Avon Transom Repair

[jondavies]

The strip of hypalon at the bottom of my boat's transom has been coming undone. When I repaired it last year, I used penetrating epoxy to reinforce the transom in a few areas where it was starting to delaminate and then glued the hypalon back in place with 2 part Bostik.

I recently noticed that the strip had come off again. The glue held up fine but a layer of plywood had peeled off the transom and was still glued to the hypalon. The "penetrating epoxy" didn't penetrate too well.

I called West System and they suggested G/Flex 655 thickened epoxy adhesive. Since it is very good at bonding dissimilar materials and has high flex, they suggested I could both epoxy the transom and glue the bottom of the transom to the floor of the boat in one step.

I spent a day prepping both the transom and the hypalon, and I applied a couple of layers of G/Flex yesterday. I worked a good amount of G/Flex into the joint between the floor and the transom and clamped it up with moderate force. I let it the epoxy cure overnight and sanded it down smooth today. I have to say it's working well so far. This G/Flex stuff (which looks like butter when mixed with microfiber filler) hardens like rock yet is flexible enough to bond tenaciously to the hypalon:

http://www.flickr.com/photos/20500808@N03/5688739238/

My next step is to replace the hypalon strip that runs across the joint at the bottom of the transom. I'm going to cut the hypalon strip an inch or so higher than the original section (almost so it touches the yellow sticker in the pic above) and secure it behind the strip of wood that holds the rear floorboard in place.

I'm tempted to use more G/Flex for this step of the process but I've run out so I think I'll switch to 2-part Bostik (as I have a fresh can). I hope the Bostik glues up well to the G/Flex. I think it will because the G/Flex has a surface like varnished wood and I'm roughing it up with 80 grit to ensure good adhesion.

I'll post a report to let you know how it goes when the job's finished. In the meantime, any tips are welcomed.

 

[nobrainsd]

Re: Avon Transom Repair

G/Flex, when used with the appropriate surface prep, is pretty amazing stuff. I use the non thickened 650 to bond flame treated UHMWPE and cross linked PE foam to carbon fiber laminates (otherwise almost impossible to bond). But you should remember that this is going to be a permanent bond. You will never get the hypalon to wood bond apart without damaging the hypalon. The regular two part glue has it's limitations, but doesn't preclude further repairs.

 

[jondavies]

Re: Avon Transom Repair

G/Flex, when used with the appropriate surface prep, is pretty amazing stuff. I use the non thickened 650 to bond flame treated UHMWPE and cross linked PE foam to carbon fiber laminates (otherwise almost impossible to bond). But you should remember that this is going to be a permanent bond. You will never get the hypalon to wood bond apart without damaging the hypalon. The regular two part glue has it's limitations, but doesn't preclude further repairs.

Thanks Kelson.

I figured it would pretty much be a one-way ticket with the G/Flex but after having my last repair fail (not due to the glue, but the delamination of the plywood) I figured some more drastic action was called for. I'm working on this repair very methodically in the hopes that I won't need to revisit this issue for a good long time. I guess I'll cross that bridge when I get there.

Incidentally, I had to cut out a strip of hypalon to reinforce the transom/floor joint. I wanted a piece that was larger than the original strip and therefore I couldn't use the old section as a template.

I got a sheet of vinyl from a fabric store and used it to make a template. It's clear vinyl so it's easy to see how the strip lines up with the joint underneath and where to cut out holes for the drain plugs etc. One of my better ideas

 

[susanexpress]

Re: Avon Transom Repair

you can use other strips