Help with CA finish

[RMayoIII]

OK so I'm pretty new at this pen turning bit but I've been reading quite a bit of info here. I tried my first CA finish the other day on a zebrawood blank and it came out very nice. About 10 coats of medium (thats all I have) and then used the abralon pads up to 4000 grit. Then I polished it with some Meguiars Mirror Glaze I had in the garage. The finish was very impressive to me so I decided to try again on a piece of cocobolo and I'm not sure what happened.... After 5-6 coats of CA I had to leave the shop for a quick relief break. When I came back the CA had turned very dull and blotchy. I tried to polish it to see if it would go away but it got worse! What is going on here???

 

[Ruby pen turning]

Wish I could help but I have done Cocobolo .... lots of Cocobolo both by cleaning the wood with alcohol and by doing nothing and never had any problems.

 

[RMayoIII]

So no finish on cocobolo? just clean and thats it?

 

[butchf18a]

Ruby's successes not withstanding, Cocobolo is very oily. This oil is most likely the source of your problem. The fix for now is to sand off the existing CA finish down to bare wood, clean the blank thoroughly with denatured alcohol or acetone, then re-apply the CA. I'm no chemist, and there may well be better options for cleaning the blank, however I've had success with DA and Acetone.

jmoicbw-bidi

 

[reiddog1]

I've never had trouble with cocobolo. Maybe its as simple as cleaning your blank with a little bit of CA activator or DA and I never touch the blank with my hands after cleaning. Just be careful of oily wood like padauk, cause the activator will make the color run. DAMHIKT!! With those type woods, I just clean them with a dry paper towl while they spin. Hope this helps.

Dave

 

[Ruby pen turning]

Ye I still do my 10 coats or so CA cleaned with denatured alcohol or not.

 

[RMayoIII]

I skipped the cleaning step and I was very "hands on" after the sanding. I'll try re-sanding and cleaning with some acetone and see what happens. Thanks for the advice. If it works out I'll try to post a pic in the "show off your pens" thread.

 

[its_virgil]

CA accelerator is the cleaner of choice for me and others...not denatured alcohol, acetone, lacquer thinner or other common solvents. CA accelerator works great and I use nothing else. Evidently I am in the minority but that's OK.
Do a good turn daily!
Don

\

 

[OOPS]

In our local pen turners club, we had a demonstration of just how oily cocobolo can be. He took a turned blank of cocobolo, and placed it into a cylinder of denatured alcohol. In about 15 minutes, the alcohol looked "dirty." This was the oil and resins coming out of the blank. He said he normally keeps it in the bath 30 minutes, then wipes and dries the blank completely. Once dry, he puts on his standard CA finish. If you are able to get a CA finish on cocobolo without doing this, then perhaps your piece of coco. is not as oily as many others can be. I hope this helps.

 

[RMayoIII]

I sanded and scraped it all off, cleaned it several times with acetone and tried again with the CA.... same thing happened again, after 5-6 coats I waited about 5 minutes and it started to go dull and chalky. I can almost watch it happen, starts off as little spots and then creeps it way all across the blank! I think I will get some denatured alcohol tomorrow and give it a "bath" after scraping and sanding AGAIN. Will the "bath" of DA affect the CA used to glue in the tube?

 

[leehljp]

In cooler weather and when humidity is present, you can expect that sometimes.

Below is a duck call that went through from the chalky to dull to shine. I have experienced this on several occasions on it wasn't always with cocobolo, even though these picture are with Cocobolo.

Chalky:
IAP Home - Photos - Imported Photo from leehljp

Flat, no chalky white finish:
IAP Home - Photos - Imported Photo from leehljp

Finished and shiny:
IAP Home - Photos - Imported Photo from leehljp


And no, I did not take the finish off and start over. I just put plenty of thick coats on and when I let it set up overnight, it looked like it did in the first photo above. From lots of experience, I know that this happens on occasion and I also know that it is not a "loss", if the finish is deep enough to sand the top layer of "chalk" off.

 

[RMayoIII]

I went ahead and sanded down the chalky stuff and still had some finish left on the blank and was able to build up from there to a good finish. I think next time I'll try the DA "bath" before finishing and see how it goes. Thanks for all the advice!