Ryans Rebel

My Feedback: (12)

I'm using a da-150 w/ std in-cowl mufflers. I have had one muffler come loose twice. How do you guys put (and keep) them on? I have not been using the supplied gasket. I simply put a small bead of ultracopper and then (blue) loctite the bolts on. Any thoughts?

Ryan

3D ONdaEDGE

Blue loctite is a waste of time. The mufflers get hot enough to melt the loctite. I went to the lawnmower store and bought a 6"x6" piece or thin gasket material for my gaskets as I had a little accident with the supplied gaskets. Ive put probably 15 flights on my DA and I havent had the bolts come loose. I guess If you wanna be bold you can put a dab of red loctite on the bolts. The only thing there is they will be a pain to get out unless you heat it up. If you could get them loose without heat, I would be afraid of what it would do to the threads in the cylinder. The only other thing I can think of is some kind of silicone sealant applied to the bolts and then tightened up. The silicone may be strong enough to keep the bolt from loosening.

GoeKeli

My Feedback: (18)

On my recent DA100/Std. muff install I used the ultra copper as a gasket and put it on the threads as loctite. It's got 6 gallons through it now with no sign of loosening.

Joe

jsm77777

My Feedback: (4)

Don't use silicone sealant on the threads, it won't hold up. Best thing is clean the bolts and threads with lacquer thinner, then re-bolt them down with blue loctite. I have had great success with blue. You could use red loctite, but you will need to run the engine and get it hot, to loosen the bolts. I know of some guys who have gone that route, but I still use blue. I also don't use the gaskets, instead I use Hi-Temp silicone between the engine and mufflers, and I also use a lock washer along with the loctite. Scott

Hammbone

My Feedback: (309)

What is ultra copper?

Thanks, Jim

JNorton

My Feedback: (2)

http://www.permatex.com/products/ind...Gasket%20Maker

Hammbone

My Feedback: (309)

Thank you.

Jim

3D ONdaEDGE

Oh yes the lock washers are the most important thing. Without them it will be hard to keep them tight. You didnt say whether you had them or not so I thought I would mention them.

quist

My Feedback: (198)

Ryan, I always tighten the screw, I dont use lock washers. I run the engine one flight and then tighten them down again. I use ultra copper, no locktite. Make sure you dont have excess vibration.

Ryans Rebel

My Feedback: (12)

No vibration. What I normally do is apply ultra copper instead of the gasket. I only snug the bolts for over night drying. I then remove one bolt at a time. Clean them and then install them T-I-G-H-T with blue loctite. Have had the same muffler come loose twice. Once damaging the cowl and the other damaging the muffler. THis last time the head of the bilt wallowed out the hole large enough for the head of the bolt to slip thru.

Will J.B. Weld hold up to the heat of the exhaust??

Ryan

Panzlflyer

My Feedback: (15)

I second the blue loctite as a wast of time.
I use Ultra Copper, make up a gasket out of copper sheet and RED loctite on the bolts as it stands heat better and can be undone with a bit of muscle and high heat.
Once you get silicone on the threads you will not get it to stay put unless you clean it out with solvents.

mglavin

My Feedback: (31)

I don't use Loctite or anything on threads and I've never had a muffler come loose.

I surface the exhaust port and muffler flange with a sanding block lightly and then clean with denatured alcohol. A skim coat of Ultra Copper allowed to dry and then lightly tighten, overnight to dry and then tighten again. Run the engine, tighten again. Fly the model and tighten one more time while warm. Forget about it.

I also use serrated internal washers when permissible. I found it worth the investment for a 1/4" drive 4mm Allen bit and a 6" extension is invaluable.

Ryan is it possible your bolt is to long?

Ryans Rebel

My Feedback: (12)

Bolts are the ones supplied by DA. Maybe 3/8" (1/2" max) thread engagement. I like the idea of letting a thin film of ultra copper dry prior to installation. I may try the gaskets this time and try my luck. I've lways worried that the gasket would compress over time allowing the bolts to loosen. I do like the idea of serrated washers, where to get? May go with red loctite too!

What about the J.B. Weld. Is it good for exhaust temps?

Ryan

Desertrat

My Feedback: (2)

Hey Ryan.

JB Weld will hold up to the temp, but it doesnt last very long - I've tried it, worked great for about ten runs then it started to crack and break off. Are you trying to use it to fix the damage? if so, consider silver solder, its pretty easy to use and it <will> hold up.

I've been using high temp silicone RTV instead of a gasket - the ultra copper mentioned earlier works just as well - and High Temp Red loctite (there is a separate strong hold red loctite) - you'll find it at any auto parts store, its for header bolts and exhausts. This is the same setup I use on my car - I've never had an issue on either the car or the airplane. You do have to torch the bolts to get them out tho, the hi temp red holds just as strong as the hi strength red loctite.

Good luck man.

Roger

Edit: Hey man I just looked at Katrina's track... If you need to evac, we got room for you here. Y'all be careful out there, I hope this one is all hype.