[StephenJames]

I would not listen to anyone who recommends option 1.
Do not use anything smaller than 2mm ID for TWFK otherwise you will kill all usable high frequencies and with 1mm ID you'll move first peak to honky 1,5kHz it will sound like a low quality radio.
For CI use any of the above options, but TWFK 2mm ID is necessary unless you are going for something like a horn with combination of 1mm or 1.5mm and 2mm.
You didn't specify lengths of tubing you plan to use. My recommendation would be anything between 12 and 18mm.

I think the last pair I did with sonions were around 18-19mm, as things get a bit tight around the aperture (I think that's what it's called) part of the shell.
I haven't tried the GK's in the custom shell yet, just a generic universal shape to test things out.

 

[piotrus-g]

I think the last pair I did with sonions were around 18-19mm, as things get a bit tight around the aperture (I think that's what it's called) part of the shell.
I haven't tried the GK's in the custom shell yet, just a generic universal shape to test things out.

18mm will already cut into highs a bit. 15-16mm would probably be a sweet spot.
For universals tuning would be a different story - even a short 1mm tube could work in certain conditions - that combined with tips would create a horn. You'd need completely different approach.

 

[stegeoc]

18mm will already cut into highs a bit. 15-16mm would probably be a sweet spot.
For universals tuning would be a different story - even a short 1mm tube could work in certain conditions - that combined with tips would create a horn. You'd need completely different approach.

Do you ever find wax buildup a problem with tiny tubes (<1mm) for customs? The pair I've been listening to recently has a roughly 0.5mm tube for the bass and recently I noticed the 2mm holes had a fair bit of wax in them. Those are easy to clean of course, but if it got in the 0.5mm I'm not sure what I'd do to get it out.
So far no problems, just a bit wary. I know you can get gauzes to git on the end, but when you have 3 or 4 tubes, that isn't really practical....

 

[piotrus-g]

Do you ever find wax buildup a problem with tiny tubes (<1mm) for customs?

Yes! definitely! 1mm tubes are a nightmare with wax buildup and very hard to clean even with vacuum

 

[mckpaul]

The issue with silicone for molds is the transparency causes the shell to flash cure sometimes and you get some ridges and stress lines on the external layer you will have to contend with

I've been using PlatSil 73-15 two part clear silicone that is almost completely transparent once set if I degas it in the vacuum pot after mixing. I've noticed sometimes while curing under the UV light that as the Fotoplast S /IO starts to harden it will separate ever so slightly from the silicone creating a visible air gap, that usually gets larger with exposure time. Thinking about it, this usually happens in spots that are close to the wall of the mold. When it does this, the finished shell will have swirls or small ridges in the area where it separated from the silicone during curing. Sometimes it will create this air gap in the initial 2 or 3 minutes of cure time (covered and creating the shell) and sometimes it will create the air gap during the secondary cure time with glycerin poured in the hollow shell. On a rare occasion I'll get a full cure through both stages with no separation at all, which of course produces a pretty much blemish free shell. The swirls are easy enough to get out with a Dremel and various tips, but of course I'd rather get shells that are as close to blemish free as possible.

I assume what I'm experiencing is basically your reference to flash curing? Which is caused by the mold being too transparent? I tried a couple of things to try to eliminate that issue. My curing light is a basic nail light with a hole drilled in the bottom and one of those little jewelry display rotating devices underneath so my mold rotates as it cures. However I found that the separation is less likely to happen if not rotating and thought maybe the vibration of the rotation might be causing it.

I previously used a two part clear silicone made by Cast-A-Mold that was pretty much clear and just as durable, but it did seem to yellow a little bit, or maybe a better description would be it became less visually transparent after a month or so. In hind site this may have been a good thing.

 

[swtnate]

I've been using PlatSil 73-15 two part clear silicone that is almost completely transparent once set if I degas it in the vacuum pot after mixing. I've noticed sometimes while curing under the UV light that as the Fotoplast S /IO starts to harden it will separate ever so slightly from the silicone creating a visible air gap, that usually gets larger with exposure time. Thinking about it, this usually happens in spots that are close to the wall of the mold. When it does this, the finished shell will have swirls or small ridges in the area where it separated from the silicone during curing. Sometimes it will create this air gap in the initial 2 or 3 minutes of cure time (covered and creating the shell) and sometimes it will create the air gap during the secondary cure time with glycerin poured in the hollow shell. On a rare occasion I'll get a full cure through both stages with no separation at all, which of course produces a pretty much blemish free shell. The swirls are easy enough to get out with a Dremel and various tips, but of course I'd rather get shells that are as close to blemish free as possible.

I assume what I'm experiencing is basically your reference to flash curing? Which is caused by the mold being too transparent? I tried a couple of things to try to eliminate that issue. My curing light is a basic nail light with a hole drilled in the bottom and one of those little jewelry display rotating devices underneath so my mold rotates as it cures. However I found that the separation is less likely to happen if not rotating and thought maybe the vibration of the rotation might be causing it.

I previously used a two part clear silicone made by Cast-A-Mold that was pretty much clear and just as durable, but it did seem to yellow a little bit, or maybe a better description would be it became less visually transparent after a month or so. In hind site this may have been a good thing.

Correct. You have to account for light intensity. With colloid, i do/ did not have that issue.

 

[mckpaul]

That is good info to know. Thank you sir! I'll have to play with my light setup and see if I can create a little distance or less reflectivity. It's a traditional nail light with four 9-watt tubes, not the newer LED version, so it does produce some pretty intense light. And that may change my timing durations for the initial cure for shell wall thickness for the various Fotoplast colors. So far I've been working with red, blue, black and have even mixed the red and blue for purple. It's about time to order more, most of them are about 6 months or more past expiration. Don't know how critical the expiration date is, still seems to be working.

 

[stegeoc]

Yes! definitely! 1mm tubes are a nightmare with wax buildup and very hard to clean even with vacuum

Oh dear, you've got me worried now Have to clean my ears more often. Do you find putting the smaller holes away from the edges helps? Or maybe just creating a wider opening at the end for it to collect in before making its way deep into the thin tubes?

 

[StephenJames]

18mm will already cut into highs a bit. 15-16mm would probably be a sweet spot.
For universals tuning would be a different story - even a short 1mm tube could work in certain conditions - that combined with tips would create a horn. You'd need completely different approach.

I'm waiting for some more 2mm ID tubing to arrive, so I decided to experiment with the 1mm ID tubing, to hear what you were talking about with the frequency response.
You were absolutely correct, highs totally diminished into a horrible midrange mess. Very AM radio sounding. Hopefully my soundlink order arrives soon with new tubing, as I'm kinda stuck here twiddling my thumbs until it arrives.
Also, I'm still struggling with getting the drivers closer to the canal. I have plenty of space in my outer ear, but it definitely gets tighter on the way in.
I'm thinking I may need to use a thinner wall to create more inner space.
What's the minimum recommended shell thickness? I'm 3d printing, and currently I'm making my shells 2mm thick, but maybe that's too thick?

 

[piotrus-g]

Do you find putting the smaller holes away from the edges helps? Or maybe just creating a wider opening at the end for it to collect in before making its way deep into the thin tubes?

Yes, that should help, but only if you manage to catch and remove the debris before it enters the 1mm tubing.

I'm waiting for some more 2mm ID tubing to arrive, so I decided to experiment with the 1mm ID tubing, to hear what you were talking about with the frequency response.
You were absolutely correct, highs totally diminished into a horrible midrange mess. Very AM radio sounding. Hopefully my soundlink order arrives soon with new tubing, as I'm kinda stuck here twiddling my thumbs until it arrives.
Also, I'm still struggling with getting the drivers closer to the canal. I have plenty of space in my outer ear, but it definitely gets tighter on the way in.
I'm thinking I may need to use a thinner wall to create more inner space.
What's the minimum recommended shell thickness? I'm 3d printing, and currently I'm making my shells 2mm thick, but maybe that's too thick?

Well... like I said using 1mm would make sense only if very short (1mm max) coupled with horn say like tips to boost highs.

Thickness would depend on the resin and printer capacity most probably, too thin wall will be brittle when dropped. I'd say if your printer is capable, go for 1mm up to 1.5mm. 2mm is excessive, for sure.

 

[sconner]

Hey @piotrus-g, are you keen on sharing what's inside of CA-1873A? I would just make for myself what's my girlfriend is using

 

[Wgibson]

I'm waiting for some more 2mm ID tubing to arrive, so I decided to experiment with the 1mm ID tubing, to hear what you were talking about with the frequency response.
You were absolutely correct, highs totally diminished into a horrible midrange mess. Very AM radio sounding. Hopefully my soundlink order arrives soon with new tubing, as I'm kinda stuck here twiddling my thumbs until it arrives.
Also, I'm still struggling with getting the drivers closer to the canal. I have plenty of space in my outer ear, but it definitely gets tighter on the way in.
I'm thinking I may need to use a thinner wall to create more inner space.
What's the minimum recommended shell thickness? I'm 3d printing, and currently I'm making my shells 2mm thick, but maybe that's too thick?

Try to test using stripped wire insulation as sound tubing. Find something with 2mm single core wire, so there are no strange festures/surface finish on the ID. Better than twiddling thumbs any day.

 

[piotrus-g]

Hey @piotrus-g, are you keen on sharing what's inside of CA-1873A? I would just make for myself what's my girlfriend is using

Hey. it's Ei.3 model no longer available. Sorry.

 

[sconner]

Hey. it's Ei.3 model no longer available. Sorry.

Exactly what I had in mind, since it's no longer made do you mind sharing what was inside?

 

[piotrus-g]

Exactly what I had in mind, since it's no longer made do you mind sharing what was inside?

XD hahaha
Truly... I don't even know how to respond to this request my dude.