MadMat Posted July 23, 2017 Posted July 23, 2017 My last few shells (3" cans) have been breaking poorly (sorry no video). Up untill now, my breaks have always been nice, symetrical round patterns, but now they are kind of "dog bone" shaped. I was able to retrieve the remains of one of my shells and the end disks were intact and connected by a chunk of paper and spiking. It looks as if the shell broke open about 3/4 of the way around, leaving a piece of the side intact, connecting the two end disks. After looking at these remains, I had the "aha" moment as to why my breaks were shaped the way they were. I haven't changed my construction process from previous shells and am wondering why this is happeneing now. Any thoughts or suggestions?
memo Posted July 23, 2017 Posted July 23, 2017 soft breaks , that is the only time I find pieces like that. my last shell left the whole bottom and disks.
dagabu Posted July 24, 2017 Posted July 24, 2017 I agree with Memo, the shell need to expand and break apart all at the same time. One of the things that 'can' cause this is all the layers can end up with a seam at the same spot, giving it a hard "spine" in one place along the can. This can cause your shell to hose break (what you call a dog bone) if broken softly. This video shows you what happens when the shell breaks like you mention. VIDEO 1
MadMat Posted July 24, 2017 Author Posted July 24, 2017 (edited) Dag,I make sure the inner and outer seams don't line up when making my shell cases. I am thinking the soft breaks were caused by the extremely high humidity we've been experiencing here in Missouri. (The day I made these 3 shells the dew point was 76F) I really need to air condition my work shop Edited July 24, 2017 by MadMat
OldMarine Posted July 24, 2017 Posted July 24, 2017 The pasted string could be relaxing as well in high humidity. I gave up on pasted string for the exact reason it replaced after drying. I use tarred hemp on everything now because it's there and then it's also there later.
memo Posted July 24, 2017 Posted July 24, 2017 Mat I think my last soft break was also caused by humidity in my burst powder. into the dry box for a few hours and I will try again. memo
MadMat Posted July 31, 2017 Author Posted July 31, 2017 I had one shell left that was subjected to high humidity. I put it in my vacuum chamber for about 45 minutes and viola! this shell broke just fine. I don't know if the break charge itself was affected or the paper or the string OR a combination of all those things, but moisture was the culprit.
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