Getting better

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EricRN

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May 16, 2019
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I’ve had some issues with plastic blanks. See here and here. Blew another one out tonight. But some are turning out quite nice.
 
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EricRN

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May 16, 2019
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Forgot the links to the errors: https://www.penturners.org/threads/getting-better.161028/



Good ones attached.
 

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EricRN

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Joined
May 16, 2019
Messages
47
Personally I find when I'm blowing out blanks it's a glue issue
That is the likely culprit, thinking about it more. All three blew out in exactly the same way, and were drilled, painted, and glued as part of the same batch. I think what happened was this--I'd used a little WD-40 to lube as I drilled (this was the batch right after the one where I got the drill bit stuck--see link above) and then I painted the blank with white acrylic. I don't think I cleaned the WD-40 off the blank sufficiently and so the paint and the glue did not stick well when I put it in. I think I may just use a little water and detergent for my lubricating liquid from now on, then rinse with water, and blow dry with compressed air. I'm also going to try painting the tube with modeling enamel rather than acrylic. The enamel seems to adhere better and gives thinner, more even coverage than the thick acrylic paint I'd used on the blanks that blew out.
 

Woodchipper

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Mar 15, 2017
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Cleveland, TN
I have had that happen with oily wood and synthetic blanks. The synthetic was a challenge to chip it off. The wood came off easily with a wood chisel and a couple of taps with a hammer. When I see smoke or find the blank is heating up, I withdraw the bit and wait a while to let it cool. No use rushing. You can take extra minutes to drill or take more time to remove the blank from the bit.
 

leehljp

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Feb 6, 2005
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. . . I'd used a little WD-40 to lube as I drilled (this was the batch right after the one where I got the drill bit stuck--see link above) and then I painted the blank with white acrylic. I don't think I cleaned the WD-40 off the blank sufficiently and so the paint and the glue did not stick well when I put it in. I think I may just use a little water and detergent for my lubricating liquid from now on, then rinse with water, . . .
Don't underestimate the microscopic oil/silicone based residue that prevents good adhesion.
 

turncrazy43

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Apr 22, 2012
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Marietta, GA
I would use a spray bottle with water and spray the drill bit frequently while drilling. keeps the bit cool so it won't build up heat and fuse the bit to the plastic blank. I drill slowly which also helps. After drilling I blow any water and debris out and then paint the inside of the blank with enamel craft paint with a Qtip to assure proper coverage. Let the paint dry overnite. I use 5 minute epoxy to glue the tube into the blank rather than CA. The CA reacts with the paint and will remove some of it leaving exposed tubes . Epoxy doesn't react with the paint.
Turncrazy43
 
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