Problems with finish - help please

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Johnka1000

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May 24, 2018
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Muscat, Oman
I have a selection of both wood and acrylic pens finished, i have used a CA finish on both. I normally put 3 or 4 thin coats then 2 or 3 medium. I then sand with 400 grit at low speed and stopping the lathe and sanding with the training until it is fully even. I then use micro mesh wet to finish the pen before applying polish. The pens look fantastic.
I have noticed however that after approximately 3 weeks white lines are appearing within the finish. On sime it is a few on other there is alot. It is hugely disappointing as I have to through about 15 pens out now as i can't sell them like that.
Can somebody please help me and give me a pointer to why this is happening.

Thank you.

Ps I can post a picture if it help.
 
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edstreet

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Aug 12, 2007
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No longer confused....
White spots is called bloom. It's a result of WATER in contact with the CA when it polymerizes. What happens when it's weeks later is you create hydrostatic pressure that slowly sucks in moisture and reacts. You need to re evaluate your choice of CA as it needs to be surface insensitive. By adding that extra amount of acid along with other additives (like plasticizers) we can easily prevent this type of problem.
 

TonyL

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Mar 9, 2014
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In addition to Ed's advice, ensure that the wood is dry prior to your CA applications - this could be a function of the environment in which you are applying the CA. You can also ensure that the ends and edges of the barrel are sealed (you can use CA - my preference is thin). If there is any open/unsealed wood grain, it may be sucking-up water from your wet micro mesh sanding. That's all I can think of. I am sure you will figure it out.
 

jttheclockman

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Feb 22, 2005
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I believe Tony hit on the culprit. Most people forget about the ends of a pen blank before doing a wet sanding. Wood can wick water in like a straw and then later release it under the finish. I do not believe it is your CA but I stay away from accelorators. They cause too many problems. One other thing the 400 grit paper you are using to smooth things out sure is adding unnecessary scratch lines that you now have to work hard at getting rid of. May I suggest starting with getting your finish smoother when applying or at least sand with the 400 before your last coat or two of med CA. Then go right to MM or if needed use 1200 grit wet/dry sandpaper. Then mm.
 

Dehn0045

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Mar 19, 2017
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US
The polish may be hiding fine scratches that reappear over time. I try to get a near perfect finish prior to the polish.
 

Loucurr

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Feb 15, 2016
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314
Location
Florida
Also, you don't need to throw the pens out. Just disassemble, sand the finish off and then redo your finish.
 
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