CA Finish bubbles up

Chris Inch

Member
Messages
31
Location
Ottawa, ON, Canada
I'm quite frustrated right now. I was commissioned by a friend to make an ebony fountain pen with sterling silver hardware. Everything was going fine, and the finish looked outstanding. I had done 12 coats of CA and sanded with micromesh to 12,000.

When I assembled the kit, and pressed in one of the pieces, the CA finish "bubbled" up and separated from the wood. :eek:

See attached full size and close up photo.

Now that the pen is assembled, I don't think there's anything I can do to fix this pen, but I don't feel right selling him the pen either. Has anyone else had this happen? Is there anything I can do to prevent it from happening in the future?

Here's some info:

Wood is ebony
Sanded first to 400 grit
Applied 12 coats of CA glue with CA accelerator after each coat
Let dry completely for 2 hours
Wet-sanded with micromesh to 12,000 grit
When I'm done, I separate the blank from bushings with a utility knife, and trim and extra CA that it sticking out beyond the end of the blank.
Press fit the kit.
 

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My first impression is your CA finish was just a hair longer than the blank... when you pressed the fittings to the wood, the edge hit the edge of the Ca and pushed it away from the wood... have experienced this myself... you'll need to refinish and make sure your facing is dead on flush.

Love the pen..
 
Finding completely dry ebony is very improbable these days. It requires considerable time to dry properly. And, it is an oily wood. I suspect a combination of not being cured and the oils are what caused your problem. You might be able to fix things by putting the blanks back on the lathe, sanding off the CA and just bringing the naked ebony to a high polish. Personally, I don't think ebony needs a finish.
 
Yes, I definitely think that the CA finish was sticking out a tiny bit past the end of the blank. I try to trim it down using a utility knife before pressing, but even doing that sometimes gives this bubbling "effect".

I like using this high-gloss CA finish on ebony to make it look like a piano key.

I was thinking actually that the wood may have been too dry, rather than too moist. I got it from a cut-offs bin at a wood store here in town, so who knows how long it was sitting there. Do you think that's possible that too dry would have this effect?

I'm still trying to master this finish and I'm fairly close. It's just the last portion of separating from the bushings and press-fitting that still needs perfection.
 
Chris asked, "Do you think that's possible that too dry would have this effect?"
No. I doubt real ebony can get too dry. Some of the nicest ebony to work is when one is lucky enough to get some antique stuff.
Please believe me when I say that most ebony purchased today is wet. I once almost imported a pallet load for the purpose of reselling and making a few bucks. I hesitated when the suppliers in South Africa told me they would cut the trees as soon as a confirmed order was received. That meant it would come wet but wax coated. I decided against the venture when I got an estimate for the cost of the air freight. :eek:
 
First off Chris, what a nice pen, and the problem just SUCKS! :bang:

Such frustration is understandable, after you did everything right, that I can see :dunno:

I think the problem could be either of the things suggested by Frank or Chuck, or it could be a combo of both.

Sorry, not answers for you :eek:
 
Chris one thing I do is take a razor blade and make a cut between the wood and bushing. When seperated I have a piece of 320 grit glued to a piece of glass. I stand the bushing on end and pull it across this to make sure the end is squared plus make it smooth. I do believe the glue was longer than the blank is what caused your problem. I have had that happen a couple of time is why the cut and the glass with sandpaper.
 
Bummer about the pen. It looks superb. (Well, except for that thing by the ring.) :doh:

I've also had pretty much the same kind of bubbling on pens I've finished with CA. And they were a variety of woods. Like you and others have mentioned, I don't think I trimmed or sanded the finish back quite far enough.

As an aside, I've not tried putting a finish on ebony, but I think it might also help to wipe the wood down with acetone or other solvent (and let it dry) before applying the finish. I know that's what's recommended before gluing with many other oily hardwoods.
 
When I do a CA finish before I assemble the pen, I put a piece of sandpaper on the bench grab the finished blanks & run both ends across the sandpaper a few times. This makes any CA overage exactly match the finished pen barrel length.
 
I don't do pens, but I use CA on bowls a lot. A couple points:

1. Twelve coats seems excessive. Something on the order of 2-3 is more reasonable unless you're using the super-thin (5) CA, even then I'd stop at 4-5 coats.
2. Accellerator is not always your friend, especially if you're using anything thicker than 50 or so.
3. The acetone wipe before the first coat is also a good idea.
 
Ok. Thanks for the tips. I once read someone doing 20 coats of CA, so I thought that "only" 12 was reasonable. I will definitely try fewer coats next time and see how the pens turn out. Thanks.
 
Good news. I managed to get the pen apart and was able to sand it down and refinish the pen. I made extra sure to sand down the ends of the blank before pressing the kit together. Here's the final result:

Thanks for all your help everyone.
 

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