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jttheclockman

jttheclockman

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I was spinning a few blanks the other day, some were acrylic, some wood and a couple were cast. As I was doing this I began to think of problems people seem to have with the tubes letting go because of glue failure. My thoughts brought me to why does this happen.???? I have used 2 part epoxy all the time and never had a failure so I am not aware of the ways these things can happen. If you put the blank on the mandrel and use the bushings, they are pushing against the sides of the blank and the tube ends. Even if you get a catch this should not dislodge the tube. Then the other thing I thought about was using a pen mill and maybe this is the way this could happen but I can not vision that.

So I ask how is it that a pen blank becomes seperated from a pen tube??? When does this usually occur and how quickly will it happen??? Can this happen even after the pen is pressed together??? Can it happen years down the road??? Thanks for clearing this puzzle up for me. :search:
 
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Lots of reasons, not enough glue coverage, not scuffing the tube, not waiting for it to completely set, heat build up, porosity of your blank sucking the glue away from the tube.

Those are just the ones that come to mind from my own personal experiences.
 
jleiwig said:
Lots of reasons, not enough glue coverage, not scuffing the tube, not waiting for it to completely set, heat build up, porosity of your blank sucking the glue away from the tube.

Those are just the ones that come to mind from my own personal experiences.
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I know what the reasons are but want to know how the blank comes loose of the pen tube and at what stage of the pen making process does this happen.
 
jttheclockman said:
I know what the reasons are but want to know how the blank comes loose of the pen tube and at what stage of the pen making process does this happen.
Click to expand...

If you knew the reasons, why then was your initial question which I answered

jttheclockman said:
I was spinning a few blanks the other day, some were acrylic, some wood and a couple were cast. As I was doing this I began to think of problems people seem to have with the tubes letting go because of glue failure. My thoughts brought me to why does this happen.????
Click to expand...
And then the next question, which was really the same as the first!

jttheclockman said:
So I ask how is it that a pen blank becomes seperated from a pen tube???
Click to expand...
Those are both how questions which I answered, not when questions. :biggrin:

To answer your when questions, it can happen at any stage, but I've mainly seen it during drilling, and sometimes during turning on fragile blanks.
 
I have had as much as half of the blank (almost 1 full side) fly off when rounding. I have lost less when rounding and alomost to finish dia when I had a catch. I had most of the problems when I was using medium CA to glue in the tubes when I first started turning. I wasnt getting enough coverage.
I now use thick CA to glue in the tubes and when it is a wood blank I will put a coat of thin in the hole and let it dry over night. I don't use accelerator to cure the thin anymore. Any accelerator that may not have completely cure/dried will set the tube instantly.
I still have a the occasional tear out when I am being way to aggressive.
I plan on trying 5min epoxy.
 
The main reasons that come to mind are due to the glues in question. CA is brittle so sharp hits/jars can 'crack' the glue from the surfaces causing a loss of grip. Epoxies are up and down the scale of brittleness, but are usually much less so then any CA. The only consistant reason that I've ever had/seen of epoxy failures is due to ill prepared surfaces, usually because they are coated with something that inhibits a proper bond(too much dust, a bit of oil, etc...)
 
jleiwig said:
If you knew the reasons, why then was your initial question which I answered



And then the next question, which was really the same as the first!



Those are both how questions which I answered, not when questions. :biggrin:

To answer your when questions, it can happen at any stage, but I've mainly seen it during drilling, and sometimes during turning on fragile blanks.
Click to expand...


I think you are playing with symantics here. I know glue failure is the reason that it seperates. My question is then when is this glue seperation take place??? What part of the pen making process does this happen?? It looks like from others responses that got what I was trying to ask, is that this could happen at any stage of turning the pen. I do not see anyone stateing that this can happen after the pen is completed.
 
I've had it happen while turning, but only when using Thick CA which has dried at least an hour, I twist the tubes when putting them in the blank. I don't recall loosing a blank to glue failure using Epoxy, or Polyurethane (Gorilla/Sumo) glue, most always happens on wood, never on Acrylicsor PR.
 
I've had failure when turning between centers. I don't use bushings, so the tube bears all of the force.

It's still very rare, but it happens (easy fix to re-glue the tube, however).
 
jttheclockman said:
I think you are playing with symantics here.
Click to expand...

Nope...just stating the facts as you posted them. :biggrin:

Anyway..I've had it happen anywhere in the pen making process, but not on a completed pen. I find that 9 times out of 10 it's when I've been rushing to get a pen completed. I've even had it happen when pressing in fittings due to not getting all the glue out of the tube. You hear a pop!, but cannot figure out what happened. When you pull the pen out of the press to inspect closer, the blank falls off the tube and hits the floor (luckily it didn't break!)

I've had someone break a pen at the plastic threads when I forgot to tell them that it was a screw on cap, not a snap fit like most all cheap pens are, but it's not due to glue failure.
 
pen mill

jttheclockman said:
I was spinning a few blanks the other day, some were acrylic, some wood and a couple were cast. As I was doing this I began to think of problems people seem to have with the tubes letting go because of glue failure. My thoughts brought me to why does this happen.???? I have used 2 part epoxy all the time and never had a failure so I am not aware of the ways these things can happen. If you put the blank on the mandrel and use the bushings, they are pushing against the sides of the blank and the tube ends. Even if you get a catch this should not dislodge the tube. Then the other thing I thought about was using a pen mill and maybe this is the way this could happen but I can not vision that.

So I ask how is it that a pen blank becomes seperated from a pen tube??? When does this usually occur and how quickly will it happen??? Can this happen even after the pen is pressed together??? Can it happen years down the road??? Thanks for clearing this puzzle up for me. :search:
Click to expand...
It usually happens to me when I get a bit of epoxy inside the tube and try to do milling. That glue bonds to the milling bit while turning. I've had some that I had a pretty hard time getting loose. The failures while turning seem to have the same cause but the bonding occurs after the tube seems to have started turning on the mandrel.
 
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