Matronics Email Lists :: View topic

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

Post cure

Matronics Email Lists Forum Index -> Europa-List

View previous topic :: View next topic

Author Message

wdaniell(at)etb.net.co
Guest

Posted: Tue Sep 11, 2007 5:31 am Post subject: Post cure

As I understand it the blue foam bits need  post cure.



I believe this is 40C for a period of 24 hours.



Can this be done at a lower heat for longer time to get the same results?



Will



17:43

- The Matronics Europa-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Europa-List

josok-e(at)ukolo.fi
Guest

Posted: Tue Sep 11, 2007 6:05 am Post subject: Post cure

Hi Daniel,



No, it is not the blue foam, it's the epoxy that needs post curing. So also cure the wings, fuse ect. For the second part of the question, not entirely sure, please correct me if i am wrong, but if you cure at say 40 degrees, and the plane ever gets warmer, it will continue to cure with bad results for your beautiful finish...



Regards,



Jos Okhuijsen

Visit -  www.EuropaOwners.org

- The Matronics Europa-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Europa-List

rob(at)hyperion-ef.com
Guest

Posted: Tue Sep 11, 2007 7:40 am Post subject: Post cure

Short answer: NO.



I have no specific information about the Aeropoxy material (there is nothing

about this on the Aeropoxy web site) but in general for epoxies (and other

thermosetting polymers)the cure temperature affects the glass transition

temperature, T sub g.  While the polymerization reaction generally behaves

in the expected fashion, i. e., longer soak at lower temperature being

somewhat equivalent to a shorter soak at a higher temperature, the critical

factor here is to have the cure temperature high enough to cure the epoxy to

a high T sub g.



The glass transition temperature is actually not a specific temperature (the

melting point of ice for example) but rather a range of temperature through

which the material transitions from being hard and glassy to being soft and

rubbery.  The higher the cure temperature the higher the glass transition

temperature, and that translates directly to a stronger airframe when

ambient temperature is high.



Jos Okhuijsen is correct on both points - cure all parts with builder

applied epoxy and cure at a temperature higher than you expect to encounter.

Best regards,



Rob Housman

Irvine, California

Europa XS Tri-Gear

S/N A070

Airframe complete



--

- The Matronics Europa-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Europa-List

jeff(at)rmmm.net
Guest

Posted: Tue Sep 11, 2007 8:33 am Post subject: Post cure

Will,

I placed all my parts in my garage attic where the temps we're hovering 

around 140 to 150F. Couldn't get the wings up there so I laid them on a 

padded surface in my driveway in the direct sun after I applied the PPG 

high build primer. It was dark gray and the temps we're higher than 

they would have been after the white final coat so I figured they would 

get all the cure they need. After the all day sun I blocked sanded them 

down again before final prime and paint. This was my second summer on 

them and they're still looking good. I did the same thing for the 

fuselage. Hope this helps.



Jeff R.

A258 - N128LJ / Gold Rush 86 hours flying and climbing slowly.



PS. Anyone out there in USA know of a good hypnotist that could 

convince my wife's subconscious mind she loves to fly? ;o)

On Sep 11, 2007, at 10:39 AM, Rob Housman wrote:



[quote] 



 Short answer: NO.



 I have no specific information about the Aeropoxy material (there is 

 nothing

 about this on the Aeropoxy web site) but in general for epoxies (and 

 other

 thermosetting polymers)the cure temperature affects the glass 

 transition

 temperature, T sub g.  While the polymerization reaction generally 

 behaves

 in the expected fashion, i. e., longer soak at lower temperature being

 somewhat equivalent to a shorter soak at a higher temperature, the 

 critical

 factor here is to have the cure temperature high enough to cure the 

 epoxy to

 a high T sub g.



 The glass transition temperature is actually not a specific 

 temperature (the

 melting point of ice for example) but rather a range of temperature 

 through

 which the material transitions from being hard and glassy to being 

 soft and

 rubbery.  The higher the cure temperature the higher the glass 

 transition

 temperature, and that translates directly to a stronger airframe when

 ambient temperature is high.



 Jos Okhuijsen is correct on both points - cure all parts with builder

 applied epoxy and cure at a temperature higher than you expect to 

 encounter.

 Best regards,



 Rob Housman

 Irvine, California

 Europa XS Tri-Gear

 S/N A070

 Airframe complete



 --

- The Matronics Europa-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Europa-List

davidjoyce(at)doctors.org
Guest

Posted: Tue Sep 11, 2007 9:06 am Post subject: Post cure

William, The data sheet for Ampreg 20 (the resin supplied by Europa

throughout my build) with standard hardener gives the following for

differing post cure regimes:

  Post Cure     Flexural strength    Tensile Strength.   Glass transition

Temp

   Regime                 (MPa)

5hrs (at) 80 C.             159                    80

78 C.

16hrs (at) 50 C.           167                    85

71 C.

4wks (at) RT                126                   71

51 C.



 Clearly it's well worth while doing a 50 C. post cure, where the bits need

only simple support, as opposed to 80 C where without complex support there

is a risk of them ending up looking like a Salvador Dali painting! I did

mine by making an enclosure  from polystyrene sheets and heated by a hair

dryer, with thermometer stuck thru the polystyrene. Other resin systems I

have worked with, have much less benefit from post cure regimes and if you

are not using Ampreg it would be worth looking at the specific data sheet.

          Regards, David Joyce, G-XSDJ



---

- The Matronics Europa-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Europa-List

astills

Joined: 24 Apr 2007
Posts: 6
Location: Phoenix,Ariz

Posted: Tue Sep 11, 2007 9:10 am Post subject: Post cure

Jeff & Will,

While I was building mine I did basically the same but placed the wings in a

black plastic bag and let set in the sun all day.

the temps were in the 110 Deg F and have had no problems. However, I did the

same with the flying surfaces and did have a problem

on the ailerons. I had to pull them back off, straighten them out and then

re-cure them in an oven to 175 Deg F for a few hours. Have had no more

problems with them since then. It's amazing how hot these things get in the

sunlight on a hot day. I consulted with a "expert" on

the cure temps and he basically said to cure them at least 20 deg F over the

hottest temps you expect the surface to get to. While I was flying the

Diamond Katana, the sensor that is in the cockpit and has leads to the

outside surfaces was a no fly set off at 150 deg's f.

Al Stills

N625AZ

- The Matronics Europa-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Europa-List

wdaniell(at)etb.net.co
Guest

Posted: Tue Sep 11, 2007 9:22 am Post subject: Post cure

Thanks to all

Will



--

- The Matronics Europa-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Europa-List

Display posts from previous:

	Matronics Email Lists Forum Index -> Europa-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum