I have learned over the years to never to tell people the best way to do things if I have never actually done it myself.
I learned this when I was a technical trainer for a large refrigeration company. I demonstrated a procedure in front of a class of 40 mechanics that I "supposed should work this way." Well needless to say..... it was a big flop because I didn't bother to do it myself before hand. I looked like a fool and I deserved it.
I never did that again.
My experience with other glues has taught me a few things. I tried to glue up a ring billet with titebond II and ended up throwing the whole sticky mess in the trash. Water based glue thickens fast as the moisture evaporates and also soaks into the objects being glued.
I test glued a dowel in a piece with epoxy and I was very careful to slide and twist as I was assembling it. When I cut it apart later, there were small voids here and there. I didn't think that was good.
I did up a test using GG and when I cut it apart the glue joint was continuous and solid. There were no voids and there was no foam in the joint. Good stuff.
Maybe I came off as a little ruff but please try it your self before saying that epoxy or cascamite is good to use for coring. Maybe do up some samples, cut them apart and show us some pictures.
Kim
Kim, I'm getting used to it on this forum so don't worry about it. But believe me, I am not the sort to say something just to try to make myself look clever or important.
I have done various coring procedures, but never the full 29" of an american pool cue butt. However, the principle remains the same regardless.
I was not telling anyone how they should do it, moreover I was adding to the discussion and gave reasons why I would choose to use either of the two glues mentioned.
I went through a stage of using polyurethane glues for several applications, industrial stuff not off the shelf. I thought it was the best thing I had ever used. But after a couple of years, I changed my mind. I rarely use it now.
Any coring/hole plugging I do, I tend to use epoxy. As I said, cascamite is a bit of a pain. If I needed to do a lot in one day, I would use that, but usually I do things one at a time so epoxy is easier, although vastly more expensive.
I completely understand your test and the voids you encountered. This is a separate issue and is more to do with how you manage to get the glue spread right in the core and on the dowel. In itself a tricky task on that length, so I fully appreciate that aspect.
I have no doubts that a butt fully cored through would glue perfectly well with polyurethane, particularly with both ends 'open'. A few notches/lines etc. would be more than enough to ensure a good key, and 'immovable' bond.
My particular point was more to do with the the hardness of the glue, and transmission of any energies. Given that there must be a gap around the dowel to fit in the hole, there must be a film of glue between the butt wood and the core wood. I am of the opinion that it's better with a 'harder' glue.
There is no point me making some experimental butts and cut them up to try to prove anything. They would all be tight fitting and it would be virtually impossible to know which was which. My concern is solely how hard the glue is and how it may affect the overall 'feel'.
Now, to add to this discussion, you have got me thinking about the difficulties of working on the long core and how to overcome the 'foam gap' (as tiny as it may be) and make the best job using polyurethane.
In my mind, the best way would be to machine the dowel in some way a bit like the grooved dowels used in furniture making etc. (but no need to be such deep splines), and make the fit very tight so that it has to be knocked in, although not so tight that it will split the core. The fact there are splines should mean the dowel can compress ever so slightly across these splines, so careful and accurate machining should avoid any potential of splitting as the dowel is driven in.
This will give a great key for the polyurethane, allow it expand out and up/down the lines, yet retain direct wood to wood contact between the majority of the core and dowel. This would overcome my concerns about transmission of energy.
Yeah, I'd be happy to do it that way :thumbup: