Re: R-12 substitutes

[Frank Deutschmann <fhd@panix.com>]

Alan Cordeiro sez:
> I was hoping to try and start a discussion on SAFE alternatives to R-12,
> and had only heard of the GHG-12 stuff and wondered if there were other
> similar alternatives available, and if anyone had ACTUALLY TRIED them,
> ( or know of friends that had ). I threw out the ISO-(BUTANE...?) 
> combination just to show how one home brew mix might be used as a 
> substitute somewhat matching all the PHYSICAL PROPERTIES, never mind the 
> side effects.

The home-brew approach definitely should only be followed if you know
what you are doing -- one of the reasons I chose that post, however,
was that it really does not provide enough info for those who are
novices at A/C work.  Other posts were more thorough, but I didn't
save them, as they provided more than enough info for a complete
novice to get in well over their head.

The safety issue is quite interesting; as I remember, most of the
thread was on just how false it really is.  A key point mentioned was
that R-12 in your car's existing system is quite flammable.

WHOA!  What's that?  R-12 flammable?

Actually, R-12 is not flammable, but the compressor lubricant is very
flamable, especially when atomized into a fine mist as in the A/C
system.

I didn't believe these claims, so I did the test at home:

(BE SURE TO DO THIS OUTSIDE IN A WELL VENTILATED AREA -- R-12 BREAKS
DOWN INTO SEVERE TOXINS ON EXPOSURE TO HEAT.)

1) Vent can of R-12 towards torch.  No response, rather dull and
boring.  (DO NOT BREATHE THE VAPORS!!!)

2) Place some compressor lube oil into a section of tubing (foot long
or so), vent R-12 into one end of tube, and hold other end towards
torch.  (BE EXTREMELY CAREFUL -- DO NOT HOLD IN HAND!)  Big
flamethrower reaction!


As I remember, one of the key benefits of GHG-12 was that it did not
require a flamable compressor lube oil.  However, it was an isobutane
blend, and so was thought to be unsafe.  In actuality, it is likely
safer than the current R-12/lube oil combination.

(I'm not encouraging anyone to home-brew R-12 substitutes, and I have
never done that myself.  However, I find the discussion quite
interesting.)

> Alan Cordeiro

-frank
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