glassdave

yep, I switched over to pre mix bonding methods several years ago after chatting with Steve Koss about the technical side of it. It really is the way to go on many levels. Ease of use and long work time, multi use product set transom bed stringers and filets etc.

looks good man!

sparky24

Where did you end up buying the corebond? could you post the exact 3m product number if you get a chance.

Borgie

https://www.apdmro.com/mobile/Produc...de=70006474343

Best price I could find as it's not stocked locally in Phoenix. It's hazmat, so really this price shipped is phenomenal IMO.

sparky24

So that is exactly the correct product and its compatible with vinylester resin? Never knew you had to wet both surfaces first with resin, thanks for the information

Borgie

Yes. The surface to be overlayed with corebond needs to be "hot coated" with vinyl ester and allowed to become tacky before corebond that's activated is applied.

sparky24

How long did you have once you were hot coated and the corebond was activated to get it spread out on both sides and then secure the transom in?

Also was 5 gallons enough for one transom?

Borgie

I made sure the surface to be bonded was properly prepped and clean. Then mix the VE (I used 3% MEKP). After applied I waited about 20-30 until it was tacky. About 10 mins waiting for it to tack up, I would start mixing my Corebond at 1.5%. The corebond has a pot life of about 45 mins at this 1.5 % as per 3M chemist( I called and talked to the adhesives chief chemist at 3M, so these figures aren't my guesses). The pot life estimate I was given was spot on fwiw.

The 5 gallon of Corebond was enough to do my complete transom along with all required fillets and stringer (rear engine stringer sections) on my single engine mirage 232 trovare, and I still had about 1.5 gallons left. Keep in mind I used corebond to bond the bottom portion of the stringers to the hull, and west systems 404 to bond the back side and each end. I was given quite a bit of great advice from glassgave btw.

sparky24

Yeah i can tell you got a lot of advice from him haha, thats why i keep asking you **** lol. Hes a busy guy though so i figure the more i can get from you the better. Take a look at my thread if you want i am ankle deep in glass right now.

I think you are the first one to do a transom with corebond on the website per glassdaves instructions, so this info is invaluable as i have been through every fiberglass thread on here 3 times and never came across this info yet

Borgie

Yes, Dave is a great guy for sure. I may very well be the first member here besides a pro like Dave to corebond in a transom, not sure. Either way it's leaps and bounds better than the traditional methods utilized IMO.

Your project is looking good man. Just about done with the fun part lol! Oh the memories! If you need anything further, don't be afraid to ask. If I haven't done it, I will say so.

For anyone else interested in my transom/stringer replacement process which I documented a few months back, here is the thread. http://www.offshoreonly.com/forums/r...are-build.html

MooresWarlock

Hey GlassDave or Borgie - I've got a quick question - I've got my 3M Corebond and getting ready to start my transom / stringer project - when you wet-out the existing inside fiberglass of the transom with VE resin - do you add any surface curing compound or does the Corebond need the surface to remain tacky for the bonding process to work properly? Thanks in advance!