CA Finish

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studioseven

studioseven

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After quite some struggling, I now feel somewhat confident with my CA finish technique. Occasionally, though I have a few small white spots on my blanks when finished. I read somewhere that this may be caused by too much accelerant or applying it too close to the blank. My next pen I would like to try it without using any accelerant. My question is: How long do I need to wait between coats before applying the next coat? I normally put 4 coats of thin followed by 4 coats of medium.

Seven
 
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Can you give us a more detailed description of the white spots you are experiencing?

Are they little specks, or larger cloudy patches?

Can you post some photos?

Bill
 
Hi,

When I have experienced small white specks, it was usually sanding residue that was either trapped in the wood grain due to an insufficient cleaning, or trapped between the layers of CA, also due to not cleaning good enough in between coats.

Not sure if this is the cause of your problem, but it has bitten me more than a few times.

Bill
 
I CA without accelerator and usually do 3-5 coats over about a minute or so, and then come back after about 10 minutes and then do another 3-5. Repeat, repeat. I use paper towel so the coats are relatively thin (as opposed to using one of the small pen part bags). First 3-5 with thin, and then medium for the rest. Brand/freshness seems to matter (maybe its in my head) but I cannot seem to get satisfying results with some CA's but others go on like butter. Also, I do not final sand until the next day or later.
 
It will depend on how thick you put the CA on, the humidity, and temp. My application usually takes araound a minute, but this can vary from 30 seconds to 3 minutes.
 
I typically use 6 thin and then 6 medium and build up as necessary. I've had small white spots before and it is usually sanding dust or has also been polish if I've used the stickfast CA polish. Usually if enough buildup those small voids can be sanded down without sanding through the finish.
 
I think the small specks come from voids or bubbles that have been only partially sanded out. One of the goals is to have a smooth even surface. You may have coated the wood with to much CA and developed curing bubbles, once you sanded, you were left with some micro "craters" The sanding dust mentioned by Warren (above) will get in those craters and get sealed in.
 
I was dogged by this as well, despite my near religious cleaning of the wood before applying the first coats of CA and after each sanding session. It turns out that the relatively grainy wood I was using would have small voids in the finish, almost invisible over the deeper parts of the grain and those voids would collect the plastic polish that I used as the final finish which would turn white when it dried. I found that a good wash of the finish on the pen would remove the white polish and resolve the situation.

I could probably resolve the situation by using thin AND medium CA (or by heavier sanding), but so far I prefer using thin exclusively.
 
I would try sanding more when you get to the medium (after a couple of coats). If the spots are round, it is possibly trapped solvents that are popping and leaving fissures. If they are the same pattern as the grain, the finish isn't level and you are filling it with buffing compounds.
 
I have the same problem!

I apologize for butting in, and I hope this isn't considering hijacking the thread, but I was going to post exactly the same problem. Also, I apologize in advance because this will be a long post.

I have just begun pen turning, and my first pens, even two out of walnut were glass smooth and without blemish. The last two, done with the same procedure, but with two perhaps significant differences, were marred by small white blemishes in the grain. I have posted a picture below.

The two differences since my initial turnings are the type of CA (my problems began when I started using Stick Fast instant CA adhesive I purchased at Woodcraft) and when I started putting that CA glue in the refrigerator.

My procedure in brief is as follows:

Turn to shape and size
Sand with 100, then 220, then 400
Clean with acetone
With lathe at slow speed, apply a couple of coats of thin CA, using aerosol accelerant sparsely each time.
Still with the lathe turning slowly, apply 4 or 5 coats of medium CA, with accelerant after each coat.
Sand with 400 until there are no low spots, and an even sandy finish is uniformly across the pen
Wet sand carefully with mico mesh going through 1500 to 12000.

Your thoughts and critiques are most welcome. I have to say that I think it is either the CA glue itself or putting it in the fridge, because this same procedure yielded absolutely stunning results before. It is only evident in my walnut turnings; my cherry or quilted maple seem just as before.

I plan on trying one more time doing two things differently; the CA glue is at room temperature, and i will, in addition to cleaning carefully with acetone, also blow the blank off then vacuum the blank before applying the CA. I will let you know how it turns out.

Thank you again, and I hope since the original poster has what seemed to be the same issue, I can be excused for posting on his thread.
 

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Warren White said:
I plan on trying one more time doing two things differently; the CA glue is at room temperature, and i will, in addition to cleaning carefully with acetone, also blow the blank off then vacuum the blank before applying the CA. I will let you know how it turns out.
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Are you storing the bottle in the fridge in between uses?
If so, that is not really the best thing to do.
You should only store new, unopened bottles in the fridge until you are ready to open them.
Upon removal, allow bottle to reach room temperature before opening.
From that point on, store the the bottle in a cool, dry location.

Bill
 
I generally don't go beyond 3 coats of thin CA. Start with 320 grit sandpaper after turning, apply 2 or 3 coats and then sand it with 600 - 800 and 1000. Then it's the buffing wheel that does the rest of the job. I use the white compound with 2 buffing wheels, the first one is a blue cloth wheel which is harder followed by a soft wheel which puts on the shine. I hope this helps.
 
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