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-   -   Aluminum-safe Silicone and Foam (https://vansairforce.net/community/showthread.php?t=37454)

RV8R999 08-29-2009 08:54 PM

contractor foam
 
I know some of you will poo-poo this but I had a similar problem on my first plane (BD-4) and used some of that contractor foam in a spray can (find at home depot or lowes). I used it on unprimed 2024 T3 and 15 years later - no adhesion or corrosion issues at all. In fact this stuff is nearly impossible to remove from well prepared (clean) aluminum. when I was testing the only way I could get the stuff off was with a belt sander. I also put a blob of it in a can of water for a month and cut it open. The interior was bone dry.

For my -8 I've primed every part with epoxy so I'm comfortable using this stuff again. I think a few distributed dabs of this will be enough to dampen the vibes enough to minimize or hopefully eliminate any fatigue cracking.

FWIW,

Ken

RV8RIVETER 08-30-2009 03:36 PM

Quote:

Originally Posted by RobByers (Post 353679)
Has anyone used this slient running stuff recently? Could it be used the the RV-12 and still be E-LSA compliant? On a related note, could you use spray on truck bedliner on the floors and in the baggage compartment?

I sprayed Silent Running on the floor and rearside firewall of my -8. I didn't feel comfortable using it in the ramp becuase of how it is sprayed, my ramp is already built, and I think a total fill would be much more effective. Haven't decided exactly what to do there yet as my ramp area and exhaust outlet is going to be highly unconventional. Am not flying yet so cannot report any results.

Mel 08-30-2009 03:42 PM

Quote:

Originally Posted by RobByers (Post 353679)
Has anyone used this slient running stuff recently? Could it be used the the RV-12 and still be E-LSA compliant?

Only if it is included in the plans.

DanH 08-31-2009 09:23 AM

<<I sprayed Silent Running on ......the rearside firewall of my -8.>>

You're in very risky territory. Remember, "self-extinguishing" means nothing when in contact with a 2000F firewall panel.

Postscript:

Silent Running publishes various data sheets on its website, inlcuding the results of test per ASTM Standard E162-02e, "Surface Flammability of Materials Using a Radiant Heat Energy Source".

It can be hard to find free web data about a particular standard, although the ASTM will sell you a copy for $43. In this case I got lucky and found an article describing the test proceedure. An 18" long sample is placed before a radiant heat source (think toaster oven elements), at an inclined angle of 30 degrees. The close end is 4.7" from the element. The element is regulated at a little less than 1250F. The test is run for a specified time period and the "flamability index" is mostly a matter of how far down the inclined sample flame is observed to progress. Put another way, how far away from the heat source must the sample be in order to become self-extinguishing?

In this case, all samples exhibited open flame to about halfway down the panel, and given the conditions we know the ignition temperature was less than 1250F.

If you must use Silent Running, apply it to the engine side of the firewall, not the cabin side.


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