# mildew and silicone - undermount kitchen sink



## MarkJames (Nov 25, 2012)

Question for the kitchen pro's. Which silicone is least likely to develop mildew over time for an under mount sink install (around the rim)? I seem to see that more and more, even in the upper range homes. Just 100% silicone, or is there something even more special? Doing a small install this week. Thanks.

Also, any advice on getting the perfect finished bead would be appreciated, i.e. no caulk residue. I figure masking is out. Maybe I'll under-apply the caulk for the mounting, then apply a final bead, once mounted, with a small tube. Is that about right for a good method? 

(btw, yes, there will be mounting clips.)


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## owattabuilder (Sep 2, 2013)

Lexel seems to be a premium clear product and I think it would be the most resistant to mildew and loss of bond.


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## Kowboy (May 7, 2009)

MarkJames:

I've used GE Silicone ll in this application at least 30 times without callback or failure. The silicone functions as a gasket only, the sink must be mechanically fastened and preferably to the sides of the cabinet. There will be no mildew without leakage. I highly recommend the Hercules Universal Sink Harness:http://www.braxton-bragg.com/index.cfm/fuseaction/store7catalog.level/bc/9145/

I can disconnect a sink, remove it from the cabinet, clean the flange and underside of the top, install the harness, apply the silicone, clamp the sink in place, tighten the harness, remove the clamps, clean up the squeeze-out, and reconnect the sink in a little over an hour, but I've done a few.

After you've clamped the sink in place, spray the silicone squeeze-out and surrounding top and sink with Windex. Spit on your finger and remove the squeeze-out on to a paper towel. The Windex keeps the silicone from sticking where you don't want it. Hit any stray spots with acetone; they will clean right up.

Leaking sinks can be much more than unsanitary. If a stone top has been "rodded" with cold steel instead of stainless or fiberglas and been bedded in polyester instead of epoxy, the leaking sink flange dumps water on the rod, it penetrates the polyester and oxidizes the rod. No stone on earth is stronger than rust. The rusting rod bursts the stone:

http://josephcorlett.hubpages.com/hub/Rusting-Reinforcement-Rod-Repair-In-Granite-Countertop

This ain't cheap to fix.


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## MarkJames (Nov 25, 2012)

Kowboy said:


> MarkJames:
> 
> I've used GE Silicone ll in this application at least 30 times without callback or failure. The silicone functions as a gasket only, the sink must be mechanically fastened and preferably to the sides of the cabinet. There will be no mildew without leakage. I highly recommend the Hercules Universal Sink Harness:http://www.braxton-bragg.com/index.cfm/fuseaction/store7catalog.level/bc/9145/
> 
> ...


Thanks Kowboy.

I'm curious how you clean silicone off a flange so fast. Blade only, or are you using some sort of solvent, also? I'm wondering because recently I removed a Kohler tub enclosure frame, and was wondering how I was going to clean it up for a reinstall.....(fortunately the owners decided to get rid of it, instead).


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## Kowboy (May 7, 2009)

MarkJames said:


> Thanks Kowboy.
> 
> I'm curious how you clean silicone off a flange so fast. Blade only, or are you using some sort of solvent, also? I'm wondering because recently I removed a Kohler tub enclosure frame, and was wondering how I was going to clean it up for a reinstall.....(fortunately the owners decided to get rid of it, instead).


MarkJames:

On stainless steel sinks, I scrape most of it off, but an 80 grit paper on my Festool Rotex 150 on grind mode removes it fairly quickly. Go right over the divider with progressively finer grits and the steel will shine:

http://ths.gardenweb.com/forums/load/kitchbath/msg0720541827804.html


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## B.D.R. (May 22, 2007)

I have been using Dow Corning for 30 yrs.
Why switch?
I made my own short caulking gun, it takes half tubes aand gets into tight spaces


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## MarkJames (Nov 25, 2012)

B.D.R. said:


> I have been using Dow Corning for 30 yrs.
> Why switch?
> I made my own short caulking gun, it takes half tubes aand gets into tight spaces


So you shortened the gun barrel & push rod?

I need short tubes today, and figure I'll pick up the tubes that don't need a gun.


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## B.D.R. (May 22, 2007)

Yes. It took about an hour.
Ground off the rivets, shortened the barrel and cut off the plunger.


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## B.D.R. (May 22, 2007)

Should patent it. 
I'm sure someone will get rich


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## 91782 (Sep 6, 2012)

B.D.R. said:


> Should patent it.
> I'm sure someone will get rich


That's treick as hell!:thumbsup:


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