Can I use thin set to install my fiberglass tub surround ?

Don't think so. Most tub surrounds come with a couple of tubes of adhesive for installation. Lacking the provided adhesive I'd use silicone. You could use construction adhesive but depending on the color of the surround it might show through.

Hi guys:

As Hk said above... no, thinset can't be used on a tub surround.

They sell a specific TUB SURROUND ADHESIVE CAULKING at your local home depot or Lowe's... won't show through the surround like construction adhesive will... also mentioned by HK... ;)

Check it out at:

Liquid Nails LN-915 Tub Surround & Shower Walls Adhesive - AZ Partsmaster

Mark

I agree with Harold and Mark...

Thin set will not adhere to the tub surround. As suggested above, use adhesive as suggested by the manufacturer. The type and brand of such a adhesive should be listed in installation instructions.