Sikaflex for trailing edge elevator stringers

[tgmillso]

Hi All,

So, I have a shipment of Proseal somewhere between the US and Tasmania, but I am at the stage I need to close out my elevator. As a substitute for using the Proseal for joining the elevator stringers at the trailing edge, I purchased locally some Sikaflex 252, which according to the product sheet is suitable for such an application. I am applying it to stringers I have primed with zinc phosphate etch primer and discovered in the Sika pre-treatment chart that although 252 can be applied to primed aluminum surfaces, the surfaces should be pre-treated with Sika Activator. Of course, no one stocks Sika Activator here, so I am wondering if I can just prep the surface with isopropyl alcohol or similar, or do I even need to worry am I being overly paranoid? Above all of this, should I even use Sikaflex 252 for this application, or should I just put the brakes on things and wait for the Proseal to arrive?
Sikaflex 252
Sikaflex Pre Treatment Chart

Thanks.

Tom.
RV7 EMP

[RV7AJeremy]

Would sika work? Certainly, the stuff is amazing! BUT, its heavy. I would be cautious about adding the weight to the trailing edge of a control surface. If it were me, I would just work on something else till the pro-seal comes in. Your building an airplane, there is ALWAYS something else to work on

[SHIPCHIEF]

I used SIKA295 left over from the canopy to bond the hinge material to the cowl. Of course I used the rivets as in the plans, but setting rivets in fiberglass is an iffy thing. Anyway, it's holding up great, even with under cowl heat.

[tgmillso]

Thanks Guys. I just found out that my Proseal has been sitting on the floor at Van's for 10 days along with the HS spar because it is too long to ship to a PO box, but I don't have regular roadside delivery as there is no delivery on our road and the driveway is 3 miles long. The postal service here wonder why they are going out of business and why FedEx are eating their lunch. I'm going to have to try and source some Proseal here, because I can't move any further ahead on the emp until the HS spar and the VS reinforcement arrive. Note to self, don't build the next aeroplane in Tasmania.

Cheers,

Tom.

[RV7AJeremy]

Tom,
you might want to consider some RTV. See section 5G (Folded trailing edges) of the construction manual. Vans recommends RTV or tank sealant, you are just trying to prevent vibration from causing cracks and I bet you can find some RTV where you are at.

Happy building.

[Joeyo68]

Hi Tom,

I work for PPG. We have an Aerospace division here in Melbourne. I have made an inquiry as to what is available locally that is equivalent to the Flamemaster tank sealant that Vans now sells.

I will let you know when I get a response.

Cheers,

Joe

[Joeyo68]

Hi Tom.

I got a quote for the tank sealer. Pretty pricey!

I'll send you an email with the quote, and tech data sheet.

Cheers,

Joe

[rsharples]

Tom, I used Sika Auto for both rudder trailing edge and elevator. It is available in 150 ml tubes from Bunnings and appears to be the same spec as Sika 227. I applied it directly to the etch primer without any other treatment. I am assuming the Sika will be as good as general RTV recommended by Vans. (I'm building in Melbourne)
"Sikaflex-227 is suitable for sealing, seam sealing, simple bonding as well as for vibration reduction and sound deadening measures in crash body repair and car body construction"

[Wedgetail]

Sika primer and activator can be bought from Blackwoods
activator I purchased was 205 from memory

[tgmillso]

Thanks guys. To Jeremy's point, Van's does state in the instructions that RTV is acceptable, and according to 27 years of RVATOR was one of the first products successfully applied for this purpose. My sikaflex has however arrived, so with 2lbs of it at my disposal (and some 2oz syringe) this is what I am opting for.
Cheers,
Tom.