[Public-List] Tiller Head - I'm stuck!

[Glennb]

hey Jeff,

there area a couple of good primers on the web regarding using an oxy/ acetylene torch.  don't worry to much about melting the bronze.  Can't happen with a small torch in your setting.  acetylene only melts mild steel. the bronze casting and shaft will help diffuse excess heat, soo no worries on that end. if younstart to get worried about a liquid state, just remove the heat and let it cool a bit.  No worries.  At worst douse with  a bit of water or,cutting oil, walah! Helps break down the seized up material.  

the important things to remember are
1) set acetylene gas first, to 5 - 8 PSI max
2) then set oxygen starting at 20 PSI
3) Fire the acetylene
4) fire Oxygen, adjust flame to optimum configuration... Short symmetrical blue inner flame, symmetrical outer orange flame
5)  adjust flow rate on the nozzle to build a larger or smaller flame for the work
6) use the tip of the inner blue flame to heat bolt and remove 

I used a full sized oxy acetlyene torch to a  heat and bend my bronze rudder shaft through a compound curve when I rebuilt my rudder couple years ago. It turns purple at the upper end of the heat chart before any serious deformation occurs.  

you could have some fun testing out the process before hand on a spare bolt to see how the material will react before re attacking the real offender in the  tiller head.  Watch for color change and shimmering in the surface of the material as it heats up.  The physical signs are good indicators of the properties of the metal. I'll bet you will have a realm hard,time, if not impossible, to melt a bronze bolt.  

iam not a fan of soaking the whole assembly as the releasing agent needs to penetrate into the thread/ shaft area.  Its messy and doesnt really address the problem as the tiller casting will mask the penetrating oil from getting down into the corrosion.  also if the plastic bag leaks or dissolves, you've got a quart or two of solvent soaking into your cockpit and or running out the drain into the water. hence oil spill.

the other thing you might need heat for is to get the tiller casting OFF the shaft once the bolt gives up.  I had a devil of a time removing mine.  as I remember I heated the casting itself to free it...then it broke anyway  so bought a new one.

 



Sent from my iPad

On Apr 3, 2012, at 5:45 AM, Jeffrey <fongemie at gmail.com> wrote:

> I have not tried CRC Freeze Off, but I need to go to town today so
> I'll pick some up.  The more I think about it, I'm a bit nervous about
> adding much more heat. Bronze can melt at 2000 degF or less.  I can be
> patient.
> 
> I like the idea of immersing the whole tiller head in solvent. I'm
> wondering what the solvents won't dissolve? Could I zip tie a latex or
> butyl inner tube section around the shaft, then fill it up with
> solvent?  Might be worth an experiment.  I don't want to dork up the
> fixture itself.
> 
> On another note, I'm finally putting some time into bringing back the
> hull. I got a new Makita polisher:
> 
> https://picasaweb.google.com/lh/photo/IOS2XxW4tIuO275NqvTAh5s2JjFi0EBE9QO4WtaoFco?feat=directlink
> 
> Much more fun than wrestling with old rusty bolts.
> 
> -jeff
> 
> Jeff Fongemie
> #116 Seagrass
> 
> http://picasaweb.google.com/fongemie
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> On Tue, Apr 3, 2012 at 7:31 AM, Mike Lehman <sail_505 at hotmail.com> wrote:
>> Has anyone tried CRC Freeze Off....it works great, mucho better than PB
>> Blaster or anything else. When you spray it on it bubbles up (like scrubbing

 1333482844.0