Blind Hole Location Using Polymorph Plastic - WIP

MTBob

Well-Known Member
This posting is related to an earlier posting I did on Polymorph Plastic and is still a WIP. I want to use this posting to focus on the technique of blind hole location.
I'm working on a cleaver handle and want to put an end cap on the handle. There are a bunch of ways to do this, but I wanted to try using blind pins between the wood and G-10 end cap to provide more strength to an otherwise questionable unsupported epoxy glue line.
The problem is how do you get pins to line up in a blind fit (2 mating surfaces in which the pins are not revealed)? Here's how I did it... and it worked.
1610729732127.png
I warmed up the plastic and pressed the wood and G-10 material into it, leaving a thin inner web of plastic between the wood and G-10. Alignment of the two pieces is important so that the mating outside surfaces are relatively parallel. I eye balled it since I have some excess material to work with on both parts.
1610729861678.png
Showing the plastic form after cooling with the shape of both parts accurately set in the plastic with a thin web in the center
1610729990900.png
I then located pin placement, leaving ample room for handle contouring. In this case the actual pin location does not need to be precise, but the pin orientation / alignment between mating parts needs to be relatively accurate.
1610730060320.png
Using those pin locations I drilled the wood and G-10, about 1" into the wood and about 1/16 into the G-10
1610730210055.png
1610730282333.png

This shows the finished pin locations in both parts, prior to glue up. Both surfaces were roughened even more before glue up, with small shallow holes drilled in both parts to accept additional epoxy.
1610731240493.png
1610731303250.png
 
The source of all good things has it - Amazon https://www.amazon.com/s?k=moldable+plastic+pellets&ref=nb_sb_noss
Pick your price point, I suspect most/all give the same result. Keep in mind that the stuff is reusable. That block of plastic that I used to locate the pin holes is easily reheated and reused.
Using this stuff is super simple. Dump some pellets or used chunks in a jar (I use a plastic yogurt container), add some water, put it in the microwave for 45 seconds - 1 minute and it's ready to shape. The stuff I have turns clear when warm, then white when room temp. I just made a number of small tool handles in a few minutes. I've had this stuff on the self for years, not knowing what it would do - now I see all kinds of applications. When hard it cuts well but leaves a typical softer plastic scruff edge that needs to be cleaned up. I've read that it can even be threaded using a tap - gotta try that next.
 
Back
Top