First watch part pen

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jtdesigns

jtdesigns

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My first watch part pen turned out okay. I used the resin saver mold (awesome). After turning and finishing I notice to some very slight separation from the tube and resin. I am using the black nickel tubes, Sil 41. After I mill the ends flush I take a drop of water thin CA and seal the ends of the tubes just in case the resin pulled back. I then use the mill by hand and re-flush the ends. Thought I was taking the necessary steps to prevent separation. I am letting the blanks cure overnight then 2 hours at 150 degrees in a dehydrator. Anyone have any thoughts as to the separation. I have noticed this in a few other pen blank where resin touches the bare black nickel tubes.
 
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Try not post curing them , just let them cure naturally . I normally post cure in a drying kiln for about an hour at 125 degrees , the heat makes the resin shrink a little more then air cured resin and on clear cast blanks seems to make the resin pull away from the tube . I have noticed if I don't post cure , the resin don't get pulled away from the tubes , so it may have something to do with the extra shrinkage I see when I post cure .
 
Overnight cure plus 2 hours at 150 sounds fine for curing, but perhaps the fast
temp change might be giving you trouble? (don't know, this is a guess) Usually when
I post cure, I'm putting the warm/hot resin and mold in the toaster oven. In fact, the
oven might be cooler than the resin is. I know that if I let the resin cool and then put
it in the oven, I'll sometimes get a separation of the resin and the tube. And sometimes
that won't happen right away, either. (just what you need, more variables..)
I can't claim a cause/effect here.. I just don't know.

As for the black nickel, I don't really remember if that's what I was using when I got
separation. I know it has happened on the nickel tubes. Brass too, but for a different
reason. (wasn't waiting long enough before turning)

Sorry to type so much without a good answer..
 
Do you think the resin would bond better with a painted surface vs the black nickel?

NewLondon88 said:
Overnight cure plus 2 hours at 150 sounds fine for curing, but perhaps the fast
temp change might be giving you trouble? (don't know, this is a guess) Usually when
I post cure, I'm putting the warm/hot resin and mold in the toaster oven. In fact, the
oven might be cooler than the resin is. I know that if I let the resin cool and then put
it in the oven, I'll sometimes get a separation of the resin and the tube. And sometimes
that won't happen right away, either. (just what you need, more variables..)
I can't claim a cause/effect here.. I just don't know.

As for the black nickel, I don't really remember if that's what I was using when I got
separation. I know it has happened on the nickel tubes. Brass too, but for a different
reason. (wasn't waiting long enough before turning)

Sorry to type so much without a good answer..
Click to expand...
 
I would think that an extra layer would be one more variable to take in.
I wonder if a primer would work?
 
But when you do labels are there parts of the tube that are exposed? Maybe I could wrap the tube in a "solid black label" then affix the parts to the "papered" tube since I do not experience this separation with my cigar label pen where the whole tube is covered.
 
That might work.. I'm still experimenting with different labels, since I can't always
get consistent results with shipping labels. I'm trying the Papilio adhesive papers now.
They look fantastic, but they need an overspray to stick well in the resin. I'm experimenting
with those, too.
 
Seems that, when you heat the resin in your "post cure", you will also heat the brass tube, making it expand. Then, when it cools, it will contract. Wouldn't this encourage separation??
 
ed4copies said:
Seems that, when you heat the resin in your "post cure", you will also heat the brass tube, making it expand. Then, when it cools, it will contract. Wouldn't this encourage separation??
Click to expand...

This was my first thought as well. If the tubes don't have any tooth to them (smooth and shiny instead of sanded and rough) you're adding to the risk factor.

I have had PR pull away from wood, let alone smooth metal.
 
Update: Watch Part Pen

I finally decided to destroy the the blank with the watch parts after noticing the separation. I wanted to do an "autopsy" to see what was going on. The results were very apparent. First, the resin is definitely not binding with the black nickel plated tubes (too smooth I guess). The more shocking part is what I noticed about the parts that I CA glued to the tubes. Apparently during the curing process, the resin was able to either attack or liquify the CA glue. The dried resin and watch parts could be easily pulled off of the pen tube but there was a very thin but definite coat of resin on the underneath side of the part making it look like the parts were applied in between coats of resin which was not the case. I am baffled. I am currently trying enamel primer and acrylic paint on regular brass tubes. Last night during curing I noticed that the resin even made the acrylic paint soft. The painted tubes were allowed to cure 48 hours before casting. I am going to see a friend who does powder coating and him do a couple tubes. Anyone have any suggestions?
 
A few suggestions on seperation:
1. Butch is "spot-on", let them cure naturally
2. Glue parts using an accelerator
 
Solved!!!!

I used acrylic painted tubes and the acrylic bit onto the slightly textured surface. The "chameleon tubes are a nogo for glueing stuff on and casting in acrylic (too smooth). Thanks for everyones suggestions. I will post pictures later. I am, however, going to invest in a HF powder coating system to make the surface even more durable.
 
I had separation on mine, and noticed it was mainly happening where the parts were pressed in. I was trying a 7mm pen with black nickel tubes and the separation matched the depth the trannny was pushed in.
I'm wondering if a layer of CA on the tube as a primer would do the job.
 
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