PVC Tube Mold Failure

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jtdesigns

jtdesigns

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I decided to switch from the 2 pour method to using some PVC resin molds. I have had decent success with the 2 pour but I was trying to save resin and some brain cells. Anyway, I ran out of the Penn State Industries resin and picked up some Casting Craft. I mixed in 4 drop of catalyst per ounce as per instructions. I set my Cigar Label pen tubes in the mold and poured. I left it overnight at room temperature and came back next morning. Blank released somewhat easily (not as easy as I would like) and I noticed what looked like slices embedded in the blank and later determined they were in fact fractures. Also the pen tube basically slid out of the resin blank leaving a slimy cigar label tube. Any thoughts from you all. Thinking about going back to square container method. I just thought the PVC mold might be a great way to conserve resin.
 
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Since nobody knows where you live it will be a bit harder to respond with ideas as to the problem you are experiencing. IF you were in Florida for instance I doubt that temperatures would be a factor. BUT, if you lived in Alaska then I am sure the temperatures would be a reasonable answer.

In other words we need a bit more information for a reasonable diagnosis.
 
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I don't use PVC, so I'm not sure. I use these. (pic)

The 'slimy' tube sounds like the resin wasn't cured. It might be 'set' but
still in the process of curing. As for the fractures.. I really couldn't guess.
That sometimes means too much catalyst, but the slimy usually means
uncured resin.. too much catalyst wouldn't give you uncured resin unless
it wasn't mixed in well. In that case you might get pockets that remain
uncured while other spots got too much catalyst and overheated..

Not really sure though.
 

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My guess is that it was not fully cured. I used the 4 drops recommended on the can, but it took DAYS to cure, in standard mold. If you were using a PVC pipe mold, I think it would easily take nearly a week, based on my results.

I later went back and attempted another cast with 7 drops per oz. Worked perfectly.

As far the cracks, I am not sure. I differ to NewLondon88.

Thanks!
Chris
 
I use pvc pipe as molds all the time. I use silmar 41, and have no problems. The outside of the blank usually has verticle lines, but these are just topical and turn away.
 
I re-read my own answer and need to modify it.. I didn't read your
post closely enough.
You're leaving the label inside the cured resin? Just the tube is coming out..
That isn't uncured resin, I apologize. That slimy stuff is the label adhesive.

Depending on the type of label, it could be the resin leeching into the
label and mixing with the adhesive backing. That forms a slimy layer that
will allow the tube to slide right out leaving the (mostly) intact label behind.

And once that adhesive is changed, it doesn't go back to being the adhesive
that you started out with.

It could also be the result of a chemical change in the label adhesive due
to heat of the curing resin. Or it could be a combination of both.. or even
something I haven't thought of. I'm not a chemist..

In any case, I think it is related to the label you are using. Finding the right
labels hasn't been easy, and between all the people casting, we've probably
tried most of them. Most of them don't work, and some only work under
certain conditions. They're not meant to dunk into resin, after all.

They mostly all look the same, but they're not the same at all.
 
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