(Phone rings)
Da!
- That VegOilGuy is making another video. - And I want my pencil back!
John Wick 3… yes! But I haven’t seen it yet, so don’t tell me.
I love John Wick, so when one of my viewers requested a John Wick Gold Coin, I leapt at
the chance to cast one with the Lost PLA Technique. I began with Fusion 360 creating something
that looks the part. It’s not exact, so don’t get picky about the details. I knew
that the biggest hurdle I had here was in printing the coin, so I made allowances for
that. It also gave me an opportunity to experiment
with print depths. To give the coin a 3D quality, I worked in layers. Each layer on this side
is just 0.2mm deep. There was a little more detail on this side,
so the layers are 0.1mm deep. So I had my doubts that anything would print.
The coin is 50mm or 2 inches in diameter which is large, but I’ve seen commemorative coins
about that size. Bigger would have looked daft and smaller would have hidden the detail.
All in all I was pleased with the coins. Printer lines were obvious along with a few annoying
snot lines, but the Lion looked good. What I’d planned on being whiskers looked more
like an open mouth, so I decided to go with that. The Lady wasn’t quite as clear, but
at just 0.1mm depth between layers, it was still pretty good.
There’s too much for me to try and clean up here, so I just used the very tip of a
file to very lightly scrub away any obvious imperfections. But that was it… no other
clean up. The prints aren’t too bad. It’s just a
standard home printer, a Creality CR10S, so perfection isn’t possible at this scale.
I bonded the two halves of the coin with positioning wax. I literally smeared it on, putting a
very thin layer on each one. I then used a little sprue wax to fill the
join and lightly sanded this smooth. I decided to do away with the sprue of my
printed sprue base, so I just cut this off. In last week’s video I mentioned that where
I had thick castings, I would try to use Risers. As this coin would be around 6mm or ¼ inch
thick, I felt risers would be needed. At its simplest, a riser is merely a thicker
section before a thinner one, so I decided to use this wax sprue for this purpose.
I can’t make my mind up if it looks like the coin’s going scuba diving, or whether
I’m modelling a new Starship Enterprise. Either way, I was hopeful the coin would have
ample feed and resist shrinkage. Up until this point, things had been going
surprisingly smoothly, so don’t blink or you’ll miss the terrifying bit.
Yes, the crucible fell showering thousand degree puddles of fire everywhere.
The reason for this slip is these grooves on the crucible. I hadn’t noticed previously
that these wear away. Look at the crucible that fell – there’s virtually no groove,
so there was nothing for the tongs to grip. So please be more vigilant about these grooves
than I was – and wear safety gear. In a mad scramble I hopped between the red
hot puddles and placed the flask back in the oven whilst I put out fires, collected the
spilled bronze, cleaned it and melted it again. So about an hour later, still flustered, it’s
hardly surprising that I forgot to focus the camera properly.
Now once a flask is out of the oven, it cools quickly and the plaster can begin to crack.
So as my flask had been out, in and out again, I wasn’t hopeful.
But thankfully it didn’t look too bad. The risers seemed to have done their job.
There’s no sign of shrinkage, though perhaps it wouldn’t have shrunk anyway.
So is it perfect? No. There are imperfections. There always were with the 3D print and the
crucible escapade may have taken its toll, but by and large I was happy. Not bad for
home casting with largely home made equipment. I hope you enjoyed this one guys. Take care
and thanks for watching.