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Cloudy patches in finish

jbrewton

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John
I am new to pen turning but I have about 10 pens under my belt. I turn both acrylic and wood. Here is my finishing routine for wood.

Wood on about 800 rpm
Sand from 150 to 600
Add thin CA 3-5 coats
Add 2 coats medium
Spray lightly accelerator between all coats
Wet sand with micro mesh up to 12000
Buff with plastic polish

My issue is that I get cloudy patches after the plastic polish. It it because of too much heat? Should I stop at 12000?



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Penpal

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Using a picture for reference would help your description leaves so many oportunities for guessing . Every factor in your making can cause this problem including not fully dry timber. The grade of 150 is quite course.

Peter.
 

GeordieB

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I second marks comment on accelerator I dont use it on finish I dont even use it at work on mitres turns the glue very brittle
 

Bammer

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As previous posts,

A picture would help diagnosing the problem

I too don't use accelerator

With all that sanding, do you clean the pen after each grit ?

I had the same issue when using African Blackwood and to some extent Walnut. I put it down to not wiping it down between grits and too much elbow grease which effectively knocked back the CA finish too far in patches.
 

EStreet

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cloudy is most often due to moisture. Accelerator does not cause cloudy problems unless it is one of the junk brands that does retain moisture or excessive heat.

There are a few other things that can cause problems as well, for example wood grain moving, paper shrinking/expanding but it all come back to water.
 

Walter

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I agree with Ed, moisture is the most likely cause, the other possibility, depending upon what you mean by cloudy is that your final polishing has gone right through the CA and back to the wood.

I never wet sand anyway, too much mess for my liking, but absolutely never would I do it on a wooden blank. Guess where your moisture is coming from.
 

Jim

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Every wooden pen i make using a CA finish i use the micro mesh up to 12000 with water ..
 

Walter

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Every wooden pen i make using a CA finish i use the micro mesh up to 12000 with water ..

Not saying it is wrong or that it doesn't work Jim, just that I don't do it due to the risk of getting water into the end grain. I also don't see the need to work through all the grades of micromesh before moving on to plastic polish or burnishing cream, to me it is a waste of time and effort, because Farecla for example will take scratches out from 600 grit anyway. But each to his own method. Nothing is wrong if it gets the right result.

John is not getting the right result, moisture seems to me to be the most likely cause and not wet sanding is one way of reducing the risk. Just a suggestion.
 

Bill Mooney

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I had problems when I used accelerator as well. I dry sand then use Farecla 300 then 500. Works for me. I don't bother with micro mesh now as I prefer the Farecla.
 

EStreet

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I think a few clarifications may be in order:

*) The most common method of using micromesh with water is more of a slurry than flushing action. Elimination of this may be in order. This is one of the big reasons why buffing became popular. However the buffing compound itself can also be a source of moisture induction.

*) 'Accelerator' is more often than not acetone, check the MSDS, I have said a number of times how bad acetone is when dealing with CA. That might be a topic for another thread. Accelerator by itself does not cause cloudy spots unless it has water, H2O in it. Accelerator is nothing more than a neutral PH chemical that causes the PH shift in the CA thus neutralizing the very weak acid stabilizer and causing the CA to polymerize. To those who have seen bloom with use of accelerator can you please state, or PM me, which accelerators you were using and how much?

*) Cloudy, referred to as bloom, is the reason that CA fumes is used to detect fingerprints, that is directly related to moisture. Moisture, water, H2O is the key. Even when you seal up the ends of the blanks with CA moisture can still get in there. This equates to the home and hydrostatic pressure in the building materials.

*) Cloudy can also be separation of the blank material to the CA finish. Be it due to material shifting, foreign materials inhibiting the CA from bonding to the material (i.e. wax) or the like. The look is drastically different between the two and once you see the difference it becomes very obvious.

Consider this. If you take your nonstabilized wood pen with CA on to a drastic different moisture environment (high MC city to low MC desert for example) there will be a shift in the wood moisture content. This shift will cause the CA finish to MOVE. If your CA is hard, rigid and non-flexible then it can CRACK. Reactive materials, antler, horn, bone, wood just to name a few, should have special considerations when you work with them, i.e. location, storage, handling, usage.
 

jbrewton

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Here are some pics. The only difference in my finishing is that on the click pen I friction polished with plastic polish. I think I more lean towards sanding through finish. uploadfromtaptalk1448730075678.jpguploadfromtaptalk1448730115344.jpg

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Bammer

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I agree with Ed, moisture is the most likely cause, the other possibility, depending upon what you mean by cloudy is that your final polishing has gone right through the CA and back to the wood.

I never wet sand anyway, too much mess for my liking, but absolutely never would I do it on a wooden blank. Guess where your moisture is coming from.


Glad you agree with me too :winking:
 
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