CA, Wait to fully cure?

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BobBerk

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Oct 26, 2009
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Carlsbad, CA, USA
Well I noticed with a couple of my first pens that after I assembled them they would get a few very small dull spots(looked awesome while still on the lathe). Looked to me like the CA glue had pulled away from the blank in those small spots. Not noticeable unless you really look close at them.
Then I started waiting before taking them off of the mandrel and haven't seen it happen since. Do you guys usually wait before taking the blanks off the lathe or assembling them? if so, how long usually?
 
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Those dull spots may be finger prints. The dust /slurry on your hands from finishing may be sticking to the blank. My final step is plastic polish then ren wax I like to wait at least 1 /2 hour if I have the time overnight.
 
Leaving them on the lathe won't help. Something that just defies logic is how a finished blank can shine so well and then be dull in spots after a few hours. The REAL reason 99% of the time is that the finish it too thin and has been sanded through. Even sanded through spots will often shine for a little while!

In the above situation again an estimated statistic is this - Sand through/dull spots was done on a mandrel 90% of the time. Mandrels will allow for .006 - .009 Out Of Round/Off Center much more often than TBC (Mandrel-less) will. And this translates into sanding miniscule amounts more on one side or in spots - usually closer to the tail stock end. And as a result, Sand Through. Yep, it will be shiny while freshly finished but the dull spots will show up in a couple of hours to a day later. These spots come from one side/spot sanded more than others because of the OOR/OC tendencies of mandrels. There are other reasons but these are the main ones. Wood with soft and hard layers (grain) will sand quicker on the soft parts and less on the hard sections, again causing spots.

Two cures -
1. Thicker finishes. Hint - don't think about trying to finish as fast as possible or just enough CA finish. Put on many layers of thin, or several layers of medium or thick. With experience, this can be cut back later. But the point is to build up enough that Sand Through is stopped.
2. Turning Between Centers (Mandrel-less) eliminates the problems presented by the mandrel. IF the mandrel is working fine then great. But the symptoms usually point to the fact that it is not. On the other hand, if a single bushing is drilled Off Center, then you will have the same problem on the mandrel but just slightly more exaggerated.

Use the calipers and measure the bushings from the hole to the outer edge - do this all the way around. If the bushing is OC by .003 or more, you can have problems. I think most vendors will only accept OC as a problem only if OC by .005 or more, but not sure. This was a topic a long time ago.
 
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well I am the newbie here but I have noticed that sanding the raw blank to at least 600 if not higher is critical. your Blo to raise the grain is good. I have not had the opportunity to use Watco yet. I have noticed that the oil just gives it amazing depth. Then in my experience with the few I have done in the last couple of days. Many thin coats of the thin CA helps get that seal coat on. No burnishing just a very light sand every few applications to get any ridges smoothed out. Then I go to the thick CA and the BLO. every couple of applications a light sand to smooth it all out. at least 4 or 5 applications to get a nice build up. then I usually let it spin under a small lamp and that helps the cure. i ty to leave it over night to gas out just my personal 2 cents
 
Thanks for all the replies. Lots of different answers/suggestions.
Guess it to be best to try and follow all the advice.
I have been putting on more coats about the same time I let them sit on the lathe longer, and have not had any problems. So hard to say which actually solved it..
 
I think some batches of CA are hotter than others and may dry to fast lifting off of the surface,cause I had just opened a new bottle and had the same result spotty ,cloudy finish the next day or so. I experimented with same bottle on scrap wood. got mostly same results cloudy. I have since put that bottle on the top shelf out of my reach,and have not had that problem since.
It worked for me.
PS this CA finish that this happened on ,not to get confused with CA/blo finish ,as they are very differnt.
 
I agree Hank Lots of thin coats are very good. Also if you light sand definitely wipe the dust off as best as possible to clean it up. I did BTC for the first time and was throughly happy with the results. but on a previous one I did had little hazy spots under the CA layers that gave a slightly cloudy look and blurred the grain a bit. So I think cleaning the blank well with acetone initially, and then light sand when it has cured a bit is a good practice. Just my two cents :highfive:
 
I think more good pen finishes are ruined during the 1st 5 minutes after completion than anything that was done wrong during its application. Avoid handling any warm finish, and resist the urge to feel it with the fingers. It is best to let any finish at least cool to room temperature before handling and waiting until the next day before buffing and assembly.

If you can't wait until it has cooled before taking it off the mandrel, then make a little rack to hold the pen barrels until they are cool.
 
RussFairfield said:
I think more good pen finishes are ruined during the 1st 5 minutes after completion than anything that was done wrong during its application. Avoid handling any warm finish, and resist the urge to feel it with the fingers. It is best to let any finish at least cool to room temperature before handling and waiting until the next day before buffing and assembly.

If you can't wait until it has cooled before taking it off the mandrel, then make a little rack to hold the pen barrels until they are cool.
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Wisdom! I want to say this ranks at the top, but then there are not mid or lower wisdom advice from you - all at the top!

From my own experience, I fully agree! Thanks!
 
I haven't posted here in a while but I have to weigh in on this one. I personally think that people worry too much about CA "finishing" - i.e. waiting between coats, sanding between coats, waiting overnight, etc. First off is it really a "finish" or is it a coating? (for those who don't know I have a CA "finish" on all of my pens and always have) For that reason I personally see no reason to sand between coats. I only use thin CA unless I am filling some sort of hole. The first "coat" or two absorbs largely into the wood so I can't see how the finish would pull away from the wood. I personally wait as little time as I can between adding coats and sometimes use accelerator to help. If I am in a hurry I will not hesitate to assemble the pen immediately as well as put it in a leather case. I can honestly say,like Hank, the only issues I have ever had with a CA finish (and I have had my share) I could blame on sanding.
 
What Hank Lee said about sanding through a thin finish is correct.

Bare wood can be polished to the same high gloss as any finish, but it doesn't stay that way very long. How long depends on temperature and humidity, but it rerely more then a few hours before you can start seeing the difference between bare wood and finished wood that is exposed to the same air. .
 
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chigdon said:
I haven't posted here in a while but I have to weigh in on this one. I personally think that people worry too much about CA "finishing" - i.e. waiting between coats, sanding between coats, waiting overnight, etc. First off is it really a "finish" or is it a coating? (for those who don't know I have a CA "finish" on all of my pens and always have) For that reason I personally see no reason to sand between coats. I only use thin CA unless I am filling some sort of hole. The first "coat" or two absorbs largely into the wood so I can't see how the finish would pull away from the wood. I personally wait as little time as I can between adding coats and sometimes use accelerator to help. If I am in a hurry I will not hesitate to assemble the pen immediately as well as put it in a leather case. I can honestly say,like Hank, the only issues I have ever had with a CA finish (and I have had my share) I could blame on sanding.
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Exactly!

Only thing I do different than what you just said is that I have switched over to thick CA on wood that is uhh... non porous I guess you would say. No problems, and saves some time.
 
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