Non-shrinking structural resin?

October 30, 2014 4:09 PM

I have a problem fixing a toilet seat, I hope someone here could help.

So I bought a bidet toilet seat (Brondell S1000.) It's great! But... the seat cracked.

The seat itself is two pieces, either glued together or snapped, and it's hollow. It needs to be hollow for the heating element and seating sensor.

Here's what the crack looks like.

So I called the manufacturer, and got a replacement. No problem.

But I'm wondering about fixing the cracked one. My plan is to see if I can separate the top and bottom, push the cracked area back out, superglue the cracked area, reassemble, then fill the hollow with... something?

I'd need something structural, so the crack won't push back in. Something lightweight, and since I'd need to inject it into the reassembled seat, something that expands.

I thought about injecting mortar with a piping bag, but that's probably a little heavy.

Expanding foam? I don't know if it would be strong enough, and I understand the foam could shrink back after awhile.

Some sort of casting resin? I know nothing about these products.

Any other ideas?

posted by Marky to Home & Garden (6 answers total)

Perhaps check out Sugru. You could use it to reinforce the cracked area and seal it once you got the cracks realigned. Dries very lightweight and sticks to a lot of surfaces (rough up the surface first).
posted by bookdragoness at 4:31 PM on October 30, 2014 [2 favorites]

Best answer: Rather than using cyanoacrylate, I'd see if you can find a solvent/cement "glue" for the plastic involved. If the material is PVC, acrylic, styrene or ABS, you can theoretically make a joint as strong as the original plastic (takes some care in cleaning to get a really strong joint). Hobby shops often have multi-use cements, and you can test them out in an inconspicuous place to see if they make the plastic soft.

If you're stuck on filling the center, I'd seriously consider a "marine expanding polyurethane foam" (put those words into your favorite search engine). You might want to build some test molds to get quantities right, these things can be scary fast expansion-wise and if you gauge it wrong blow out your material, but that'll be water resistant, relatively strong, certainly filling...
posted by straw at 4:52 PM on October 30, 2014

Seconding an expanding foam of some kind. Heck, Gorilla Glue might do the trick.
posted by fifthrider at 6:42 PM on October 30, 2014

Gorilla Glue might do it. I think that's an expanding polyurethane glue.
posted by supercres at 6:43 PM on October 30, 2014

Use some fabric tape or something to make the joint more secure.
posted by theora55 at 8:24 PM on October 30, 2014

To build on what straw said, those materials actually "glue" together via "solvent welding" rather than ordinary surface-to-surface bonding. The solvent temporarily melts the surfaces and they blend together into a single contiguous region. When the solvent evaporates, you (assuming you started with clean, dry surfaces) literally have a bond that's at least as strong as the surrounding material.

In the case of PVC or CPVC, I believe the solvent is usually acetone.
posted by ZenMasterThis at 5:49 PM on October 31, 2014