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Weep-No-More, Fuel Tank AN4 CS Rivet Sealer

100-psi Proseal fuel tank AN4 counter sunk rivet sealer.  This is an additional fuel tank rivet sealing method to be used prior to painting and is applied from the outside of the fuel tank.  When the syringe is placed over the rivet and force is applied, the compliant contact surface of the syringe will seal the edges to allow pressure to build, seal the rivet with proseal, and minimize clean up.  The compliant seal works on curved wing surfaces.   In fact, the seal is so good, 10ml of air spring back was found during testing on rough workbench.  It is best to seal the rivets when the fuel tank is installed on the aircraft for support of the tank. Seal ALL fuel tank outer surface rivets. The kit includes two syringes and one palm load spreader. One syringe should be sufficient for both tanks.

The syringe plunger is a light press fit to the palm load spreader for steady control.   The syringe has been tested to 40 lb force, equivalent to 160 psi syringe pressure.  At 160 psi pressure the fluid will bypass the plunger seal to relieve pressure.



1)  Drain the fuel tank

2)  Thin Proseal with acetone to allow it to flow

3)  Load the syringe with 3cc maximum to prevent plunger column bending. 

4)  Place syringe over AN4 counter sunk rivet and apply 25 lb 

4A) Alernate: Place syringe over each half AN4 rivet and apply 25 lb, requires two presses

5)  Wipe off the excess, it will be minimal

6)  Allow a couple days for the Proseal to set before adding fuel    


Syringe barrel inner dia. = 0.567 inch

Syringe barrel inner area = 0.25 square inches
25 lb / 0.25 square inches = 100 psi


The RV9A aircraft in the photo is 10 yrs old and 1100 flight hours and used this sealing method prior to painting.  No weeping fuel tank rivets or blisters on either fuel tank.  


additional info click here

Weep-No-More, Fuel Tank AN4 CS Rivet Sealer

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