Orangish DT,
I had the same problem with mine so I used a BK11 and BK14 sheath to fix the problem. My approach is a little unorthodox but I was really happy with the out come.
1. Took the standard BK sheaths and removed the eyelets for later use.... I restraighten them and use them again.
note: only the larger eyelets are reusable the others are too small so you can set them aside for future projects
2. Take the remains of the two sheaths and place them in a dip-seal melting pot, a pressure cooker or regular pot will work. I like to set the temperature at about 450* for this.
3. You want to use a thermometer to test cause once the mixture cools it's really hard to work with so you gotta work fast.
note: I usually read a small test batch and I find that a ceramic coffee mug works best for this due to it's insulating properites. It must be ceramic though.
4. You'll need a large flat area to work on and I like to use a granite slab because the high temperature of the cooling plastic doesn't affect it or melt anything.
At this point you can scoop the melted plastic out..... you'll need to roll it out to the right thickness. Note that my roller is stainless steel (440C).
5. I don't like to give away all of my secrets but once you get the right thickness you can lay a large sheet of Kydex over the top and apply pressure, this will
transfer the texture to your melted plastic that you've rolled out.
6. Getting the plastic the right thickness is a little tricky too so I find that if you cut strips of Kydex and place them about the width of your roller apart you
can get the height just perfect. For this project I used .090 which is pretty sturdy for Kydex and with your reformed plastic should be just fine.
7. Here's a pic of the finished product:
I like to cut the plastic into either a 12x12" piece or 12x24" but you need atleast 4x BK14 sheaths for that size
From this point I treat it just like Kydex and I don't show my proprietary methods to anyone but there's how to vids on Youtube to guide you along. I find that from two Becker sheaths I can make a full BK11/14 sheath and still have enough left over for a belt-loop which is pretty handy.
Here's a pic of two I've made from melted BK11 sheaths:
The belt-loops I make from the melted Becker sheaths are pretty cool too and I make them fit lot's of carry options:
Have fun, wear safety glasses, thick gloves and be safe. Also be sure to post pictures of what your project comes out like.
Thanks,
Eli
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edited to add: I forgot to mention that you'll end up with an extra eyelet from the Becker sheath.... I've got a pretty cool chainmail suit that I've fashioned from these but you need to heat them in a forge..... I'll post a tutorial of that part later.