Designing Kitchens and Bathrooms - Thinset or Construction Adhesive

I am building an outdoor kitchen and am using granite 12" tiles for the top. I want to run a band of 3.5" pieces of granite around the counter top. Thinset is proving to be a challenge, and I was wondering if the construction adhesive I used on the hardibacker to steel stud frame could be used to glue the granite pieces to the steel frame. Do I need to wrap the frame with quarter inch hardibacker and then glue/thinset the granite tiles or can they go right on to the steel frame? I did the top with a dry powder thinset from Lowes and mixed it with water, but it was a real struggle for me to keep the tiles from pushing the thinset out of the sides and turning into a mess. I was thinking construction adhesive would be a good alternative. It says it is made for exterior, bonds to metal, wood, stone, etc. and lasts forever. It's a polyurathane construction adhesive if that helps any. Is thinset really a superb adhesive? Thanks.

No construction adhesive!

Tell us how your outdoor kitchen is framed? Hardiebacker is not water proof, and if you were to use it outdoors, it would have to be coated with a waterproofing liquied like RedGard.

Thinset has been used for setting tiles for thousands of years and is the only proven way of doing so. You can't be affraid of getting your hands dirty. If you are, you shoudn't be doing this project.

Re: Pushing the thinset out on the top - Did you use the proper notched trowel to spread the thinset when doing the top? If yes, then typically the tile are set, pressed to increase the bond and then left alone- there shouldn't be appreciable thinset squeezing up at the edges unless your moving the tile too much , or maybe the thinset has too much water mixed in.

Even using polyurethane construction adhesive (which I use a lot of), I would be concerned with the poly to steel bond in the long term. To increase the holding ability, you might drill a series of 1/8" holes in the steel studs to allow the poly to squueze through and increase the holding power.

You say this is an outdoor kitchen. Are you aware that hardibacker is for interior use only. This came directly from the jameshardie q&a's see the link below.

Q. Can I use HardieBacker cement board in an exterior application?
A: In accordance with National Evaluation Service Report NER-405, HardieBacker board is recognized only as an interior substrate.

http://www.jameshardie.com/homeowner/products_backerboard_quarterInch.shtml?openTab=jsnavLink3#18

Forgot to mention, you can use a cement board like wonderboard for exterior use.:)