CA finish over oil

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TattooedTurner

TattooedTurner

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Should an oil finish (I now use Minwax Antique Oil which according to Mike Peace is Danish oil without the varnishes) be allowed to fully cure before applying a CA finish over it? This would mean setting the blanks aside for a couple weeks which I'm ok with, but why wait if there's no need to?
 
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Jay,
In many cases that I have experienced with oily woods, in particularly ebonies, CA does not adhere well. It can hold and not be a problem. However I found problems on the ends, when separating the bushings from the turned and CA finished blanks. The snapping would cause the CA to lift from the blank on the ends. That is what drove me to investigate and move to TBC.

If CA is put on over "not fully cured" antique oils, I don't know what would happen but I would figure that it would cause similar problems what I had with the ebony woods.

In all fairness and logic, I have not had any more problems with CA and ebonies in nearly a dozen years, so the adhesion is not any better now than it was before, I am simply not applying the same forces on it as I was before - meaning that it might work, only it may be more sensitive to shock (drops bumps) of different sorts.

Just my opinion. :smile:
 
They use CA/blo as a finish but to me if I spend all that time making the pen blank and turning it why take a chance with adhesion. When using CA/BLO as a finish you are rubbing it till it drys and heats up when it dries. Let it dry and then top coat. That would be my suggestion.
 
Thanks to all 3 of tou for the quick replies.

leehljp said:
Jay,
In many cases that I have experienced with oily woods, in particularly ebonies, CA does not adhere well. It can hold and not be a problem. However I found problems on the ends, when separating the bushings from the turned and CA finished blanks. The snapping would cause the CA to lift from the blank on the ends. That is what drove me to investigate and move to TBC.

If CA is put on over "not fully cured" antique oils, I don't know what would happen but I would figure that it would cause similar problems what I had with the ebony woods.
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I've had the same thing happen on the ends of blanks. Brushguy from YT mentioned that a month or so after doing BLO/CA finishes on wood brushes they were getting returned due to cracks and such. Several months back I made a beautiful figured Koa mech pencil that just yesterday I noticed had fine spiderweb cracks all through it. I'm not sure when it happened because I rarely use it of but I used BLO and probably within an hour applied the CA. Due to the CB being pressed on a tenon it's almost impossible to remove without ruining it. I have a sneaky suspicion it's due to the BLO not being dry.

jttheclockman said:
They use CA/blo as a finish but to me if I spend all that time making the pen blank and turning it why take a chance with adhesion. When using CA/BLO as a finish you are rubbing it till it drys and heats up when it dries. Let it dry and then top coat. That would be my suggestion.
Click to expand...

Thank you, that's pretty much what I was thinking. I'm making a Cambridge FP for myself, not my favorite kit, but I'm using a beautiful redwood burl and I don't want anything going wrong. I'll play it safe and let the oil cure for 2-3 weeks. A little insurance can't hurt.
 
George883 said:
Silly question Hank, but what is TBC? I'm a newbie. Thanks.
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TBC= Turn Between Centers

Turning between centers

Hi Folks, I’ve seen lots of recommendations of turning between centers. This is not a problem for me if I’m using wood, but with acrylic I have to admit I’m a big lost. With a Shopsmith, I don’t have a chuck or collet on the drive side. (I do have a Nova chuck on the way) However, what would...
www.penturners.org
 
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George883 said:
Silly question Hank, but what is TBC? I'm a newbie. Thanks.
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I will give you a link: http://content.penturners.org/library/tools_and_jigs/Dead_Center.pdf

That is not the best, but the start of using TBC on this forum. I called it "Mandrel-less" originally, but others called it correctly as Turning Between Centers.

If you note in the PDF, I made a cone shaped "drive" out of aluminum and made sure it went nose to nose with the tail stock's live center. The MAIN POINT is that it is the drive center and live center that holds the blank, not a mandrel.

The reasons behind it were three fold for me. The FIRST was that I often had the blank glued to the bushings. On oily blanks (ebony) - CA can "lift" off of the ebony on the ends when you separate the bushing from the CA'ed blank. TBC stopped that for me. The SECOND vantage was that I am obsessive in precision even though I am not an engineer. Mandrels can 1. get bent even a minuscule amount, or 2. tightened a quarter turn too tight and make it out of round (Not technically correct but you get the drift), or 3. the tail stock turned too tight, or for new pen turners 4. using the wrong tail stock live center on a mandrel which causes it the mandrel to wobble. TBC takes care of all of these. The THIRD reason for me is that I often dropped a mandrel spacer and had to look for it, or dropped the mandrel nut and had to hunt for it. I like to take the blank off and check it, sometimes two or three times during a turn, especially when turning segmented blanks. It is so much easier to do this on TBC than on mandrels. Fewer objects allow simpler turning to.
 
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