Empenage Rivets?

[914pete]

Leonard used stainless rivets that he paints to assemble the empenage.  Is there an appropriate aluminum rivet alternative?  I was going to place my 6061-T6 aluminum order today to build the vertical/horizontal stabilizers.

[914pete]

Is everyone using SS rivets and painting them?

[joecnc2006]

I used Aluminum rivets, but i think i have more in a row in some places than the plans show.
I have seen others use them also. but use at your own risk. (have to state that)....

[914pete]

Thanks for responding Joe.  Is there a disclaimer we can sign for this group and the info provided here unto, to which, there for, etc LOL.

I was reviewing the tensile/shear strength of each type of rivet and will decide for myself which to go with.  I'm thinking the aluminum rivets would hold up fine.  Just wondering if anyone used standard non-structural aluminum blind rivets in currently flying Eagles or any ultra lights for that matter and had any obvious issues.  I also read a Bimetallic article which stated using SS rivets to hold together aluminum sheets is generally safe however using aluminum rivets in SS sheets will cause corrosion.  So it seems painting the SS rivets might not be necessary.

[Tom XL-7]

There is a product made just for this situation. Tef-gel.  A gelled Teflon paste
Might cost a bit 20 bucks plus shipping, Amazon has it and it would apply towards free shipping.
What would structural alum rivets cost and could I pull them with one of my hand squeezers.
Tom XL-7
20 bucks is cheaper than taking it apart because something came loose

[Dan_]

I'm not a designer or engineer, but I would be inclined to believe most if not all force on the tail feathers will be in shear instead of tensile.  If you use aluminum rivets with steel mandrels the steel left behind increases the shear greatly.   Plus you multiply the shear strength of one rivet by the number of rivets. 


It seems to me there won't be much shear on the items that stay aligned with the slip stream.  The rudder will see the most force applied by the air, so the question in my uneducated opinion becomes how many rivets does it take to be stronger than the rudder spar tube..?

If one is that worried about it you can always pay the big bucks to get the structural rivets. 


Wicks comes readily to mind: http://aircraftproducts.wicksaircraft.com/viewitems/cherry-rivets/cherry-q-rivet-bs-series

If you bounce around on Wicks rivet area you will see some all aluminum structural rivets. ($.33 a piece)

Cherry max... 50,000 psi shear strength are around a $1.40 a piece.

[Tom XL-7]

Just have to point out.
In an effort to avoid dissimilar metals, we use an alum rivet with a steel mandrel. 
Sometimes things don't make sense. And that is the structural cherry rivet.
Tom XL-7

[Tom XL-7]

Ok I found a reference to an alum rivet with a zinc plated and clear chromate finished steel mandrel
Sounds better
Tom XL-7

[joecnc2006]

Exactly how much of the mandrel is left inside of an aluminum rivet, and what is the calculated sheer strength of it. vs the thin aluminum gussets, which one will fail first.
I'm sure many builders flying already with great success have purchased rivets from the aviation isle at Lowes or HD.

[Tom XL-7]

There are many types but the simple pop rivet snaps off leaving the ball for clamping pressure.  Others, especially alum rivets meant to be on the exterior of your aircraft snap off flush or just under. Cherry calls them a type Q. They have matching metal mandrels. So on a normal pop rivet you won't have the mandrel at the sheer line.
 I'm taking the easy way out and doing what the boss called for. Stainless steel, the paint applied to the hole and the rivet, wet on installation.  maybe I will freak out and buy some of the teflon paste. It never dries. Stays a paste, as it is also meant for screws and bolts that are to be removed.
If you use the 4130 leading edge on the vertical, as has been recommended by some builders. you open yet another can of worms as you are riveting a thin sheet of alum "gusset"  to a piece of steel.
Sometimes you just can't win!
Tom XL-7

[Tom H]

There has to be some moisture for galvanic corrosion to take place.  If you use paint, epoxy or some coating on the rivet, this should exclude moisture.  And, the whole part, rudder, elevator, etc., is covered with fabric and dope, polyfiber, whatever, which should provide add'l protection against moisture.  If the airplane is kept out of the weather, I don't think there will be any corrosion for a long time.  If left outside all the time, there will be other issues besides this one to be concerned about.

I have used SS rivets from Home Depot, put a bit of 2 part epoxy in the hole, and set the rivet.