Silicone myths or real issues…

[Backfromthedead]

silicone just doesn’t adhere to plastic…u can scrape it off with ur finger… ticking time bomb imo and u give up the ability to tighten it down the road if needed… (knock on wood) ive honestly never had an issue with bulkheads even the cheap ones. Most if not all my fish room uses reg old $5-8 bulkheads, thin rubber gaskets and i use them on every scenario possible. Glass tanks, acrylic, 55gal plastic drums (curved surface), plastic totes and even on my pond liner tanks… i have them in the floor of a 500 gal through a sheet of plywood under the tank… half the room uses “used” bulkheads i salvaged from buying tanks and what not to boot. Prob older than myself ?… those do worry me a tad but life goes on. Ive actually cracked one of those in the tank floor working under the tank and swapped it out while the tank was full ?. Took a salty shower at the time, but u cant do that using silicone lol… whatever works for u/if it aint broke dont fix it i just never understood peoples troubles with using a bulk head. Every toilet in the world uses one for the top tank… no silicone is needed lol… the screws in the tank are also just a rubber gasket.

I gotcha. I sorta agree with John above that the silicone creates a much better custom fit gasket for the bulkhead. Like I said for whatever reason my bulkheads have sprung leaks when I used just the rubber gasket. Entirely possible that I drill many of my holes too large or they have rough edges that require the silicone to fill them.

I know you've played with plenty of glass, but I think i know most of your fishroom is acrylic. Holes are usually a lot cleaner in acrylic at least when I'm the one drilling lol. It may sound silly but I think a custom fit silicone gasket might just be a bit more useful in glass vs. acrylic.

 

[wednesday13]

I gotcha. I sorta agree with John above that the silicone creates a much better custom fit gasket for the bulkhead. Like I said for whatever reason my bulkheads have sprung leaks when I used just the rubber gasket. Entirely possible that I drill many of my holes too large or they have rough edges that require the silicone to fill them.

I know you've played with plenty of glass, but I think i know most of your fishroom is acrylic. Holes are usually a lot cleaner in acrylic at least when I'm the one drilling lol. It may sound silly but I think a custom fit silicone gasket might just be a bit more useful in glass vs. acrylic.

Agree with ya there for sure, 90% acrylic fish room over here… any glass i do have running and drilled myself are mere 40’s and 55’s for sumps (childs play for ya lol). Seems we all have our “preference” for what we work with most. Ive pushed the limits of silicone gaskets for tank windows… just not bulkheads… With glass ur getting full adhesion at least on 1 side of the gasket. With acrylic/plastic its zero on both sides, the rubber actually “sticks” better. Id go as far as solvent weld a bulkhead in acrylic before i broke out the silicone. it really is worthless on acrylic ?

 

[fishdance]

Sorry, PU (not PE). Polyurethane adhesive.

Rubber is similar with technological developments. Old traditional rubber has been replaced with neoprene, EPDM, nitrite, butyl, etc. Some would be poor aquarium choices but some are fantastic. And choose the best suited density, thickness, hybrid or interlayered for your application. An air impregnated (slightly spongy) EPDM 3mm gasket is much more reliable than silicon for a glass bulkhead.

 

[HarleyK]

Curious, What time frame did it take for the fish to die and what type of fish?

thx

Bettas and catfish. Died within a week. Then I keep the tank running for another half year or so. It was planted (mostly Crypts and Vallisneria) and the plants did fine. Tried another betta with the same result. Then I took the aquascape apart and converted it into a swamp habitat and planted fly traps etc. Circa 1997/1998