Thread: Fuel tank sealant and sight tube material

Have just removed the wings on my 2006 ctsw for inspection on fuel filtres and replacement of fuel level sight tubes.
Would appreciate advice on what the best gasket compound is used for resealing the tank inspection ports and what are people using for the replacement sight tubes.
The gasket compound specified in the manual is not known in Australia.
My original sight tubes have discoloured to be useless, the material is still very soft and pliable and I am concerned that the easily obtainable poly tube, which is rather stiff will become very brittle within a short time.
Any experts out there on an excellent specification for sight tubes?

Hi Angel,

I've got the same trouble with my CTLS. I'm currently looking at fitting a Jabiru Sight Tube Assembly but it will be a month or so before I get to doing it. Figure I can fit a blanking plate and then attach the Jab sight Tube to this with holes for fuel entry drilled in suitable places. There is a 2 part fuel tank sealant available through Whitworth Marine Supplies ... it's a "Fibretech" product, or go to your nearest GA maintenance outlet and they should steer you in the right direction.
Waggles.

For what this is worth, today we completed a 100hr inspection, which is 51hrs and 6-7 weeks since required tubes were changed and we changed out ‘the required tubes'. They 'clouded' with first fuel load, and were impossible to read.... We submitted a LOA to remove and replace when this occurred. The tube ‘shrank in diameter’ and ‘stiffness’ due to possible accelerated oxidation. (This might be cased by alcohol in the fuel in California). We sent the tubes to FD-USA for review.

Thanks for yr input Waggles. After a fruitless search for information on superior sight tube material I fitted the clearest pvc I could find. but I dont hold much hope that an improvement will result. As far as the sealant is concerned I finally was able to locate the one recommended in in manual, that is HYLOMAR [single pack] which worked well. found it at Sprint auto parts of all places. And its only $13 a tube.

I ordered tubes from FD and after a few tanks of autogas they have turned milky, but are still readable after 100 hours. - WF

I have been having problems with fuel seeping around the gas caps during flight on my CTLS. I have put on new gas caps, tightened them up and still have strips of gas stains to the flaps, down the flaps, even to the fuselage after about 2 hours of flight. I only put about 10 gallons to a side and it even happens in smooth flight. I have tried looking for thicker gaskets for the caps but with anything larger the cap will not fit. Anybody?

we have allways used FD site tubes in all three CT's and never had a problem getting a year and hundreds of hours with readable tubes. We use mostly auto gas except on trips and all though the tubes do cloud a bit we have a Stream Lite LED rechargable flashlite that hurts your eyes in broad daylight, and have no problem reading the site tubes with that light. pilot1950 , is there another CTLS close enough to go "steal" his gas caps for a quick flight and see if the caps are the problem. Those stains are bear to get off, arn't they.

Our A&P (who only works on CTs) replaces the sight tubes every year or two. We have the night lighting package, which has some LEDs that illuminate the area. I've always found that sufficient to see the liquid level if it shows in the tube.

Doug

With the annual for 2010 I tried replacing with the clearest PVC I could find 12 months ago but they to are discolouring .
At the time I thought of trying something like the Jabiru sight glass as well -Actually I bought a couple when I was in the Jabiru factory whilst attending the Wide Bay Air Show in August 2009 but when I went to fit them they were too awkward so I decided to make something more suited to the CT s requirements.

After several revisions I got up to designing and cutting out the upper and lower sections and even had the 3 mm sight GLASS panels cut the end result they currently weigh 220 grams each and use a single O ring to seal against and cushion the glass. Some how I got sidetracked on all the other distraction projects and haven't quite tested them.

The idea is that the top section is easily removed to allow the fitment of say a piece of old tape measure cut to fit in the centre section and measurements taken with each 5 litres of fuel added once recorder the graduations can simply be engraved on a blank centre section which goes back in on final install. If for some reason you need to modify the scale it is just a matter of engraving a new centre section

Weight savings may be achieved by milling off material around the brass nipples and indeed replacing the Brass for Nylon fittings.

The only other concern is that they will need a mounting bracket to allow them to sit vertical rather than flush against the cabin bulkhead.

I am hoping this will provide a good a clear means of observing the fuel level - perhaps the addition of a small LED on the very top might be an option down the line

As my annual is past due I should get my act together and finish a set for installation pronto.

Peter