Silicone Mold Fits Too Tightly Around Receiver

I have custom silicone molds made by ReSound for my Quattro’s. The right mold fits my receiver pretty well. The cavity for the receiver is just a little smaller than the receiver at the insertion opening. When the receiver goes in, a little lip of silicone pops over the receiver end with the wire to keep the receiver in place and a fairly gentle but firm tug on the receiver wire can slip the receiver back out of the mold.

The left mold is a different story. The opening for the receiver is way smaller than the size of the receiver and it takes a fairly strong push to embed the receiver in the mold. I’ve already asked the audi’s office about getting the receiver out of the mold before attempting it myself (the reason for removal is to replace wax guards once a month). I was told “just pull on the wire and if the wire breaks, we can replace it at a minimal charge(!).” Well, easier said than done. I tugged pretty hard on the wire and the receiver wouldn’t come out. What worked was to face the mold with receiver, speaker side down on a table, pry the top of the mold with the wired end of the receiver open from either side while pushing down on the mold. The silicone sides of the mold got compressed down, the receiver popped out of the top of the narrow opening in the mold, and I was able to pull the receiver the rest of the way out with my pinched fingers.

So I’m interested in opinions and any similar experiences. One thought is to put in a request to have ReSound remake the mold with a suitable opening. I think cutting the opening to enlarge it might make the mold prone to tearing. Same with the pushing, prying motions I’m going through to extract the receiver from the mold opening. I’ll be surprised if the silicone doesn’t disintegrate sooner or later or I don’t rip or indent the mold with an errant fingernail while struggling to push the receiver out of the mold opening.

Suggestions or solutions, anyone?

My audiologist had a nifty screwdriver-like tool to do this, but we’ll have to make do. I use the back end of a drill with the diameter large enough to not damage the receiver. Point of the drill on the table, backend through the hole in the custom mold and pop the receiver out.

Just pulling the receiver by the wire seems the most bad way of doing things: That’s the way I get my hearing aids out of my ears. I wouldn’t want the domes stuck in my ears: It’s really a hassle to get them out!

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A most excellent idea! I was thinking of some blunt instrument to push the receiver out from the speaker opening but I couldn’t think for the life of me what type of rod I might already have - and I do have a bunch of very small drill bits so one of them is likely to be big enough to do the trick-what a great suggestion (after I clean the oil and gunk off the chosen one!). I had thought of my Jodi-Vac needle since I stick it in the receiver opening all the time to vacuum the opening and the wax guard area but just as you suggest, it seemed like the annular ring of the Jodi-Vac needle would put tremendous pressure on the receiver screen, probably not a good idea.

Needs to be cut with a core drill really - to take out the slug of silicone rather than spreading the mould with a normal drill.

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I decided that the easiest solution for me was just not to push the receiver all the way into the mold. Holding back the last mm or so, the lips of the mold are kept open around the main body of the receiver and it’s easy then to pull the receiver back out of the mold when I want to change the wax guard. Avoids having anyone mess up with a drill. The mold clings so tightly to the receiver that the receiver is in no danger of slipping out of the mold in my ear (and the slight pressure of my ear canal on the mold further helps retention).

How thin a core drill would you recommend for Phonak Spiraflex tubes?

I’ve found 2.5, 3 and 4mm diamond core drills on AliExpress. Would they work nicely on silicon rubbers or epoxy resins?

It seems when you want smaller diameters, they only offer solid core diamond drills: they don’t cut, but sand their holes. Is this the correct approach or just something I couldn’t find on AliExpress?

Not sure, they might be too narrow for a core drill so you’d need a conventional one.

Get your vernier calipers out and check the outside diameter and then work out a % smaller for an interference fit given the modulus of the silicone :wink:

Or just pick the drill that’s a bit smaller by looking at it…