I"m not a Gluer,,,,,,,,,,,,,,,,,,,,,,,I'm a Screwer

[dicklaxt]

I guess I ought to clarify that "of wood parts".

My question is this,heres the scenario... if you position two wood pieces with glue between and hold hand pressure for a few seconds you will get a bond, now add the third piece of wood holding hand pressure again for a few seconds repeat this procedure for as many pieces as you need.Now you take the complete assemly and apply mechanical pressure, that is greater than hand pressure most certainly,,,,,,,,,,,,,,,now finally the question. Will this mechanical pressure weaken the bonds or break the bonds of the bonds already attained on the individual glueups??

dick

[WoodMangler]

Dick

You truly have an engineers heart :)

I take an acid brush, pour some glue in an 'ol plastic butter tub, brush glue evenly on all surfaces and assemble the rings as I go, then I mash the whole thing down using the drill press and let it dry.

Aint had one fly apart yet :)

[dicklaxt]

But........whats the answer to the question.

dick

[laughner]

I think the answer you are looking for would depend on how long you are talking about between hand pressing and mechanical clamping.

I would think that if you are taking a long time to mechanically clamp (15 minutes or so), the glue joints would have time to set, but would still be pliable enough to take the pressure of the clamps and re-form to the greater pressure. Essentially, breaking the bond and creating another bond

If you are talking about a quick assembly process (only a couple of minutes), I would think the "bond" wouldn't be a bond at all. It would actually be a vacuum created between the boards by the glue and would be subject to manipulation of the clamps. I have boards slipping and sliding all the time when I'm laminating boards. But I use too much glue all the time. I'd rather have glue squeeze out than a failed joint or blank.

If I'm incorrect, I'll appologize now and cover my tail. This is what I've noticed in my (limited) experience.

[WoodMangler]

My answer is "How could anyone know?"

Given all the variables of temperature, wood species, wood moisture content, surface preperation irregularities, humidity, clamping pressure, type of adhesive, age of adhesive, adhesive film thickness, joint cleanliness, and on and on and on...

I think you ask a question that nobody could possibly answer without an incredible amount of data.... so I chose to give the best answer (i.e "advice") I could! :)

[dicklaxt]

Why don't you test it ? and then let me know :+

[WoodMangler]

I could I guess, but then only one of us would have gotten any experience eh ;)

[Sawduster]

As far as breaking or not breaking bonds, I too, think that it would depend upon the time element, and humidity and temperature, all three having some effect, but I think that the point is really a mute one, unless of course the time element is greatly increased. With tight fitting joints to begin with, and with the proper thin coat of glue, the clamps are not going to be moving the two pieces to any great extent anyway. In those cases, the clamping pressure needs only to squeeze out any little amount of excess glue. With segmented stuff I lay the pieces for each 1/2 ring on a strip of masking tape with the edges of the miter cut pieces snuggly against each other, apply glue into each joint and wrap the pieces together with only light addititional hand pressure. I then stretch another piece of masking tape across the open area to add a bit of tension to help keep the joints closed. This is nowhere near the pressure applied with clamps, and these joints have not failed, The pressure in this case is minimal, so I have to wonder what real benefit is gained by cranking a pipe clamp across a joint with tremendous pressure, other than to bend the workpieces into a proper fit.

[Lou_williams]

Jerry,

Your right. High pressure from clamps in not only not necessary it causes more problems.

You only need to clamp with enough pressure to bring the wood joints together. With proper jointing and workmanship it takes very little pressure to get a very strong joint. Minimum glue, light pressure, good surfaces and you get great glue joints.

[Sawduster]

I've heard tales (tall or otherwise) from real old timers of edge glueing by simply (well, maybe not so simply) getting two near perfectly matched edges, applying a bit of glue to one, rubbing the edges together to distribute the glue, then holding them together a few second by hand in proper alignment, then setting them down with no clamps and walking away while they cured. I don't think that even on my best day I could get joints that I would be comfortable with not clamping. I do, however, often times, glue up, apply clamps, then remove the clamps a half hour or so later to be used on the next glue up. Like most everyone else, I do not have enough clamps. I've not had problems with any on which I've done this, although if it is cold, I will leave them on longer while I go in where it is warm to have a cup and let the numbness go out of my hands to see how badly that knuckle or finger I smacked or whatever is gonna hurt.