Silicone boot from scratch, round 3

DrafterDan

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So this time I'm experimenting on a different Surefire boot, it's from a vintage Laser Products torch.

This boot is much thicker than the standard 6P boot, so I have hopes that this will turn out even better than the thin-walled 6P boots. First, the subject!
I find it interesting that the diamond pattern looks, um, pieced together? Like two halves that didn't quite mesh.

cAQLRM.jpg


I used a box with a shiny side, makes it easier for the plastic to release. Just don't show this post to my wife, she doesn't know she donated the materials.
Yay, a very exciting 2" tall box! I put down a layer of clay for the master to sit on, we are making the top part of the mold first. I have the boot upside down in this picture, it's not easy photographing a black object without a light box. Yes, I used a fat marker as a rolling pin. Don't judge.
5Ghu9x.jpg


Here's a trick I learned from the store I bought the molding material from: fill the insides with clay, so the dimensions of the switch don't change as you are molding it. Less of an issue with this thick-walled boot, but it worked great on the earlier 6P boots I did.
This also means the seam between the mold halves will be at the extreme bottom of the boot. There may be some flashing to clean up, but it should be in a spot where it doesn't matter.
6Vkzbo.jpg


Here's my favourite part, the silicone catalyzation. By the way, I'm using Smooth On Smooth-Cast 300. It's great to work with, but has a couple small issues I'll address in detail later.


It does have a slightly alarming amount of bubbles, but as far as I can see, they weren't actually touching the master. We'll find out at the end when we unmold the silicone copy. Solution? Purchasing a vacuum container, which is way overkill for the amount of material I'm using.

After the unboxing, we have this. The clay is all goopy because of the heat of the chemical reaction, but that just makes it easier to clean up. I did spray a release agent (two coats, actually) to the master and the surface of the clay. This is an important step. The brush that's in several of these photos is there because I'm using it to brush away excess agent, and brush it across all detailed surfaces, so everything is covered evenly.
Plus, wear gloves, that release agent feels weird when it gets on your skin. I had windows open to keep any off-gassing to low levels.
dbxD1H.jpg


First half, done! I know you see the little black flecks in the mold, I'm thinking they came off the master. The odd part is that I couldn't find any divots on the master itself. Strange, but I did look at the diamond pattern under a 10x loupe, it seems smooth and ready to go.
Flip this plastic half back into the cardboard box, and get ready to pour the second half. Tape it up for leaks really well, this casting liquid has a low viscosity, and it will absolutely find any way out and get all over your workbench. Guess how I know this.

I used a bit of clay at the perimeter to ensure a good seal. Second pour went just like the first. Notice the locating points I drilled into the surface.

Jovta2.jpg


So now we have two halves. Apparently the release agent wasn't fully in one of the locating pins, it snapped off when I took the halves apart. You can also see the main filling sprue point at the center, with two small air vents at the edges. This is also important, the silicone has to push the air out to fully fill the mold.
0Wfkqk.jpg


So here is where I'm going to leave this for today.
YWxRdc.jpg


The silicone was mixed, put into a glue syringe, and shot into the mold. It will be several hours before it cures enough for me to crack it open and see how the new boot looks.

On the Silicone itself, a few notes.
One of the things I'm not 100% happy with is that the silicone I'm using is shore 50. A medium press boot from Oveready is at roughly shore 65 -70ish. I'm guessing at the numbers, but you see what I'm getting at. As far as I can tell right now, this is the hardest available at a craft/ hobby level. You buy this stuff in 55 gallon drums, and you can specify exactly what you need. For the hobbyist, You buy DIY kits and your choices are limited, and even so, fairly expensive. The two kits, silicone and plastic molding ran me about $100. So far I've made 6 boots, including this one above, and I probably now have enough material for less than 10 boots.
The second thing is the color. The silicone as it comes is bright white. The catalyst agent is a dark blue, so that will challenge you when you try to color it. I did the blue boots previously to my liking, but this one is black. I added probably 3 times the pigment for this one than what I've done with the blue experiments.
A smaller but still relevant point is that for each pour, I mix up 50ml of material. This actual boot is probably about 3ml? This is because that's the smallest amount my mixing container will allow. Plus I'm concerned about ratios if I were only to mix up, say 10ml of silicone. From my experience, things mix better in larger batches.

So with the silicone in the mold, I'll have to wait for it to fully cure. I'll report back in the next day or so to let you know how it turned out.
~D
 

louieatienza

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That's pretty cool! Would it be possible to maybe add a piece of rubber or such in between pours to "stiffen" it up?
 

DrafterDan

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Thanks guys, and I like Louie's idea, however it wouldn't be practical. In all fairness, if this project made buttons that were too soft to use, I'd have abandoned it a while back. Yes, they are a bit softer than what we may normally be used to, but they are perfectly serviceable. One of the first buttons I made is on my car torch, an 18650 E-series with a modded Lumens Factory head. I certainly don't baby that torch, and use it at jobsites as well. It has held up admirably.

On to the results! Original on the left.
EPi3Lc.jpg


AcQOhK.jpg


Yes, it is not a fully black black. With this material, there is no way to get it darker without compromising the ratios of the cure. Also, there is a few bubbles that crept into the top corners of the mold. That's from the material not reaching every nook-n-cranny when I spooge it in there. My plan for the next round is to dab some in the corners before putting the mold together and then spooging it in. Without a positive injection system, this is the best I can do.

So it took 1.5 hours to make the mold, and produce one button. With the hard part done, it should be about 20 minuted per button now, with at minimum a 4 hour cure before unmolding. So this is far from an efficient method, but it works.
 

DrafterDan

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I've finished with the batch of boots. I feel these will work quite well. Of course it could be done better with many thousands worth of injection molding equipment, but for what I've invested, these are great.

wPSssc.jpg


Original is the lower right one. The very first one did have a couple bubbles in the grid pattern, so I did some experiments. Before putting the mold together, I used a wooden tool to work some of the silicone into the corners of the mold, then assembled and shot it in as before. They did turn out much better.
~D
 

moonswamp

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Jan 5, 2019
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nice job done !
Why not try some other colors with this ? :)
and how to remove those [FONT=Arial, sans-serif]burrs ?[/FONT]
 

DrafterDan

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Thanks MS,
I have done blue, and have the ability to do pretty much any color. The person I made these for wanted black, so there you go. The sprue points are easy to trim off with a blade, no trouble at all. It's just silicone, after all.

I did a glowing blue boot, which turned out pretty cool.
5kvKfj.jpg


nice job done !
Why not try some other colors with this ? :)
and how to remove those burrs ?
 

Nitroz

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Very nice! The one on the top left looks just as good as the original, imo.

Now I would like to see one in V10 green glowing away.
 
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