Swiss cheese transom? Step inside for a good long lasting fix.

[RaisedByWolves]

I dont know what the boneheaded previous owner of my hull was thinking, but there are enough holes from mounting fish finders to sink the Titanic.

I know for sure this was a one owner hull, but it looks like the guy bought and mounted every newfangled FF that came out with no concept of reusing the old holes or really much else for that matter.

So when I removed the FF that was on the hull to install my new SI Ff I was dismayed to find 8-10 holes all within inches of each other. #-o

Looked like this.





Once I cleaned up the surface it looked even worse as some holes weren't readily visible in the daylight.

Now for the meat of what Im getting at. A lot of guys use JB weld to patch holes, and thats fine, its what Im using here. What I wanted to add is a better way to prep your holes before slathering them with that wonderful grey goo.

Im going to show you the two holes I have access to both sides of.

What I did was countersink both sides of these holes to form a cross section that looks like this >=< or this if you dont have a proper countersink this )=( can be done with a simple file or oversized drill.



Example.





Inside:

Outside:

I have no idea why so many extra pics are showing up. ](*,)

 

[RaisedByWolves]

Anyway... \/


What I like to mix my epoxy with is a flexible machinist scale. They mix epoxy's very well as being flexible you can really scrape up the mix to ensure proper mixing and they make laying the epoxy on thin a breeze.


When you apply the epoxy it will come through the back side and form runners like this, just flatten them out to cover the back of the hole and level it out. You can see the squiggly lines where I took an air tool with a carbide burr to the backside of the ones I couldn't access with the drill. I just looked through the holes until the bit blocked them then gave a tiny blast with the burr to make a counter sink but not go through the hull.

Im trying to make things better, not worse. :wink:


Potato pic.

Now after smoothing the epoxy out on the back, of course you have runners on the outside. Use the edge of your scale or scraper to knock these down flat.

 

[DaleH]

Yes =D> , that is called the 'mushroom' technique and was popularized by West Systems when they 1st developed or applied epoxies to wooden boats or to FRP boats with wood used in the construction.

Epoxy cures and adheres via a chemical bond and the intent of sandwiching a material between 2 layers of epoxy in effect also makes a mechanical bond or 'locking feature' with the parent material. That actually is a technique that should always be employed with epoxy for the best bond! Examples include roughing up the surface/hole prior to gluing, or like where I've used it to repair broken forends on rifle stocks, I'll embed a graphite arrow shaft in a hole through to join the 2 pieces. But the shaft was ground with a Dremel grinding bit to have scars/deep scratches or even 'Swiss cheese' holes throughout the length to ensure the epoxy permanently 'traps' the shaft in place. Never had a call back in 30-years, so it must work well!

 

[RaisedByWolves]

Board is being buggy today, so ill have to do this bit by bit.

PLMK if pics aren't showing.

Once everything is knocked down it will look like this.


Im going to let it cure until tomorrow before I sand it flat and mount the new FF.








IMO I should have used DEVCON epoxy as it would be less saggy, but at $60 for a one pound kit Im not sure many people could relate.

This seems to work OK, you just have to keep up on the sags to prevent the hole from opening up if it sags too much.

 

[RaisedByWolves]

Yes =D> , that is called the 'mushroom' technique and was popularized by West Systems when they 1st developed or applied epoxies to wooden boats or to FRP boats with wood used in the construction.

Epoxy cures and adheres via a chemical bond and the intent of sandwiching a material between 2 layers of epoxy in effect also makes a mechanical bond or 'locking feature' with the parent material. That actually is a technique that should always be employed with epoxy for the best bond! Examples include roughing up the surface/hole prior to gluing, or like where I've used it to repair broken forends on rifle stocks, I'll embed a graphite arrow shaft in a hole through to join the 2 pieces. But the shaft was ground with a Dremel grinding bit to have scars/deep scratches or even 'Swiss cheese' holes throughout the length to ensure the epoxy permanently 'traps' the shaft in place. Never had a call back in 30-years, so it must work well!

Yeah, its intuitive once you think about it.

The Previous owner just used 5100, and while that works it is easily dislodged by an errant stick or passing turtle unless you glob it on.

This wont even be noticeable once its painted over.