88 sea ray floor from hell

gm280

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Jun 26, 2011
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Peanut butter is some form of thickened resin. Usually, it's thickened with Cabosil, which is a fumed silica powder (sometimes called Aerosil). Usually, chopped fiberglass strands are added to give the mixture strength. Peanut butter made with cabosil dries very hard and is difficult to sand. Other thickeners, like microballoons, can be used if the hardened mixture needs to be sanded. For polyester resin, it's important to use thickeners that are waterproof; thickeners like talc or sawdust generally shouldn't be used with poly resin.

I would add that the proportions of each (thickener and fibers) are not very scientific or precise; most of us experimented and came up with a consistency that worked for us. One of the often cited videos is one created by Friscoboater when he was documenting his restoration. It's a good starting point: https://www.youtube.com/watch?v=N3kmr9ZctUo

Yes, PB or peanut butter is a mixture of Polyester Resin, Cabosil, Chopped 1/4" Strand Fiberglass, and of course MEKP. As an example I usually would mix 500ml of 435 Polyester Resin with 500ml (or there about, maybe more or less) add in the 1/4" cut strands of fiberglass to your liking, and the MEKP. Then mix it all up well and apply with a putty knife or plastic spreader. You can experiment with the percentage of everything to your liking. However, DON'T use Microballoons with Polyester Resins. Microballoons only work with Epoxy Resins. For polyester Resin you use Glass Bubbles. It does the same thing, but works with Polyester Resin.

So Microballoons with Epoxy Resin

Glass Bubbles with Polyester Resin
 

imp0ster

Petty Officer 2nd Class
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Apr 18, 2010
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189
Cabosil impregnated resins are used for packing areas, not for flowing out glass. I'm a fan of composites as you can tell by my build. They're the way to go and will never rot. They quiet the ride down, are far easier to cut and drop a respectable amount of weight. I had my body building buddy jumping up and down on the deck with 0 flex. Bulkheads are nidacore too so don't let people tell you it's not for vertical loads because that's BS. I've had 8 people on my floor in the back and no worries about it.

We had some egg harbor come through with a nidacore floor and the fighting chair bolted to it. Chair bolts ripped clean through because they never layered up behind the floor. The chair areas you'll want to glass some 2x4 behind the nidacore to hold the bolts.
 
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JASinIL2006

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Feb 10, 2012
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5,745
Yes, PB or peanut butter is a mixture of Polyester Resin, Cabosil, Chopped 1/4" Strand Fiberglass, and of course MEKP. As an example I usually would mix 500ml of 435 Polyester Resin with 500ml (or there about, maybe more or less) add in the 1/4" cut strands of fiberglass to your liking, and the MEKP. Then mix it all up well and apply with a putty knife or plastic spreader. You can experiment with the percentage of everything to your liking. However, DON'T use Microballoons with Polyester Resins. Microballoons only work with Epoxy Resins. For polyester Resin you use Glass Bubbles. It does the same thing, but works with Polyester Resin.

So Microballoons with Epoxy Resin

Glass Bubbles with Polyester Resin

I probably should have been more specific - there are 3M glass bubbles, also called microspheres, that are additives for poly resin. They make an easily sanded filler. The microballons are really for epoxy, as you noted. Thanks for the clarification.

In any case, PB made with poly resin, cabosil and chopped fibers will be quite strong, but very difficult to sand after it has cured. The microspheres in poly resin will make for easier sanding (but will also make for a less strong compound).
 

tpenfield

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Jul 18, 2011
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Looks like our OP Chadomosis has not posted anything since September and has not been on the forum in the past month. Not sure how this project is still going :noidea:
 

Woodonglass

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Dec 29, 2009
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25,932
Cabosil impregnated resins are used for packing areas, not for flowing out glass.

I'm going to respectfully disagree. Anyone that's ever tried to lay fabric in a "Square" corner understands the importance of having a nicely formed coved joint. Just like rounding the edges of the wood. Fabric just doesn't like to conform to a 90 degree angle. Composites are nice but not required for Inland Lake boats. High Performance ocean going craft could benefit from their usage. A Wood Cored structure on a boat, that has been correctly fabricated and glassed, will be strong and last for the life of the boat as long as it's maintained and cared for properly. ;)
 

imp0ster

Petty Officer 2nd Class
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Apr 18, 2010
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I always cut the material to fit the corners but I usually am dealing with different materials than standard wood and cloth. I agree 100% about a properly done wood project will last a lifetime as my father taught me this and has build probably over a hundred still going strong. However, from the factory, how many have you ever seen done right? The old Formulas were about the best I've seen. Even Cigarette and fountain cheaped the process and we've had several come through rotten as hell.

I actually call this the rotten boat forum. I hope he didn't give up on his project.

By the way it's nice to have people with different opinions or different methods of fabrication in a real discussion. I stay off most forums because of the angry know it all know nothings.
 

Woodonglass

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Dec 29, 2009
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"However, from the factory, how many have you ever seen done right"

This is exactly my point. When an iBoats restoration project is done, using the correct methods, and future maintenance and care are practiced then there is NO need for High Priced components. The wood will do a more than adequate job with a Great Cost Savings.
 

Red Herring

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Oct 1, 2012
Messages
536
I'm sure wood can work really well, but I understand the need to be without it as well.

My build is quite different, but I decided to not use any structural wood anywhere. Since my stringers and bulkheads were hollow and solid fiberglass I didn't have to demolish them. To maintain the form you can use pretty much anything, I've used closed cell polyurethane. It's easy (and messy) to tool. You just need to make sure that the glass is thick enough to carry the load by itself.

This usually does end up being heavier than plywood/glass. In my case it didn't matter, but inthe Searay it might.
 

Chadomosis

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Aug 3, 2016
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85
Looks like our OP Chadomosis has not posted anything since September and has not been on the forum in the past month. Not sure how this project is still going :noidea:

Back at it! Of course the wife's projects take some priority, but I'm back in the saddle. Floor is layed out, and ready to cut on a CNC. Just waiting for my quality plywood to be delivered.
 
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