Ca pen finish ends cracking

[Woodguy95]

Ok so it's my second post and the help I've recieved from this forum.
I've got a really big problem with my ca pen finish. I love the shine I can get and the durability of that pen finish. However when I press the parts on the pen it will always crack on the ends no matter how much I sand the ends to take the edge off. I also make a verry thin ca finish.

Other issue, when I have to unstick the blanks from the bushings it will chip a bit.

Thanks for the answers and if you have an alternative of a finish that is as durable as the ca finish please give me your way of dooing it

 

[JimB]

You have some choices to fix the issue with the blank sticking to the bushings. One is to not use bushings when doing your finish. Mount the blank between live center and dead center. Just don't over tighten. Second choice is to wax the bushings. Third choice is to use Delrin bushings. They are available from some vendors or you can make your own.

As far as the cracking when pressing in your parts I am going to say you did not sand the ends enough even though you think you have. How are you sanding the ends?

 

[epigolucky]

I found that finishing between centers helps with the glue not sticking to the bushings. You will still need to sand the ends after finishing, but that should reduce if not eliminate that problem.

When assembling, I found that using a chamfering tool (I think that's what its called) to take the inner edge off the tube will make pressing pen together much smoother - this drastically reduced cracking of my CA finishes. Hope this helps.

I've heard the polyresin dipping method produces a nice shine and is very durable - I haven't tried it yet, but maybe some others can offer some more info in this area.

 

[Woodguy95]

I start by cutting the excess glue with an exacto then I sand the ends using 400 grit sandpaper untill I feel no burs anymore.
For finishing between centers do you make a jig to hold the spinning end (sorry I'm french and does not remember the exact word)
I'll try the poly resin for sure
Thanks for the quick replies

 

[epigolucky]

For finishing between centers do you make a jig to hold the spinning end (sorry I'm french and does not remember the exact word)

I use a dead center in the head stock and a 60 degree live center (I think that is the word you are looking for?) in the tailstock.

 

[rd_ab_penman]

Apply CA finished between centers without bushings.

Les

 

[1080Wayne]

Another possible cause of the cracking during assembly problem is misalignment of the insert with the tube .

 

[csr67]

I recently switched from using derlin CA bushings to doing CA finish between centers. This is a huge improvement in quality and in speed of production. Also, make sure you are removing the burr from each tube before assembly. I use a cheap $4 Harbor Freight pipe deburr/reamer tool and it works great:

 

[Rick_G]

Another possibility not mentioned is a little glue getting inside the tube and not being removed. It doesn't take much to reduce the interior diameter of the tube so that when you push the fitting in the tube expands enough to crack the wood. I put my CA on between centers without bushings and then after sanding the ends I run a small pen knife around the inside of the tube to make sure any glue that may have migrated inside is removed.

 

[jttheclockman]

Make sure the tubes are cleaned out from any residual CA finding its way in them. I too ream the ends to relief the burr on the ends of the tubes. Need to keep components straight all the way as you press in.

The CA may have been fractured prior to the completing of the pen due to the sticking to the bushings. You just did not notice it and when you pressed the parts in this expands the tube somewhat. Finish without bushings is the most logical answer. I use derin cones I made for this. Basically take the place of a live and dead center. I also have just used the live and dead centers too. If you check back in the finishing forum this question was asked about a couple weeks ago and you may find other answers there too. Good luck and happy turning.

 

[qquake]

I made some bushings out of a Delrin rod.

http://www.penturners.org/forum/f14/homemade-tbc-bushings-135821/

 

[plantman]

If you purchase a 5/8th tapered reamer it will fit all size pen tubes and remove the glue and any flaring of the inside of the tubes after squaring the ends. This will also true up your tubes so that they are perfect circles. I use fingernail polish hardener to reseal the tube ends after squaring and before pressing. As for freeing your bushing, all suggestions stated above are good ones, and I have used most if not all of them. But, I still turn almost of my pens on a mandrel with bushings on my micro mini metal lathe. I like to turn a lot of 2 barrel pens, and this way I can turn, sand, and finish both barrels at once. After I apply and sand down my CA, but before I polish it, I take a metal knife file and remove any CA down to the bushing. Now the bushing will slip off with little or no effort and the ends of the blanks will be even and square. I never use the bushings for a measurement, so if I file them a little , it doesn't matter. Always use a calipers for your measurements on blanks and fittings. Jim S

 

[edstreet]

You do realize this has nothing to do with the bushing material right?

Will give you a hint ... Method.

 

[wouldentu2?]

Other options are using a small round file to remove any CA in the tube and to remove the tube about every 5 coats to lightly sand the ends of the tube. Even if you finish between centers do the sanding.

 

[Heartwoodturning]

I use a length of 6mm threaded metal rod to remove glue stuck to the inside of my tubes.

 

[Sabaharr]

I have found in the past that I got CA or epoxy inside the tube while gluing it up. I tried the exacto knife removal method with some success but the best way is to not get it in there in the first place. So I jam both tube ends into a sheet of dental wax before glueup. Once set sand the ends square and the wax pops out with a punch or use your mandrel. Reamed tubes with no glue on the ID and parts inserted straight should fix your cracking problem.

 

[thepenfriend]

Thank you all for the great information... I too had this same problem when assembling my finish pen and just when I think everything looked good I started noticing on some of my finished wood pens there would be small chips on the end. Came to the forum and with all of your help I had discovered that I was leaving small amounts of CA left inside the tube that decided to run inside while applying. Even after sanding down the end I couldn't figure out why. Examples of when I first was having the problem are posted. Now I carefully remove any internal CA and things have been going good. So...thank you all for the great advice because Lord knows it was driving me nuts as to why this was happening and I couldn't figure it out...