heat/cold and uv abuse on joints

[slittle]

Hi all,
I have a unique situation I just want to double check on.....

2cm Stanstead or similar light gray granite has been installed by a mason over interior heat/air conditioning radiators, and double as window sills at table level in a hotel lobby.
Pieces are about a foot deep and 3-4' long each.
The joints were left open 1/16"-1/8", there is nothing in them. There is no movement in the pieces though. I'm unsure of how they were installed.

These sills are at the bottom of 8' tall glass panels over looking the street level front of the hotel.

I've been asked to fill those joints.
I'm looking for recommendations on best epoxy to color and fill so my customer can have years of use without failure. I'm slightly concerned about the cold a/c under the stone with the baking uv heat coming through the windows.
I'm more concerned with uv light and heat affecting color or life of the joining material.

Thanks again, for the always valuable responses!
Best,
Stephen

[Stone Dude]

The best product to use for this, in my opinion, would be Bonstone Last Patch Gel, or Touchstone Glacier.

They are both urethanes. Urethanes will withstand the UV light and not yellow or fade.

1. Last Patch Gel is a 2 part 50/50 mix knife grade. It cures hard, but will allow for a small amount of expansion and contraction. It can be colored. It can't really be sanded and polished

2. Touchstone Glacier (also by Bonstone) is the same as the Gel, but it can be sanded and polished.

Both of these products are moisture and UV stable, and will not bleed into the material.


Here is the Gel
http://www.easystonecare.com/Last-Patch ... on-lpg.htm

Here is the Galcier
http://www.easystonecare.com/SearchResu ... ch=glacier

[Angel]

can you use these products in an exterior application(outdoor bar)?

[Dan R.]

I would suggest a one part Urathane caulk.

[Joe Little]

I would suggest a one part Urathane caulk.

x2 or 100% silicone, dow has a natural grey that would be close.

Price both and let them decide, IMO

[Stone Dude]

can you use these products in an exterior application(outdoor bar)?

yes

[Dan R.]

Urethane caulk is what is normally used for caulking exterior cladding ( skyscrapers) and exterior pavers. All the granite sidewalks in downtown Chicago have urethane caulk. It is super strong and withstand extremes in weather and pressure.

[Matt Lansing]

I agree on the urethane caulk.

You can typically get it at a commercial window contractor's place.

Dymonic by Tremco is what I usually use and it will last forever.

[Stone Dude]

The original post said it is interior, unless I misunderstood.

[Matt Lansing]

My thought on the caulking was because it was on an exterior wall and the sills are mounted on masonry adjacent to large windows. There will be movement no matter what so caulk is my call.

[Stone Dude]

that makes sense. If they have a color that works for you, Sika Flex would be a good option. it's urethane caulk, but the colors are limited

[Dan R.]

We use Sika or Vulkem 116 (I think that is the number) for Urethane caulks. Be very careful, it is sticky stuff. Tape the joint, lay the bead and tool it with a plastic spoon and let it be. Do not give into the temptation to "fix" it a little It is a losing proposition.

[RBatstone]

Sika flex. That's what we use on all our cladding

[slittle]

Well for some reason I haven't been getting my email notifications for all your responses, thanks!

I sealed the stone last week as they decided to hold on the joint work until after Labor Day when less guest traffic and not too cold to open the doors and vent the lobby while I do the work. So....
I have time to learn more from anyone else interested in sharing.

Thanks again....about to post another one, I've seen it before....but didn't have to do anything about it......