Epoxy & pen tubes - maybe not such a slick idea?

Friction heat could very well have softened the epoxy to failure, though I'd be surprised it would lead to total failure unless the trimmer ran for a very long time in there.

A few other thoughts that spring to mind:

Try using a fine sandpaper (320, 400 or 600) to very lightly rough the surface since the epoxy isn't going to seep into the material to aid in bonding.

Clean the tubes with acetone or similar cleaner to make sure there is no body or manufacturing oils on the metal.

Was the tube too lose so as not to be in good contact with the wood? Or could it have been too tight so as to glue-starve the materials?

I've not glued pen parts, but use Ace's 5-minute epoxy on other turnings and glue blocks with no trouble.

I use both superglue and epoxy for pens and have not had a failure with epoxy. I trim the barrels by hand so I don't get much friction. I use epoxy when I have a loose fit on the tubes because it fills gaps better than the thin superglue. I'd clean the brass tube and give it another shot.

Good luck!

Use poliueretan glue "Hazel" skrev i melding news: snipped-for-privacy@nntp.charter.net...

I have this problem once in a while with CA, also... In looking at the "spun" tubes, it seems that it was operator error in getting either enough glue between the brass and the wood, or not spread evenly..

I recently got dragged into the epoxy thing (I really don't like the mixing, etc.) when I got into plastic materials for pens.. CA doesn't hold, they suggest titebond and it doesn't either... they ALL spun when I milled the ends..

I went to epoxy, cured at least over night, and it worked better... but some still spun loose during end milling..

I square with the disk sander sometimes, which doesn't spin the tube, but has 2 other problems:

After sanding, I have to deburr the tubes or they wont fit on the mandrel....

If they have a problem that would cause them to spin during milling, you won't know it until you assemble the pen..

Glue failure can cause the tip (while firmly pressed into the tube) to move forward out of the blank when you press the transmission into the other end... DAMHIKT

Mac

Did you sand the outside of the brass tube before gluing?

No experience here, but that rarely stops me from offering my 1-cent's worth:

Consider sanding circumference-wise instead of lengthwise - the tiny ridges may act like small barbs to help against pulling out and also to help trap the glue... But then again, the lengthwise ridging may help eliminate tube spinning...

We do a little of both, with 80 grit.

nope.. (assuming that this is in reply to my post)

I thought you only sanded them if you were painting them?? Mac

Out of 30 pens, only three had that problem. I've always taken 80 grit sandpaper and preped the outside of the tubes before insertion - more surface area always gives better results. I never really considered which *direction* to sand - I just sanded both ways. I also learned that rotating the tube while inserting it in the wood hole gives a better spread of adhesive.

I sharpen my drill bit fairly frequently, so I may have made a slightly larger hole than required.

Given that others had have this problem, I'm supposing that it's just me not applying enough glue initially (I'm cheap like that). I was able to reglue the problem tubes and have it work fine, so I'm not that worried about it. But it would be nice for future times. Thanks for everyone's help.

Sand the brass tubes, not the outside of the turned pen.

Brass tubes are pretty smooth; the glue can grab and hold better if it also has a good mechanical bond. Sanding the brass provides a mechanically rough surface for the glue to adhere to. The mating surfaces act like keys (think microscopic mortises and tenons, or smooth jaw chucks vs serrated jaw chucks) to resist movement.

The "tube insertion tool" that came with the kit my wife bought is totally useless...

If I use gap filling CA than sets a little slower, I have time to put glue on the tube, put it 1/2 way in while twisting, then pull it back out and put it from the other end of the blank.. seems to distribute the glue better... My early ones seemed to be glued really well on one end and not much CA on the other end... YMWV

Mac