To Jeffco or not to Jeffco that is the ??????

[CBarber]

My fellow composite devotee's, as y'all may remember from this very forum and now also in the CSA Newsletter (No 92)I had a bit of an issue with Jeffco sealant failing in the strake of my Velocity SE. In some areas it failed in mass, in others, it faied in smaller areas....however, any failer is not only unacceptble and cause for concern it is also just a real PITA.

 

I have replaced the inner skins of the right strake and have the process down and shall start the left strake asap. The new glass is being layed up with fresh EZ-84 epoxy.

 

I have taken some of the "good" cut out Jeffco sides from the strakes, as well as some EZ84 parts I had aroung the hangar and have had them soaking in Auto fuel (purchased from the pumps just across the street from EFD) which is up to 10% ethanol, for about a month. When I have examined the pieces, both Jeffo and EZpoxy, all seems ok. No separtion of the Jeffco from the EZPoxy and niether seems to have softened. Softening is one of the problems I have seen discussed.

 

I am at a point of chosing if I should finish the strakes out by trying to apply Jeffco again or just staying with straight EZpoxy. I have a new $450 batch of Jeffco in the hangar and a couple of new gallons and a half kits of EZpoxy....that cost is done, so cost is, and never was a factor. I read Gary Hunters reply to my problems in the CSA newsletter (Gary has been to my hangar a few times and was my EAA tech counselor for my first conditional inspection a while back) and his comments on Jeffco sometimes having problems with adheasion is taken to heart. Due to this and my Jeffco failure I am leaning towards staying with straight EZpoxy. I have read here (or related email lists or likely both) of folks flying with straight EZpoxy strakes for decades....even with Ethanol and other additives in the fuels. My reason for using Jeffco in the first place was due to the "conventional wisdom"....or so I thought (ie, list servers, Velocity, Inc etc) that it was the stuff to use to eliminate concerns about fuel additives, ethanol, diesel fuels etc....guess not.

 

So, since I am using an auto conversion and continue to plan to use auto gas should EZpoxy be up to the task? I know some have said it will, but I am asking for confirmation of this data point in case I misunderstood. I am confidant that EZpoxy WILL adhear to EZpoxy and I can add to what I have already used to rebuild the right stake and now on the left strake. Obviously the idea of not only having to do this again, not to mention the anxiety of even have to worry about it at 10000 feet....or 10 feet....or 500 feet AGL is not the way I hope to fly my plane.

 

I have also made some test strips of new lay-ups of EZpoxy satuated glass onto Jeffo. I let it cure and returned the next day. I could not pull the test strips off the Jeffco without it destroying the glass. The bond did NOT separate at all, The glass itself faild, not the Jeffco to EZpoxy bond. I did this with well sanded surface as well as surface that had no sanding on both Jeffco to EZpoxy and EZpoxy to Ezpoxy. All bonds seemed very stout...howerver, neither of these batches have been soaked in Autogas/ethanol.

 

I will also be looking into the proseal that Gary mentions as well. It too had been mentioned but I thought it was more for sealing leaks but I shall endeavor to find out.

 

Also, I expect to fill the strakes with water and let set for a while and see if I have leaks before I seal the strake tops back on. My hangar partner just did this with the VariEZ he is restoring. He is haveing to address leaks in his stakes as well, just not caused by a bad Jeffco application.

 

Come on guys/gals, Wayne, Terry, John and all else, what say ye. This is when I need some cold, hard commentatry, thoughts, concerns, brain farts etc. It is appreciated.

 

Thanks.

 

All the best,

 

BTW, I will try to write in a more "publishable" manner in case my writing may show up on CSA again....geeeeszz, when you read what you wrote in e-mail in a more formal published form it makes you kinda cringe...wait, maybe I need to re-read this........naahhhhh, I got a plane to build;)

 

FINALLY, the Wings over Houston Airshow is coming up on Oct 25/26. On the 25th, Saturday, EAA Houston, EAA Chapter 12 will be having an open house in my hangar Alpha Papa. Please, if you can make the Airshow, please stop by the hangar and say Hi. I will be the guy trying to explane why my strake tops are cut open.