Re: [Paddlewise] pressurize the boat / glass construction

From: Tord Eriksson <tord_at_tord.nu>
Date: Sun, 8 Apr 2007 17:02:58 +0200
On Sunday 08 April 2007 05:28, Doug wrote:
> I noticed the Epic website mentioned post-curing at elevated
> temperatures. I'm still not sure how important this is. The guys who
> build the strip boats usually elevate temperatures temporarily in musty
> basements or mid-winter workshops - but that's just to finish off
> curing.

The important thing is elevated temperatures to kick off the curing
and to make the epoxy more fluid - people vacuum-bagging their
their stuff (like (model) airplane makers, from one-offs to series 
production) often use elevated temperatures to get an even,
reliable glue joint.

Some 3M spray glues, like #77, need heat to activate fully, thus
is nice to work with: First you spray, sparingly, with #77, let it dry
(an hour or more - all solvents should have evaporated) till it is no 
longer tacky, then apply the glass cloth/CF/Kevlar, and heat (a 
small iron is ideal, or you could use a hair dryer), bit by bit, till the 
glass (or whatever you use - veneer, maybe?), is applied just as 
you want it - any mistake: apply heat and redo, till OK.

Then slow-curing epoxy, a release film, like Mylar (or similar), 
and then into the vacuum bag, tape it closed, attach the hose 
and then attach the pump, and now some heat - mirror-smooth 
finish is the norm!

Some do entire boats, or complete bar tops, this way, saving lots 
and lots of time and money! 

If you do an entire kayak this way I guess you have to fill it
with dry sand, or some other rigid stuff, that can't compress!

You have to do the inside first, of course, before progressing
to the exterior. Or make a big flotation bag, that fills the entire
interior, that is slightly pressurized, to make a bag-in-a-bag,
so to speak!

Tord

Tord
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Received on Sun Apr 08 2007 - 08:00:20 PDT

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