Tip to eliminate the acrylic dreaded white spots!

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randyrls

randyrls

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I was turning a set of blanks this evening when just about the time I got the blank to size I started noticing small white spots. Tiny bubbles in the acrylic!

I tried to fill the spots with thin CA, but wasn't able to remove them completely. The white spots on dark red were VERY noticeable! This blank is very pretty, and I didn't want to throw it away. I remembered that I have some Transtint Dye I used with dyed wood burl blanks to make the colors "POP"!

The Transtint made the spots disappear, and then a quick coat of CA finish completed the job! This blank looks FABULOUS!

Can't wait until tomorrow and turning the nib section.
 
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IF you can, I would really like to see a pic of the bubbles in the acrylic BEFORE you fix them.

I am not trying to nitpick---but acrylic should have been under enough pressure when made to make bubbles nearly impossible---I could learn something from seeing them.

Thanks!!
 
hunter-27 said:
I hate to be the one to say it, but...............No pics, didn't happen.:eek::biggrin:
Click to expand...

Ok; Pics follow.

This post is only to show how I dealt with this situation. The blank is REALLY beautiful and I want to complete it. The depth of the blank is amazing!

This is the blank showing the small white pits. It really stood out on the red blank.






This is after finishing. I applied Red Transtint dye to the blank to subdue the white spots. Then I put thin CA as a finish. Not up to my usual finish standards. I will retry the finish.
 
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I suspect the "white" is actually acrylic sanding dust caught in small pits in the surface. If you don't clean them out completely (which can be difficult), then putting a CA finish on top will simply trap the dust there.

Tinting the dust to match the blank sounds like a novel and effective solution.

When I turn an acrylic or pr blank and run into small pits, I fill them with CA before sanding. That way, the dust doesn't get into them at all.

Regards,
Eric
 
Sylvanite said:
I suspect the "white" is actually acrylic sanding dust caught in small pits in the surface. If you don't clean them out completely (which can be difficult), then putting a CA finish on top will simply trap the dust there.

Tinting the dust to match the blank sounds like a novel and effective solution.

When I turn an acrylic or pr blank and run into small pits, I fill them with CA before sanding. That way, the dust doesn't get into them at all.

Regards,
Eric
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I agree with this summary, it does not appear there were any "bubbles", more like tiny "chip outs" from the tooling. An air compressor and blow tip also will help remove the dust before applying. With the exception of filling any pitting or on an embedded cast, I guess I don't do a CA finish on most acrylics, just sand and polish.
 
Had something similar happen with a snake skin blank.

Tried filling with CA and it didn't help, so I tried sanding down as far as I dared (I didn't notice the hole until after final assembly, so I had to take the pen apart). Once I got down as far as I dared, I noticed that the hole went a bit deeper than I'd initially thought. Tried to vacuum out the hole, and fill with CA, but the results weren't all that great. Probably got some CA in there from the first time sealing some of the white in. Don't think there's much I can do now, but I'm sure it will still look decent. Pretty sure it was a bubble.
 

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Ghost, A snake skin blank is made from either PR or Alumilite and can have voids, whereas an acrylic blank is made under much more pressure and very,very rarely has a void and I agree to a certain extent with Eric and Landon that the white spots in the voids were sanding dust and the voids were caused by tooling not caused when cast now to PR and Alumilite voids happen as I stated but the effective way to "hide" the is as Eric said do not sand and fill with CA. In my opinion you do not ever need a CA finish on any acrylic or PR but on most alumilite blanks you do....
 
OKLAHOMAN said:
Ghost, A snake skin blank is made from either PR or Alumilite and can have voids, whereas an acrylic blank is made under much more pressure and very,very rarely has a void and I agree to a certain extent with Eric and Landon that the white spots in the voids were sanding dust and the voids were caused by tooling not caused when cast now to PR and Alumilite voids happen as I stated but the effective way to "hide" the is as Eric said do not sand and fill with CA. In my opinion you do not ever need a CA finish on any acrylic or PR but on most alumilite blanks you do....
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Well now I'm glad I posted that. Still being a newbie I appreciate the info. That was my first non-wood attempt, and someone graciously gifted it to me, so I really didn't know what to expect.

Sorry for the thread derail. BOT.
 
I use a compressor and blow the dust off of blanks, even wood, prior to finishing. It really gets imbedded dust out of the pores or any inclusions that the blanks might have from tooling or creating. It works really well and I am only using a 1 gallon compressor.
 
Thank you for posting the picture!!

It appears to be commercial acrylic, as you said (sorry that word is thrown around a lot, so I didn't think it really was--my apologies for doubting!!)

As Roy says, I have never seen bubbles in acrylic---so how can you tell what you have??? Here is a "rule of thumb": Bubbles are round--EXACTLY round.

Tool marks are not likely to be round.

Using those guides you can determine the origin of the "holes". This also tells you if you will be likely to be able to sand them out. If it has bubbles, it probably has more than one--sanding will probably just expose the next one--so unlikely to work great.

The compressor is the best method I have found, followed by a dousing with DNA. Why DNA? It is also an accelerant of CA, in case you don't get it all off, it just helps with the next step, a thin CA coating or 5.

Remember the CA will appear to have the hole as the coats build, so you build high enough to sand down the CA OR work on the hole, specifically--build it "proud" of the blank, then sand to meet the blank.

Either method works.

The transtint is a great addition to the idea, since it WILL hide any dust you missed.

Hope this all helps!!
 
ghostrider said:
Had something similar happen with a snake skin blank.

Tried filling with CA and it didn't help, so I tried sanding down as far as I dared (I didn't notice the hole until after final assembly, so I had to take the pen apart). Once I got down as far as I dared, I noticed that the hole went a bit deeper than I'd initially thought. Tried to vacuum out the hole, and fill with CA, but the results weren't all that great. Probably got some CA in there from the first time sealing some of the white in. Don't think there's much I can do now, but I'm sure it will still look decent. Pretty sure it was a bubble.
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Ghost, this isn't exactly a fix to the problem. It looks like that is a sierra kit so you could knock out the end finial and switch it to the other side so the clip can cover the filled in hole. Since both sides should be turned to the same diameter. Like I said, it's not a fix, but it can take the eyesore away and that is a beautiful blank.
 
Brooks803 said:
ghostrider said:
Had something similar happen with a snake skin blank.

Tried filling with CA and it didn't help, so I tried sanding down as far as I dared (I didn't notice the hole until after final assembly, so I had to take the pen apart). Once I got down as far as I dared, I noticed that the hole went a bit deeper than I'd initially thought. Tried to vacuum out the hole, and fill with CA, but the results weren't all that great. Probably got some CA in there from the first time sealing some of the white in. Don't think there's much I can do now, but I'm sure it will still look decent. Pretty sure it was a bubble.
Click to expand...

Ghost, this isn't exactly a fix to the problem. It looks like that is a sierra kit so you could knock out the end finial and switch it to the other side so the clip can cover the filled in hole. Since both sides should be turned to the same diameter. Like I said, it's not a fix, but it can take the eyesore away and that is a beautiful blank.
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Yeah, I know (and I do appreciate the advice). Unfortunately, that blank also has a pretty bad crack (more like a lack of adhesion to the skin) dirrectly under the clip at the edge of the blank, so it actually looks better this way. If I turned it around to the back side (opposite the clip), they'd both show. I just accepted it as one of those things that has no remedy. I already sought the advice of a quality pen turner in my area, and received the same conclusion. Of course, that doesn't mean I'd discount any ones idea if it worked. Short of making it disappear, I don't think it can be helped.

And again, thank you for the help.
 
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