Chipped fin repair?

[cpmaynard1980]

This is one of those questions that could fit a multitude of bike so I decided to ask in this section of the forums. Plus this is a better forum then most that Ive came across.

Does anybody have any good information on cooling fin repair? Ive been looking around and have came across everything form jbweld to just leave it alone. Ive read its possible to build it back with weld and another forum that said you cant weld cast.

Anyone have any eperiance with this? Thanks in advance.

[BA80]

I don't think there is really any way to permanently repair a busted fin. I've thought about just grinding and shaping the break so it looks like it's supposed to be there.

JAT

[fredintoon]

- - - Does anybody have any good information on cooling fin repair? Ive been looking around and have came across everything from jbweld to just leave it alone. Ive read its possible to build it back with weld and another forum that said you cant weld cast. - - -

Hi Charles,
sure you can weld cast aluminum.
Strip down to bare casting, vapor-degrease, TIG-weld in an inert gas glovebox, file smooth & bead-blast.
Is it worth doing?
For a museum display rebuild? Maybe.
For a bike you are going to ride? Nah.
Cast iron can't be welded but with extreme care broken off fins can be brazed back on (heat to just below brazing metal melt temperature, torch-braze, cool slowly) .
I've seen cast iron fins fudged up with plastic to re-sell antique bikes to the unsuspecting. Not good, they tend to fall off and they worsen the cooling.

[trbig]

On my guardrail "incident", the pickup coils were ground off by the asphalt and the cover broke out from the engine case. A local shop does aluminum welding, (Mig) so I just had them weld some extra material around the broken lip that the ignition cover bolts to. I used a flat file to shape and get it level with the rest of the lip and drilled and tapped new holes for the cover. No ovens or anything were used, and it's held just fine.

Short story long, if you have a shop locally that welds aluminum, it should be quick and easy to apply some extra material, then file to shape, if it's that important to you to fix something it's doubtful anyone else would ever notice.

[motoman]

Hi Charles,
sure you can weld cast aluminum.
Strip down to bare casting, vapor-degrease, TIG-weld in an inert gas glovebox, file smooth & bead-blast.
Is it worth doing?
For a museum display rebuild? Maybe.
For a bike you are going to ride? Nah.
Cast iron can't be welded but with extreme care broken off fins can be brazed back on (heat to just below brazing metal melt temperature, torch-braze, cool slowly) .
I've seen cast iron fins fudged up with plastic to re-sell antique bikes to the unsuspecting. Not good, they tend to fall off and they worsen the cooling.

Cast aluminium can be welded as Trbig stated, but cosmedically may not be worth the cost.

In reference to Fred's input, cast iron CAN be 'stick' welded with nickel rod......an inch at a time and peened before cooling for stress relief........just a many decade certified welders input......

[TopCatGr58]

Can I interest you in this idea!?

Check out this product:

http://bluemagicusa.com/index.php/bl...d_epoxy_putty/

T.C.

[fredintoon]

In reference to Fred's input, cast iron CAN be 'stick' welded with nickel rod......an inch at a time and peened before cooling for stress relief........just a many decade certified welders input......

Hi moto,
by an amateur who's welding mantra is length replaces strength using a Lincoln A/C buzzbox in his garage?
Perhaps not, eh?

[motoman]

Hi moto,
by an amateur who's welding mantra is length replaces strength using a Lincoln A/C buzzbox in his garage?
Perhaps not, eh?

Whatever works.......just don't confuse the two...........