Most glues are used as you described, glue and then clamp, but CA is the exception to that rule. It is not usually quite right to say clamp and then glue, though there are times when I do exactly that, but position and glue is exactly right. The thinnest viscosity glue is the right one for this. It will get in if there is any room at all for it. With inlay work I use the dust of the wood being inlaid into, and place the dust then add glue till it is saturated. Repeat as necessary. If you do need to clamp, seal-a-meal bags are perfect. It is also possible to pad CA as a finish with your hand inside such a bag. I do not like waxed paper as it has the potential of creating finishing issues.

The time I do clamp first is when I am gluing biding inside an archtop's ff holes. As good as I can make them fit, they really don't, and the CA gets in there and does the job. I first did that 20 years ago, and haven't heard about the failure if it happened.
 
Yup, yup, and indeed yup. I should have placed the inlaid disc in the cavity and let thin ca wick down in between the edges. My mistake was that I thought I would gain something by using medium ca. And that I put in the cavity first, so when I pressed the disc down I had it lying on top of a too thick layer of glue. The fit was such that I needed some force to press the disc in, and the excess glue out.

Dunce hat properly donned, and glued to my head.

Since my backwards way of doing this inlay meant a wood to wood joint, I would have been much better off using Titebond.

All your answers are much appreciated, thanks. I think any future attempts will be less stressful and more successful thanks to you.

Sven
 
Sven said:
Yup, yup, and indeed yup. I should have placed the inlaid disc in the cavity and let thin ca wick down in between the edges. My mistake was that I thought I would gain something by using medium ca. And that I put in the cavity first, so when I pressed the disc down I had it lying on top of a too thick layer of glue. The fit was such that I needed some force to press the disc in, and the excess glue out.

Dunce hat properly donned, and glued to my head.

Since my backwards way of doing this inlay meant a wood to wood joint, I would have been much better off using Titebond.

All your answers are much appreciated, thanks. I think any future attempts will be less stressful and more successful thanks to you.

Sven
Click to expand...

Well, you've just described my exact process. Maybe I've been doing it wrong all this time but it worked on this piece I must completed this week. I'll happily join you in wearing a dunce cap! ;) BTW, as I've said before, not all ca glues are created alike. Get a good brand and "stick" with it.
 

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Another gorgeous work of art, Chuck! After you draw up the concept, do you rout the design on the headplate freehand, then fit the pieces, or cut the pieces and then rout the cavity?
 
Habanera Hal said:
Another gorgeous work of art, Chuck! After you draw up the concept, do you rout the design on the headplate freehand, then fit the pieces, or cut the pieces and then rout the cavity?
Click to expand...

The individual pieces are cut first then assembled as one or two large pieces, the outline is scribed, then routed and glued. I build my inlays upside down so that I don't run into any surprises when sanding due to uneven thicknesses of materials. Before the entire piece I glued into the cavity I will block sand the back to clean up any glue. It's import to work clean as you progress. Depending on the piece I will usually fill the cavity with medium CA, as Sven describes it, and press the piece it. If done properly it will lay flat and lock into place. Before the CA has a chance to dry and shrink I will keep flooding the seams with CA. That's an important step to eliminate bubbles. Very, very rarely do I use thin CA to set the piece in as I did with this inlay. I had no other choice, there were too many small pieces. Either way works, just keep filling in with more glue as it dries. The problem with using thin CA on a large inlay is that thin CA shrinks a lot and the outer edges may dry before the entire cavity has a chance to get filled.
 

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Gaah! I'm not calling my decoration "inlay" again, not after seeing that. Thanks Chuck, for taking the time to spread your knowledge. Pearls before... fellow builders, at best.

Sven
 
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