CA Finish Cracking

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I have been using thin CA to finish pens for some time without a problem. However recently I found 4 pens where the CA finish is cracking. I have reviewed many posts and see many methods of application but am still confused. I have been using 10 coats of thin CA with activator. As a test I now spray activator on the blank first followed by 4 coats of thin CA without activator. I let the blank dry over night and then micromesh to 12,000 grit. I then apply 3 more coats of thin CA and agin let it dry overnight before again using micromesh. Question: Are others using activator first on the blank before applying CA. Any other thoughts on getting a great finish?
 
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BCnabe

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Any chance you're using Stick Fast CA? I had the same problem when I did. I did not use accelerator though.

I've switched to Mercury Adhesives Flex and haven't had it since. I am using their accelerator. I put the CA on and then give it a shot or two of accelerator.
 

leehljp

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Lately, several people have mentioned cracking CA. I never had a problem with it; it might be technique and it could be the brand. I remember one fellow with cracking CA before the last couple of years and that was about 7 or 8 years ago. he was putting his pens in display cases with the sun shinning into the room/store and the heat was causing expansion/contraction problems on the wood, which caused the cracking. By the way, those particular pens were cross-cut blanks. Crosscut blanks have different expansion rates than straight grain.

My thoughts are first: How thick a layer of CA are you adding? Do you use calipers to measure your turned blanks and then the thickness of the amount of CA. Very thin coats will be more prone to cracking than thicker coats.

My second thoughts are: why use activator? CA cures quick enough without it. In your warm and humid environment, CA should cure just as quick without activator.
 

mecompco

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I'll second Mercury Flex. I use five coats of Mercury Flex thin with Mercury activator between applications. Leaves a nice smooth finish that requires little to no sanding. From what I understand the "flex" component reduces the chance of cracking. Mercury Flex was supposedly designed specifically for use as a finish.
 

Rounder

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I use 5 coats of thin CA with a light spritz of accelerator after each coat. Then I use 10-15 coats of medium CA with a light spritz of accelerator. I then wait maybe 30 min. to an hour and then sand 400 through 12000. Polish with #2 Novus and wax with Renaissance wax. I do not wet sand. When wet sanding I always had issues with clouding. Not sure why as many wet sand with no issues. Never had any issues with cracking. Do not know the name of the CA I use right off hand but it is not Stick-Fast.
 

leehljp

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I'll second Mercury Flex. I use five coats of Mercury Flex thin with Mercury activator between applications. Leaves a nice smooth finish that requires little to no sanding. From what I understand the "flex" component reduces the chance of cracking. Mercury Flex was supposedly designed specifically for use as a finish.
Michael,

I used to have some CA flex, but that was so long ago that all that was available in CA was black. I have epoxy flex (rubber) that I used for gluing tubes into brittle blanks, such snakewood.

I have seen several references to flexible CA (clear, Mercury) and will have to give it a try. Thanks for mentioning this.
 

robertkulp

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Michael is correct. Mercury Flex was developed as a pen and other turning finish. I met with Mercury’s CEO a couple of years ago and Eric later asked if I wanted to help them with a new type of CA. After testing it myself and sending it to some others for testing, it became apparent that this was unlike anything else I had used (and I have used a lot of brands of CA). Of course, it’s also a great adhesive. Unlike some other “flex” brands, Mercury’s does not contain rubber, yet it won’t crack or “shatter”.

Another thing that makes it different is that it has a long open time and is intended to be used with accelerator or another form of activator, such as BLO. Many people make the mistake of avoiding accelerator with Mercury Flex, as they would with some other types of CA. This results in a very long (for CA) cure time.

Feel free to contact me if you need any application or technical info about it. I’m glad to help in any way I can.
 
Joined
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Marco Island, FL
I have been using thin CA to finish pens for some time without a problem. However recently I found 4 pens where the CA finish is cracking. I have reviewed many posts and see many methods of application but am still confused. I have been using 10 coats of thin CA with activator. As a test I now spray activator on the blank first followed by 4 coats of thin CA without activator. I let the blank dry over night and then micromesh to 12,000 grit. I then apply 3 more coats of thin CA and agin let it dry overnight before again using micromesh. Question: Are others using activator first on the blank before applying CA. Any other thoughts on getting a great finish?
Thank you all for the responses. YES, I WAS using Stick Fast but have just ordered Mercury Flex. While the problem only occured with 4 pens out of several hundred I am not taking any chances.
 

robertkulp

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How well does Mercury flex keep in the case of infrequent usage? I keep having my stickfast go bad on me.
Mercury Flex CA has a realistic shelf life of about a year. Unlike other brands, Mercury has an unconditional, lifetime guarantee on all their products. If there is ever a problem, contact your dealer for a replacement.

Mercury’s CEO, Eric Ferher, explains it like this... “We stand behind all our products no matter when they were purchased. The Mercury warranty is simple…. Unconditional.”
 

Lenny

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There is a well documented issue with Stickfast CA glue cracking when used as a pen finish. I have never heard of any other glue having that problem. I use the EZ Bond glue Monty used to sell here, now sold by Exotic Blanks. I have never had an issue with it as a pen finish.
 

Gary Beasley

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There is a well documented issue with Stickfast CA glue cracking when used as a pen finish. I have never heard of any other glue having that problem. I use the EZ Bond glue Monty used to sell here, now sold by Exotic Blanks. I have never had an issue with it as a pen finish.
It was not simply Stickfast, but the version supposedly engineered for finishing, in my experience. I never had a problem till I bought a bottle and started using it. Problem went away soon as I discarded the bottle. I look forward to trying the Mercury CA.
 

robertkulp

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I just posted asking this same question, i was using the Mercury flex, cracked like a SOB
http://www.penturners.org/forum/f62/ca-cracking-156976/

About 10 coat of thin, glue is fairly new. I think the cracking is do to it not completely curing between coats, even with accelerator, this stuf doesn't seem to cure nearly as fast as regular CA.
You're correct... Mercury Flex CA doesn't cure as quickly as regular CA. It's engineered with a long open time and is designed to be used with accelerator. If your finish cracked, it sounds like you used too much for each coat. It requires just a minimal amount and using too much at a time will cause problems.
 
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