Ping Robatoy

[Frank Boettcher]

hey what kind of silicone do you use for the seal between an undermount stainless steel sink and solid surface?

I recently used some GE silicone II window and door for a little outdoor project and it took it about ten days to cure. Stayed literally gooey for that whole time. Kind of got me concerned about a sink that can't be out of service for that length of time.

It was very, very hot for the outdoor project, but I thought that would accelerate not slow down the cure.

Also, do you pull up the clips to almost there, give it a little cure time then pull up the balance, or get it all at once.

Thanks

Frank

[Robatoy]

This kind of advice costs money.

I use Gutter And Flashing (awning) Silicone II (GE). It sticks to metal better. The clear is best. The stuff DOES expire, so keep an eye on the date. Also, make sure it is very clear and runny, and not cloudy, milky and rubbery. It has to feel wet. It helps if you buy it from an outlet that you know has high turnover. The fresher the better.

Sure sounds like a bad tube to me.

That depends on how flat the flange of the sink is. I tighten them, but not in a nutso-cuckoo way. I try to use a sequence, a bit at the time, give the silicone a bit of time to escape. (I use small blocks of MDF, hot-melted in place on the bottom of the countertop so the sink doesn't float all over the place. I also make sure there is a nice bit of squeeze-out which I do NOT remove until a day or more later. Just a sharp Olfa blade pointing down to the sink edge and touching it. A cord of dried silicone should peel off. Don't try to remove it wet.... Under the counter, I smear the silicone all over the bottom of the flange and deck, almost like an undercoating.

Make sure you clean and clean and clean the metal on the sink flange with methyl hydrate and 200-320- grit sandpaper...careful not the scuff the shiny bits which will be exposed later.

Overtightening can create too much squeeze out. Neither surface is porous, so don't think 'wood' as you clamp. A standard double sink will use 10 -14 strong clips. It is said, that the silicone alone will hold the sink, and the clips alone should as well. The combo, double- good.

The adhesive is strong enough for big aquariums (ia?)..but they keep things nice and straight and clean.

You owe me 2 cents.

r

[Frank Boettcher]

Thanks, good information, some things I had not thought of, alignment blocks in particular, can see why they would be very helpful if not essential.

I checked my silicone. Bought it two months past expiration. At the friendly BORG. Will be careful to check the next tube.

I'm good for that $.02 next time I see you. Since you previously advised the use of and method for installation of perforated flange studs for the clips, is that up to $.04?

Frank

[Frank Drackman]

Thanks for taking the time to provide an excellent answer. Advice like yours makes this site extremely valuable.