Is yours a classic Tony?
Regards
Brian Davies
-----Original Message-----
From: owner-europa-list-server@matronics.com
<owner-europa-list-server@matronics.com>
On Behalf Of Tony Renshaw
Sent: 30 May 2020 14:22
Subject: Europa-List: Re: Europa-List Digest: 2 Msgs - 05/29/20
Gidday,
Well with much trepidation and about a 4 hour reduction to 20 degrees Celsius
ambient
temperature I opened up my little refrigerator panelled camper van box
thingy and FaceTimed it to Kingsley Hurst to share in the anguish. It worked,
it all survived and my straight edges are all still 100% as they were before,
straight.
Thanks for the input & advice fellas, now to build a box for the wings and
moreso
work out how best to distribute the heat around the wings, using the same heater
but an entirely different shaped box, less amenable to a circular airflow.
Tony R.
> On 30 May 2020, at 4:39 pm, Europa-List Digest Server
> <europa-list@matronics.com>
wrote:
>
> *
>
> =================================================
> Online Versions of Today's List Digest Archive
> =================================================
>
> Today's complete Europa-List Digest can also be found in either of the
> two Web Links listed below. The .html file includes the Digest formatted
> in HTML for viewing with a web browser and features Hyperlinked Indexes
> and Message Navigation. The .txt file includes the plain ASCII version
> of the Europa-List Digest and can be viewed with a generic text editor
> such as Notepad or with a web browser.
>
> HTML Version:
>
>
> http://www.matronics.com/digest/digestview.php?Style=82701&View=html&Chapter
> 20-05-29&Archive=Europa
>
> Text Version:
>
>
> http://www.matronics.com/digest/digestview.php?Style=82701&View=txt&Chapter
> 20-05-29&Archive=Europa
>
>
> ===============================================
> EMail Version of Today's List Digest Archive
> ===============================================
>
>
> ----------------------------------------------------------
> Europa-List Digest Archive
> ---
> Total Messages Posted Fri 05/29/20: 2
> ----------------------------------------------------------
>
>
> Today's Message Index:
> ----------------------
>
> 1. 01:45 AM - Post curing, My Saga (Tony Renshaw)
> 2. 07:36 AM - Re: Post curing response (Kelvin Weston)
>
>
>
> ________________________________ Message 1
> _____________________________________
>
>
> From: Tony Renshaw <tonyrenshaw268@gmail.com>
> Subject: Europa-List: Post curing, My Saga
>
>
> Gidday Bud, Phil, Pete, Kingsley, and co.,
> Post curing, what a headache.!
> The Ampreg 20 by Gurit as Bud said requires post cure to gain its full
> strength,
> nevertheless of course it gets hard, goes rigid at room temperature and years
> later with fluctuating temperatures, one could think its ok. My conclusion is
> that the 50 degrees for 16 hours is mandatory if you want the full design
> strength,
> however like all certification requirements there are safety factors you
> eat into or make obsolete if you dont. The post cure increases one of the
> strength
> characteristics by 45 %, thats a lot!
> So, Im of the view you can post cure anytime after construction and 20 years
of
> fluctuating temperatures unless they are probably up over 80% of the desired
> temperature, repeatedly, and for extended duration each heat cycle, wont
> achieve
> the same. Ill be honest, my flight controls are that age too. Im worried, they
> are cooking as I speak, have been for 8 hours, and I have two temperature
> indicators saying one thing, and a Weber dual temperature food probe saying
> 10%
> more, the first 2 in the mid forties, the Weber meat probes, one at 53, the
> other 54. The temperature sourcing is at the top of the controls surfaces.
> The
> actual heater is set for 49 degrees, is mounted 200 mm from the roof, and as
> it contains the heat sensor I find it hard to believe the temperature could be
> 8 degrees hotter a couple of feet below the heater, this would be unlikely.
> Anyway, Ill tell you in the morning when I open the door.... yes, I have been
> unable to visually monitor anything. If its all melted, keep chainsaws away
> from
> me!
> Bud, I got to read what you said and yet in the master email your response was
> all gobbly-gook. This used to happen to me with Graham Singletons emails too,
> I never worked it out but Kingsley sent it through to me so I read what you
> have
> said.
> Thanks fellas, wish me luck when I open the door tomorrow morning.
> TR
>
>
> ________________________________ Message 2
> _____________________________________
>
>
> Subject: Europa-List: Re: Post curing response
> From: "Kelvin Weston" <kelv@kdweston.biz>
>
>
> Gents
>
> The Europa Build Manual calls for a post-cure, see Chapter 37, Page 2, which
states:
>
> "The first thing that you need to do with your flying surfaces is post-cure
> them
> at a temperature between 40 - 50C. This will improve their strength and cook
> off any remaining volatiles and moisture within the epoxy system.
> Make a simple oven with foam blocks, timber or sheets and an electric fan
> heater
> and cure your flying surfaces for 8-10 hours.
> Do take care not to get them too hot and make sure that they are fully
> supported."
>
> The Ampreg 20 and 21 datasheets from Gurit shows an initial cure at a minimum
of
> 18C (ideally 24hrs at 21C) followed by an elevated post-cure of 5 hours at 70
> - 80C or 16 hours at 50C.
>
> The datasheet also states:
> 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.
> When post-curing it is recommended to use a ramp rate of 10 degC/hour when
> heating
> from ambient to the post-cure temperature, to ensure that the thermal
> performance
> of the laminate stays ahead of the oven temperature. Higher ramp rates
> may result in the resin softening and distortion of the part.
>
> The resulting specs with standard hardener for Ampreg 20, 21 and 30 are all
> very
> similar and result in a Tg of around:
> 58C - Room temperature cure (28 days at 21C)
> 73C - Elevated post cure (16hrs at 50C)
>
> The ultimate Tg for Ampreg 20 and 30 is stated as around 98C. Ampreg 21 was
slightly
> lower at 91C
>
> --------
> Regards
>
> Kelv Weston
> Kit 497
> kelv@kdweston.biz
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=496570#496570
>
>
>
>
>
>
>
>
--
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
|