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To: flyrotary@lancaironline.net
Date: Sun, 19 Jun 2005 20:22:37 -0400
Subject: Re: [FlyRotary] Six-Port Intake Progress (tube molds)
Message-ID: <20050619.202238.2332.3.JBKER@juno.com>
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From: WALTER B KERR <jbker@juno.com>


On Sun, 19 Jun 2005 13:31:32 -0600 "BillDube@killacycle.com"
<billdube@killacycle.com> writes:

>         Someone on the list suggested using bicycle inner tubes 
> filled with sand 
> to model the runners. This worked pretty well for the crude model 
> that I 
> needed. I cut the tubes slightly longer than the required length, 
> put ~ 10 
> gauge aluminum wire down the middle, filled the tubes with perlite 
> (from 
> the garden store) and then sealed the ends.
> 
>         I was able to insert the tubes into the ports and then bend 
> them into the 
> correct shape so they would join the main intake at the correct spot 
> and 
> would also line up with the injectors.
> 
>         Next, I'll measure the bends and build the CAD model.
> 
===================================================
Bill,  I used the bicycle tubes to make fiberglass runners. Look at the
www.rotaryaviation.com site and you can see photos under Bernie's RV9A
project. I used PVC pipes the ID of what I wanted the runners and the
length of  the runners. Spit the pipe longways, tape back with duct tape
on outside. Insert a peice of bike tube that is smaller in diameter than
runner. Tie wrap end shut, fill tube with sandblasting sand, give a shot
of shop air, and continue filling until up to end of pipe. Tie wrap off,
remove PVC. You can now shape this sausage into whatever shape you
desire. 

No CAD required, you now have the mold. Shoot the mold with PAM or some
other separating agent and wrap with F/G. When cured dump the sand and
remove the intertube. You will have a very smooth inner surface. Can
finish the outside later if it produces the desired results

Bernie, off to Bahamas tomorrow to do volunteer construction, yuk hot and
no AC at night!