Help! Tubes and Bushings stuck to mandrel

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Nov 1, 2018
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12
Location
Sterling, VA
Hello all, I have been running into a problem recently. After I am done finishing a pen when I try and remove the blanks from my lathe (a PSI Penpal) the blanks and bushings become stuck on and will not budge. The mandrel is just a plain 7mm rod. Any solutions?
 
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I always clean my mandrel after every turned pen and I also clean my bushings after every couple pens turned. I clean all the finish from the outsides and use q-tips to clean the insides. It can build up finish after a while and I've had it to cause my bushings to get stuck on. If that is not the case, you may want to see if your bushings got damaged somehow. Unlikely if all of them are sticking though.
 
First of all, you are far from the first one to have that happen. 2nd, be very careful but wax the mandrel lightly. Don't do it excessively so that the wax gets onto the blanks. Next, as you coat the ends with finish, do it more towards the middle and move to the ends. Be sensible about the applications towards the end and don't overdo it there.

Lastly, if you really want to avoid blanks sticking to the mandrel, go to turning between centers - without the mandrel.
 
Like Hank, I am a TBC advocate, that would solve your problem for sure. Another possible solution is to use HDPE bushings for the finishing step (https://www.exoticblanks.com/Bushings-for-CA-Glue-Finishing-Set-of-4.html). I am assuming that your trouble is with CA adhereing the pen barrel to the bushings and/or the mandrel. CA doesn't like to stick to HDPE, but will build up over time and to have to clean them off with a skew periodically.
 
I use the HDPE bushings also. I just scrape the buildup off with my fingernail. Comes off pretty easy.
 
Hank is spot on. this is a common situation.

To get finish or CA off of things like bushings, CA nozzles and tips, and HDPE cone bushings I have an empty quart size paint can (purchased at borg store) with about 1" of acetone in the bottom. I just chuck whatever in the can for a day or two. Seal the can. I use tweezers for extraction. Good as new.
 
also check the bushings. They sometimes develop a small burr on the outside edge that hangs on like glue. Use a small file to remove the burr and no more sticking.
 
To remove stuck bushings I would put the rod in my vice where the rod could move freely but the bushing would sit on top of the jaws. A couple wacks with a hammer would break them free. I found that they would stick when I clamped them too lightly and the bushings would spin on the rod while turning. They would almost "weld" themselves to the rod.


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I clean my bushings with a bit of acetone in a baby food jar. Soak it for a couple of hours, remove and wipe. So far, I haven't had that problem. But, the day isn't over. I'm wondering if the "freezing" problem would be from putting too much CA or finish on the blank.
 
This may be a very silly question: Are you sure the mandrel is the correct diameter? Perhaps, it is larger than 7mm in some spots or bent in some spots. If the tubes are bushings slid on ok, then I am stumped.
 
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