Don't do it.  Several recent glue strength tests, Fine Woodworking for one, have proven Gorilla Glue wanting.  Titebond has better holding power than Gorilla Glue.  Epoxy has proven just fine for scarf joints and you really shouldn't have any problems with cleanup, just don't slather it on too thick.

Gorilla glue also has a habit of expanding a bit during the curing process; which could turn into a bit of a headache

- this is speaking from experience having used Gorilla Glue for wing spars while building an RC airplane out of balsa... (ran out of epoxy and didn't want to run to the store, turned out to be a big mistake)

Glad I asked the question.

Epoxy it shall be.

 thx

Jeff

Wouldn't Titebond III be just as strong as the epoxy, but with faster cure  times and easier cleanup?  I am going to start my Mill Creek Hybrid (First boat build) tomorrow and was going to post this question.

 Thanks

Nate 

I'm in the middle of building a Chesapeake 16 and I chose to use Titebond III for scarfing my panels.  I'm sure it will be fine.

The real strength will come from the sandwich of epoxy and fiberglass that will encase the hull.

I'll let you know in a few weeks if I break apart and sink due to this choice ;^)

John

John,

We'll be in the same boat so to speak as I used Titebond III as well.  Glued p the scarfs this morning.  I have used it in the shop for years,just cautious as this is my first boat.

 Nate

Strength is not the issue with Titebond III vs. epoxy. It's plenty strong, the wood will break before the glue joint fails.

Thickened epoxy glue's main advantage is that it's gap-filling. You can get away with a less-than-perfect fit between the pieces and still get a perfect scarf. With TBIII and other glues a void will leave a weak spot that can become the starting point for fatigue failure.

Another possible issue is water. Epoxies are waterproof, TBIII is water resistant, albeit very water resistant. For use in the inside of a glassed and epoxied panel, this is not an issue unless the epoxy barrier gets damaged. Even then, TBIII's water resistance is such that there shouldn't be a problem as long as the damage gets repaired in a reasonable amount of time.

So it should work just fine for scarfing.

Laszlo

I, inadvertantly, ran my own distructive testing laboratory.

I built a pirogue out of 4 half sheets of underlayment scarfed together. The boat came off my roofrack at about 65MPH and landed in the road. It was all scuffed up but not a seam let go. Epoxy is the reason it survived. No amount of coaxing will ever cause me to abandon my jug of epoxy.   

The main reason I can come up with to stick with epoxy over TB is for appearance of a bright finish. If you don't get all the TB wiped off the surfaces before it cures it will not allow the epoxy to soak in like the surrounding wood when you glass the boat and you'll see blotchy areas at the scarfs.

George K