Epoxy adhesive on Cast Iron cylinder fins

[Spanner]

I have a broken cooling fin on my 1926 Raleigh.  Rather than risk having the piece welded/brazed back on, does anyone have any info or experience in using epoxy to do this job.  Years ago I epoxy'ed a steel sleeve into an exhaust port OK but that was a shrink fit as well.
Any help or info would be most welcome.  
Thank you.

[geoffus]

Yes you can, with a good resin. I use Plastibond here in Oz.  It's a bit like semi-liquid putty with a separate hardener.
1.  Clean edge of fins but don't file smooth.  Clean thoroughly with thinners two or three times.  You can if you want sandblast first as you have to repaint.
2.   Drill holes in broken edges of both fins either side, so that they roughly line up.  Drill 1 mil. or 1/32 holes in about 1/4 inch if possible.  Then get wire to fit in holes, making sure the wire is in the centre.  Araldite the wires into the holes.
3.   Put piece of plastic under bottom of fin (if more than one fin, one at a time).  I use old ice cream tubs, as this does not stick and this saves a lot of time in cleaning underneath.  Then fill with putty.  You may have to do this a few times because of small holes, etc. until satisfied.
4.   Respray and bake in oven to 180 C from cold for half an hour, let cool down slowly.  Leave door of oven open as this stinks.  Wife may not like this as it does linger.

The only way you can tell the difference is by running a fingernail up the fins.  You get ping clunk ping.  Never had any trouble with this arrangement - takes heat and doesn't crack.  If rough-cast, use a little sand in paint and brush on, then spray.  This saves you having to re-bore after welding.
Hope this helps,
Regards, Geoff      

[Spanner]

Dear Geoff,   Many thanks for taking the trouble to reply.  Sounds a good method.  Are you aware of another good website www.honestjohn.co.uk   ?
Have a look at its discussion area (you may need to register).  Absolutely loads of stuff there and is very much used here in the UK.  I've posted questions here about 6 times now and the response is really good.  I asked about epoxy on fins at this site and had loads of replys the most interesting suggesting I check out 'Jb weld' as they have an epoxy that goes up to 500 degF which is more than enough.  I have ordered some of this and coupled with your method we should be onto a winner.
Thanks again Geoff for replying.  Isn't the 'net wonderful.
Best wishes,  Mark.

[geoffus]

Thanks for your email.  The wire is just like reinforcing in concrete.  Just a quick story: a barrel I did for a friend that had about three fins missing, 2 inches down to 1.5 using this method.  The bike was parked at someone else's place for 12 months and asked to be started once a month for about ten minutes.  Unfortunately, the guy was a 2-stroke man.  The valve-lifter was explained to him but not the advance and retard, and was left in retard.  (This man could kick start a Jumbo.)  And sure enough he did as asked but never advanced the timing.  So when picked up, the new exhaust pipe chromed was bubbled and a very funny shade of yellow and blue.  But the fins were as good as new.
   The stuff I use is good for 300 C, the paint 550 C, although paint these days is not as it was.  It always seems to be new and improved.  I think this means new cheap ingredients and improved profits.  So when I get anything that works, I try to stick to it.
Please let us knpow how everything works out,
Regards, Geoff