Using Heat on Stuck Things, it works based on Physics

[Larry C. Leung]

You are making the assumption that the pipe is in a confined space. 
The pipe does not have to expand up into the cool areas. It may 
simply expand outwards (i.e. pipe diameter will enlarge, just like
the hole). So heating from ANY direction will still expand the hole.

You may be able to keep the OXY sensor from expanding by
wrapping it and only it in wet towels while heating from below. 
The problem is the sensor threads are of a metallic material with
fairly good heat conduction abilities, so the mere contact of those
threads to the pipe may be enough to heat the sensor threads so
that they expand too. 

LL - NY

On Mon, 22 Dec 2003 23:17:11 EST SuffolkD at aol.com writes:

Lister(s): 
I'm no expert in the properties of metals........but Dan's post
referenced made sense to me. 
Here's why:  The O2 sensor (Dan's post) is a threaded hole in a Round
pipe. 

If one heats the round pipe with a torch, the metal (for this example)
will expand from the bottom up if the flame is pointed there:  the bottom
of the pipe when heated will expand...........in this example I can see
the top of the pipe (where the threads are) being compressed from the
heat - from the bottom of the pipe - expanding. 

If one tries to heat the top of the pipe where the threads are: it would
be difficult to keep the heat from the O2 sensor which would expand from
the heat in this case making the sensor expand in the threads still
causing a "bind." 

Which would be the better option? 
If I could keep heat from the sensor and use a pin point flame, I'd go at
the O2 threads in the "top" of the downpipe. 

So in review I think WHERE the flame is pointed will be the most
important if heat will help in taking things apart. 
Gentlemen? 
-Scott by BOSTON 



From: "Larry C. Leung" <l.leung at juno.com> 
Subject: Re: quattro Digest, Vol 2, Issue 162 Using Heat on Stuck 
Things,    it works based on Physics 
To: quattro at audifans.com 
Message-ID: <20031221.153314.-407579.1.l.leung at juno.com> 
Content-Type: text/plain; charset=us-ascii   
Dan, et al, 

Although it seems like the hole should get smaller, quite the 
opposite is true (unless you do something foolish like heat 
the stud/bolt instead of the surrounding material or nut).... 

BTW, I had a lot of difficulty with this topic until I thought it out. 

If you think of the material around the hole as being made of 
links, each link will expand, correct? 

If so, then the circumference of the hole will get larger, right? 

Thus, the holes diameter will actually increase rather than 
decrease. It seems counter-intuitive until you think it out carefully. 
Thanks to Larry Gonick in his book, Thinking Physics. 
The heat also helps break the bonds of corrosion, but that's another 
topic. 
Happy Holidays, all! 

LL - NY, a.k.a. the Physics Teacher 

> From: Dan Cordon <cord4530 at uidaho.edu