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Old 09-09-2009, 20:25   #1
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Epoxy Winch Pads?

I need to make some new winch pads for new winches that will go in new locations.
They are on a odd slope and will be an oval shape at the bottom and round at the top.
What I have done so far is cut plywood at the diameter that I need for the bottom of the base (template with fastener hole layout) and then drilled 3 of the 6 holes for the bolt layout, but only with 1/4" holes. I then took 1/4" bolts and with the edge that will be touching the high side of the combing through bolted the plywood template to the combing. I then put 2 other bolts into the plywood and with supporting nuts leveled/positioned the plywood base template. In the center of this template I cut a 4" hole to later pour epoxy into. I have made a slightly larger and slightly oval template that I have slid down over this so that it is tight to the sloped combing. I'm now planning to take sheet plastic (a little thicker than a plastic bleach bottle) and wrap it so that the bottom is inside the bottom ring/template and then fasten the top (perhaps tack it or wrap it with tape) to the smaller (proper winch base size) top ring/template.
This will give me the sloped bottom, level top and have the slight cone shape that I'm looking for.
And now for my question:
I'm thinking of filling this form with a mixture of West Epoxy (very slow hardner) and cut up fiber glass strands (cut my self).
In terms of the size/mass of this base, it is approximately 9" diameter with one side touching the sloped combing and the thicker side being approximately 2 1/2" high. I will then paint it and the hope is that it will appear to be part of the boat.
Dose anyone see a problem with this method?

Let me know if you would.

Thanks,
Extemp.
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Old 09-09-2009, 21:00   #2
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Extemp,

The epoxy casting mixture should be resin, slow hardener (not very slow) and high density filler to ketchup consistency. You have to layer the cast, pouring layers of 10 mm (3/8") when the previous layer is just starting to cool down. You do not need to add any fiberglass with this mixture (it even better without because you can't wet it out good enough with the mixture, and get into other trouble when you wet it out before putting it in).

The reason of not using the very slow hardener is strength I think. The biggest problem is going to be the heat. Put ice around the mold and start with thin layers, increasing each new layer with one pump resin/hardener until you think it gets hot enough. Too much and it starts boiling, which weakens the cast (yes, I had that once and had to start over ;-)

Make sure you have enough epoxy & filler because you want to finish it completely before cure.

All above is from memory, I'm pretty sure it's correct but can look it up if you have doubts. It is described in their book.

Don't forget to wax the mold...

You could cast with threaded rods in place if you dare.

After cure, coat it with epoxy/hardener mix before sanding (so pores are filled with epoxy, not with sanding dust). After that, you can use a fairing mixture with microlight filler if needed. The last coating must always be resin+hardener so if you do any fairing, you must coat again. I would add some white pigment to last coat to help the painting (assuming it's gonna be white) and to provide some UV protection before the paint goes on.

After that, the hard part: painting it. Awlgrip 545 primer 2 layers and the "normal/standard" awlgrip finishing coat. Don't use the awlgrip 2000 etc. because it's weaker. I never like the painting part.

ciao!
Nick.
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Old 10-09-2009, 06:39   #3
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Extemp,

Did you consider making a male plug out of styrofoam, pouring Plaster- of- Paris (or similar) around it in a container, and then stratifying you epoxy mix in the mold as Nick suggests. I have done this a number of times for all sort of boat items. True-ing up stanchion bases, windlass alignment pads, winch mounts on curved mast surfaces, turtles for offset hatches, etc.
Good luck
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Old 10-09-2009, 19:32   #4
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Quote:
Originally Posted by s/v Jedi View Post
Extemp,

The epoxy casting mixture should be resin, slow hardener (not very slow) and high density filler to ketchup consistency. You have to layer the cast, pouring layers of 10 mm (3/8") when the previous layer is just starting to cool down. You do not need to add any fiberglass with this mixture (it even better without because you can't wet it out good enough with the mixture, and get into other trouble when you wet it out before putting it in).

The reason of not using the very slow hardener is strength I think. The biggest problem is going to be the heat. Put ice around the mold and start with thin layers, increasing each new layer with one pump resin/hardener until you think it gets hot enough. Too much and it starts boiling, which weakens the cast (yes, I had that once and had to start over ;-)

Make sure you have enough epoxy & filler because you want to finish it completely before cure.

All above is from memory, I'm pretty sure it's correct but can look it up if you have doubts. It is described in their book.

Don't forget to wax the mold...

You could cast with threaded rods in place if you dare.

After cure, coat it with epoxy/hardener mix before sanding (so pores are filled with epoxy, not with sanding dust). After that, you can use a fairing mixture with microlight filler if needed. The last coating must always be resin+hardener so if you do any fairing, you must coat again. I would add some white pigment to last coat to help the painting (assuming it's gonna be white) and to provide some UV protection before the paint goes on.

After that, the hard part: painting it. Awlgrip 545 primer 2 layers and the "normal/standard" awlgrip finishing coat. Don't use the awlgrip 2000 etc. because it's weaker. I never like the painting part.

ciao!
Nick.
Thanks Nick.
Sounds good.
Quote:
Originally Posted by Blue Stocking View Post
Extemp,

Did you consider making a male plug out of styrofoam, pouring Plaster- of- Paris (or similar) around it in a container, and then stratifying you epoxy mix in the mold as Nick suggests. I have done this a number of times for all sort of boat items. True-ing up stanchion bases, windlass alignment pads, winch mounts on curved mast surfaces, turtles for offset hatches, etc.
Good luck
I can see where that approach would make sense in some applications, but in this case, why would I take the time to make a mold which would have to be faired and finished to make perfect when I can cast in place and make that good?
Am I missing something?
Could be.

Let me know.

Thanks,
Extemp.
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Old 12-09-2009, 09:30   #5
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Extemp,

I would add some white pigment to last coat to help the painting (assuming it's gonna be white) and to provide some UV protection before the paint goes on.
ciao!
Nick.
Any suggestions as to what to use for "white pigment"?

Thanks,
Extemp.
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Old 12-09-2009, 10:18   #6
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Originally Posted by Extemporaneous View Post
Any suggestions as to what to use for "white pigment"?

Thanks,
Extemp.
That's easy: West System White Pigment Epoxy additive ;-)
But I think gel coat pigment will work too.

ciao!
Nick.
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Old 18-09-2009, 15:17   #7
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That's easy: West System White Pigment Epoxy additive ;-)
But I think gel coat pigment will work too.

ciao!
Nick.
Thanks Nick.
So far so good. The pads are cast and turned out well. I will have to a small amount of fairing though.

A question from your previous post.
You mention "Awlgrip". Do you prefer their products to Interlux, and if so why?

Regards,
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Old 18-09-2009, 22:27   #8
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Extemp,

Yes, there's always fairing unfortunately...

Well, both paints are Dutch products from Akzo Nobel so both are good (paint is a real historical product of Holland, being the first nation to export it as a ready to use product). I just used BilgeKote and was really impressed with it.

When you take their top-products, both are LPU based so I would expect very similar performance over time. That, said, I think the awlgrip 545 primer is the best primer, even if you use another topcoat. I've been told that for brushing Sterling LPU works better than Awlgrip but hey, that's a yankee product! ;-) My problem with Sterling is that I never found their website. I found one for Europe, it's a single page with their address and phone number... in Belgium!

It's my feeling that the Interlux 2-part LPU is very similar to the Sterling. It's also my feeling that Awlgrip will last longer and holds the gloss longer, but is more difficult to apply by brush or roll&tip. So, if you're spraying: Awlgrip and if you're brushing: Interlux (or Sterling if you really want ;-)

It's also all nasty stuff before it cures. My wife stopped me painting our new fridge boxes with Awlgrip because she was sure I was about to die from it. I had to hire someone like if he could stand it better...

cheers,
Nick.
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