Cake Frosting Applicator for Applying Resin/Mill Fiber Mix Warning

Cake Decorator can ruin your airplane


I recently heard a great suggestion for applying the resin/mill fiber mixture to the rib and spar tops of wings, stabilizers, rudders, etc. The idea is to get a cake decorating tool or a plastic ziplock bag with one corner cut off and squeeze the mixture out just as a baker does when applying frosting to a cake.

This sounded like a great idea until I almost ruined one of my elevators using this technique. The problem when using a cake decorator to dispense resin/millfiber mixture is that the resin tends to get squeezed out first (with some millfiber) giving you a wetter than desired mixture (resin rich), then later in the operation you start to get a much dryer than desired mixture.


When this happened to me I closed my elevators and began to notice that the second elevator was not closing all the way as it had done in the practice (dry) run. The thicker/dryer millfiber mix was holding the lower skin a 1/8″ above the ribs and spar.

I was able to salvage the job by using some very serious clamping along the rib and spar locations. It all worked out in the end, but it was a real scare there for a while rushing to get it all clamped before it cured.

This method of application should work great for a resin/q-cell (cabosil) mixture, but in my opinion it should not be used with millfiber.