We'll guys. It looks like one or two are interested in this shroud so I
bought some plaster of paris and I'm going to attempt to make a mold of
some sort. I may have to make a negative mold out of the glass and
resin instead but we'll see.
On the issue of the mold melting I would suggest that if cooled
properly the slight amount of this that touches the fins shouldn't be a
problem. What I have done is where the shroud goes between the outer
outside and second cooling fin i used a lay-up of RTV and bid. You can
buy at any auto parts store the red RTV stuff thats supposed to be good
up to 650F. lay a 1" X 10 strip of bid on plastic. Start working the
RTV into the bid just as you would a regular lay-up. I went 4 layers
thick then on the last one I didn't work any RTV on the outside of it
just worked it into the previous layer's excess. This will allow you to
glue the one side of this onto the side of the shroud. After the lay up
add another piece of polyurethane just like when you made tapes of bid
in the build. You can then let it cure about a half hour trim it to
shape and glue it with epoxy to the side of the shroud. This will stay
slightly flexible and be the part that touches the motor most. I could
be all wet here but a good friend of mine made all his own baffling on
his EZ using this stuff and it's still working 800+ hours. Here is a
picture of the shroud off the engine so you can see what I mean.
I'll keep yas'all posted as to my progress on the mold. Hey maybe I
should just make a bunch of these and sell em;) After all I am a
capitalist! Let the bidding start!
Regards,
Jeff R.
A258 - N128LJ / Gold Rush 176 hours and climbing slowly.
On Feb 10, 2009, at 8:04 AM, rampil wrote:
>
> The Tg for Aeropoxy is 194-196F depending on which hardener is used.
> see:http://pages.sbcglobal.net/ccanedy/aeropoxy_main.html
>
>
> The only Tg for polyester resins I could find on the web were in the
> range of 53C or about 112F
>
> Post cure baking pushes the layup towards the final Tg.
>
> Fortunately an engine shroud is small enough to actually bake with
> reasonable equipment, unlike a wing.
>
> --------
> Ira N224XS
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=229521#229521
>
>
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