Repairing cracked vernalift muffler

[Josephcrawl]

I have a vernalift muffler with a substantial crack in the top. Has anyone repaired these with epoxy/fiberglass? I'm in a bind and can't get a new one at the moment.

Thanks

[Opie91]

Originally Posted by Josephcrawl

I have a vernalift muffler with a substantial crack in the top. Has anyone repaired these with epoxy/fiberglass? I'm in a bind and can't get a new one at the moment.



Thanks

Do some research but as long as it is wet and made of glass pretty sure they use vinyl ester resin for that.

Check out lbifiberglass.com

[gonesail]

mine was repaired with epoxy and cloth. works fine.

[boatpoker]

Epoxy/glass will work, Vinylester/glass will probably work, polyester/glass will fail.

[Opie91]

Pretty sure Vinylester resin has better heat properties than epoxy.

[capt jgw]

Epoxy will soften around 200 deg F or less so it's not suitable for exhaust. I'd use vinylester.

[boatpoker]

Originally Posted by capt jgw

Epoxy will soften around 200 deg F or less so it's not suitable for exhaust. I'd use vinylester.

My experience is different. All the eopxies I have used have been spec'd up to 300F. I have used it several time for FRP mufflers and it has worked well.

[Opie91]

Originally Posted by boatpoker

My experience is different. All the eopxies I have used have been spec'd up to 300F. I have used it several time for FRP mufflers and it has worked well.

Repairing a water lift muffler in a properly designed system could easily be more about the bond than the heat properties. So epoxy may be better in applications.


Either it is better than a crack.

[Josephcrawl]

Well it's done. I put a couple of layers of 4oz glass over the cracks and wet it all out nicely after a healthy sanding and some acetone wipe up.

I'll report back on success or failure

[Scubaseas]

Stop drill the ends of the crack. Clean really well. Wash with soap & water, or alcohol or MEK or, or. Clean before you grind or sand, then clean again with alcohol. JB Weld works OK, West Marine G Flex Epoxy works even better. Add some 6 oz cloth if you want. Should be fine. Be nice to find out why it cracked like is the exhaust clogged or did an exhaust hose collapse? Like how much back pressure do you have at WOT.

JB Weld can withstand 550*F when fully cured. They also make a high temp product. Never underestimate the power of JB Weld or duct tape.

[FPNC]

Centek uses a high temp polyester resin, maybe with a fire retardant in certain MIL applications. Mandrel turned glass strand and chopped strand glass mat. Repair with same. Normal polyester resin and chopped strand mat will work for most repairs. Stay away from 'cloth' .

[boatpoker]

Originally Posted by FPNC

Centek uses a high temp polyester resin, maybe with a fire retardant in certain MIL applications. Mandrel turned glass strand and chopped strand glass mat. Repair with same. Normal polyester resin and chopped strand mat will work for most repairs. Stay away from 'cloth' .

Are you aware of the secondary bonding issues with polyester ?

[stormalong]

I repaired mine about 30 years ago. The lid was separating from the main body. Couldn't separate the two without damage. Repaired with epoxy and glass cloth over the joint. I was relatively inexperienced with those back then.

The repair is still good.

[FPNC]

Originally Posted by boatpoker

Are you aware of the secondary bonding issues with polyester ?

Yes. 30 years of fiberglass experience with manufacture and repair of recreational, commercial and US Navy high speed light craft.

Grind before you apply. Vacuum the surface, do not wash or solvent clean the freshly ground surface.