Coring issue

Newton

Newton

AzB Silver Member
Silver Member
Juat did 2 forarms and as usual I pushed a wet paper through the forarms hole before I incerted the dowel.
On my second ebony forarm I used "well amount" of wather on the paper since the first was kind of damped paper. The second was whet.

The glue did at this time settle so quick that I had trouble running the core through the forarm. Actually-I did not get it all through just flush.

Now-I like to keep the tolerances tight where the dowel and the hole is very tight...

How much do you allow in clearance between core/hole and do you bother to use wather before you incert the core?

Was just thinking that I possibly should not be so anal on tight fit and let the poly fill more...?
K
 
That topic was just discussed in a thread about gun drills. There was a lot of info there that you should find useful in addition to several answers to your question.
 
Newton said:
Juat did 2 forarms and as usual I pushed a wet paper through the forarms hole before I incerted the dowel.
On my second ebony forarm I used "well amount" of wather on the paper since the first was kind of damped paper. The second was whet.

The glue did at this time settle so quick that I had trouble running the core through the forarm. Actually-I did not get it all through just flush.

Now-I like to keep the tolerances tight where the dowel and the hole is very tight...

How much do you allow in clearance between core/hole and do you bother to use wather before you incert the core?

Was just thinking that I possibly should not be so anal on tight fit and let the poly fill more...?
K
Click to expand...

Hi,

I use a .013 Gap .750 core and .737 dowel and spray the water over the glue on the dowel before slowly inserting and rotating the pieces together.

If you put the water inside the core on some woods it can swell too tight before the job is done

Rick
 
I allow about .010" difference. I also cut grooves around the core every half inch or so to hold more glue.
 
Lexicologist71 said:
That topic was just discussed in a thread about gun drills. There was a lot of info there that you should find useful in addition to several answers to your question.
Click to expand...

I was going to send him there also.

I think ALL of the info that you could need about coring was there!
 
cueman said:
I allow about .010" difference. I also cut grooves around the core every half inch or so to hold more glue.
Click to expand...

Do you cut the groves perpindicular or parallel with the core? I was wondering if you cut them and used them as vents so that the air would escape.
 
opiesbro said:
Do you cut the groves perpindicular or parallel with the core? I was wondering if you cut them and used them as vents so that the air would escape.
Click to expand...

It should be both, IMO. Cutting rings around the diameter and then connecting them with a cut that goes from the first ring all the way through all the rings and then out to beyond the outer limit of the wood blank you have cored. This allows the glue to fill all rings, and excess glue and air can then escape the cored wood and not cause any hydrolic back pressure and also helps with getting the core all the way thru the blank without binding due to too much pressure.
Hope this helps explain it.
Dave
 
Newton said:
Juat did 2 forarms and as usual I pushed a wet paper through the forarms hole before I incerted the dowel.
On my second ebony forarm I used "well amount" of wather on the paper since the first was kind of damped paper. The second was whet.

The glue did at this time settle so quick that I had trouble running the core through the forarm. Actually-I did not get it all through just flush.

Now-I like to keep the tolerances tight where the dowel and the hole is very tight...

How much do you allow in clearance between core/hole and do you bother to use wather before you incert the core?

Was just thinking that I possibly should not be so anal on tight fit and let the poly fill more...?
K
Click to expand...
I have tried wetting the blank the same way as you describe, and it took a drillpress being used as an arbor press to get the core dowel thru all the way. I now just rely on the moisture content of the wood and present in the air to get the curing process going. Haven't had a problem since going this route. Too much moisture at the beginning will accelerate the expansive end of the poly glue too fast and then you have the issue you just experianced. I wouldn't change your specs yet, as the tighter the wood core is to the wood 'skin' if you will, the better it will be as a finished cue, providing you have enough adhesive in place. Too much of a space between those parts, and the cue won't feel the same when hitting some balls, IMO.
Happy new year buddy, hope all is well,
Dave
 
Make an undersized dowel and tape 80 grit paper around one end.
You can sand and scratch with that tip.
Also, don't use a wet towel. Only little steam .
 
Last edited:
I size my dowel so that it is a nice easy slip fit in the bore, about 12 to 15 thou.

I blow through the bore several times. This puts a little moisture in the bore from my breath. I have never used any water on any thing that I put together with gorilla glue. My humidity is between 40 and 50 percent.

I coat the dowel with glue and squirt a good amount into the bore and follow it with the dowel, twisting it as it is pushed through the bore. The excess glue comes out ahead of the dowel telling you that there was enough.

Don't forget to put a piece of cellophane tape over the ends of the dowel to keep the centers from filling up with glue.

I get a nice foam ring on each end as the glue expands and sets up. I put a clamp on each end of the dowel where it comes out of the bore. This makes sure it stays where it belongs. The pressure of the expanding glue can squirt the dowel out an inch or so on one end.

I have had some foam come out through a birds eye in the middle of the piece and occassionally a little bubble at the joint of 2 pieces even if the fit was very good. It turns off and is not noticeable.

When the glue is hard, bounce the piece end wise on a hard floor. It will sing with the same tone a solid piece of wood makes.

great stuff this gorilla glue!!!!

Kim
 
Last edited:
I can't wait to get my coring dowels down to size. Fighting with an A joint is a pain I can live without.
 
Thank you all for your feedbacks and PM- all are highly appreciated.

I whent down to the shop today and did a clean up of the machines and checked the forarm I mentioned.
It has swelled with the bobles in the end where I started the dowel, and a little less in the flush end. I'll poste some pics tomorrow.

I use the 0,650 drill and it produces a hole just a tad under 16,5mm. I know-it should be bigger but that's the hole it produces.
The dowel is normally "hand fittet" with light cuts until it could barely be pushed in without any glue-not using force.
This dowel was 16,45-16,46mm.
Now-lesson learned , my experiment was not wise and I would continue with a barely damped paper, NOT whet.
I had also put a paper "dot" in the dowels center but this dissapeard when the end came out flush. So this paper could also be the problem jaming the core...:o
A spiral cut is made in the dowel and the glue scraped off while installing the core-is normally scratched off with my hand and "refilled" on the top..

Rick- spraying water on the glue was a new one... I guess you use a spray/mist wather bottle?

Dave- sounds like we have the same experiences - hoope you had a nice celebration last night :-)

Kim - breathing heavily through the cored forarm sounds much better than adding the wather as I do. I'll try it on my next-however I would make very much shure that all dust is blown 110% off....

Again-thank you all and I have learned. I do however seem to have a tighter clearence than my fellow friends up here. It might be to tight I guess...

Kent
 
Last edited:
Kent[/QUOTE
The dowel is normally "hand fittet" with light cuts until it could barely be pushed in without any glue-not using force.

A spiral cut is made in the dowel and the glue scraped off while installing the core-is normally scratched off with my hand and "refilled" on the top..


I do however seem to have a tighter clearence than my fellow friends up here. It might be to tight I guess...
Kent[/QUOTE]

Kent, I also hand fit the dowels as you do, I'd say the dowel is usually about 5-6 thousands under the hole diameter when done. I don't use any water at all and have had no troubles.

Alan
 
Last edited:
Newton said:
Thank you all for your feedbacks and PM- all are highly appreciated.

I whent down to the shop today and did a clean up of the machines and checked the forarm I mentioned.
It has swelled with the bobles in the end where I started the dowel, and a little less in the flush end. I'll poste some pics tomorrow.

I use the 0,650 drill and it produces a hole just a tad under 16,5mm. I know-it should be bigger but that's the hole it produces.
The dowel is normally "hand fittet" with light cuts until it could barely be pushed in without any glue-not using force.
This dowel was 16,45-16,46mm.
Now-lesson learned , my experiment was not wise and I would continue with a barely damped paper, NOT whet.
I had also put a paper "dot" in the dowels center but this dissapeard when the end came out flush. So this paper could also be the problem jaming the core...:o
A spiral cut is made in the dowel and the glue scraped off while installing the core-is normally scratched off with my hand and "refilled" on the top..

Rick- spraying water on the glue was a new one... I guess you use a spray/mist wather bottle?

Dave- sounds like we have the same experiences - hoope you had a nice celebration last night :-)

Kim - breathing heavily through the cored forarm sounds much better than adding the wather as I do. I'll try it on my next-however I would make very much shure that all dust is blown 110% off....

Again-thank you all and I have learned. I do however seem to have a tighter clearence than my fellow friends up here. It might be to tight I guess...

Kent
Click to expand...

Kent,

Yes I use a spray bottle. If you go on the GG site and watch the video they show the spray bottle being used.

Polyurethane Glue is designed to be used with water. Water is the catalyst for this stuff, I would make sure you are using enough. Without enough moisture you may not get the expansion coefficient maximum. I have experimented without water on a test piece and the tone on the piece is not the same as the same piece of wood using the spritz water bottle.

Jmo,

Rick G

The Tulipwood and Padauk ones ( 2nd and 7th from the left ) have not been faced yet revealing the expansion of the glue using the water spray.
IMG_4006.jpg
 
Last edited:
I use a water bottle also, spray the corded area apply g-glue then spray on top of glue, slide two pieces together with twisting motion. ...............Frank
 
Rick,

With the amount of foam you have I see the effect more water gives. However, I think I need to start using a larger gap between the core and the material in case.
Hmm, I'm not sure if I would like to experiment to much, the pics show the gabon I have talked about and also a 0,775 cored mopani piece (the other is production cue and a blank).
The Mopani was done with a damped paper - still narrow gap - but OK bubbles.
Since you use more glue and more water (ie you get more glue inside due to a larger gap) I guess your having a larger expansion and foam/bubble build up due to this.

The core on the gabone broke when I at the end could not move it with a rubber hammer and went for a metal one ....


Thanks
K
 

Attachments

  • 1.jpg
    1.jpg
    80.4 KB · Views: 207
  • 2.jpg
    2.jpg
    82.6 KB · Views: 200
  • 3.jpg
    3.jpg
    63.6 KB · Views: 254
You must log in or register to reply here.
Back
Top