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Propane as R-12 Replacement?

Discussion in 'The Hokey Ass Message Board' started by El Caballo, Jan 9, 2014.

  1. 59 brook
    Joined: Jun 12, 2005
    Posts: 1,017

    59 brook
    Member

    so this is traditional hot rodding?
    not trying to step on toes but i really dont think this is what they used traditionally
     
  2. HUSSEY
    Joined: Feb 16, 2010
    Posts: 628

    HUSSEY
    Member

    Oh my god...I can only hope that you are beeing sarcastic.

    I would go with a134A conversion. I've done several and while they wont perform as well as the R12 inan R12 system, they do quite well.

    The R414 sounds interesting though.
     
    Last edited: Jan 9, 2014
  3. summersshow
    Joined: Mar 3, 2013
    Posts: 899

    summersshow
    Member
    from NC

    Propane works excellent to replace R-12... Its just gotta tiny hitch... Its super dangerous incase of leaks or a wreck... Also super illigal. If someone gets hurt from someting that happens then your facing criminal neglegence...
     
  4. Propane (straight) has a pressure-temperature (P-T) curve that is closer to R-22. R-22 is common for house A/C systems. Propane mixed with isobutane is what most of the hydrocarbon R-12 replacements are. Note the hydrocarbon in the name indicates it is propane and other hydrocarbon-based chemicals. The isobutane helps it mimic the R-12 P-T curve.

    Will straight propane work? Yes, but it has a problem getting too cold and freezing up the evap unit. Is it dangerous? Depends on what you think, the system is sealed with no air and as long as no big leak it will never get to explosive percentages in air. In an accident it could leak, but so can gas or other flammable liquids from the vehicle. Anti-freeze can burn for example when it flashes off a hot exhaust manifold.

    I would make sure to at least label any propane so you do not contaminate the next guy's recovery system. Legality is up to you, it is kind of a fuzzy area.

    If you charge with anything: R-12, R-134a, propane, whatever else you should always use gages and monitor pressures. I will say that propane will run a bit higher pressure than R-12 and takes about 1/3 the amount vs R-12. The attraction for propane in R-12 system is that propane will dissolve the mineral oil lube as used in R-12 systems. R-134a will not dissolve mineral oil and that is why for best conversion results you should flush out old oil and then recharge with new POE (aka "ester") oil with the R-134a.

    The reason R-134a does not work so well in R-12 conversions is not the R-134a, it is due to the condensers for R-12 are not as good efficiency and that limits what the R-134a can do for cooling. Put a newer style parallel flow condenser and it takes more heat out of the hot high pressure liquid/foam/vapor mix coming out of the compressor. More heat out of the high pressure liquid results in colder evap temps due to the temp drop due to high pressure liquid to low pressure gas after the orifice/valve expansion.
     
  5. Have you ever heard of "cool cans", these guys are talking about their "cool cans"! (or was that can coolers?)
     
  6. gimpyshotrods
    Joined: May 20, 2009
    Posts: 16,573

    gimpyshotrods
    Member

    Think Safety Third!
     
  7. pdq67
    Joined: Feb 12, 2007
    Posts: 787

    pdq67
    Member

    IMHO, this just about as good an idea as M/B wanting to use CO2 in their car A/C systems.

    Top pressure is 3,000 pounds and bottom pressure is 2,500 pounds!

    pdq67
     
  8. Torana68
    Joined: Jan 28, 2008
    Posts: 1,131

    Torana68
    ALLIANCE MEMBER
    from Australia

    Dunno if you can get these gases over there but this is a drop on gas, no conversion , no changes, my system works as well or a bit better than new
    http://www.hychill.com.au/products/
     
  9. archied1067
    Joined: Aug 5, 2007
    Posts: 425

    archied1067
    Member

    Propane is to dangerous wouldn't use it!! Propane i dont think would carry the oil through the system very well and would cause compressor failure fairly quickly!! Hot shot in a r12 system I heard works well for a while until it eats up rubber seals found in automotive systems. Hot shot works well in r12 systems found in commercial refrigeration ( freezers and coolers) For auto motive I would stick to r134a even though I'm not fan of the stuff. I don't even like 134 in commercial applications. I like 404a the best to get temps down low


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  10. nrgwizard
    Joined: Aug 18, 2006
    Posts: 1,132

    nrgwizard
    Member
    from Minn. uSA

    Hey, Ruffdawg;

    What did your son use for compressor oil? Mineral oil? I'm guessing he started w/an R-12 system?

    & for you guys that think the R-12/22/134/et-al gasses are "safe", - with or without a fire - maybe a rethink is in order. I'm always curious what actually works, how well, & drawbacks (& there are always drawbacks to everything - it's a matter if you can live w/them. No pun intended). I'm not overly fond of the "blends", for a number of reasons. Ammonia isn't something I'd want to play w/either. I do know a little about refrigeration & a/c history. I don't envy the guys that did this w/o any safety equipment, the side effects weren't nice. & I got to witness some of them up close when I was much younger. :( .

    Marcus...
     
  11. The EPA strictly regulates all automobile refrigerants. Propane and hydrocarbon refrigerants are illegal for use in automobiles, as of August 2010, mainly because of concerns about their flammability.
    If you have an explosion or fire because of it, you can and will be held criminally liable.
    Just food for thought.
     
  12. gimpyshotrods
    Joined: May 20, 2009
    Posts: 16,573

    gimpyshotrods
    Member

    Yup, and might void any help from your insurance company.
     
  13. Back in the day. .... Before 2010.. I ran a car with propane in the AC for about 3 years. Worked better than any refrigerant.
    Would I do it Again? Hell no.
     
  14. my47buicksuper
    Joined: May 23, 2013
    Posts: 302

    my47buicksuper
    Member
    from sunny fl.

    Well look at it this way if you ever brake down on the side of the road and your a/c system is filled with propane and you got some hotdogs and a lighter at least you won't be hungry.


    "I'm not responsible for anyone or anything getting killed or destroyed by cooking hotdogs over your a/c system"

    But if you must try please post pics
     
  15. archied1067
    Joined: Aug 5, 2007
    Posts: 425

    archied1067
    Member

    Never used propane as a refrigerant just don't like the fact of pressurizing it. Any one have a PT chart on it???


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  16. 64*thunderbolt
    Joined: Dec 26, 2013
    Posts: 10

    64*thunderbolt
    Member

    Very very dangerous, propane as everybody knows is not only flammable,it's a explosive gas, a/c systems are prone to develop leaks,both inside and outside the car,even a small leak would make your car into a bomb,do it the right way, safe, easy and cheap,buy a retro kit and put R134 in it.
     
  17. KRB52
    Joined: Jul 9, 2011
    Posts: 994

    KRB52
    Member
    from Conneticut

  18. icsamerica
    Joined: May 23, 2012
    Posts: 62

    icsamerica
    Member

    The only safe replacement is R134a. HFC-152a is also flammable.

    Converting any system to R134a is easy and will perform great if you consider the following 4 points.

    1. Orings and hoses "Should" be R134 compatible for good sealing. If you have an old system with flare fittings replace them or use flare seals which are like flat orings.

    2. You'll need a much larger condenser with R134 for best results in temps over 80 degrees. R134a system efficacy rates fall off a cliff when the condenser gets hot. Most R12 condensers are too small for R134. Some full sized 70's and 80's Cadillacs were oversized to begin with and will work well with R134. You can crutch the system with an auxiliary electric fan wired to run when the compressor is engaged.

    3. Use a universal ester oil.

    4. For best results you have to adjust or replace the expansion valve with one that is designed for R134. Some expansion valves have an allen head adjustment screw accessible from the low side, some don't. This is necessary to keep the pressure high for proper 134 expansion. You cant run R134 at R12 pressure and expect good results.
     
  19. bobwop
    Joined: Jan 13, 2008
    Posts: 6,081

    bobwop
    ALLIANCE MEMBER

    but let's put it all in perspective...how dangerous is two pounds of LPG?

    and how many of you carry a 20lb, or even 100lb, cylinder in your vehicle?

    just thinking out loud
     
  20. Two pounds of it when the line breaks and the spark happens will be PLENTY!
    And it's not like taking the 20lb bottle to the store for a refill, where if you get in an accident it will probably just fly around ! It doesn't have a line connected to it to burst open and blow up. and there are plenty of examples of those BBQ bottles still blowing up in a wreck

    A 100lb bottle? Loose in a vehicle? that's just plain stupid! :eek:
     
  21. Good way to blow yourself up....thier are kits to retrofit old r 12 to safer stuff
     
  22. bobwop
    Joined: Jan 13, 2008
    Posts: 6,081

    bobwop
    ALLIANCE MEMBER

    ok, I will try again. The little bottle of LP on my torch is more than the A/C system would hold. How big of a fire will that little bottle turn into?
     
  23. castirondude
    Joined: Jan 26, 2012
    Posts: 496

    castirondude
    Member

    If you do it right there will not be any oxygen in the system so it can't burn. Also if the line ruptures it will be pure propane coming out which doesn't explode. i think the gasoline in your carb is more dangerous than propane in your ac system.

    As a kid i once convinced my dad to fill a balloon with propane and hold a match under it :D the first one just popped and blew out the match so we tried another. The 2nd one did light and it made a flame that dropped to the ground and spread, then disappeared.

    I have a big bottle of freeze12 and it's been great. Used it on
    my o/t minivan with 150k miles when i bought it in 2008 and it was blowing snowflakes at me. now it's still running on the same charge at 220k miles

    Sent from my Verizon 4G LTE smartphone
     
  24. 1946caddy
    Joined: Dec 18, 2013
    Posts: 1,515

    1946caddy
    Member
    from washington

    I wouldn't use hotshot in a car system. Several years ago my son was moving to Las Vegas and I was towing his 87 BMW down on a trailer. his A/C system worked great . My A/C didn't work on my truck so I took it to a guy who put in the Hotshot because of the R12 system. I also had he remove the R12 from my sons BMW and refill with Hotshot so he wouldn't have trouble in the future. Long story short, both systems went out within one week and when I took it to a A/C repair place, they said all the O-rings were shot and leaking. He said that Hotshot could be used in residential HVAC systems but not cars. Turns out at least with the people I've talked to, R12 is readily available but just cost more. Most A/C shops keep the R12 and reuse in the old systems.
     
  25. sunbeam
    Joined: Oct 22, 2010
    Posts: 4,539

    sunbeam
    Member

    Your car could look like an Allstate Mayhem commercial.
     
  26. 1946caddy
    Joined: Dec 18, 2013
    Posts: 1,515

    1946caddy
    Member
    from washington

    Ever waited a few seconds to light a propane BBQ after the gas was turned on? Usually gets everyone's attention.
     
  27. speedfreek155
    Joined: Sep 10, 2011
    Posts: 312

    speedfreek155
    Member

  28. archied1067
    Joined: Aug 5, 2007
    Posts: 425

    archied1067
    Member

    Didn't I say hotshot turns o rings to shit!! Hot shot only good in commercial apps!! I think the refrigerator in my trailer is cooled with propane??


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  29. archied1067
    Joined: Aug 5, 2007
    Posts: 425

    archied1067
    Member

    Most freon is safe to use for experienced technicians. Most freon as most of you is not dangerous or explosive. In resent years we have been receiving transport refrigeration units with 404a or 134a. These units come from the orient. Once on our docks all repairs are done by our union. These units are exploding killing mech. Or seriously injuring the mechanic. The freon is exploding as soon as it comes in contact with the atmosphere. Be care full out there we have also heard of units being charged with these cheap freons in commercial and residential applications.


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