Scarf Depth - Triton Recore

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Triton 185
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Scarf Depth - Triton Recore

Post by Triton 185 »

Hello,

I am about to vacuum bag (with Epoxy) the original skins down on my Triton. I will be using 1708 biaxial Mat to lay up the scarf between the joints in the skins. I have measured the thickness of two layers of biax to be a little less than 1/16" (3/64"). The total width of the scarf on two skins when butted together is 2 1/4",

My question is regarding the scarf joint depth and how many layers of biax do I need to make the joint strong enough? Do I grind to 80% of the thickness of the original skins or will 50% do because the biax and epoxy is much stronger than the original materials.

Thanks for any thoughts on this!
"The more you know, the less you need."
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Tim
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Re: Scarf Depth - Triton Recore

Post by Tim »

Grind to the depth that equals (or slightly exceeds) the total thickness of the new material you intend to install in the scarfed areas. Scarf/taper depth is always directly related to the thickness of the new material involved in the patch, not necessarily the full thickness of the old material.

2 layers of 1708 is typically sufficient for seams. The total thickness ought to be closer to 3/16" for 2 layers of 17 oz. biaxial fabric with mat backing, though (aka 1708). 1/16" sounds scant, unless we're not talking about the same material.

Have you considered installing entirely new material instead of reusing the old top skins?
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Triton 185
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Re: Scarf Depth - Triton Recore

Post by Triton 185 »

Thanks for the information Tim. The material I have must not be 1708, but rather a lighter weight. This material will take about 4 or 5 layers to make up the 3/16" thickness - which I will do. It is biaxial for sure though.

I am laying solid glass under the mast area and beam and any other location that fittings are located. I am using Divinycell and System 3 epoxy. The original core was strip planked balsa.

I considered laying up new material for the recore. I'm going to do the house with the old skins because I am working against the weather and ready to go that way. I am considering using new material when I do the decks next spring or if we get another warm spell before winter here in Canada. We are expecting snow and below freezing this weekend. I have a tarp and large electric heater set up to get a full cure in time.

If re-using the outside skins is the deck not as strong or stronger than the original? I would imagine using new biax instead of re-using the skins would result in a stronger structure. Is this necessary or ideal?

Thanks,

Stephen
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Chris Campbell
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Re: Scarf Depth - Triton Recore

Post by Chris Campbell »

This is a bit off topic - but where in Canada are you that's expecting snow and below freezing? We've got warm an sunny on Saturday and warm and wet on Sunday here in Halifax... Just curious!

Thanks,

Chris
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Rachel
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Re: Scarf Depth - Triton Recore

Post by Rachel »

Stephen,

On the thickness and layers issue: Are you using biaxial cloth that is simply that alone? Or are you using "biaxmat," which consists of a layer of biaxial cloth stiched to a layer of mat (the "1708," for example, would mean 17 oz. biaxial cloth stiched to 8 oz. mat). If you're using biaxial cloth that does not have the mat attached to it, perhaps that could account for the thinner layers.

Rachel
Triton 185
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Re: Scarf Depth - Triton Recore

Post by Triton 185 »

This is a bit off topic - but where in Canada are you that's expecting snow and below freezing? We've got warm an sunny on Saturday and warm and wet on Sunday here in Halifax... Just curious!
I'm in Calgary. Being so close to the mountains the temperature really drops at night. It has been a great fall and quite warmer than normal. It is not unusual to get snow in September.
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stone
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Re: Scarf Depth - Triton Recore

Post by stone »

Wow , just a comment as well on the weather.Yesterday was actually the first day I had been to my boat since spring. Its finally getting to be boat working weather where I am. Hard to imagine you are dealing with low temps. Good luck.

Hi Rachael ,1708 has a 3/4oz mat stiched to it .
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Rachel
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Re: Scarf Depth - Triton Recore

Post by Rachel »

Stone,

Thanks for correcting me. I thought I "knew" that the mat was 8 oz, but I must have made the assumption that since the "17" in 1708 meant the biaxial cloth was 17 oz, that the "08" would mean the mat was 8 oz. I'm sorry if I led anyone astray.

Rachel
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