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OKLAHOMAN

OKLAHOMAN

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Joined
May 17, 2006
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Costa Rica
:eek: I've probably cast well over a couple of hundred cactus blanks and about a year ago ran into this same problem, never could find the solution or figure out the cause as it just fixed itself. Now it's back, the fourth blank, use epoxy tinted to glue in the tubes, use creamcoat to reverse paint the blanks and tubes, happen on both the blue shown and on black
IMG_3043-1.jpg
IMG_3043.jpg
 
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I don't know Roy, but I'm having the same issue most of the Dichro blanks I'm trying to make. And since mine are cast on the tube its even more frustrating.
 
The only thing I can think of is maybe the paint wasn't fully cured and pulled away as it dried. Was there any play room between the drilled hole and tube when it was glued in? The fact that it's so sporadic leaves me stumped too.
 
Looks to me like the paint on the inside of the blanks has pulled away, like it was sucked off from perhaps the epoxy shrinking a bit when it dried and the paint was not adhered enough to the inside of the blank. That is just a guess of course, but from what I can see it does not look like the paint inside the blank came off by scraping it while inserting blank. I would investigate the paint. How good does it adhere to plastics. What is the shrinkage rate on your epoxy. Is the inside of the blank clean enough before painting..perhaps you used a new drill bit and it had oil on it which prevented the paint from sticking well enough. How smooth is the hole? Too smooth a hole, paint won't stick as well. Some idea to think about at least.
 
to me it looks like you don't have enough mechanical adhesion and the paint is lifting. Try sanding the tube a bit with 400 grit paper and paint it. after paint dries scuff it lightly with 600 grit and glue in place
 
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