silicone

Sink Tool Holder Plug Repair

We have this sink organizer thing that holds a sponge, a bottle of dish soap, a scrubber, etc. and there’s a little plastic plug that goes into a drainage hole in the bottom of it. Well, there was, but it wore out and broke, so I made a new one.

I modeled one in OpenSCAD based on the measurements of the broken one…

Then I used that to difference it from a block to create a mold I could 3D print using PLA plastic. (I did consider printing in TPU but I had to do some other silicone casting as well so I went this route.)

Here’s the new plug made from silicone. It’s pretty simple, nothing fancy, so I assumed it would work just fine.

Here it is stuck into the hole. It’s flexible so it squeezes in just fine…

Here’s a view from the top where you can see the plug in the hole. Again, a simple project. I’m hoping it holds up because another cast I did with this silicone came out a bit weird.

In this closeup image you can see the lines in the piece caused by the 3D printed mold. They don’t matter for this sort of thing though. (I probably didn’t print the mold at a high resolution.)

3d-printed-mold

I bought a water bottle about two years ago after my old one was stolen (I know, who steals a water bottle!?) While the new bottle was much better, since it was insulated and could keep water cold for more than a day (with ice added in) one of the things I didn’t like about it was a small rubber ring used to seal the cap. The rubber ring had a split in it (maybe to assist with the seal?) and it was difficult to clean, and eventually it broke from attempts to vigorously clean it.

smooth-on

I replaced the sealing ring by 3D printing a small mold and then casting a replacement using Smooth-Sil™ 940 silicone. The silicone is a two part mold, with a volume of 100:1 for part B to part A, which is why you get a giant tub of silicone along with a small bottle of whatever the red stuff is.

ring-and-mold

This was my first silicone casting at home for a personal project. I’ve done casting at work for prop making, but this time I didn’t have a vacuum chamber, and I was doing a tiny part all by myself.

silicone-ring

So how did it turn out? Pretty good! I used a digital scale and filled a cup with 10 grams of part B, then added 1 gram of part A and mixed it all up with a popsicle stick and smeared it into the cavity of the 3D printed PLA mold. I let it sit overnight then used a sharp knife tip to pry it out. There was a thin skin around the piece but it peeled right off.

cap-with-ring

So how does it fit? It’s good but not perfect. If I make another one I may decrease both the inside diameter and outside diameter. It could fit a bit more snug, and it could have just a wee bit more clearance when inserting into the bottle. (I’m guessing between 0.1mm and 0.2mm, maybe)

I’ve got plenty more silicone, and it is food-safe, so I want to experiment with making some food molds, and yeah, I’ll probably 3D print the objects to create the molds from, taking a page from Anna Kaziunas France.