[NSRCA-discussion] Wing Cores

Fri Dec 28 06:41:59 AKST 2007

I used contact cement for many years but switched to epoxy after my first  
try with it.  I experienced the issue with the contact cement turning loose  
when it gets hot in the sun but the bigger issue for me was being able to keep  
the wing or stab straight as I was laying on the skins.  Seemed I always  got a 
bow or twist using the contact cement approach while the epoxy approach  gave 
me some time to get the cores and skins straight before it cured.

Don

In a message dated 12/28/2007 7:26:36 A.M. Pacific Standard Time,  
ejhaury at comcast.net writes:

I conducted some tests a few years ago with  different adhesives. Essentially 
equal size foam blocks to which 1/4" x 1" x  4" balsa pieces were glued to 
each side with Sorghum, 3M77, epoxy, and  Probond. After a 24hr. cure, adhesion 
(in tension)  was measured. Both  contact cements failed at the glue joint 
without pulling any foam beads. The  foam failed in both cases with the epoxy & 
polyU. My conclusion was  that the latter provided a good deal better adhesion. 
OTOH, I've successfully  built a lot of wings with the contact cements that 
provided good service.  

Earl

----- Original Message ----- 

From:  _Karl G. Mueller_ (mailto:kgamueller at rogers.com)  
To: _NSRCA Mailing List_ (mailto:nsrca-discussion at lists.nsrca.org)  
Sent: Friday, December 28, 2007 8:51  AM
Subject: Re: [NSRCA-discussion] Wing  Cores

I had used the contact cement method back in the 70's with  the 3M-77glue.
It worked great. But after a few years sitting out in the  sun the contact 
cement
would dry out and the sheeting would delaminate. This was  on a painted wing.
The sheeting would come up in bubbles and the only way to  fix this was to 
iron
it down with an iron set to just below the melting point  of the paint. This 
would
reactivate the glue again and the sheeting would stick  down to the foam core.
After that I changed to epoxy and never had any problems  like that again.
If you only have your plane for about 2-3 years it is not  a problem, but I 
usually
keep my planes for 6-8 years and that's when it will show  the problem of 
delaminating.

Karl G. Mueller
_kgamueller at rogers.com_ (mailto:kgamueller at rogers.com) 

----- Original Message ----- 
From:  _Jay  Marshall_ (mailto:lightfoot at sc.rr.com)  
To: _'NSRCA Mailing List'_ (mailto:nsrca-discussion at lists.nsrca.org)   
Sent: Friday, December 28, 2007 7:54  AM
Subject: Re: [NSRCA-discussion] Wing  Cores

I tried the contact method with the JWR Blue  adhesive last night; I coated 
both balsa and foam surfaces, waited 15  minutes, and pressed them together. 
Worked fine. Now I have to make a  choice between this or epoxy for sheeting. 

Jay  Marshall 
-----Original  Message-----
From:  _nsrca-discussion-bounces at lists.nsrca.org_ 
(mailto:nsrca-discussion-bounces at lists.nsrca.org)   [mailto:nsrca-discussion-bounces at lists.nsrca.org]  On 
Behalf Of J N  Hiller
Sent: Friday,  December 28, 2007 5:36 AM
To: NSRCA Mailing  List
Subject: Re: [NSRCA-discussion] Wing  Cores 
I used 3M-77 for years because it was quick &  easy. Contact cement is very 
unforgiving and twisted / warped wing panels  needed to be dealt with 
occasionally. I am somewhat more patient now and  use finishing resin epoxy. 
Jim Hiller  
-----Original  Message-----
From:  nsrca-discussion-bounces at lists.nsrca.org  
[mailto:nsrca-discussion-bounces at lists.nsrca.org]On Behalf Of Nat Penton
Sent: Thursday, December 27, 2007  12:37 PM
To: NSRCA  Mailing List
Subject: Re:  [NSRCA-discussion] Wing Cores 
Jay 
I  will be interested to see how you come out if you have the foam supplier  
cut your cores. High taper ratios ( two or more ) call for smaller cutting  
wire. Who and where is the supplier located - I need some foam  ? 
Is  the the JWR Blue adhesive similar  to 3M 77 contact adhesive  ? If so you 
want need the vac bag. Most builders use epoxy or  polyurethane glue for wing 
 skinning.             Nat 

----- Original  Message ----- 

From: _Jay  Marshall_ (mailto:lightfoot at sc.rr.com)  

To: _'NSRCA Mailing List'_ (mailto:nsrca-discussion at lists.nsrca.org)    
Sent: Wednesday,  December 26, 2007 11:11 AM 
Subject: Re:  [NSRCA-discussion] Wing Cores 
Thanks Jimmy. I  found a local source that provides foam board, blocks & 
shapes for  many applications, including packaging and constructions forms. They 
cut  four blocks of 1# to 4X36X18 and then gave me a can of glue to try – all  
at no cost. Great people to work with! They can even cut the wings if I  
provide the masonite templates!  
Jay  Marshall  

-----Original  Message-----
From:  nsrca-discussion-bounces at lists.nsrca.org  
[mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of jimmy graver
Sent: Wednesday, December 26, 2007  12:03 PM
To: NSRCA  Mailing List
Subject: Re:  [NSRCA-discussion] Wing Cores 
Jay, I am  looking to cut foam wings also this a source I found for foam.  
_http://www.aircraftspruce.com/catalog/cmpages/styrofoam.php_ 
(http://www.aircraftspruce.com/catalog/cmpages/styrofoam.php)  
I buy  my spruce from them and there service is good. Hope this  helps. 
Jimmy  Graver

----- Original  Message ----- 

From: _Jerry Stebbins_ (mailto:JAStebbins at worldnet.att.net)   

To: _NSRCA Mailing List_ (mailto:nsrca-discussion at lists.nsrca.org)    
Sent: Tuesday,  December 25, 2007 5:23 PM 
Subject: Re:  [NSRCA-discussion] Wing Cores 
Jay, depends on  where you are. There are places in/around Atlanta--check 
with Mike  Hester-he buys all the time.ACH foam Technologies.  I just bought 7  
sheets in Nashville. Mix of 0.5 and 0.9 oz foam (virgin). Company was EFT  
Corporation. Might try them.1 615-832-6222. 
Jerry

----- Original  Message ----- 

From: _Jay  Marshall_ (mailto:lightfoot at sc.rr.com)  

To: _nsrca-discussion at lists.nsrca.org_ 
(mailto:nsrca-discussion at lists.nsrca.org)    
Sent: Tuesday,  December 25, 2007 3:48 PM 
Subject:  [NSRCA-discussion] Wing Cores 
What is a good  material and source for wing cores? I have someone to help 
cut  them. 
Jay  Marshall  

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