For bonding I use epoxy usually but sometimes vinyl ester. Those two have a way way higher peel strength than standard poly. Much less likely to separate. Poly is great for molding parts, lay ups and new glass work but for repairs and bonding go with something stronger.

Thank you I will be going with the arjay 7121.

I was just told by a guy at a fiberglass store that Bostick would be the best way to go as far as bonding the floor to the stringers. I'm not sure how I feel about that. He said putties have much more of a tendency to crack and the flexibility of Bostic is what you want to bond your floor to the stringers. Any input on this matter??

I usually don't use pre-made putties but mix my own from epoxy resin and just add the additives to it. I sometimes use the VE due to I had 55 gallon drum of it and it worked well to even tho epoxy is more flexible. I add some different thickeners and also milled fibers to strengthen the putty and haven't had no cracking problems with VE. I can see cracking tendencies when using a poly base putty but even then look at the potter built hulls that were bonded together with "potter putty" it is a basic poly based putty that is super brittle that will crack if you hit it with a hammer. Not many of those boats had problems with floor separation that I have heard of and out of the many I have cut on it is hell getting it apart sometimes and that's after 40 years! I think using a VE product like the AJ 7120 or 7400 (with the milled glass) would work well. It is designed to do what you are doing and will bond twice as good as the original potter putty and be much more flexible to prevent cracking. The Bostik stuff looks to be good for General Construction like concrete and cabinetry but a boat I wouldn't use it in. There product is designed for a different market. I would use a proven method of 40 years with the aid of modern better resin. I never used ArJay but it sounds like a good product and I have heard good reviews on it from the boat world. I never heard of the other stuff until I Goggled it.

Thank you very much! Decision is final I will be using aj 7121.

7121 is the way to go, you will tear the fiberglass before it brakes loose. you cant believe how solid the deck is in mine. you can jump up and down and it feels like you are on the sidewalk.

also 7121 is vinylester based

I haven't posted in awhile and have been busy. tightened up a bunch of loose ends before installing the floor. Put the floor down with arjay 7121, glassed in in, and started building the cap. Its flipped upsidedown right now and will get a couple layers of biaxial on the bottom.

.

.