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Question About Adhesive for Foam "Ribs"

Starting soon on my Elevator and Trim Tab. I've cut and shaped the foam trailing edge "ribs" for the elevator and trim tab ribs.
I see the manual calls for Tank Sealant when it comes time to bond the foam to the skins.

Which of the sealants from the catalog (1/2 hour or 2 hour working times) will be best for this application, what quantity will be needed, and is there another acceptable adhesive that works well?
Thanks
 
I used the 2 hour working time sealant and it worked fine. Can't pin point the amount needed but a nice even 1/32" layer on top works (good luck measuring that). I just smeared it on until a uniform, thin layer covered the sides of the foam pieces. The foam takes the sealant very easily.

If I hadn't used sealant I'd of used the .5" wide 3M double sided sticky tape we use for trailing edges. That stuff STICKS.
 
Tank Sealant only, please

I would recommend against the double sided tape to attach the ribs. The application here is different than the rudder trailing edge.

In the rudder trailing edge application, the tape is just used to hold everything in place while you rivet.

In this application, the ribs must adhere permanently. I wouldn't risk the double-sided tape adhesive degrading over time.

Just my opinion.
 
I would recommend against the double sided tape to attach the ribs. The application here is different than the rudder trailing edge.

In the rudder trailing edge application, the tape is just used to hold everything in place while you rivet.

In this application, the ribs must adhere permanently. I wouldn't risk the double-sided tape adhesive degrading over time.

Just my opinion.

I agree with Eric

A few things to keep in mind.

The expansion coefficient of aluminum is very different than it is for the foam.
The adhesive used needs to account for this (and the tank sealant does a very good job)

The foam is very open celled. An adhesive that will extrude into the cells of the foam is needed, to get a good bond. The VHB tape works very well on a smooth surface like aluminum... not so mutch on something like open cell foam.

There is a lot of in service data proving the tank sealant works well with the foam ribs (it has been used on RV's since it was incorporated into the RV-9 elevators and trim tab in 1999.

.5 hr or 2 hr will both work well. you will just have to be very well prepared and work efficiently if you intend to do all of the bonding at once using one kit of .5 hr.
 
I used the .5 hr tank sealant for the trim tab ribs. I was well prepared and got the ribs installed but it was a race that I barely won.

I would just buy the big can now and put it in the freezer until you're ready for the tanks.
 
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