Fillets vs. Cleats

[Dan_Smullen]

Because I love a discussion among the experienced, I'm bringing this up from my build thread.

I guess the 2 most popular schools of thought applied to joining 2 pieces of material together perpendicularly, are cleats or fillets/tabbing.

Both would not exist if each did not occupy a place of propriety. Each with its pros and cons, but each best suited for different situations. Let's assume both examples below are completed using epoxy thickened with with wood flour and cabosil. Cotton fibers or milled fibers in the mix, I believe, would improve the properties of each.

Regarding joining deck/gunwale cap to the tops of frames, I chose fillets and tabs, but would like to hear other opinions whether or not cleats would be more resilient.

I believe the fillet and the glass provide a more resilient joint because of the glass. Although the cleat provides more glue surface, I believe there is always the potential for the bond between frame and cleat to crack.

Picture below for demonstration. Please discuss!

[rbecker08]

I do not claim expertise or to be experienced but I agree with you on fillets with glass for different reasons. I have better positioning that way and get there faster using fillets. For cleats I will always have squeeze out on the top that must be sanding flush before the next layer is attached, basically adds a step for me where as the fillet and glass is be completed in one pass. If i need more strength I use more glass. Cleats are useful when I don't have access to the joint after completion.....like attaching the sole but I prefer glass. Very curious on others opinions too, should be a good topic.

[Fuzz]

I feel like the amount of glue surface is key to making to joint hold up. In either case quality of work plays a huge part. Did you get a good bond? In this case where you are glueing down decks or gunwales I would go for cleats. My reason is it would be much faster and easier to use cleats than it would be to try and fillet and glass. If the joint had easy access and was visible I would fillet and tape.
Having ripped a few boats apart I have seen some interesting stuff come from so called well built boats. Both good and not so much. I have seen tabbing that was so well attached it acted like a primary bond. I have also seen tabbing that could be popped loose with a pry bar with little effort.

[silentneko]

I think you are making it to complicated. Fillets and glass are for areas you can easily access (hull, stringers, transom...) during the build. Cleats are for areas you can't, like when laying a floor or deck down.

[VT_Jeff]

Fillets and glass are for areas you can easily access (hull, stringers, transom...) during the build. Cleats are for areas you can't, like when laying a floor or deck down.

This was my exact impression as well, and I think it was the route Dan was planning, until some voices indicated that he should be using cleats.

[jbo_c]

I’m with Neko and Jeff. I’ll never cleat where I can reach to fillet and glass.

Jbo

[Matt Gent]

Same here. Only place I've used cleats is to temporarily support the panel before putting in the fillet (and I often use local cleats for that), or for blind assemblies.

[fallguy1000]

All about access. If you don't have good access; use cleats.

[TomTom]

Forgive me but I never noticed you had glasses and filleted in your original post. Yes that will be as strong as the cleats - it’s strong enough to hold the frames/ stringers to the hull, so it should work fine there. If it was me, I would glass the topside of the gunwale as well. Both at the butt joint to prevent it flexing and also to prevent checking.

[OneWayTraffic]

I'd probably cleat under the gunwale. Overly strong and no need to glass upside down. For my cabin I'm going to stitch it on the boat, glue seams then remove for tape and epoxy both sides. Can't do that with the gunwale so cleats it is. Upside down glassing isn't my idea of fun.