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F24 Lower longeron - Adhesive

Posted: Sun Jun 13, 2010 9:33 am
by Frank
'The time has come to fix the Balsa fairing strips to the lower longerons.
The Structural repair manual says to use 'Plastikon' - long gone I think.
What would you good folk use? bearing in mind that the fuselage frame has been powder coated and the balsa fairing may have to be removed some time in the distant future - I'm thinking of 3M contact adhesive but am a little concerned that it may attack the powder coating and I do not have any 'gash pieces'to test on.
Also - would it be wise to seal the balsa prior to covering and if so would Stits epoxy varnish be suitable?
Many thanks
Frank Cox
F24 R46 Argus G-BCBL'

Re: F24 Lower longeron - Adhesive

Posted: Mon Jun 14, 2010 1:16 pm
by ROBERT COON
'Hi Frank,
How's the headliner and side panels coming along?  In regards to the lower longerons, I offer some experience having gone through this process a year ago when we were covering the fuselage.  It would be wise to at least scuff sand the frame to where the longerons will attach.  I'm not sure if the powder coating will pull away, but our two part polyeurethane did.  We covered the fuselage in two panels, bottom first followed by top envelope.  On the belly, when the polyester was ironed, the tension created alot of pressure pulling on the longerons, which, in our case, pulled them away from the frame, along with the paint.  The fix was to sand the frame, re-attach the balsa longerons with T-88 (2 part epoxy) and clamp.  When the sides and top were covered the reverse pull of the fabric tightening set the longeron in place - pulled from two directions now.  We haven't had any problems since.
I did use three coats of polyeurothane varnish with a top coat of epoxy varnish before covering and that worked well, even though it's a bit of over kill.  Hope this helps.
Regards.
Bob
UC-61K Argus III
HB-690
F24-R46 

--- On Sun, 6/13/10, Frank wrote:


From: Frank
Subject: [fairchildclub] F24 Lower longeron - Adhesive
To: fairchildclub@yahoogroups.com
Date: Sunday, June 13, 2010, 10:32 AM


 



The time has come to fix the Balsa fairing strips to the lower longerons.
The Structural repair manual says to use 'Plastikon' - long gone I think.
What would you good folk use? bearing in mind that the fuselage frame has been powder coated and the balsa fairing may have to be removed some time in the distant future - I'm thinking of 3M contact adhesive but am a little concerned that it may attack the powder coating and I do not have any 'gash pieces'to test on.
Also - would it be wise to seal the balsa prior to covering and if so would Stits epoxy varnish be suitable?
Many thanks
Frank Cox
F24 R46 Argus G-BCBL








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'

Re: F24 Lower longeron - Adhesive

Posted: Mon Jun 14, 2010 2:58 pm
by F.J. & D.A. Cox
'Hi Bob,

I'm just finishing off the wiring and while I'm waiting for parts I'm fitting the balsa lonerons - much cutting and sanding!. The only balsa I could get was from model supply shops in 3ft. sections - dosen't seem to be a problem maiting them up as I go along.

Then the plan is to tackle the head lining and side panels. - I've actually played around with your pattern to see how things fit and line up - could be a tricky job getting it right first time!.

Thanks for the info - I actually have envelopes - maybe it could help the pulling problem if I shrank the whole thing (very carefully) such that nothing actually moved over the balsa although I understand that keeping any seams in an envelope straight could be a problem - (maybe some covering experts would like to come in here) the reason I was considering using contact adhesive was to hold the balsa to give it some small degree of movement and allow relatively easy removal for repairs etc. - not by me I hasten to add!

Whilst I'm here - do you know of a supplier of 'Cotton Duck' - for the baggage bay - I'm having problems getting the correct weight and weave over here.

With best regards and hoping '690 is getting closer to 'slipping the surly bonds of earth'

Frank
----- Original Message -----
From: ROBERT COON
To: fairchildclub@yahoogroups.com
Sent: Monday, June 14, 2010 8:16 PM
Subject: Re: [fairchildclub] F24 Lower longeron - Adhesive



Hi Frank,
How's the headliner and side panels coming along? In regards to the lower longerons, I offer some experience having gone through this process a year ago when we were covering the fuselage. It would be wise to at least scuff sand the frame to where the longerons will attach. I'm not sure if the powder coating will pull away, but our two part polyeurethane did. We covered the fuselage in two panels, bottom first followed by top envelope. On the belly, when the polyester was ironed, the tension created alot of pressure pulling on the longerons, which, in our case, pulled them away from the frame, along with the paint. The fix was to sand the frame, re-attach the balsa longerons with T-88 (2 part epoxy) and clamp. When the sides and top were covered the reverse pull of the fabric tightening set the longeron in place - pulled from two directions now. We haven't had any problems since.
I did use three coats of polyeurothane varnish with a top coat of epoxy varnish before covering and that worked well, even though it's a bit of over kill. Hope this helps.
Regards.
Bob
UC-61K Argus III
HB-690
F24-R46

--- On Sun, 6/13/10, Frank wrote:

From: Frank
Subject: [fairchildclub] F24 Lower longeron - Adhesive
To: fairchildclub@yahoogroups.com
Date: Sunday, June 13, 2010, 10:32 AM



The time has come to fix the Balsa fairing strips to the lower longerons.
The Structural repair manual says to use 'Plastikon' - long gone I think.
What would you good folk use? bearing in mind that the fuselage frame has been powder coated and the balsa fairing may have to be removed some time in the distant future - I'm thinking of 3M contact adhesive but am a little concerned that it may attack the powder coating and I do not have any 'gash pieces'to test on.
Also - would it be wise to seal the balsa prior to covering and if so would Stits epoxy varnish be suitable?
Many thanks
Frank Cox
F24 R46 Argus G-BCBL

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