Muffler epoxy

[Matt Brown]

How hot does exhaust get? I have a carbon fiber muffler for my K-77. The carbon part broke loose from the aluminum header. I’ve cleaned up the two pieces and looking to buy some epoxy to put them back together. I’ve had good luck with the family of JB Weld epoxies. They have two high heat choices. One good to 500 degrees F and the other to 2400 degrees F. I can get both at Ace hardware tomorrow.
Randy Smith chime in, it’s one of your mufflers? I didn’t hear about supporting the muffler until after it broke loose. I made up a support for the back end and tried gluing it with CA. It worked well enough to get through the Nats but now I want to fix it right.

Matt

[Gary Dowler]

Either should work fine. I've hit a few mufflers with my infared thermometer and never seen a number anywhere near 500 deg. Probably half that.

Gary

[Brett Buck]

I’ve had good luck with the family of JB Weld epoxies. They have two high heat choices. One good to 500 degrees F and the other to 2400 degrees F.

  2400F? Which one is that?  In any case, that's *far* above the melting point of aluminum, so, good to go.

     The exhaust on a stunt plane it generally pretty low, 3-400 degrees at most.

    Brett

[Matt Brown]

  2400F? Which one is that?  In any case, that's *far* above the melting point of aluminum, so, good to go.

     The exhaust on a stunt plane it generally pretty low, 3-400 degrees at most.

    Brett

JB Weld Extreme Heat. I was thinking it may not have the bonding strength of others but I was thinking 500 may not have been enough. I remembered dynoing my race engine back in the ‘90s and exhaust temps were pushing 1100 degrees.

Matt

[Lauri Malila]

I have never had problems with std JB-Weld. I didn’t even know that hi-temp version exists. L

[Brett Buck]

I have never had peoblems with std JB-Weld. I didn’t even know that hi-temp version exists. L

   Me neither, and everybody uses the regular kind to seal pinholes in their tuned pipes, where it's probably more heat-resistant than the epoxy used to make it.

   Brett

[gene poremba]

 I repaired a cannister muffler on a DA-100 motor with regular JB weld at least 6yrs ago. I sold the plane recently and the cannister muffler I repaired is still in use. It was a repair on a very low stress area (exhaust exit tube) but sees engine exhaust regularly. Cheaper than a $200 set of cannisters...Gene

[Phil Spillman]

Hi Matt, Funny you should mention muffler repair and JB Weld at this time! I have recently tried to repair a ST G-21 .46 engine muffler mount for the second time and have yet to try it out! I hope to do this this Thursday morning at our next flying session! I'll let you all know how it worked out!

Now Matt, would you please give us all a report as to how your repair worked out and which formula of JB Weld you used? I used the "regular" stuff in my efforts both times since I really didn't know that there were differing blends to acquire until reading this thread!

Thanks for the segment!

Phil Spillman

[Dan Berry]

Scotch-Weld DP 460 would be my choice.

[Matt Brown]

I used the JB Weld high heat, high strength epoxy putty. I’m not real thrilled with the putty but if it doesn’t hold, I’ll try something else! The putty can’t really soak into the mating surfaces like a liquid epoxy so I have my doubts.
It seems very solid but engine vibration and the flexing of the nose of the plane may be too much for it. I have to reinstall the tank and then engineer some kind of soft mount for the back end of the muffler. I had it hard mounted last go around.

Matt

[RandySmith]

How hot does exhaust get? I have a carbon fiber muffler for my K-77. The carbon part broke loose from the aluminum header. I’ve cleaned up the two pieces and looking to buy some epoxy to put them back together. I’ve had good luck with the family of JB Weld epoxies. They have two high heat choices. One good to 500 degrees F and the other to 2400 degrees F. I can get both at Ace hardware tomorrow.
Randy Smith chime in, it’s one of your mufflers? I didn’t hear about supporting the muffler until after it broke loose. I made up a support for the back end and tried gluing it with CA. It worked well enough to get through the Nats but now I want to fix it right.

Matt

Hi Matt
Use  standard  slow  JB Weld, not the  5 minute  type, it will  work well,  and  yes  I have tried to tell everyone  for  years  that  you need  to support the  back of any  rear muffler  or  header muffler  or  pipe.  It is  best to try to use a soft mount at the rear, it does not need to be  beefy or  very hard. it is  really there just to support the end and  stop the oscillation or vibration  of the  muffler.

Regards
Randy

[Matt Brown]

Hi Matt
Use  standard  slow  JB Weld, not the  5 minute  type, it will  work well,  and  yes  I have tried to tell everyone  for  years  that  you need  to support the  back of any  rear muffler  or  header muffler  or  pipe.  It is  best to try to use a soft mount at the rear, it does not need to be  beefy or  very hard. it is  really there just to support the end and  stop the oscillation or vibration  of the  muffler.

Regards
Randy

My first mount was some foam tape underneath the muffler and a rubber band around it to hold it in place. Rubber band nor the foam tape survived the heat. Next I tried a brass strap screwed down around it while resting on a piece of soft balsa. I think that was too hard. I think next will be some silicone surgical tubing for both the rest pad and to hold it in place. Should be firm enough to hold it while spongy enough to let it absorb the vibration.
I’ll use regular JB Weld if there is a next time!


Matt

[M Spencer]

Winter when the glues thick & stiff , it seems to not work .
Unless you sit it on cardboard on the (hot) coffee cup . for flavour .

Common sense really . but , with it thin & runny it mixes well & sets ,
with it coagulated with the cold that could not be said of it .