I'm starting my own transom replacement this fall. I'm doing the stringers as well. I'll post some picks as I start digging out the old plywood. I've helped do a transom before but this is the first time on my own boat. I'm hoping my multi tool (fein saw) will dig most of the old core out. Post some pics if you have a chance, I'd like to see how it's going.
When I replaced the transom core on my Midland 19 I cut around the outside of the transom with a 4.5" masonry cut-off wheel on an angle grinder. After removing the outer fiberglass skin I replaced the core ( 2 laminated layers of 3/4" marinetek plywood) I used # 10 screws and 1" fender washers to clamp the fiberglass skins to the cores until the epoxy cured. Afterwards I removed the screws and filled the holes before gelcoating.
For epoxy glue I thickened it with cabosil until a paste. I used slow hardener. I applied the epoxy with a 1/8" notched trowel
Correction; I earlier said I used a 1/4 notched trowel it was actually 1/8" notched trowel
if i can figure it out ill post but the transom looks like it has been cut out and replaced before [very ugly job] so im not sure if i can keep any of the existing glass skin i think ill have to cut allmost all of it out. maybe wrap the inside fair the outside i have two solid glass seats/storage attached maybe cut and wrap to them also??
yes flat i wonder if i can cut most of it out except about a 3 inch perimater fit in a new ply transom then overly glass on the outside overlay and wrap the insde corners then wrap the seats/storage boxes
I've been reading up on Nida-bond, the pour in stuff for transoms. I think I might give it a shot on mine. I'm cutting out the inside and adding some new glass. I've seen the chainsaw method where you just gut-out the old wood and pour in the nida-bond but I think I'll get a better bond to the old polyester resin if I cut it and grind it out.
I've replaced a few transoms. For me found it easiest to cut the inside fiberglass edge with a diamond wheel on a 4' grinder. Use a carbide blade on a skill saw to cut the inside transom into smaller manageable sections and remove them.
Usually the outside fiberglass skin is approximately 1/4', try not to damage that when taking the plywood layers out. Cut new plywood cores to fit, completely seal them with thinned out polyester resin. When dry apply two layers of fiberglass mat to the transom, saturate with resin, then apply one of the plywood cores.
Add two more layers of mat, saturate with resin, then add the last plywood core. Clamp, but use caution not over clamp. Might have to use some braces from floor,stringers or were ever you can to insure a good fit.
Sounds complicated, but its not that hard to do. Just a little messy, Oh when cutting and grinding be sure to wear natural fibers ...cotton, wool ect. cuts down on the itching.. definitely do not wear synthetic fibers.