Duracool 12a - Page 2 - PeachParts Mercedes-Benz Forum

Cap'n Carageous · #16 06-20-2002, 04:33 PM

Yall hang on now!!!.. heeerrrreee we goooooo....

leathermang · #17 06-20-2002, 04:48 PM

Rebootit, I am putting r12 into my system. That two gallons of oil is not in the form of vapor... much different than what I am describing as the fire hazard in an accident...

However, for those that have not seen the other threads... the fire hazard is only one part of the question having to do with evaluating substitutes for R12...

leathermang · #18 06-20-2002, 04:51 PM

Bill,, we are not talking about a closed system once an accident happens.... but I really need that drill bit... and will bow out of this discussion if that is what it takes to have it delivered this Sunday...

leathermang · #19 06-20-2002, 04:59 PM

NO, you can't trick me.. I am out of here,, I really need that bit...

#20 06-20-2002, 05:26 PM

the 2 gallons of oil is not a vapor in a closed system. When the system is cracked open in a collision it will be sprayed and will be a fine mist. Remind you of anything, like say what an injector does to diesel fuel? Ever see a car hit the wall at indy? The fuel is liquid but at a high speed impact it all of a sudden makes one hell of a big fireball.
Like I said r12 would be best and should have never been banned in the first place. I looked around and called around and if I could have found it for ~ $15.00 pound it would be what I used. Even on ebay the stuff is selling for $30.00 can when you figure shipping. I had one car for sure to do, and wanted to do something with the 240 because I have not been happy with what temps it had when real hot. Also was having a problem with compressor lockup when first started because of high pressure. The oils used for r12 are not compatible with 134a and the oils for 134 don't work with r12. I don't care what anyone says you can not flush all the stuff from a system. Trace amounts are not suppose to be a problem but these are cars I plan on holding for a long time, not something I will sell in 2 years. I wanted something that works, was inexpensive, and proven. I found it in the 12a.
Also the -10hg I quoted was from the manufacture. I pull a -29hg for at least two hours before filling. Not many shops will do that, and if all they will do is pull to -29 and stop what good did it do? The moisture starts to boil away at around -29, but if you don't take the time to suck it out then you may as well not have bothered in the first place. It is good insurance to replace the drier any time you crack open a system, but also not written in stone that "thou shall replace" either. If your system was in good shape with clean oil and no leaks experience has shown me it will be fine.
I would love to demonstrate volitile gasses with anyone here. Ever seen how far a basketball will fly when stuffed into a 50 foot section of 14" steel pipe filled with acetylene O2 mixture and set off with a spark? When done in Clearwater Fl it will bring every cop for two miles looking for the home that had to have blown up

Or on the smaller side a plain ol brown paper lunch bag filled with the same thing and tossed next to the guy welding in the shop

Man I miss the sign business at times

190D22 · #21 06-20-2002, 05:40 PM

So I have to get my system flushed in order to run this duracool stuff? I don't really want to get rid of my R12 that's in my car... seeing how expensive it is

There a way I can get it evacuated from the car and still keep it? Where do I get duracool?

#22 06-20-2002, 06:02 PM

If you have r12 and it is working I wouldn't touch it. No matter what anyone tells you there are no (none nothing nada) drop-in replacements for freon (r12). Any old gas will have to be removed before adding ANY replacement.

leathermang · #23 06-20-2002, 07:02 PM

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=1835657466

I think this works out to less than $19 per 12oz can INCLUDING SHIPPING....so $27 for expansion valve, $36 for receiver/dryer, $16 for flush , or free if I use my Argon bottle

.... I should be able to do it for three cans...which I do not think is bad considering all the advantages and that this is what the system was designed to use...I have some other old cars if I have any left over...:p

190D22 · #24 06-20-2002, 11:33 PM

While we're on this subject... what properties makes a fluid/gas a good refridgerant? Is it its evaporating properties? If so why not use ether or C02? What's so special about R12 that makes it better than R134a?

airfoill · #25 06-21-2002, 12:04 AM

Rebootit,

I bought a case of Duracool but haven't used it yet because I had my 240D converted to 134 before I bought the Duracool. The temps at the ducts right now hover around 58 degrees with 134; not impressive at all. I'm very tempted now to just replace the 134 to the Duracool after reading your first post about getting temperatures in the 30's.

A friend of mine borrowed some of the Duracool a week ago for his Chrysler minivan and I wanted to see if the stuff works. He used it and according to him, it does work, although he said that at idle, the system doesn't bring down the temperature as fast as the r12 it had before but once the car is running down the road, it does bring the temperature down to r-12 levels. His minivan has a dual evaporator system so there may be differences in how the duracool works there. I don't know.

Also, about the fire hazard if the compressor was to sieze; this would not be an issue because a siezed compressor would occur within a closed system. Oxygen is not present within a closed system, and therefore, no fire. You need oxygen to ignite the oxygen/hydrocarbon mixture. And remember too, that you need the correct mixture to light the hydrocarbon. Remember how hard it is to light a propane torch? THink about it. I believe the fire hazard risk is extremely small. If it was such a great risk, what do we do about all those gasoline powered cars on the road today with all that gasoline when they are wrecked.......a ticking time bomb.

I agree with Bill.....the risk is very very small and the benefits are great......cold a/c.

Herb
'82 240D
'87 300SDL

leathermang · #26 06-21-2002, 08:44 AM

Herb, this is one of the reasons I questioned Rebootit starting a new thread.. where it would not be close to the former discussions about the fire hazard...

I have never said that the fire hazard was great with respect to the compressor failing and producing an explosion,,, and I said exactly what you said for the physics of the argument..or that an inside the passenger compartment explosion was likely....

It is the situation where the system is broken by an accident... that air, ignition source and this stuff as fuel would be a cause for concern..and most importantly it would be at a time when one might be injured and not able to flee the fire...

leathermang · #27 06-21-2002, 08:46 AM

190d22...I am reserving this space to answer your question later, ,, will copy the info from my ac manual... Greg

franklyspeaking · #28 06-21-2002, 08:59 AM

I would agree with those who think Duracool is a safe alternative.

At the plant where I work, we use Propane and Ethylene as refrigerants to cool the processes in two of the units. The compressors are around 10,000HP, and the capacity of systems are 10 to 15k gallons. It takes about two or three trucks of the stuff to fill up the system. When the compressors trip the ethylene/propane is flared off (burned), because there is not room in the system for expansion of it all. There has never been a serious incident with these systems in 25 years. The key to operating them safely is in the fact that they must be purged of all oxygen with inert gas for 24 hours before they are charged. To get fire it takes 3 things - Oxygen, combustable material, and an ignition source. You can effectively eliminate fire by controlling just one of these three things.

It would be a pretty rare occurrence that a leak would line up with an ignition source in such a way as to ignite the refrigerant (the propane torch analogy above), and we're talking about less than a pound of this stuff. Most wrecks would do catastrophic damage and the leak would be over almost before it started. Ignition of 12 ounces of propane in open air would do little damage and most probably be confined to the engine compartment.

Good discussion, but most arguments against it have little basis other than emotion.

My $.02 worth.

#29 06-21-2002, 09:21 AM

All refrigeration is based on the fact that a liquid going to gas creates cooling. R12 134 12a etc. have a reasonable low boiling point of around -22 (if memory is correct) meaning it is easy to compress back into a liquid state so it can be pumped back and allowed to expand into gas again. CO2 would not work as it goes from gas to more or less solid, think dry ice. Other gases like argon, require pressures far higher than you would want in an A/C system. Even at 2000 psi it is still a gas. Sure if allowed to expand from a tank at a high rate it will cool, but it would take way more than the liquid state freon allows. Propane, butane, etc. also work great as refrigerant. Low pressure to become a liquid, low boiling point. The first type of refrigeration used after the "ice box" were filled with liquid ammonia and used a flame to boil the liquid from one side to the other. As the first tank ran dry the whole thing would teeter-totter over and the flame would light under the other side. No compressor needed, no real moving parts other than the balance beam the two tanks sat on. I know of some of these units still being used in some old country stores in Ky. The big chest type coke coolers were first made this way. No electricity is needed, only a flame source either kerosene or propane.
leathermang I'm sure can explain in greater detail

leathermang · #30 06-21-2002, 11:55 AM

Franklyspeaking, That " plant where you work" ... How many miles per hour does it travel ? R12 was chosen specifically because we are discussing MOVING refrigeration systems.... which by their very nature involve much higher risk of accident than stationary facilities.