Muddywater,
Looks like you've done your homework. Let me throw some comments and suggestions at you.
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Originally Posted by muddywater
...we laid in 5 more layers of 1708 biaxial over the outer skin extending out over the corners.
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Quote:
Originally Posted by muddywater
...for the inner skin I decided to go with
1 layer 1708 (mat side facing the core)
3 layers of 24 oz triaxial (no mat)
1 layer of 1708 (mat side facing out)
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You've grasped a fundamental concept in the construction of cored laminates that most guys miss entirely. The strength in a cored laminate comes from the laminate, not the core. You built up the laminate on both sides of your transom core which will make it much stronger and more durable than a strong core with thin laminates. And as you say, you don't need mat if you're using epoxy resin.
Quote:
Originally Posted by muddywater
I would love to hear any opinions on how to improve my workflow because we are still pretty inefficient and I still have a deck to do.
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You said the stitchmat is hard to wet out unless it's horizontal. I agree. I use a wet out table and then roll or fold the wetted glass, move it to the layup, and roll it in with a grooved roller. That allows me to get the wet-out done quickly before the resin wants to kick. The real trick is to get your resin out of the mixing cup as fast as you can after mixing. During warm weather, resin builds heat fast in the cup, but once it's spread in a thin layer in the wetted glass, it doesn't build heat, so it doesn't kick as quickly. You can also chill your resin and hardener in a cooler or fridge until you're ready to mix. That will give you more working time.
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Originally Posted by muddywater
I made 2 plywood templates to make sure my fit was perfect ...
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For templates, use masonite. Works well and is cheaper than plywood.
Quote:
Originally Posted by muddywater
I have learned to be wary of some of the other sites though as I have seen some really bad info. On one site I recently looked at, some guy posted that all the strength comes from the chopped strand mat not the woven roving or axial cloth saying that it must be stronger since the fibers went in all directions. It was then taken as gospel by all the others there, and then rehashed by others quoting the so-called expert.
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The internet is full of incompetent X-purts. The strength in a FRP layup comes from the glass/resin ratio. The more glass you've got the stronger it is. Mat soaks up a bunch of resin relative to the amount of glass it contains. If an all mat layup had the best strength to weight ratio, all our boats would be laid up with a chopper gun.
It's nice to see someone doing good work on the first go. You've got to be smart enough to know what you don't know, and educate yourself before you try to tackle something you've never done before. Looks like you've done that.
Dave