polyurethane glue

[knothole]

i am having trouble with titebond polyurethane glue holding the tubes inside the pen blanks.sometime if i do both sides of the blank one side seems to hold ok the other tube spins inside the blank.i drill a 9/32 hole and before i put glue into the hole i wet a q tip and run it into the hole then i put the glue in and use a straw to insure the glue covers the total inside of the hole.then i add the glue to the outside of the tube. i wait
at least 24 hrs before i try to use the blanks. could i be getting the inside of the pen blank to wet. the glue foams like it should
any suggestons
thanks

 

[woodscavenger]

Do you rough your brass tubes with coarse (60 grit) sandpaper to give the glue something to hold to?

 

[Old Griz]

I know I and others have said this a couple of dozen times... try epoxy... a lot of us who had problems with poly glue switched to epoxy and no longer have problems.....

 

[Dario]

Believe it or not...too much water can cause too much foaming and resulting to a weaker bond.

I use Gorilla glue (GG) almost exclusivelt but about to experiment on 2 part epoxy now. Anyway, I never had any problems with GG. Here is how I do it. Note, I always do this in batches of atleast 10 (and up to 30 a time) .
1. I spread at least a couple sheets of newspaper on top on the table (or any working surface you'll use)
2. Sand the tubes with a coarse sandpaper (the coarser the better)
3. Put on gloves (medical exam gloves work great)
4. Squeeze a glob of glue in both ends of the blank. Note no water here...not even a breath in hole.
5. Spread the glue with a bamboo (BBQ) skewer. (I am still using my first skewer now.)
6. Put the tube in just by the tip.
7. Squeeze some GG along the entire length of the tube. A bit more at the part being inserted.
8. Start inserting the tube rotating the tube as I go in...making sure that there is enough glob of glue covering the area where the tube and blank meet (blank hole opening).
9. Lay the blanks on the newspaper...spaced about 1/4" so they won't accidentally stick to each other (I never had any tube migrate on me yet but you can use rubber band if you want to make sure).
10. Reapeat until all done.
11. Wake up next morning and collect them all...clean up with a knife and I am done! Ready to move on to the drill press with the barrel trimmer

EDIT IN NOTES:
1. The bubbles/blanks may stick to the newspaper but I don't mind.
2. San Antonio is humid...maybe that is why I don't have any problem even without adding water.
3. I did some without sanding the tubes and none of those failed either...I sand for good measure.

Hope this helps.

 

[dougle40]

Just to give you some options , here's the method that I use . I use polyurethane glue exclusively (I use Tightbond) and have never had a failure .

1- Breath into the hole in the wood , this seems to add just the right amount of moisture .

2- Apply some glue to the surface of 1 end of the tube and insert it into one end , twisting it as you go , then remove it , add some more glue and insert it from the opposite end with the same twisting motion . I usually start from the end opposite the center , that way the tube can be placed closer to the center end so that you have a better grain match when you're done . I usually leave them to dry over night .

While I'm not saying that sanding the tubes isn't a good idea , but I don't sand them at all and as I've said , I've never had one let go on me yet .

 

[MDWine]

I do pretty much the same thing with mine, although I do breath through the hole to get some moisture in it. I don't have any problem w/tubes squeezing out. I don't use any water, I spread the glue thru the tube with a skewer [], and sit them on wax paper to keep them from sticking. Maybe epoxy will be better for you, but it is too messy for me. One bottle, one application...

 

[Paul Russell]

Slow down on your rough turning technique. When you are taking the blank down from square to round with your roughing gouge (or spindle gouge), take light passes. If you get bad catches during this phase, it can torque the glue joint to the point it will break.

 

[RussFairfield]

They should be holding.

Are you sanding the tubes? The brass has a light coating of oil from when they were formed, and sometimes there is oxidation on the surface. This should be removed with a light sanding before they are used. I use 120-grit.

You can skip the water. You don't need it with the Titebond brand of poly glue.

How long are you waiting between gluing and turning? You can sometimes get away with 4 hours with the Titebond Poly, but you should be giving it a 24 hour cure before turning.

Check this link to my website. It will take you to a description of how I glue the brass tubes into the wood.

http://www.woodturner-russ.com/Pen23.html

 

[Mudder]

Originally posted by Old Griz
<br />I know I and others have said this a couple of dozen times... try epoxy... a lot of us who had problems with poly glue switched to epoxy and no longer have problems.....

Tom have you ever had a blowout with Epoxy or a pen that cracked over time? I'm curious because I have had it happen with both CA and Epoxy. This is why I keep going back to Poly because, for me, it is a little softer and has a little give to it that I think allows the blanks that I use to expand and contract just a little and avoid cracking. Especially in the slimlines which are my best sellers (don't know why but they sell 3:1 over everything else.)

Of course if you turn a lot of stabalized woods or acrylics then you would need not worry about expansion and cracking and Epoxy would give you more working time than CA. I think that glueing is like finishing, there is no one thing that is best for everything.

 

[alamocdc]

No cracks, but I've had a blow out, but then I also had one with poly. Like tom, I use epoxy exclusively now.

 

[Old Griz]

Never had a pen blowout with epoxy that was not the cause of me having a catch with the skew and the wood that come off had a coating of epoxy on it and the tube section... just a massive catch because I was not watching what I was doing.
Also never had a pen crack over time (other than some ebony, but that sometimes happens with ebony).
I don't turn a lot of stabilized woods... but I do turn a lot of fancy burls that sometimes have inclusions and pits and still have not blown one off with epoxy.. other than as stated above from a real bad catch...

 

[knothole]

thanks for all the info you sent about my titebond polyurethane not holding the tubes inside the pen blanks.i had done about everything that was suggested i did sand the tube before i put it in the blank. maybe i got some bad glue.

thanks

 

[dougle40]

You can skip the water. You don't need it with the Titebond brand of poly glue.

This is an answer that I just received from Titebond with regards to using water to dampen the wood before applying Titsbond Polyurethane glue .

<b>Dear Mr. Rounding,

Thank you for your inquiry. Titebond Polyurethane Glue is a moisture curing adhesive. The directions on the bottle cover this information much better than our technical data sheet. Moisture in the air or in the materials to be bonded will cause the glue to harden. When bonding nonporous materials or extremely dry wood, or when temperature or humidity are low, we recommend lightly spraying the applied glue with water or wiping the surface with a damp cloth prior to applying the adhesive. Naturally, it is also important that the joints fit tightly and good clamp pressure is applied while the glue sets. I hope this information is helpful to you.

Sincerely,

Marc Bergdahl
Technical Specialist
Franklin International</b>

I hope this helps clear up any questios with regards to this .

 

[DCBluesman]

Thanks, Doug, for getting the info straight from the source! [8D]

 

[Old Griz]

<b>"Naturally, it is also important that the joints fit tightly and good clamp pressure is applied while the glue sets."</b>

Something that can not be done when glueing a tube into a drilled pen blank... and might be a cause of some problems with poly glue failures....

 

[Dario]

I'll stick to Gorilla Glue [] for poly...never had any problems with it.

 

[DCBluesman]

I've glued up a couple hundred tubes with Gorilla Glue and have had no blow outs other than "pilot error". I think this may be a case of if it works for you, do it.

 

[Geo in Winnipeg]

I'm just a beginner and haven't done any where near as many glue-ups as most of the others here; but I have never had any problem with epoxy.