Thanks Jonathan, Bud, William, and Lance,
I trialed my setup using my refrigerated van modified camper, cranked it up to
48 degrees Celsius, and now ready to do it properly after considering and making
a few changes, like changing my heating source from radiant to ceramic and
fan assisted, to minimize any thermal gradient effecting the closest component,
even though I am using a fan to swirl around the interior airflow. I do plan
on following Gurits technical data sheet for Ampreg 20, 16 hours at 50 degrees
Celsius.
I vaguely recall and would like to ask, can the post cure wait till after wing
filling?
I believe not, but have this lingering memory that possibly it could wait.
Thanks again fellas.
Regards
Tony Renshaw
Sent from my iPad
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> Total Messages Posted Thu 05/21/20: 4
> ----------------------------------------------------------
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>
> Today's Message Index:
> ----------------------
>
> 1. 02:52 AM - Post curing question re trailing edges (Tony Renshaw)
> 2. 05:21 AM - Re: Post curing question re trailing edges (JonathanMilbank)
> 3. 04:24 PM - Re: Post curing question re trailing edges (budyerly@msn.com)
> 4. 07:09 PM - Re: Post curing question re trailing edges (William Daniell)
>
>
>
> ________________________________ Message 1
> _____________________________________
>
>
> From: Tony Renshaw <tonyrenshaw268@gmail.com>
> Subject: Europa-List: Post curing question re trailing edges
>
>
>> Gidday,
> I am considering post curing my tailplanes, ailerons and flaps and am
> wondering
> if people believe I should support the trailing edges, Im very happy with how
> straight they are at the moment, and I dont want to wreck them. I have T
> shaped
> aluminium straight edges I could use with double sided tape to stabilise them,
> or do people believe with 50 degrees for 15 hours it should be materially
> stable already and should just boil off the hardener? Any advice or
> suggestions
> about supporting these components would be appreciated, even whether I can
> simply
> prop them up so air can get completely around them, without any hotspots.
> Im concerned even whether having them rest on specific hard points could be
> an issue at 50 degrees.... personally I think not, but I dont want to find out
> the hard way.
> Regards
> Tony Renshaw
>
>
>
> ________________________________ Message 2
> _____________________________________
>
>
> Subject: Europa-List: Re: Post curing question re trailing edges
> From: "JonathanMilbank" <jdmilbank@yahoo.co.uk>
>
>
> Hi again Tony,
>
> When I did my post curing about 25 years ago, I didn't support the trailing
> edges
> as far as I can remember. But then I had the leading edges pointing down, so
> the trailing edges were up and unlikely to sag. Also I didn't post cure at 50
> degrees C, rather at 45 to leave a safety margin in case the heat control was
> inaccurate. The end result seemed / is satisfactory.
>
> To the best of my limited understanding the hardener doesn't "boil off", but
simply
> continues to react with the resin while facilitating the hardening process.
> I'm ready to be corrected in this matter. Ampreg 20 is the product which I
> was using.
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=496454#496454
>
>
> ________________________________ Message 3
> _____________________________________
>
>
> Subject: Europa-List: Re: Post curing question re trailing edges
> From: "budyerly@msn.com" <budyerly@msn.com>
>
>
> Being in Florida in a hot barn I never have done a heater post cure on the
> stock
> XS E glass aircraft, during the summer, but on the carbon fiber spar work in
> the winter, I did as the Gurit literature states to do a post cure to achieve
> proper cure of its slower hardeners.
>
> Never lay a freshly cured aileron flat between supports, it will sag. Always
allow
> a component to cure above 75F-80F for 8-12 hours minimum. Even Gurit medium
> hardener cures fully at these temperatures. To get a bit more stiffness one
> should post cure Ampreg 20 series epoxy used in thin components laid up with
> thin glass over foam. Aeropoxy 2032/PH3660 fully cures at room temp in 8-12
> hours and for those very thin components exposed to desert sun, a heat cure to
> 120 F is recommended. Paint the component any color you want as long as it
> is white and you won't have issues with the glass parts deforming. Dark
> colored
> painted surfaces should be heat cured in a well supported mold or surface
> to preserve their final shape before heat curing in an oven (normally heated
> to about 140-150F) as the surface temperature will be quite hot for a dark
> blue
> painted surface, but a white painted surface will be cool to the touch even
> in direct sunlight, therefore high temp heat cure is not necessary for white
finished
> Aeropoxy parts.
>
> In Florida my metal building in the hot sun post cures even Ampreg 20 series
within
> one day at roughly 100-110F for 8 hours. Over a few weeks at these temps
> it really hardens the cure. For those in a hurry Gurit says 50C or 120F for
> 16 hours is sufficient for slow cure hardener (which really stays sticky for
a
> long time and does not deep cure without heat ((NASTY). Dark painted surfaces
> should be cured at a slightly higher temp for about 8 hours. The Gurit rep
> I contacted was comfortable with a room temp layup and cure of their medium
> hardener
> if the temps throughout the layup time and cure was accomplished over a
> few days at this warm room temp. But even if post cured at 50C, the thin
> glass
> structures like an aileron will not be stiff enough to be stored only
> supported
> on its ends in a horizontal position if stored in high heat. He suggested
> that thin parts be stored long axis horizontal with the parts either vertical
> (TE down or up) if supported only on its ends or just stack it vertical
> leaning
> against the wall perfectly vertical.
>
> PTW Aeropoxy preferred all components be supported fully if stored at high
> temperatures
> (like dessert sun in a hot metal building) even if heat cured to 120
> F.
>
> Gurit has declared their Ampreg 20 series epoxy laminating systems obsolete.
Their
> new 3X series fully cures at a warm room temp 20C like Aeropoxy 2030. Post
> curing the laminate will greatly increase mechanical/thermal properties. The
> system will achieve similar properties with a cure of 5 hours at 70 - 80C or
> 16 hours at 50C. The latter temperature is easily achievable with low cost
> heating
> and insulation techniques.
> The post cure need not be carried out immediately after laminating. It is
> possible
> to assemble several composite components and post-cure the
> entire assembly together. It is recommended, however, that elevated
> temperature
> curing should be completed before any further painting /
> finishing operations. Furthermore, care should be taken to adequately support
the
> laminate if it is to be post cured after demoulding, and the
> laminate must be allowed to cool before the support is removed.
>
> Bottom line: Properly support your components while curing, post curing, and
in
> storage.
>
> Best Regards,
> Bud Yerly
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=496457#496457
>
>
> ________________________________ Message 4
> _____________________________________
>
>
> From: William Daniell <wdaniell.longport@gmail.com>
> Subject: Re: Europa-List: Post curing question re trailing edges
>
> I made supports/cradles from eps
>
> William Daniell
> LONGPORT
> +57 310 295 0744
>
>>>> On Thu, May 21, 2020, 05:55 Tony Renshaw <tonyrenshaw268@gmail.com> wrote:
>>>> Gidday,
>> I am considering post curing my tailplanes, ailerons and flaps and am
>> wondering if people believe I should support the trailing edges, I
> =99m very
>> happy with how straight they are at the moment, and I don=99t want
> to wreck
>> them. I have T shaped aluminium straight edges I could use with double
>> sided tape to stabilise them, or do people believe with 50 degrees for 15
>> hours it should be materially stable already and should just boil off the
>> hardener? Any advice or suggestions about supporting these components wou
> ld
>> be appreciated, even whether I can simply prop them up so air can get
>> completely around them, without any hotspots. I=99m concerned even
> whether
>> having them rest on specific hard points could be an issue at 50
>> degrees.... personally I think not, but I don=99t want to find out
> the hard
>> way.
>> Regards
>> Tony Renshaw
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