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derekcohen 07-23-2011 05:22 PM

Glueing up.
 
This may be a little simplistic for some.


It occurred to me to keep a record of glueing up the two Military cabinets. In part, I always look for feedback to improve methods. And in part, it may help someone what to do - or what not to do! http://www.woodcentral.com/webbbs/smileys/smile.gif - as glueing together dovetailed cabinets can be a little unnerving.

I left off last weekend at this stage - a dry fit of the two cabinets ...

http://i13.photobucket.com/albums/a2...essreport3.jpg

Here I present the right hand cabinet, which will have three drawers and three shelves ...

http://i13.photobucket.com/albums/a2...essreport2.jpg

Glue? I am using Titebond III. It has about 15 minutes of open time, and is required to be clamped for 30 minutes for the initial bond.

The internal "seen" surfaces (around the shelves) have been scraped. All other internal surfaces are planes flat and smoothed but scratches and scrapes are left be. They will never be seen.

The clamps are ready, the glue bottle is clean. I have made up a fresh bunch of spatulas.

I make glue spatulas from an old, broken, cheap tape measure ...

http://i13.photobucket.com/albums/a2...ests/glue4.jpg

I start with the sides:

http://i13.photobucket.com/albums/a2...ests/Glue1.jpg

I only add glue to one side, not both. I find it easier to place the glue on the pin board as there is a wide area, and it can be plastered on evenly and completely.

First one side ...

http://i13.photobucket.com/albums/a2...ests/glue5.jpg

Then the other ...

http://i13.photobucket.com/albums/a2...ests/glue6.jpg

And lastly the centre (even if it is end grain) ...

http://i13.photobucket.com/albums/a2...ests/glue7.jpg

The clamps do double duty. As the boards warp a little and are no longer as straight as they were when first built, the clamps pull the join into alignment. Secondly, by angling the clamps you are able to alter the pressure on the sides and square up the angle.

http://i13.photobucket.com/albums/a2...ests/Glue2.jpg

Next the centre divider is glued in. Glue runs the full length of the stopped dado, and I add a little more for the undercut edge. I am never sure whether one should leave an unglued section for expansion here?

http://i13.photobucket.com/albums/a2...ests/glue3.jpg

I clean up with tepid water as I go.

Now the top can be added ...

http://i13.photobucket.com/albums/a2...ests/glue8.jpg

http://i13.photobucket.com/albums/a2...ests/glue9.jpg

I had worked hard on the dados and the runners of the drawer supports and the shelves to fit well. I did not want to be surprised at this stage with sticking parts, drying glue, and panic. Happily the shelves slid in smoothly, the lower one first ...

http://i13.photobucket.com/albums/a2...sts/glue10.jpg

I only glued the first quarter of the dado. This would allow the solid shelves to expand and contract with changes in the weather.

http://i13.photobucket.com/albums/a2...sts/glue11.jpg

I did the same with the drawer supports althogh these will expand differently, probably hardly at all (as they are all mortice-and-tenon joints).

http://i13.photobucket.com/albums/a2...sts/glue12.jpg

Clamps ensure that there are no gaps at the front ...

http://i13.photobucket.com/albums/a2...sts/glue13.jpg

And then diagonal braces are used to fine tune the squareness ...

http://i13.photobucket.com/albums/a2...sts/glue14.jpg

That came out just fine:

http://i13.photobucket.com/albums/a2...sts/glue15.jpg

Next up - smooth planing the outside and building the bun feet.

Regards from Perth
Derek

Poto 07-23-2011 06:14 PM

Re: Glueing up.
 
This is really helpful, Derek. I've only glued up one dovetailed cabinet, but I didn't do it in stages as you did. How long did you wait after gluing the sides to the bottom before putting the top on? I'm just thinking about rearranging all those clamps, and the possibility of things shifting.

It looks like you used a lot of glue, but didn't get a whole lot of squeeze out. You only needed to clean up near the corners by the look of it.

I'm also impressed that you stopped to take pictures. Talk about cool under pressure!!! I'm always in a panic during glue ups. Perhaps I need more practice...

RONWEN 07-23-2011 09:31 PM

Re: Glueing up.
 
That was a tough glue-up Derek. And as Poto says I'm surprised you were cool enough to take pictures during assembly.
The old tape measure is a great tip.
One expert I've read says don't bother adding glue to any end grain on DT's but it just feels right to do.

Okami 07-23-2011 10:03 PM

Re: Glueing up.
 
That's a tricky glue-up Derek, there's a lot of potential for things to go panic stations on that:D
those shelves can be glued in, no worries. The grain is going in the right direction for it to "move" with the cabinet sides (just as the top and bottom will). You need some Bowclamps Derek:D
The drawer supports need fitting to allow the sides to move freely. Just glue in the front and a screw is all that is needed.
When I clamp dovetailed cabinets, I cut the depth of the pins a whisker short allowing the tails to protrude on the top and bottom for easy clamping. When dry, I plane it all flush.
That's a well done glue-up derek, and very calmly done by the looks of it!
I'm always a bit nervous with these :Dtypes of glue-ups

kevros1 07-24-2011 06:18 AM

Re: Glueing up.
 
A great description and photos.
It seems as though you used a bracket for the diagonal clamp (closest to the handle). Can you describe what you used?
Thanks

derekcohen 07-24-2011 06:52 AM

Re: Glueing up.
 
No bracket. The clamp is resting on another clamp (one across the width).

Regards from Perth

Derek

RickChristopherson 07-24-2011 04:37 PM

Re: Glueing up.
 
Quote:

Originally Posted by Poto (Post 70797)
It looks like you used a lot of glue, but didn't get a whole lot of squeeze out. You only needed to clean up near the corners by the look of it.

I'm reading between the lines, but I would guess that you think Derek had too much glue on his pieces, right? I was quite pleased to see how much glue he had used. (I'm getting old; we haven't had this discussion before, have we?)

For the longest time, I couldn't understand why so many woodworkers on the internet were always complaining about the short open-time of their glues. Were they just working really slow? Then I finally realized how prevalent it was for many people to apply their glue in super thin coats on both pieces of wood, and more often than not, even using a little brush. It's this thin application of glue that results in such short open times.

To see this effect first hand, take an eyedropper of water and put equal amounts on a smooth surface in two puddles, but spread one of those puddles out into a thin layer. Now observe how long it takes for each of those equal volumes of water to evaporate.

As for cleanup, it should never be more than just wiping up the corners. Use a clean wet rag, and make sure your rag doesn't have a lot of glue already on it from a previous joint as you work. Driving glue into the pores is usually a result of using a hardly-dampened rag. Use a bucket of water to clean your rag and wring it out so it isn't dripping wet. Roll the rag opposite to the direction you are wiping so you are not pushing glue ahead of the rag like a snowplow.

derekcohen 07-24-2011 04:57 PM

Re: Glueing up.
 
Hi Rick

Thanks for your thoughts. By way of reply I thought that I would post a copy of two replies I made to Bill Tindale over at Wood Central, since he raised similar queries.

Reply #1:


Many thanks for your thoughtful reply. You raise many of the issues that are often in one's mind, and the choices that we have to consider. I will respond from my experience here, mainly to clarify what went on in my head and what was unseen in the pictures (not that cool under pressure as suggested by having time to take all the photos!).


You are using way to much glue. It takes a film of glue only two molecules thick to form the bond. Try brushing it on with a small brush. Before assembly scrap all that extra glue off with the spreader, or don't put it on to begin with.


Although it looks a lot of glue in the pictures, the fact is that there was very little squeeze out - the tiniest bead only. Squeeze out was immediately cleaned up with clean paper towel soaked in tepid water. I'd rather that there was a little squeeze out - the merest suggestion thereof - than none as then I am reassured that I put on enough glue.


For glue to work it has to wet both surfaces. If one puts it on both surfaces there is no doubt it has wet both surfaces. I think it a waste of time to glue the end grain.


There are two schools of thought when it comes to one- versus two sides. I have done both. In this situation, with as many dovetails to glue, the open time of the glue would effectively have been halved - that would not have been sufficient (and THEN I really would have panicked!).

With regard end grain, I do agree with you .. intellectually. Emotionally it is another thing :) ... my fear of leaving some join unsupported gets the better of me.


If you put glue only on one surface(not recommended) then put it on the surface where the excess will be pushed to an outside joint, not an inside corner. In this case glue the tails.


Yes to ensuring that the surfaces coming together do not create a starved joint. I made sure that the glue was a little thicker at the top of the pins. Pushing one end over another does not favour gluing the tails - that does not make sense. I chose the pins because it is easier to spead glue fully over the surface.


I don't risk a partial case glue up and I have never seen a professional shop that does either. Somewhere down the road you will get one of these joints off a bit and not know it till the rest of the parts get added. Glue gets applied one joint at a time and that joint assembled until the whole of the case is done.


I think that if I did this more frequently (2 or 3 large projects a year is my quota, with a dozen small ones thrown in that do not require this kind of pressure), then I would be more efficient and more confident. I have better control working with smaller sections. I wonder how others feel? In any event, your point about having a joint move is taken - which is why I am fanatical about measuring and monitoring the squareness as I go along (you can see several squares being used in the pictures). As I mentioned, clamps are used to maintain the angles, not simply to add pressure on a join.


It is unimaginable that more than 20 min would be necessary to do the assembly. I do often get help applying glue in a complicated assembly. I use liquid hide glue for dovetails. It has slow tack so assembly is aided.


I am in a double-bind with hide glue - I lack experience in using it, and therefore I avoid it. I recognise the advantages regarding repairs (as Warren mentioned below). Help? Rufus (the Golden Retriever) would rather chew any Jarrah than help me. And Aura (my son's shih tzu cross maltese) just bats her eyes at me, then lies down to rest) ..


http://www.inthewoodshop.com/Furnitu..._m7a0e1e58.jpg


Diagonal clamping is risky. When the case is dry fit I check for square in the unclamped state. If it is not square then I fix the issue. If clamps are needed to square a case then spring back is likely and the result is unsquare.


I will find out whether there was any springback later - I am in your camp here. I do not rely on these braces to square the carcase. They were just fine tuning - there was a fraction of a mm that I wanted to correct.


There are two times important to glue. One time involves how long the joint can be left exposed to air. This time is typically in the range of 10 min and it of course depends on temperature and humidity. Glue can be diluted with 5% water to increase this time. The second time is how long after assembly can the joint be adjusted. 10-15 min is typical and it depends on moisture content of wood and variety of glue.


Thanks. Good info.


For reference, it is Winter here and the weather is cool (18-21 Centigrade/about 65 degrees F).


Reply #2


Below are a couple of images from the glue up today. The first one was about average for the amount of squeeze out I generally experience, while the second is a little more than average. Both are, I believe, quite a small amount, and far less than I think that Bill was imagining. Yes/No?


First image ..


http://i13.photobucket.com/albums/a2...sts/glue16.jpg


Second image ...


http://i13.photobucket.com/albums/a2...sts/glue17.jpg


Regards from Perth

Derek

RONWEN 07-24-2011 08:17 PM

Re: Glueing up.
 
I really like (hot) hide glue for easy to assemble projects but I don't have the nerve (skill?) to try it on dovetail joints. It has such short open time I can only imagine headaches on even the smallest DT joints. The upside I guess would be that half-way assembled joints could be taken apart & retried (again and again :).


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