Tips for sealing the exhaust

[Rodney Kirstine]

Since this is my first nitro helicopter, do any of you have any good tips for getting the exhaust to seal and stay sealed?  I cleaned both surfaces really good, installed a brand new gasket, used lock washers, and it still leaked.  Do most people use just gaskets or are you using RTV, or something else even?

[Brandon Bartolomucci]

The biggest trick (as normally I never use any gasket or sealant) is take the heli up and get it to normal operating temperature. As soon as you land and stop the blades (have the tool in your pocket) tighten the screws down a little more.

The heat will have everything expanded so when you tighten it up and it cools it will stay in place.

For extra security you can use the gaskets or a hi-temp RTV sealant which is what I'm going to start doing just to give it a try.


Regards,
Brandon Bartolomucci
Sent from my iPhone

[flyalan]

What Brandon said! I used a little ATV the last time I removed the muffler. I hadn't done that before but like Brandon, wanted to try it.  Just be careful you do not get any ATV inside the engine. Bits of ATV will take out your glow plug at the most in opportune time..


Cheers
Alan

[scotty82]

I never use a gasket. A nice smooth surface and give it a good clean with isopropyl alcohol. A small amount of RTV sealant around the motor and exhaust header. I do up nice and tight and go for a fly. I let the motor cool down and nip up the bolts a bit more. I have never had any leaks.

[Ross Lawton]

Hi Rodney,

The best stuff i have used is Loctite 548 Flange Sealant or Gasket Eliminator, this stuff seals the faces between the engine exhaust port and exhaust manifold. It is based on an Anaerobic type product so it will cure and seal where required and the excess will not set like an ATV type sealent which can break off and foul the engine and glow plug.

I will generally install a second nut or lock washer or an Aero-Tight nut which works in a similiar way to a nylock nut but is all metal so is unaffected by heat, vibration or oil.

Hope this helps,
Ross

[Bill Mullin]

I've had to use a sealant on both of my machines.
Permatex red rtv is what has worked best so far for me, along with the gasket.
I put a film on the gasket, put gasket on engine, put film on pipe and assemble.
By film, I mean the thinnest amount you can possibly spread out on the parts.
If you can see the red color of the rtv on the parts, it's probably too thick and will foul the plug.
These are OS 50 and OS55, btw.

[Mark Burberry]

Also remember to allow the RTV silicone to set up properly before flying. Generally overnight. I prefer Black "Type 2" RTV silicone. VERY thin layer as already stated.

A nut like this also works well: http://www.use-enco.com/ProductImages/6746812-21.jpg. Which you can get from anywhere like McMaster.com etc.

Some basic direction: I usually use 1000 grit sandpaper. Lay the paper flat on glass or something similar, spray with a shot of alcohol or wd40 and push in 1 direction holding it flat until the surface looks flat and polished. Rinse with alcohol, joining surface downward so any chafe falls out with the spray, then wipe with towel. Then I put a micro-thin coat of silicone on the muffler joining surface. You need to let it set up overnight as well with no fuel contact. To much silicone dissolves with nitro and causes flameouts during flight. It also fouls the glow plug, hence using a very thin coat on the muffler and proper set up time.

Mark

[Tommy Wagner]

This is what I used in the past it was a tip from Tim Jones
PC-Farenheit Epoxy Putty


 it works better then any of the epoxy. I'm using aluminum gasket now and have not had any problems so far.


Tommy

Sent from my iPhone using Tapatalk

[KevinM]

Permatex Black Ultra or Ultra Black has been working great! usually can get lots of filghts and no breaking down like the orange RTV.  Havent tried that epoxy that Tim jones uses...may try that in the near future!

[Chris Sexton]

I have been using hand made cork gaskets. SO far no issues. I got some automotive sheet gasket cork at autozone. Supposed to be good on high heat big blocks /shrug

[Shane Butler]

+1 one the Permatex but no gasket. Use very sparingly you don't need much. I even use it on the bolts holding muffler. Works well.

[Azimm]

I've used no gasket and JB Weld many many times... use an old credit card to get a paper thing layer you don't want it pouring out the sides... that means its going on the inside as well...

This stuff hold up to the heat and easy to remove when you are ready to.   zero leaks

[Darren Lee]

If the flanges are flat and the bolts are tight, no gasket or sealant or epoxy or anything else is needed!

[Rodney Kirstine]

I ended up using gaskets since I had already ordered them.  I sanded the face of the exhaust to get it really smooth and then I went with a little bit longer screws and used two nuts.  The jam nuts are working great.  I haven't had a leak since I added them.

[Bob Heybrock]

I have had pretty good luck recently with a copper OS gasket, resurfacing the muffler, seal things with a thin layer of red Loctite then heat with a mini torch which will "set up" the red Loctite. None of my buddies seem to like this idea but I learned this trick in my auto repair business. The Anaerobic sealer sounds like a great idea too, I will try that next time as I admit it is difficult to keep the flame away from the fan shroud.

Also, I have rethreaded my muffler bolt holes with heli-coils (Power Coil brand) and have been very impressed with the strength of them, 3mm by .5mm thread pitch if interested.

Chris, I admire your patience with the cork gaskets!