Requirement of backer board for stern cleats?

[ktm_2000]

I added 3 layers of 1708 on top of the cleats set in epoxy. I have to say I dislike epoxy when working with 1708 as I spent an enormous amount of time bubble busting and even with that still ending up with a bubble in the upper part of the starboard side. It won't affect anything but it seems that the epoxy doesn't break down the styrene binder and allow the cloth to move around items.

I could have also done a better job planning out and cutting the bottom as I will probably end up grinding out a fair chunk where it goes around the original hull to deck joint.

port side
https://photos.app.goo.gl/wxMjbj6NVXFYMZPC9
starboard side
https://photos.app.goo.gl/jrDCpvXsazeF7WhZA

[ktm_2000]

one other thing, to get the glass over the bolts with the heads cut off, I gave each one a couple light taps with a hammer to press through the glass and then needed to also use a utility knife to make small incisions to open the holes a little bigger so the glass wouldn't distort.

[Tony Meola]

Matt

Nice work. Hard to tell from the pictures, but make sure you leave a radius in the matt where the mount bonds to the hull, I remember Capt. Pat saying that improved strength. Why I have no idea but that is the way I see all the good glass work done.

[Tony Meola]

I found this in the tips section. (http://bertram31.com/proj/tips/epoxy.htm) It appears it gives you more surface area to bond too.

Fillets in general

Fillets are the strongest reinforcement that can be added to a angled joint. As illustrated in the following diagram, the surface area of the bond is greatly increased, by the two contact sides of the fillet. The amount of this increased surface area is dependent on the radius of the fillet and the area of the primary bond line. The greater the radius of the fillet, the greater the increase in strength.



Let's say that in this case the bond line is 1/4" wide and 12" long, giving a primary bond surface of 3 square inches. By adding a fillet with a radius of 1", the bond strength is increased by a factor of 9 times, or 27 square inches.

The radius of the fillet should be at least equal to the width of the primary bond line, which would yield an increase of 3 times the strength without the fillet. Less than this, while it still increases the strength of the bond, the fillet becomes more cosmetic than structural.

Large radius fillets should be build up in stages, where as small radius fillets can be added in as little as a single step.

[ktm_2000]

Hi Tony,

I agree, When the plates were bonded in, I did a rather large fillets on the outside. It may not show up well on the screen but I put a 45 degree fillet on the edges, it probably extends the size of the plate by 1" towards the middle of the boat, on the outside you can see the curve of the hull shape, I leaned the outside edge against the hull and used filler to fill in the gap left over.
https://photos.app.goo.gl/Cw3kzfY3bP8KFrM57

[ktm_2000]

the glass was still somewhat tacky so I put a 500 watt halogen on one side at 7am and switched it over to the other side at noon, should be good to go onto the next step tonight after work.

[Tony Meola]

That looks like the transom will come apart first.

[Rocky]

Those are looking real nice Matt. There won't be any pulling away of the plates now, and when faired, will look part of the boat, nice job. The turning of the 1708 around those inside corners, hugely strong.

[Carl]

I have to say I dislike epoxy when working with 1708 as I spent an enormous amount of time bubble busting and even with that still ending up with a bubble in the upper part of the starboard side.

Also the sharp corners on the plate are a bear to work the cloth. Cloth does not like making sharp bends, moving forward try knocking down the sharp corner with a grinder or...

That's a tip I missed till after I had a problem.

Polyester it does seem a bit easier, sometimes...

[ktm_2000]

I sanded down the area in the transom to prepare to put 1.5oz mat over everything and transition over to using vinylester based products so I could finish up with a gelcoat surface. It took a bit of playing around with the grinder and vise grips to get the screws I was using to fill the holes out because the epoxy and glass stuck to them quite well, but they did come out.

The thickness of glass of the stern cleats covering was different than that where I added the storage module so I cut chunks of 1.5oz mat to fill the area to the same thickness then 1 final piece to go over everything and match up to what I did on the hull sides. I think I did a better job on the starboard side getting the layers the right thickness and on the port side I will need to do some sanding or fairing to flatten things out.

https://photos.app.goo.gl/tBtptHYaPv8s6NzLA

I was painting the spashwell with gelcoat so I mixed up a bit more and coated the area with gelcoat, I do not expect this to be the final surface but wanted to fill the weave of the 1.5oz mat, it will get sanded flat and faired afterwards.

Starboard side
https://photos.app.goo.gl/6t9qLQxGgroaEBbZ6

Port side
https://photos.app.goo.gl/5FgAQGWRF5GtdtBu8

[Rocky]

Boy, your really on the ball Matt,
Coming along nicely. The fairing is the hardest part, for me at least.
Very time consuming. Ugly, pretty. Ugly, pretty. And repeat. And repeat! Then get out the kite string and see oop, low spot!
Have fun with it.