What exactly did I do to this acrylic acetate blank?

[williaty]

So I just turned my first acrylic pens (two Sierras), the first one being acrylic acetate bought from Ed. I backpainted the blank white with Krylon Fusion and that seems to have worked because I can't see the tube. However, I did something else to the blank that has caused a problem. Inside the blank, I've either fractured it or scratched it somehow. The outside surface is completely smooth and glossy, so this has to be inside. Look just to the right of the blue wavy line and you'll see a series of faint horizontal white lines stacked up like woodgrain. If you look towards the bottom crossing the wavy blue line, you can see some heavier lines at a steeper angle. In certain light, these lines are all VERY visible to the naked eye.

What on earth did I do to this blank?

 

[D.Oliver]

They could be scratches from drilling. The might be stroke patterns from whatever instrument you applied the paint with (a brush or q tip for example). They also might be caused by the paint cracking. Sometimes the paint doesn't play well with the CA glue and epoxy we use. Based on he heavier lines at the bottom I don't think they are scratches from drilling.

 

[D.Oliver]

How long did you let your paint dry before you glued the tubes in?

 

[SteveG]

It is probably surface texture (scratches, lines, etc.) caused by the drilling process. You painted over that surface, but can see it from the "outside". There is little you can do at this point, unless you can get the tube out by use of some solvent or heat, without damaging the blank. Then you would have to get all the adhesive/paint out of there. then sand the inside of the hole until it is smooth. Then you could repaint, etc. I suggest that you toss this one, it is a learning experience.

For the future...on all near-transparent blanks you will need to smooth the inner surface after drilling, and prior to painting. The more transparent the blank, the more effort is needed to make it look good.

 

[williaty]

The Fusion is a spray paint, so nothing went into the bore to distribute the paint.The paint dried about 30 hours before the tubes were glued in. The glue was Gorilla Glue polyurethane.

 

[mecompco]

With translucent blanks, I think it's always a good idea to sand the inside after drilling. I paint the tube, the inside of the blank, and the epoxy (maybe overkill, maybe not). Oh, and let the paint dry for 24 hours, then let the epoxy dry for another 24.

 

[ed4copies]

The marks appear to be near perpendicular, relative to the "paper" in the pattern. This leads me to believe they are not drill bit induced (THIS IS NOT A STATEMENT OF FACT, IT IS AN OPINION!!)

As a statement of fact, I can tell you I have seen similar marks, caused by a reaction with chemicals. At one time, I did a lot of research when I wanted to make clear blanks to use for demonstrations--several chemicals reacted with some acrylics and resins, and not with others. ConFuSING!!!

For jollies, I would try different paint next time---let us know if you find a "never-fail" solution!!!

Ed

 

[mark james]

I'd love to see the finished blank from a general photo distance. I suspect it is not as drastic (or even noticeable) as indicated.

We are very critical of our own work (yup, me too), but much will not be noticed by other than other turners. Let's see the final turning from a distance!

 

[1080Wayne]

Not sure we are all looking at the same lines . The lines on the right hand side about half way down which angle up at about 10 degrees to the right , I would interpret as drilling lines . The ones at the bottom of the photo angling up to the left at about 30 degrees look like fracture lines to me , probably caused by aggressive drilling .

Totally agree with the sanding the hole suggestion , and also with Mark`s comments .

 

[williaty]

They're actually far worse in person than they are in this picture. My wife came home, saw the piece sitting on the kitchen table, picked it up, and before she'd even brought it up to inspection distance she said "Oh, this looks horrible! What went wrong?"

The chemical reaction idea is interesting. I've seen LocTite crack plexiglass in a pattern like this. The Fusion paint smells really weird, so it's possible there's some unusual chemical in it causing a problem. I may try buying some Testor's model paint for the future. Problem is that I don't have any more of this material unpainted to experiment upon.

 

[LouF]

Krylon Fusion paint is for plastic this may be part of the problem.

 

[williaty]

Acrylic acetate is a plastic, hence buying the Fusion just for this project.

 

[LouF]

I thought he painted the tube with Fusion my mistake.

 

[SignWave]

I wonder if the expanding polyurethane glue created pressure from the inside of the blank. Just a question.

 

[thewishman]

Something that may help the blank - put it back on the lathe and give it a good once over with the 1500 micromesh. This blank looks great with a matte finish, I even stopped painting the inside because I think the brass tube showing through makes it look better. Not the case on all blanks, but this one works well for me - I sell them to the first looker, almost every time.