---------------------------------------------------------- Europa-List Digest Archive --- Total Messages Posted Wed 05/27/20: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:34 AM - Post curing response (Tony Renshaw) 2. 06:23 PM - Europa Capacitance Fuel Gauge (Tony Renshaw) ________________________________ Message 1 _____________________________________ Time: 05:34:20 AM PST US From: Tony Renshaw Subject: Europa-List: Post curing response 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 > On 22 May 2020, at 5:02 pm, Europa-List Digest Server 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 20-05-21&Archive=Europa > > Text Version: > > http://www.matronics.com/digest/digestview.php?Style=82701&View=txt&Chapter 20-05-21&Archive=Europa > > > =============================================== > EMail Version of Today's List Digest Archive > =============================================== > > > ---------------------------------------------------------- > Europa-List Digest Archive > --- > Total Messages Posted Thu 05/21/20: 4 > ---------------------------------------------------------- > > > 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 _____________________________________ > > > Time: 02:52:27 AM PST US > From: Tony Renshaw > 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 _____________________________________ > > > Time: 05:21:11 AM PST US > Subject: Europa-List: Re: Post curing question re trailing edges > From: "JonathanMilbank" > > > 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 _____________________________________ > > > Time: 04:24:38 PM PST US > Subject: Europa-List: Re: Post curing question re trailing edges > From: "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 _____________________________________ > > > Time: 07:09:33 PM PST US > From: William Daniell > 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 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 > ========== > ========== > ========== > ========== > ========== > > > ________________________________ Message 2 _____________________________________ Time: 06:23:34 PM PST US From: Tony Renshaw Subject: Europa-List: Europa Capacitance Fuel Gauge Gidday, In the process of trying to resurrect this project Ive wondered with my fuel system about the capacitance probe I fitted, and the head for it. I dont recall in my tidying up the workshop seeing it, nor recollecting what it looks like. If anyone can shed any light on this Id appreciate it. 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