CA Glue Fracturing


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Hi Guys,

As you know, I am new to turning.

I have done maybe 15-20 pens so far, and had some really good experiences, and some really bad ones.

Recently, I have been getting my CA finish down to a procedure that works pretty well for me, but I keep ending up with one or more of the bushings being glued to the blank. I can free it simply by spinning the blank but its a gamble if the glue will fracture on the bushing or on the blank. So I end up with small chipping of the CA near the ends of the blanks.

Is there an easy way to avoid this and/or a quick way to repair it without sanding down and starting over?

You can see it near the middle band on the cap.

post-7224-0-13449400-1353969783_thumb.jp

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ive noticed it with my pens as well, its either happening when i pull the pens off the mandrel or when i am pressing the kits together. only thing i can say is watch for both and see where its happening. if its on the mandrel you might need to wait longer to pull them off the lathe give them more time to cure. if its happening when pressing then it might be the pressing causing it, in that case you might need to sand the edges so the glue isnt overhanging. not sure how to repair it but might be helpful in the next series of pens.

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I assumed it was simply my technique, so I stopped using this particular approach. Don't take this the wrong way, but I'm glad to know it's not just me...

Only thing I can suggest, and I haven't tried this yet myself, is to switch to a thin coat instead of a thick. Sure, it might take more coats, but it might also avoid this chipping issue. (plus, you can "break" the seal between the bushings and the blanks in between coats to prevent it from chipping worse.)

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jHop, going thin vs thick won't solve the problem. I have tried many combo's of glues with the same result. When I first started, I only used thin CA and had the same issue.

I am planning to try the waxing and the spinning of the blank after every few coats. The xacto knife makes sense, and I'll keep on close by for occasional use, but I know that any scratch on the CA and its back to sanding and starting over, so I'd like to avoid sharp objects near the blank once its finished. I tried just taking the point of a scraper and cutting the blanks lose, which worked, but it also damaged the blanks finish a bit. Better than the CA chipping, but still noticeable.

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You can always get finishing bushings. They are made of UHMW. It takes a few seconds to pop off your current bushing set up and set them up, but it is not a problem. I use a mandrel saver, so it literally takes a few seconds.

here is a link to the bushings http://penturnersproducts.com/index.php?main_page=product_info&products_id=136&zenid=f545dd070798eef14507f3509241a926

Do you use a pen mill? if you cut the blanks loose and err to the fat side, you can trim it right back down to perfection.

I

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I did a little experimenting last night with a few of the techniques reccomended, and I thought I would just update for anyone who is having a similar issue.

One thing I didn't specify is that I don't have any issues with the standard slimline/spacer type bushings. The problem is unique to the heavier bushings that slide into the tubes part way. With the smaller bushings the CA bonds the tube to the bushing, but that isn't an issue. The larger bushings bond directly to the wood of the blank and cause problems.

"Spin the bushings" technique:

1) Only use thin CA. I found the bond from a single pass of medium was enough to cause visible chipping, that the micro mesh didn't hide.

2) Spin the blank free of the bushing with every pass or the buildup will cause visual chipping. A Mandrel Saver type system (see PSI for details) is a lifesaver here. I don't think I would have the patience without it.

3) There will be very fine fractures from when you spin the blank free (even with a single coat of thin) of the bushing, but a wet micro mesh sanding at the end seemed to clean it up.

"Waxing the Bushing"

1) This isn't a solution in itself, or at least not for me. It made the glue come off the bushing with ease, but then I still had glue overhang off the end of the blank that caused fracturing when I tried to remove it.

2) I found this worked very well for cleaning the bushings after each pen (which I hadn't been doing). Its a time saver,

3) I reccomend hitting the mandrel as well. I found small CA bumps in my mandrel that were interefering with the blanks/bushings sliding on and off.

"Xacto Knife"

1) I found this to be a gamble too. I cut into the blank a few times because I missed the nearly seemless bond between the bushing and the blank.

2) I will use this as a backup plan, but I don't think its a long term solution.

I haven't tried the "Universal Finishing Bushings" reccomended yet. I don't want to pay shipping on an $8 item until I am ready to place a bigger order. I will definatley give them a try though.

Thanks again for all the ideas!

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  • 3 weeks later...

I tend to have the same issue,I usually try to pull the bushing straight off the blank after scoring (rolling the mandrel with the knife) the ca just above the blank on the bushing, then on a flat surface sand the end if the blank on 320 grit paper to get rid of anything left , rub some BLO on the ends and call it a day.

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I do a ton of pens in multiple styles. I just wax the entire bushing before putting my CA finish on. Have never experienced the cracking, nor do I see overhanging glue very often. When I do, I slowly sand it off by hand. Shouldn't take much. I finish using about 8 coats of medium CA and BLO using Russ Fairfield's method. Take a piece of paper towel, add a few drops of BLO, and then add CA to towel. Rub onto spinning (slowly spinning) pen. You can check out Russ' videos on Youtube.

Also, have you checked out the International Association of PenTurner's website? Lots of discussions, videos, etc on using CA there. www.penturners.org

Adam

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