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Re: Molded fiberglass kayak seat
By:mike allen
Date: 9/28/1999, 2:54 pm
In Response To: Re: Molded fiberglass kayak seat (Hank)

> Hey Mick,

> I think that sitting on the plaster saturated
> foam would squeeze out the plaster leaving the foam to rebound when you
> release the pressure.

Unfortunately, if the foam does not retain your butt's or yak's shape after it is set, then the idea is pretty much useless. But I wonder, how would it spring back? If the plaster is cross linked maybe the worst you get is a little bit of a fuzzy surface?

> The plaster may have be forced into the foam with out making it too thin.
> Plaster doesn't "dry" - it sets just like epoxy, water is the
> catalyst. The strongest plaster is made by (slowly) adding enough water to
> a bowl of plaster powder until the water starts to well up to the surface.
> Adding too much water causes the plaster to be weak and soft.

This sounds ominous, obviously it would be weak.

> The change is fairly fast but you
> would have to sit very still until the plaster was well set or it would be
> likely that the cross linking would be disturbed and the mold would be
> fragile until it was glassed.

This shouldn't be a problem - full plaster facial masks are made on people fairly easily.(breathe thru straws)

> In your suggestions you are trying to make a mold by containing the
> plaster with foam or plastic sheet. This can be done but it can also be
> very messy. A quick frame made of cardboard or wood is often easier.

The idea of containing the mold is to make it light and thin - say 1/2 - 1" thick. So that you can move it around , cut it and shape it easier. Or add more plaster etc. here and there to fix it, say extra burlap on the back. The idea of the two cheap plastic sheets (say 6 mil) is that all the mess is contained. Just throw the plastic in the garbage can.

OR SAY!!!!! Say you're wearing a tyvek suit over your wetsuit (an old worn out one or you wrap yourself up really well in plastic (sorta like on friday night - but leave out the vegetable oil!). Then take an old pair of jeans, cut off most of the legs, smush them thru a bowl of plaster and pull them one and sit down on some foam or any thing that's soft!( no! not the cat!) As they're setting up, cut from the waist down the tops of each leg so you can get out. Maybe a real light form? jeesh, maybe I should think this one through!

The idea of draping the 1st sheet over the coaming and also then the second is to automatically make a form that hangs over the coaming - that's if one wanted to do this - I don't, but might work.

But the top plastic sheet is not what one really needs. What you really need is something like a thin rubber sheet that will push down and not wrinkle when you sit in it to make a smooth form. Like (ahem) I tried to hook one of my condoms over the coaming lip, but it juuuuust barely wouldn't fit! ( of course it was long enough for my legs etc)....

I dunno, any reaction to any of this stuff Hank?

-mike

Messages In This Thread

Molded fiberglass kayak seat
Hank -- 9/27/1999, 12:30 am
Re: Molded fiberglass kayak seat
Paul G. Jacobson -- 9/28/1999, 9:09 am
Re: Molded fiberglass kayak seat
Dave Uebele -- 10/1/1999, 11:33 am
Re: Molded fiberglass / sand/plaster butt casting
darren -- 9/30/1999, 1:15 pm
sand/plaster butt casting
Paul G. Jacobson -- 10/1/1999, 2:37 am
Re: Mold release recipe
Hank -- 9/28/1999, 7:42 pm
Re: Molded fiberglass kayak seat
pete czerpak -- 9/27/1999, 1:58 pm
Re: Molded fiberglass kayak seat
Shawn Baker -- 9/27/1999, 12:43 pm
Re: Molded fiberglass kayak seat
Hank -- 9/27/1999, 1:03 pm
Re: Molded fiberglass kayak seat
Ross Leidy -- 9/27/1999, 9:44 am
Re: Molded seat picture
Hank -- 9/27/1999, 11:43 pm
Re: Molded seat picture
Shawn Baker -- 9/28/1999, 12:08 am
Re: Molded seat picture
Jay Babina -- 9/29/1999, 9:16 am
Plaster & Wax and lessons learned
Hank -- 9/28/1999, 9:12 am
Re: Plaster & Wax and lessons learned
Shawn Baker -- 9/28/1999, 10:21 am
Re: Plaster & Wax and lessons learned
Stan Heeres -- 9/28/1999, 12:10 pm
Re: Molded fiberglass kayak seat
Hank -- 9/27/1999, 12:48 pm
Re: Molded fiberglass kayak seat
mike allen -- 9/27/1999, 3:33 pm
Re: Molded fiberglass kayak seat
Hank -- 9/27/1999, 11:33 pm
Re: Molded fiberglass kayak seat
mike allen -- 9/28/1999, 2:54 pm
Re: Molded fiberglass kayak seat
Paul G. Jacobson -- 10/1/1999, 3:30 am
Re: Molded fiberglass kayak seat
Hank -- 9/28/1999, 5:11 pm
Re: Molded fiberglass kayak seat
Shawn Baker -- 9/29/1999, 6:27 pm
Re: Molded fiberglass kayak seat
Hank -- 9/30/1999, 12:34 am
Re: Molded fiberglass kayak seat
Shawn Baker -- 9/30/1999, 12:43 pm
Re: Molded fiberglass kayak seat
mike allen -- 9/30/1999, 2:34 pm
Re: Molded fiberglass kayak seat
Hank -- 9/30/1999, 3:48 pm
Re: Molded fiberglass kayak seat
Shawn Baker -- 9/27/1999, 2:19 pm