A

ao.frog

Well Known Member
Hi.

We've just sealed all the openings etc on the baffling and by mistake we used white (clear) RTV.

I'm wondering if we schould replace the clear RTV with red (high temp) RTV?

Maybe the clear RTV in the baffle seals could remain, but what about the RTV which are along the engine case?
It says on the RTV tube that it's ok up to 170* Ceclius (don't remember the F-grade), but 170 seems very little when it comes to along the engine case for example?
 
I'm coming up on 1000 hours with clear RTV on the baffles, no sign of any problems with it. If you look up the specs, the orange or red high temp stuff is typically only a bit higher rated than normal RTV. Dig around on the web, you'll find typical specs for both.
 
All should be 400F and OK...

Mel said:
The RTV on the baffles should be rated at 400*F.
Click to expand...

The black stuff is rated to 400F (and the other non-hi temp stuff)...

http://www.gasketinc.com/afterMarket/viewProductLine2.aspx?prodLine=222

Hi-temp RTV is either 500F or 600F and is usually red... but not always.... this Permatex one is black

http://www.gasketinc.com/afterMarket/viewProductLine2.aspx?prodLine=225

...any good quality RTV should work on the baffles... and don't forget to seal the gaps at the top and bottom of the oil cooler where it is attached to the rear baffle...:)

Buy a good quality RTV at your local auto parts store.... those should meet the 200C number...

Do they sell Permatex products where you are?

gil A
 
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Numbers

Hi.

Thanks for the inputs.

The clear RTV I've used is bought from Spruce, part # 09-27800.
It's marked: "Resistant to weathering, -85 to 350F, (-65 to 177C)"

The red one is Loctite 5399 and it says on the label that it's for temps -60 to 275C, max 350C.

So I guess I can start out with the clear RTV and see if it holds up?

Re Permatex: I don't know if I can get that here in Norway, but I'll check it out for sure.
And yes; we've remembered to seal off by the oil cooler. There where quite a few openings there! :)
 
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It will take care of its-self

ao.frog said:
Hi. We've just sealed all the openings etc on the baffling and by mistake we used white (clear) RTV.

I'm wondering if we should replace the clear RTV with red (high temp) RTV?
Click to expand...
It will take care of its self, it will be gone in 5 hours of flying. The red high temp Permitex®, is like to engine baffle sealing, as rivet's are to aluminum or duct-tape to home repair, they go together. Wear cloves and watch your clothes, it sticks to everything and stays like pro-seal. Just make sure the surfaces are clean with some solvent. If you scuff it, it really will grab on.
 
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Red may not be best...perhaps copper.

gmcjetpilot said:
The red high temp Permitex?, is like to engine baffle sealing, as rivet's are to aluminum or duct-tape to home repair, they go together.
Click to expand...


It is my understanding that in the Permatex range the newer Ultra Copper RTV is in fact significantly superior to the Red RTV. It's more expensive (always the way) but it's completely compatible with aluminium and it can operate at higher temperatures than the Red product (up to 700 degrees F). It's also very oil resistant. For baffles and particularly for general FWF requirements this may be the way to go. Check here for further info:
 
How hot des it get

Captain Avgas said:
It is my understanding that in the Permatex range the newer Ultra Copper RTV is in fact significantly superior to the Red RTV. It's more expensive (always the way) but it's completely compatible with aluminium and it can operate at higher temperatures than the Red product (up to 700 degrees F). It's also very oil resistant. For baffles and particularly for general FWF requirements this may be the way to go. Check here for further info:
Click to expand...

Yeah.... but Lycoming has a max. temp on your cylinders at 500F, and most folks use a 450F personal maximum. The rest of your Lycoming is oil cooled and should be at a significantly lower temperature.

You shouldn't be able to get any part of your baffles too hot for the red RTV stuff to not work...:)

gil A
 
Seeing red.

az_gila said:
Yeah.... but Lycoming has a max. temp on your cylinders at 500F, and most folks use a 450F personal maximum. The rest of your Lycoming is oil cooled and should be at a significantly lower temperature.

You shouldn't be able to get any part of your baffles too hot for the red RTV stuff to not work...:)

gil A
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Gil I understand what you are saying. But the truth of the matter is that many builders tend to use the RTV not just on the baffles....they tend to use the same product everywhere...including sealing the firewall transitions. In reality they would probably be better off using a proper 2000 degree F firewall sealant on the firewall but the RTV proves to be convenient to use in small applications. On that basis I recommended the Copper over the Red because on the firewall any increase in temperature resistance is an advantage...and the price difference is stuff-all.

And George.....Red is Red, and Copper is Copper (unless of course one is colour blind resulting from activities that we were warned could be detrimental to the eyesight). ;)
 
Red Smed

Captain Avgas said:
And George.....Red is Red, and Copper is Copper (unless of course one is colour blind resulting from activities that we were warned could be detrimental to the eyesight). ;)
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Hey, I have perfect vision and bell curve hearing and my mind is as sharp as.......what was I saying?

No, negative maverick the "copper" is the color of the tube, I'm talking about the goop that comes out, its red; when it dries, its the same color as the SCAT tube, a dark red orange.

Trust me every 6 mo I have a doctor checks my eyes and asks me what I see and if he can stick his finger.......................humm in my ear? :rolleyes: Any way the "RED" goop in the copper tube is good for a lot of stuff.
 
Ok, I'll make myself a target for the purists and admit that I used ordinary "Roof & Gutter Silicone Sealant" to seal the baffles to the engine. No sign of deterioration after 80 hrs. I used the same type of sealant on my previous homebuilt aircraft and it was still Ok after 460 hrs. Maybe the higher temp stuff would be better if, for some reason you need to use it in really hot areas like the cylinder heads. The advantage of the roof and gutter sealant is that you can get different colors to coordinate with your engine. I have grey sealant which goes very nicely with my grey/red engine :cool: :rolleyes:
Fin
9A Flying
 
about RTV sticking....

RTV won't stick to a wet surface.

Apply your RTV to the location of interest and then wet your finger and tamp it into place. It won't stick to you (or very little will) and you can get the RTV to fill in the gaps better.
If water isn't handy you can use spit.:D

Kent
 
kentb said:
RTV won't stick to a wet surface.

Apply your RTV to the location of interest and then wet your finger and tamp it into place. It won't stick to you (or very little will) and you can get the RTV to fill in the gaps better.
If water isn't handy you can use spit.:D

Kent
Click to expand...

Yeah spit works good, for ten uses, then you better remember that your about to lick an RTV tainted finger...Please ask me how I know!! :p
 
Red vs Copper

My local auto parts store charges the same amount for the Red and Ultra Copper RTV ($4.99), so I picked up a tube of the Ultra Copper.

I discovered that the Ultra Copper is doesn't have the acetic smell of the Red RTV. It's also labeled as "sensor safe", so it's probably better on the aluminum then the Red.
 
How many tubes???

Forget the color, how much is needed for sealing? I'm trying to decide how many 3oz tubes (which equal dents in my wallet).

For you folks that are anal about details, assume that it is a neat job with no large gaps. Just a routine seal of the baffles around the engine and the fabric glued on (which is also riveted). Also assume a generous enough application to seal properly, not sparing and not glopped on.

In layman's terms - "just right".

BTW - Ultra Copper is $4.94 at Autozone.

Thanks

Webb
N32WW (RV7A)
 
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Have a look at the McMaster-Carr catalog. They have hi temp silicon sealant in larger tubes (need a calking gun) in different grades and colors, including a nice aviation blue. And I think the larger tubes are cheaper per ounce than buying the small 3 oz tubes. You'll find many other uses for the stuff as well...
 
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