[NSRCA-discussion] Wing Cores
Earl Haury
ejhaury at comcast.net
Fri Dec 28 06:24:24 AKST 2007
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
To: NSRCA Mailing List
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
----- Original Message -----
From: Jay Marshall
To: 'NSRCA Mailing List'
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] 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
To: 'NSRCA Mailing List'
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
I buy my spruce from them and there service is good. Hope this helps.
Jimmy Graver
----- Original Message -----
From: Jerry Stebbins
To: NSRCA Mailing List
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
To: 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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