Mending broken fins

[RichV]

While in the process of cleaning and painting an engine I broke the tip of a fin off. It happened back a few weeks and I didn't find the broken part until today.

Here is my question. How do I mend it? I figure there are three ways (discussed many times on this forum) to fix the fin:

1. JB Weld - This is a popular method mentioned throughout the biker world. It is a darker gray when cured and will not conduct the heat. You also need to have the fin.

2. Two part putty - Comes in two bars and you cut off equal lengths. message them together into single uniform color mass. Hardens quickly and can be shaped. This is available from many manufacturers and is used to re-mold the fin if the broken off part is missing. Once again, no heat conduction.

3. MiG/TiG welding - By far the best solution for heat conductivity and it can be filed/ground down. You have to find someone that can weld it and you must have the broken off part (of fabricate one)

The fourth way, which is not a fix, is to file it down and make it look normal. I can also do the same thing on both sides. However, I'm OCD and it will eventually kill me. That said, I could blend it with the cylinders since it's the last fin. It will be different but no one (except another XS11 restorer) will notice.

So here is my break.



It's only a small part. Here is what the break looks like with the cylinders attached from below and above. As you can see, it is noticeable.




So what I'm looking for is any good stories on which one works out best.

Thanks

[mack]

If I remember correctly

Crazy Steve had a fix that worked good. Thats the good news. The bad news is that he isn't posting as often and it may take time for him to respond to a PM. I'll search but it was a while ago, diver ray or marty might know it right off.

[RichV]

Thanks.

I have time. I'm retired

[BA80]

I have thought about this for my own stuff and I think the best remedy is to round it to look natural and do the same to the opposite side.

No one will ever be the wiser and all it costs is elbow grease.

JAT.

[Old Red]

I if it was mine I would do what Greg said. If you really want it back on there have it TIG welded back

[MaximPhil]

Hi Rich,
Let me start with. I am not Normal nor do I want to be.
On the race car we used a 50/50 rule for cosmetic issues. If it looked good from 50 feet @50MPH it was good to go
I would round it to look natural perhaps follow the curve of a much lower fin.
Also note the inside 25% is covered when you install the exhaust header.
I would NOT deform other side to match.
Phil

[James England]

Fix it, don't round......

[TopCatGr58]

Hey Rich,

I have a TIG welder, but it's only for STEEL, it's DC, so it can't work on Aluminum...I tried....all it does it heat the aluminum to a melting point too quickly below the surface, so it collapses like a sinkhole before I can see/tell what's happening!

I can MIG weld aluminum somewhat...did it to make my gauge cluster box and mounting brackets. MY Mig welder is AC so it can break thru the Al.Oxide surface that forms on aluminum just exposed to air. However, not sure about being able to get down in there with the other fins possibly in the way. I'd be willing to TRY....but my time is a bit tight right now....preparing for a vacation trip to ALA to visit my 87 y/o mom, getting her packed up to move to FLA., and then to attend XS SouthEast the following weekend. You say you're not in too much of a hurry. I could visit you with my welding stuff after I get back from my trip to TRY/ATTEMPT to weld it if you would like.

OR...I/we could ride up there to your place, get the head/broken fin from you, take it back to my place for easier access/working on it without having to lug my welder and large gas bottle and such up there?

Otherwise, let's look at it this way. The fins are for COOLING. There's still SOME fin there where it broke off of. So...there will stil be some cooling affect from the residual fin. If you were to measure the surface area of the part broken off, and then the total surface area of ALL of the other fins, I would bet you would find that you will be loosing maybe 1% +/- of total cooling surface area....doubtful that it would have any functional/detrimental affect to the performance of the engine.

SO...I personally would grind it down to match the fins pattern just below it and be done with it. But my OCD isn't as bad as some folks!

T.C.

[BA80]

Hey Rich,

SO...I personally would grind it down to match the fins pattern just below it and be done with it. But my OCD isn't as bad as some folks!

T.C.

+1

[jwhughes3]

Create a clay casting if the fin with broken piece in place. Use a melting pot to melt a small quantity of aluminum then pour into clay mold. File down when done. No welding required.


BTW I have never done this just read about it on the net somewhere.


John

[RichV]

TC no worries. I'm actually leaving to visit my mother (same age) in TN just before XS Southeast as well. I'll see you in NC and we can talk about it then. I'm inclined to "try" JB weld then round it off it it looks bad or doesn't hold.

In any case, it's low on my priority list. I need to strip and repaint the case, valve cover and cylinders first. I also need to clean the head better and strip it.

[RichV]

Create a clay casting if the fin with broken piece in place. Use a melting pot to melt a small quantity of aluminum then pour into clay mold. File down when done. No welding required.

I've actually cast aluminum before. I don't have the furnace anymore but if I did I could make it work with a simple mold. Anyway, I would have to practice a lot before even trying.

Also, this isn't pure aluminum is it? It's an alloy so I would have to source the metal from another unused part. I bet the melting temp is higher than pure aluminum.

[skids]

I tried the regular JB Weld and it got "rubbery" after heating up. That little tab that broke off will not make a big difference with heat dissipation.

[James England]

I tried the regular JB Weld and it got "rubbery" after heating up. That little tab that broke off will not make a big difference with heat dissipation.

it won't make any difference at all. Just appearance....

[crazy steve]

Haven't tried it, but hear good things....

http://muggyweld.com/super-alloy-5