Found the source of the smoke fluid leak inside the plane: The in line filters (ala DuBro, Hayes, etc) had slightly unscrewed during line installation.

Solution: 3/8 inch shrink tubing. Needs to be slightly expanded to fit. You do that with a long nose pliers inserted inside the piece, spreading the handles to stretch the shrink tubing. Place it around the filter before it returns to original size. Then heat shrink it.

When you need to clean the filter, remove the tubing.

I do this on filters in the fuel line to the engine if they might be hitting metal from vibration.

G'day Mate,
Why do you filter smoke fluid?
It goes through the pump gets heated & turns into smoke & then out to atmosphere, do you need the filter?

Shrink tubing makes good hose clamps too. Easy to remove and looks better than the wire ones. Just don't use it on something like inside your tank where you need positive clamping power. Use the good stuf, not the stuf you get at radio shack. It's to thin to do any good. The thicker the shrink tubing the more clamping forse.
Shawn

I filter the smoke fluid because:

1. The pump instructions tell me to
2. My tubing to the heater is 3/32 inch id or larger while my preheating coils are 1/16 id; crud which might pass through the pump might not pass into the muffler
3. I need to connect sections of tubing in any case and use of the filters handles that.

Yes. I picked up a lifetime supply of the heavy shrink tubing on ebay. It is clear, not black.