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Old 06-16-2013, 07:32 AM
SHF SHF is offline
Join Date: Oct 2008
Location: United Kingdom
Posts: 16
Default RTV

The "riviting the rudder" instructions call for a daub of RTV. Some web searching learns that this is a brand name silicone adhesive, not sold in my part of the world. Looking for a replacement can I use any silicone adhesive or should it particularly be a gasket sealant, or something else for that matter.

Can anybody advise please?

thanks Roger.
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Old 06-16-2013, 07:51 AM
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Mel Mel is offline
Join Date: Mar 2005
Location: Dallas area
Posts: 10,150

A silicon adhesive is fine. Just be sure that it is marked "safe for aluminum".
Many silicon adhesives contain acetic acid that contributes to corrosion.
Mel Asberry..DAR since last century
A&P/EAA Tech Counselor/Flight Advisor/Nat'l Test Pilot School
Specializing in Amateur-Built and Light-Sport Aircraft
North Texas (8TA5)
RV-6 Flying since 1993, 172hp O-320, 3-Blade Catto (since 2003)
Legend Cub purchased 12/2017
FRIEND of the RV-1
Eagle's Nest Mentor
Recipient of Wright Brothers "Master Pilot" Award
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Old 06-16-2013, 09:01 AM
Bob Axsom Bob Axsom is offline
Join Date: Mar 2005
Posts: 5,685
Default Room Temperature Vulcanizing

I use a lot of Dow 736 (red) in the high temperature areas and Dow 732 (black) in other areas on my dark blue airplane. Comes in a tube with a seal in the end that has to be broken and has a separate plastic cone that can be cut to different lengths for controlling the size of the opening. It has very good adhesion and "rubber" qualities when cured (24hrs full cure - skins in minutes). Can be used to: stabilize wire routing through a hole in metal, make flow fillets, etc. When I am making gap seals on parts like strut cuffs that are going to be removed a lot and I don't need the strength of the expensive Dow products I buy some similar "rubber in a tube" from an auto parts store. Great stuff.

Bob Axsom

Last edited by Bob Axsom : 06-16-2013 at 12:56 PM. Reason: typo
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Old 06-16-2013, 09:22 AM
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Rick_A Rick_A is offline
Join Date: Oct 2005
Location: Highland Village, TX
Posts: 1,419
Default Look for "Sensor Safe"

If you go the an auto parts store and don't find a silicone sealant labeled "safe for aluminum", look for one labeled as "Sensor Safe". These are the one that don't have acetic acid in them.
Rick Aronow,
Flying 7A Slider;
RV-12 (ELSA, Dual G3X), SOLD
Highland Village,TX
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Old 06-16-2013, 10:48 AM
David Paule David Paule is offline
Join Date: Dec 2009
Location: Boulder, CO
Posts: 3,616

The one I used was Permatex Ultra Blue, 81724 (77B). It's marked "sensor-safe RTV gasket maker."

The first auto-parts place I stopped at had it.

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Old 06-16-2013, 01:07 PM
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Karsten Karsten is offline
Join Date: May 2010
Location: Germany
Posts: 20

In the Netherlands and in Germany you could use Sicaflex-521 UV!
It is ok for aluminum.


Empenage kit almost done
QB-Wings almost done
Fuselage in progress
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Old 06-16-2013, 04:53 PM
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Walt Walt is offline
Join Date: Aug 2005
Location: Dallas/Ft Worth, TX
Posts: 4,874

Or good ole pro-seal.
Walt Aronow, Dallas, TX (52F) RV7A, IO360, C/S, 1500+hrs

EXP Aircraft Services LLC
Specializing in RV Condition Inspections, Maintenance, Avionics Upgrades
Dynamic Prop Balancing, Pitot-Static Altmeter/Transponder Certification
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RV7A built 2004, 1700+ hrs
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Old 01-31-2017, 12:22 PM
jckonekamp jckonekamp is offline
Join Date: Jan 2014
Location: Rosario, Argentina
Posts: 1
Default RTV Substitute - UPDATE

Here in Argentina I've found a great substitute from SIKA. Is almost the same (or the same) as the Sikaflex 521 UV. It's called Sikabond AT-Metal, and made in Switzerland. It's a grey hybrid polyurethane silicone, non aggressive to aluminum.
I had some RTV left from a previous plane that I decided not to use because it has been opened last year.
Here are the pictures. Hope it helps.

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Old 08-28-2017, 09:05 AM
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maniago maniago is offline
Join Date: Aug 2014
Location: Bowie MD
Posts: 701

Originally Posted by Mel View Post
A silicon adhesive is fine. Just be sure that it is marked "safe for aluminum".
Many silicon adhesives contain acetic acid that contributes to corrosion.
Well, this is painting with too broad a brush really. Gotta do the homework. Dow 732 is acetic acid cure, but is used on AL airplanes, is MIL spec and Boeing compliant.
MustangII (FoldingWing) "FirewallFwd&sundries": IO360B1E,RSA,C2YR-BF/F7666-2,Superior sump,James; 2xHXr,MiniX,EIS,480,327,240,SL30,Navworx; SteamAlt,AS,VSI
Don't be a hater; I'm a cousin with thin wings!
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Old 08-28-2017, 12:33 PM
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az_gila az_gila is offline
Join Date: Jan 2005
Location: 57AZ - NW Tucson area
Posts: 9,743

Note that RTV is not a trade name it's a shortened description of "Room Temperature Vulcanizing" rubber.

Perhaps something got lost in the translation to EU languages?
Gil Alexander
EAA Technical Counselor, Airframe Mechanic
Half completed RV-10 QB purchased
RV-6A N61GX - finally flying
Grumman Tiger N12GA - flying
La Cholla Airpark (57AZ) Tucson AZ
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