Creating custom 6P tailcaps, part deux

Okay, my first attempt at making a mold for silicone boots was educational, but not terribly productive. Thankfully, the 2-part resin stuff was only about $10, so not a big deal. I went to a custom mold supply shop not too far from me, and after $80 worth of product, I'm ready to go. Actually I'll need to spend about another $18 for some silicone colorant, but the resultant supplies would probably last for about a hundred tailcap boots. Or plenty for some other ideas I'd like to work with.

So on to part deux. Proper tools in hand, we'll begin. Working with pro materials kinda makes things fun again!

With my square plastic mold, I put a layer of clay down, including inside the tailcaps for support.
Note to self, next time get straight-sided containers...


After spraying on two layers of release agent, I'm ready to pour.
I tried to pay close attention to the transition of the boot flange to where the second pour would happen. I also used a marker cap to poke registration holes, thanks to a suggestion from the mold making people.


Okay, the pour is a bit hectic. After you pour the part B into part A, you have two minutes of 'pot time' before it starts to set up. That includes about 30 seconds of mixing. Once poured, I had maybe 15 seconds to move some bubbles away from the boots. Note that they suggested I pour in the lowest part of the mold, to allow the material to find its own level, and to greatly reduce bubble formation. It started to get stiff right about the two minute mark, and seconds after that it transformed from clear to white, very interesting to watch. Here you can see the barrier still kinda clear between the plastic and the clay.


After that, I had a nice hard plastic half-of-a-mold. I broke it out of the plastic container, and with a layer of clay to hold it in place, I set up for the second half of the mold. Here's where A straight sided container would have been helpful. I thought I'd sealed it nicely with clay, but once I poured a good deal leaked out due to the taper of the sides. I had to quickly make a second batch of resin and repour on top, but thankfully it solidified together as one unified section. I did make a video here of the first pour, to try to catch the transition from clear to white. It's rather shakey, as I was realizing that it would not cover the posts, and you can see just how much I spilled. I can post it if you're really interested, but it's certainly not my best camera work.

Final outcome, after a good deal of cleanup with razor knives and files? A pretty decent mold. mold. It did get a touch rough in one area, but it's on the inside of the boot, you'd probably never see it. From here, I need to drill the sprue channels, and wait for my silicone colorant to arrive. I'm making blue, because it's my favorite color, and I've even got some blue glow powder just for kicks. I should mention that the particular 2-part silicone I bought was a hardness of Shore 50, which felt like the best stiffness for such thin-walled things such as these. The only small problem is that the color is kinda a baby blue. I have a sample kit of colorant arriving, so I'll have more leeway to make a hue I like. Plus, it says it has a 45 minute pot time, so I have plenty of time to mix in glow powder, and then let it sit for the bubbles to disipate.


All of this work is still experimental. Ideally, I want to make my own design of boot via 3D print, and make a better mold. Next step is to mix up some silicone and do a test mold. This is where good quality release agent will come into play. That tiny bottle, maybe 2 oz, was $10 - but it does what it's supposed to.

Second (of three) pours. You can see this stuff is pretty low viscosity, which is why it found its way out of the container...

https://youtu.be/WdDj73poAYY

Good stuff! I wonder if you will still be able to get enough glow powder in the tailcaps so that they glow well and not sacrifice the strength of the silicone.

I wonder too, Nitroz. That's the next step!

I did a test molding last night, and looked at it this morning. Mixed up 50ml of silicone, because that's the smallest amount my measuring cup would allow. The mix ratio is 1 part hardener to 10 parts silicone. I put in some dark blue pigment, just a small amount to see how it would work. The hardener agent itself is dark blue, which does help change the color, but it does appear that I can put in about twice the pigment for a richer blue.
Vladimir the helper cat is always ready to provide support.


You can see the sprue holes I drilled into half of the mold. One hole for each boot was a touch larger, so it fits the glue syringe. Both tailcaps were done with about half of what I put in the syringe, so I definitely need to get smaller disposable measuring cups....
The silicone kit came with two pounds of material, so I'm not too worried.


Instructions say wait 24 hours, but looking at it this morning, I cut apart the plastic bag I used to transfer the mix to a glue syringe, and it was solid. This was after 13 hours. It came out nice and clean, but with some spooginess along the circumference. I should be able to clean that up with sandpaper, but it's something to consider in my next mold. I'll have to define where the mold halves come together a lot better.



I did manage to rip the flange of the boot pulling it away from one of the sprues, will have to cut it free next time. The second boot has not yet been removed, so that should be good.
Overall, it's pretty exciting, I have my first custom boots! One thing I'm seeing right away, is that even at Shore 50 hardness, it may be too soft. I do feel this is totally workable, and will install in a torch tonight, but I may want something stronger.

Anyone want a sample boot? Next batch will be with glow powder, and hopefully a richer blue.

*edit, the last image came out a bit small. Should be good now.

awesome!

That's very excting. Well done Dan.
P

Good to see success coming your way after all the effort. The boots are looking good. :twothumbs

Thanks, I've still got lots to learn, but these are pretty good for a first round trial. I'm planning on making a new mold over the weekend, to include some thoughts about the flow of the silicone to reduce bubbling.

upon close inspection, the second boot has some bubbles in the cross-hatching. Physically, the boot works quite well, but it is maybe a bit softer than I'd prefer.


This was the second boot that I was more careful pulling out of the mold. It's now on my car torch, so it will be a good long-term test.

Wow! That looks nice for a first attempt.

I can't wait to see the glow cap.

Second mold made, and second round of tailcap boots done. I redesigned where the sprues were, and where the halves of the mold came together. It's now at the base of the flange, which makes a cleaner boot. I tried holding my finger over the exit sprue, to push the silicone to every little corner. I still got a few tiny bubbles in the grid design at the top of one button, but I think it helped. It also seeped out between the halves, but it's really thin so it cleaned up quickly. The tan areas are where I put some wood filler to fill up some of the bubbles that appeared.



Differences from this and first batch, more blue! Plus, for the 50ml of silicone (plus 5ml of hardner), I added 3ml of blue glow powder. Details below.
I paid more attention to the cure time of the silicone with this batch. The directions say it has 45 min of 'pot time', but it really means you'd better get the silicone in the mold within 5 minutes. It starts to gel quickly, which means less ability to flow into the details. The image below shows about 6 minutes after I added the hardener, it was already the consistency of molasses.
I added three times the blue pigment than from the first batch, probably 1ml in volume. I'm happy with this color! Side by side shows first batch color next to new.


The boots popped out without fuss. One of them does show a bit of bubbling on the grid pattern. I'm thinking of putting in a small amount into that half of the mold before I assemble and push in the remainder of the material with the glue syringe. I bet that would alleviate this issue.


Glow! We have glow!
The powder seems fine to me, but when it's glowing it does appear far more granular. Not sure why that is, powder coming together when I mix it, making small clumps? I will do some more testing, but the amount of powder I added really doesn't seem to have any impact on the strength of the boot.
I put my pigment and glow powder in the silicone first, mix it up and then add the hardener.


Sharp eyes may notice the two cavities in the mold for rings. My intention was to make some of those rings for the gap between 6P bodies and stock tailcaps. Unfortunately, it was rather a failure. Too many bubbles, and the aluminum masters I made were really, really tough to remove from the mold. I did soak them pretty good with the release agent, but the one with knurling just had too much of a grip to be removed cleanly. That also affected the mold, which of course should be perfect. I may try again with some ideas that came to me, but I'll focus on the boots for now.

Wow, this is really cool. Never thought you could even make them like this. Really digging the glow in the dark even if it isn't done yet.