What am I doing Wrong?

[Racer3770]

Just recently got into label casting and I'm slowly trying to single out an issue with each new batch of labels. Last time, all my castings had bubbles in them. I took care of that. Now, when I turn the blanks down, they have this paper-like white edge on the corners.
I print the labels, wait a day or two, and apply them to the tube. Then I put a thin CA finish around the label. I wait another couple of days for the CA to degas. Then, I cast in silmar 41. Do I need to trim the label up (the small overhang off the edge of the tube) before I cast? When I go to square my blanks up it seems like the label gets ripped. Tips?
Thanks!

 

[arkie]

I believe what you are seeing is the tube and PR separating from each other. I normally equate this to a lack of a proper bond between the resin and the colored tube. The ends see the greatest concentration of stress during turning and this is where you are most likely to see separation, which I see on both ends of your blank. There may be many causes for this, but in my personal experience it was only a problem when I tried to switch to powder coated tubes to save some time. I don't see it now that I am back to nail polish.

 

[Cwalker935]

I started experiencing this problem (I suspect it had something to do with a change in the label adhesive but don't really know why) and eliminated it by brushing the labels with PR rather than CA, letting dry and then casting the PR under pressure.

 

[vtgaryw]

PR will definitely separate from whatever it's supposed to be encapsulating under sometimes mysterious and not always repeatable circumstances. I've found that the smoother the substrate under the PR, the more it is prone to doing this.

You definitely need to be careful to apply as little pressure from your tailstock as you can on blanks you've cast with PR. I have better luck with TBC bushings, or just turning between centers.

Gary

 

[stuckinohio]

You can sometimes fill the gaps in with thin CA.

plug the tube with something like play-doh then soak thin CA into the area with the gap. Let it dry then put some more onto the tube and it will hopefully take up the space. If it doesn't get all the bubble filled you can always trim a tiny bit off the length to reduce it some.

 

[vtgaryw]

PR will definitely separate from whatever it's supposed to be encapsulating under sometimes mysterious and not always repeatable circumstances. I've found that the smoother the substrate under the PR, the more it is prone to doing this.

You definitely need to be careful to apply as little pressure from your tailstock as you can on blanks you've cast with PR. I have better luck with TBC bushings, or just turning between centers.

Gary

 

[Racer3770]

So you guys don't think it's the label ripping apart when I trim the blank? Do you trim up the label?

 

[arkie]

No, in this case I think it is the PR separating, and others appear to agree. However, you should trim the blank by sanding, rather than by mill, which will reduce the chances of several other bad things happening.

 

[m4skinner]

So you guys don't think it's the label ripping apart when I trim the blank? Do you trim up the label?

I trim the label flush with the tube before I cast.

 

[arkie]

As do I, with a razor knife, and trim the ends of the casting by sanding either before turning, or at least while well over finished size.

 

[jsolie]

So you guys don't think it's the label ripping apart when I trim the blank? Do you trim up the label?

Yep. I trim the label overhang off with a hobby knife. I also let things rest for a day before continuing with the next step.

Are you wiping down your tubes with anything before applying the label? Since I started wiping down tubes with a paper towel or napkin that's ever so slightly damp in one spot with Windex, I haven't had any problem with the labels adhering to the tube. Of course I do wait until the tubes are completely dry and wiped down with a clean napkin/paper towel before applying a label to them.