I found the post searching “epoxy”this is quoted from oldtimer57:I have good luck by going to a hobby store. They stock everything from 5 min epoxy (avoid this like the plague) to overnight cure. I personally do not like the putty crap either. Easy to get air pockets. Here is my approach to epoxying in a new transducer. 1. You need the epoxy, and a round cardboard tube that is slightly larger than your transducer. A good paper cup, or even a plastic cup will do just fine, just cut it off about 1” or so from the top and save that part. You can use the bottom for mixing the epoxy. Finally get some modelling clay from wal-mart in the toy section. 2. Figure out where you want to mount the thing and clean the hull carefully. Mark the location by drawing a circle using your round cup as a guide. Scuff this up with coarse sandpaper to make sure the expoxy will bond. 3. Position the cup top and then use the modelling clay on the outside to hold the cup in position and also to seal the cup to the hull so that your expoxy wont run out underneath the edge of the cup. 4. Now mix up the epoxy, being careful to equally mix the two parts so that everything will cure properly. I usually pour a little into the cup, and then use a small spatula to make sure the epoxy wets the entire hull area without trapping a bubble. Now wet the bottom of the transducer with the epoxy as well. Carefully place the transducer in the cup, press down against the hull, and then cover the transducer with epoxy. Use something to hold the transducer down so that it doesnt tend to float away from the hull since the epoxy is pretty dense. 5. Check to make sure the transducer is all the way down, and that the epoxy comes up at least 1/2 way up the side of the thing, and then leave it alone. If you use 24 hour epoxy, Id let it set for 48 hours. Then peel the modeling clay and the cardboard cup away and you are done. Usually the slow-curing epoxy is quite a bit less viscous than the 5-minute type. The main thing you want to avoid is vigorous stirring while mixing as that can lead to lots of air bubbles. They will generally dissipate by floating to the top, but the fewer you have to start with, the better. To remove this later, a wood chisel and a hammer with the chisel set at the junction between the epoxy and the hull will pop it right out… Hope this works
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