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Tony Hanna
05-29-2006, 04:11 PM
Just finished up a half-assed r134a retrofit on the sundance and it works, but not as well as I'd like. I'm getting 52-58 deg. duct temps on a 92 deg. day and I was wondering if this is about normal for a stock r12 system charged with 134a? Any advice on getting this thing to blow colder would be appreciated. If nothing else, I may dump the 134a and go with a hydrocarbon refrigerant like a propane/isobutane mix or something similar.
Thanks,
Tony

turbovanmanČ
05-29-2006, 04:54 PM
Did you replace the reciever/dryer? that makes a big difference. Also, how much did you charge it with? I have done lots of conversions using 134 a and never noticed poor performance. How is the fan? is the condensor sealed to the rad so the fan gives it a good pull?

Tony Hanna
05-29-2006, 08:11 PM
Did you replace the reciever/dryer? that makes a big difference. Also, how much did you charge it with? I have done lots of conversions using 134 a and never noticed poor performance. How is the fan? is the condensor sealed to the rad so the fan gives it a good pull?

Sure didn't. On top of that, I had to replace a hose, so it's been open to atmosphere and I have no way to draw a vacuum on it to get the moisture out. I just purged the system with about half a can before I started to fill.
I can't remember exactly how much I used, but I charged to 35 psi on the low side.
Out of curiosity, what have you noticed in the way of duct temps on a converted system?
Thanks,
Tony

looneytuner
05-29-2006, 09:16 PM
Find a shop that will just pump it down for you after you install the drier. There have to be some old geezers like me that remember not having the money. You also have to drain the old oil and add 134 friendly oil.

Boogieman142
05-29-2006, 10:14 PM
yeah, there is a tsb on this also. 134a runs a higher pressure than r-12 but r-12 cools better. I guess i got lucky and my r-12 system is still working(i can get the gas for it). If you want a cheap vacuum then find an old refrigerator/freezer and take the compressor out(make sure there is nothing in it) and hook up the right connectors to the vacuum side of it and attach a vacuum gauge for testing vacuum on a car. Thats what i did and it works great. Thats prolly half of your reason why it doesn't work. Our cars don't use the orifice tube style so air in the system is more crutial, they use the txv system, it varies a valve according to the temperature and because temp and pressure are porportinate of each other(70*=about 70lbs) it uses that, it is very accurite and does not need to cycle the clutch as much. If it is cycling the clutch a lot then it prolly has some air in the system. The oil that is in there from the r-12 will not mix with the 134a so you need to take all of that out and put in ester oil or you will have compressor failure. This is just a little on it, i hope it helps.

Tony Hanna
05-29-2006, 10:34 PM
Find a shop that will just pump it down for you after you install the drier. There have to be some old geezers like me that remember not having the money. You also have to drain the old oil and add 134 friendly oil.

Right, I used esther (sp?) oil since they claim that it doesn't have any problem mixing with any residual oil left in the system.
I wonder if a compressor out of an old refrigerator would pull enough vacuum to draw down the system? I'm sure I could find one easy enough.

Anyhow, here's my plan. I'm going to run it as-is for now since it's still better than nothing. I've ordered some es12a refrigerant and when it gets here, I'll buy a new drier. Before I install the drier, draw it down, and charge it, I plan to completely flush the system. I'm curious to see how well this es12a refrigerant works. According to the advertising and some other stuff I've read, it's supposed to perform better than r12 does, so it should do quite a bit better than r134a. The only down side I can see is that it's a hydrocarbon and as such is flammable, but so is just about every other automotive related substance. If it makes the ac work good, it's a risk I'm willing to take.
I'm still curious to know if anybody has measured air temp at the vent vs. ambient after a 134 conversion? I'd like to know how far off the mark this thing is. I'm getting a 34-40 deg. drop with the ac on recirc. depending on engine rpm.
Thanks,

Tony Hanna
05-29-2006, 10:55 PM
If you want a cheap vacuum then find an old refrigerator/freezer and take the compressor out(make sure there is nothing in it) and hook up the right connectors to the vacuum side of it and attach a vacuum gauge for testing vacuum on a car. Thats what i did and it works great.

That's awsome! You answered before I even asked the question.:thumb: I was watching a movie and it took forever to type the post.
edit: While I'm thinking about it, which service port is used when pulling a vacuum? Low side, high side, or does it even matter?
Thanks,

ottawa rogue
05-29-2006, 11:08 PM
shouldn't really matter. if you can, hook up to both the low side and high side
also, a refrigerator compressor won't generate as high a level of vacuum as a dedicated vacuum pump(especially if you have an old one), so leave it on for at least an hour, more if you can.
one other thing, they make a variable orifice tube for CCOT type systems to help with the cooling issues on retrofits.
while we don't have this setup on our cars, you might ask a parts store if there is an expansion valve made for 134a, maybe a later model part?

Boogieman142
05-29-2006, 11:10 PM
in theory it doesn't matter what side you use to pull a vacuum but most people use the high side because thats the easier hose to use.

Boogieman142
05-29-2006, 11:13 PM
our systems are a txv typeso they already have the variable orifice. a refrigerator will generate enough vacuum. An hour is about right that you want to pump it down, a little high tho. I do atleast 45min, you can do whatever you want, just make sure it is a perfect vacuum(depends on elevation but generally 28-31)

Tony Hanna
05-29-2006, 11:14 PM
shouldn't really matter. if you can, hook up to both the low side and high side
also, a refrigerator compressor won't generate as high a level of vacuum as a dedicated vacuum pump(especially if you have an old one), so leave it on for at least an hour, more if you can.
one other thing, they make a variable orifice tube for CCOT type systems to help with the cooling issues on retrofits.
while we don't have this setup on our cars, you might ask a parts store if there is an expansion valve made for 134a, maybe a later model part?

Hopefully I won't need to worry about the expansion valve since I'm getting away from the r134a in favor of the es12a. Supposedly the es12a behaves enough like r12 that it will cool just as good or better than r12 with no modifications to the system.
Thanks,

Boogieman142
05-29-2006, 11:17 PM
supposovely it will but just remember to make sure there are no leaks in it at all. Also make sure your compressor can handel it.

ottawa rogue
05-29-2006, 11:18 PM
just caught your post on the es12a--DON'T USE IT!!!!!
if you happen to spring a leak in your evaporator core, there's a chance that you could turn the inside of your car into a barbeque. if you don't want to use 134a, try to find some Frigc or other non flammable substitute

i really think that if you flush out your condenser and evaporater cores(you can get away with using brake cleaner-just blow it out really good with compressed air), and use a 134a compatible reciever-dryer, you should be good. and see if you can get an expansion valve that is designed for 134a if you can.
134a is more sensitive towards charge weight, unlike r-12 if you overcharge it, it'll stop cooling.
i've got some conversion capacity charts, let me know what your R-12 charge weight is and i can get you a pretty close idea of how much 134a you should need
Bryan

ottawa rogue
05-29-2006, 11:23 PM
our systems are a txv typeso they already have the variable orifice. a refrigerator will generate enough vacuum. An hour is about right that you want to pump it down, a little high tho. I do atleast 45min, you can do whatever you want, just make sure it is a perfect vacuum(depends on elevation but generally 28-31)

ya, they'll work ok, i had one i used for a few years until i finally broke down and bought a robinair:D
only problem i had is that i could never get more than 27" of vacuum out of it
that what i get for scrounging:D
wasn't really sure if chrysler had released a txv for 134a apps, it's been a few years since i worked on cars for a living.
do they still use the same part --- the r-12 apps?

Tony Hanna
05-29-2006, 11:24 PM
Out of curiosity, how do you guys reccomend flushing the system?
Since it started out with r12/oil, and now has r134a/oil/stopleak, I'd like to flush all the crap out of it before I switch over to the es12a.
Also, how many oz of oil is it supposed to take once it's been flushed. When I did the 134a, I just put a bottle in it and figured that would be good enough, but I'd like to be sure and get the exact right ammount this time.
Thanks,

ottawa rogue
05-29-2006, 11:28 PM
well, you can go out and buy a really nice flush kit $$$$$$, but that wouldn't be the TD way:D
or you can get a few cans of brakleen, spray them in the evap core and condenser and blow out the mess with compressed air
this actually works pretty good, just remember to blow the stuff out in the opposite direction of refrigerant flow and wear safety glasses(don't ask):D

ottawa rogue
05-29-2006, 11:29 PM
and on the oil, a couple of ounces in the condenser inlet and maybe an ounce in the evap inlet should do the trick, annd if you want to get really fancy, pull the compressor and drain the oil out of it.
if you put any oil in the compressor, just remember to turn it over by hand 20-30 times to make sure it won't lock up

Tony Hanna
05-29-2006, 11:37 PM
just caught your post on the es12a--DON'T USE IT!!!!!
if you happen to spring a leak in your evaporator core, there's a chance that you could turn the inside of your car into a barbeque. if you don't want to use 134a, try to find some Frigc or other non flammable substitute

i really think that if you flush out your condenser and evaporater cores(you can get away with using brake cleaner-just blow it out really good with compressed air), and use a 134a compatible reciever-dryer, you should be good. and see if you can get an expansion valve that is designed for 134a if you can.
134a is more sensitive towards charge weight, unlike r-12 if you overcharge it, it'll stop cooling.
i've got some conversion capacity charts, let me know what your R-12 charge weight is and i can get you a pretty close idea of how much 134a you should need
Bryan

I really need to type faster. You guys are answering all my questions before I even get the chance to ask them...
As for the flamability risk, I'm willing to take it. In order for something catastrophic to happen, it would have to leak inside the passanger compartment in enough of a volume to create an explosive atmosphere before it could dissipate which would take a pretty sizable leak. It just doesn't seem very likely to me. What seems more likely is the stuff igniting due to a broken line or condenser in a wreck, but that would be underhood which would put the firewall between me and the flames. Add to that the relatively small ammount of refrigerant in an auto ac system, and I just don't see it being much more dangerous than carrying a couple cans of hairspray in the car.

turbovanmanČ
05-30-2006, 01:15 AM
DO NOT Flush the system, its pointless and unless you had a compressor blow bits into your system, your just making things worse. Only add enough oil that you took out, so if you replace the reciever dryer, add like 2 oz's then add another 1 oz as when you pull it down, you loose some oil. The old R12 oil is fine, when left in the car/van. I also like to pull a vacuum down for around an hour. When I get my van running again, I'll take some temps.

ottawa rogue
05-30-2006, 08:02 AM
I just don't see it being much more dangerous than carrying a couple cans of hairspray in the car.

:eek: :eek: :eek:
Dude, i really don't want to know :D :D

Tony Hanna
05-30-2006, 09:16 AM
:eek: :eek: :eek:
Dude, i really don't want to know :D :D

Sure you do. Potato cannon fuel. :thumb: :D

Seriously though, while I don't regularly carry hairspray in the car (don't have enough hair to need it), I did have 6 gallons of methanol in the hatch of the Daytona for the alky injection system. I was just looking for something that a person might have in their car to compare the fire/explosion potential to.
With the way our ac systems are designed, it just seems to me that the chance of a large enough leak inside the passanger compartment to cause an explosive atmosphere is remote. More likely, any fire or explosion that happened would be on the other side of the firewall and be the result of a massive breach in the system due to a crash.

Another thought just occurred to me. If you can use an old referigerator compressor to evacuate an ac system, why couldn't you use one in conjunction with a tank to reclaim the r12 left in junk cars? Run something like that off a generator, and 1 trip to the local boneyard would keep you in r12 for awhile.
Just a thought.

MiniMopar
05-30-2006, 12:50 PM
FSM has a chart that shows how many ounces of oil to put into the system of each component that might be replaced. That would apply to anything that you would flush out as well.

There are other refridgerant oils out there that are compatible with either the mineral oil used in R12 systems and the ester or PAG oils used in R134a systems and work well with R12 and R134a. The one I have used recently is a synthetic type oil and it seems to work well. It doesn't absorb moisture like mineral or ester oils do.

ottawa rogue
05-30-2006, 12:52 PM
Ok, thats cool:D nothing like launching a "spudnik":thumb:
that's about all a refrigerant recovery system is when ya think about it,that and a filter. if you could find a way to vent the compressor's exhaust to a fitting instead of atmosphere, i'll bet you could do it:thumb:

ottawa rogue
05-30-2006, 12:56 PM
FSM has a chart that shows how many ounces of oil to put into the system of each component that might be replaced. That would apply to anything that you would flush out as well.

There are other refridgerant oils out there that are compatible with either the mineral oil used in R12 systems and the ester or PAG oils used in R134a systems and work well with R12 and R134a. The one I have used recently is a synthetic type oil and it seems to work well. It doesn't absorb moisture like mineral or ester oils do.
i was wondering when they'd come out with something like that .
it's been about 6 years since i've worked on cars professionally, heavy equipment pays better around here:D so i haven't really kept current with retrofitting.
when i do a retrofit, i usually use the ester oil

turbovanmanČ
05-30-2006, 01:11 PM
Ester oil is the ticket, mix's with all refrigerants and this way, you don't need to stock 10 different types of oil, :(

ottawa rogue
05-30-2006, 07:17 PM
Ester oil is the ticket, mix's with all refrigerants and this way, you don't need to stock 10 different types of oil, :(

ya, isn't it fun trying to figure out what viscosity of PAG goes with what system:mad:

on a related note, i was taught that PAG oil will degrade the rubber in O-Rings, so i always use POE or mineral to lube o-rings.
a couple of days ago, one of my co-workers more or less told me i wsa full of it-but this is also the same guy who is champion of 134a use in our shop:D
any thoughts on this?

turbovanmanČ
05-31-2006, 01:43 AM
ya, isn't it fun trying to figure out what viscosity of PAG goes with what system:mad:

on a related note, i was taught that PAG oil will degrade the rubber in O-Rings, so i always use POE or mineral to lube o-rings.
a couple of days ago, one of my co-workers more or less told me i wsa full of it-but this is also the same guy who is champion of 134a use in our shop:D
any thoughts on this?

That was in the first days of 134a coming out. Its proven not to effect the old o-rings but of course if you take it apart, you use the newer version.

Tony Hanna
05-31-2006, 11:39 PM
Ok, thats cool:D nothing like launching a "spudnik":thumb:
that's about all a refrigerant recovery system is when ya think about it,that and a filter. if you could find a way to vent the compressor's exhaust to a fitting instead of atmosphere, i'll bet you could do it:thumb:

I was thinking a little more about that, and adding a pop-off valve rated a little below the burst pressure of the cylinder might not be a bad idea. That or a pressure switch that would shut the compressor down.
I wonder what they use in the way of a filter? Maybe a person could find something that would do and work it in. It would be pretty cool to build your own recovery rig at a fraction of the cost of buying one.

ottawa rogue
06-01-2006, 09:37 PM
get a liquid line filter from a HVAC shop for a central air unit, that should be about all you need.
the filters in the commercial stuff are basically just a filter and a dessicant bag to filter out water, maybe you could use something like a cheap universal reciever-dryer for the moisture, or find an inline filter with dessicant
like this one
http://totalhomeair.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=523629&Category_Code=

Tony Hanna
06-02-2006, 10:22 AM
get a liquid line filter from a HVAC shop for a central air unit, that should be about all you need.
the filters in the commercial stuff are basically just a filter and a dessicant bag to filter out water, maybe you could use something like a cheap universal reciever-dryer for the moisture, or find an inline filter with dessicant
like this one
http://totalhomeair.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=523629&Category_Code=

I bet you're right, that one would do the trick, the only question I have is for how long? I wonder how many systems you could empty before the dessicant would become saturated? Also, I wonder how sitting around between uses would affect it?
Correct me if I'm wrong, but won't most dessicants give up their trapped moisture when heated? Maybe you could work it in so that it was easily removable from the system, and just pop it in the oven at a certain temp for a certain period of time prior to each use. Then it should last until the filter plugs right?

ottawa rogue
06-03-2006, 03:10 PM
i wouldn't know the answer to that one, most of the recycling equipment i've used either has a little indicator on the filter housing that changes color when it's time to change the filter, or they susally have an hourmeter and tell you to change after so many hours of use.

i've seen filters that are threaded at bot ends, maybe you could get one like that and just screw on a couple of hoses with the anti blowback fittings on them to keep some refrigerant trapped in the lines at all times?

we keep going like this and this thread is gonna get moved to fabrication:D

Tony Hanna
06-03-2006, 04:00 PM
Actually that might not be a bad idea. If one of the mods could split the thread and put the diy recovery system posts in the fab section.
I'm on the hunt for an old referigerator compressor right now. After I find that, I'll start piecing all the goodies together and we'll see how well she works.:thumb:

r00tcause
06-03-2006, 04:50 PM
Just finished up a half-assed r134a retrofit on the sundance and it works, but not as well as I'd like. I'm getting 52-58 deg. duct temps on a 92 deg. day and I was wondering if this is about normal for a stock r12 system charged with 134a? Any advice on getting this thing to blow colder would be appreciated. If nothing else, I may dump the 134a and go with a hydrocarbon refrigerant like a propane/isobutane mix or something similar.
Thanks,
Tony

If I was doing the conversion...

Id go to a yard and pull the entire system from a 2.5 NA 93+ shadow/sundance/spirit etc

93+ cars should all be 134a already.

Tony Hanna
06-03-2006, 05:11 PM
If I was doing the conversion...

Id go to a yard and pull the entire system from a 2.5 NA 93+ shadow/sundance/spirit etc

93+ cars should all be 134a already.

That's a good idea, but if they are anything like the other early 134a systems that I've seen, they didn't work very well from the factory. I think I'm just gonna have a go with the hydrocarbon refrigerant. It'll either work or it won't or I'll burn.... We'll see.

ottawa rogue
06-03-2006, 10:24 PM
Good luck Tony- it's better to burn out than fade away:D :D

Tony Hanna
06-05-2006, 12:22 PM
Well, the es12a finally made it, and I found a compressor out of an old Pepsi cooler. All I need to do now is run to the parts store and pick up some oil and a new dryer. Any suggestion on what kind of hose to use for pulling a vacuum? I need to find something I can clamp over the tube on the suction side of the compressor and attach a service port fitting to the other end. Most importantly I guess is finding something that won't collapse under vacuum. You think a section of the hard plastic coiled air line would work?
Thanks,

ottawa rogue
06-05-2006, 10:19 PM
it might. if you could find one, an old hose from a manifold gauge set would be the best thing, you could flare the end of the line slightly, or if you've got a store that sells hydraulic fittings, have them make you one with a SAE 45deg female flare fitting on one end. best bet would be the manifold gauge hose though

Tony Hanna
06-06-2006, 12:24 AM
Cool, thanks!
Well, the Pepsi cooler compressor fell through. The cooler is sitting in John's basement, has been since he moved in, and I went down to have a look at it and see what I'd need in the way of tools to pull the compressor. Turns out somebody got to it before me and the compressor is already gone.:(
I'm assuming that I don't have to be too picky selecting a compressor for vacuum pump duty right? Surely I'll run across an old fridge, freezer, window ac unit, dehumidifier, or something eventually.

MiniMopar
06-06-2006, 01:54 AM
If you have an air compressor that has pretty good flow (like a painter's compressor), you can use one of those venturi-style vacuum pumps. That's what I have. It pulls a HARD vacuum and very quickly. I was totally shocked at how well it works. It was cheap...I think I got it from JC Whitney.

The key is keeping the input pressure above 90psi or so, which requires a good compressor that can not only keep up, but catch up to it.

Tony Hanna
06-06-2006, 03:13 AM
If you have an air compressor that has pretty good flow (like a painter's compressor), you can use one of those venturi-style vacuum pumps. That's what I have. It pulls a HARD vacuum and very quickly. I was totally shocked at how well it works. It was cheap...I think I got it from JC Whitney.

The key is keeping the input pressure above 90psi or so, which requires a good compressor that can not only keep up, but catch up to it.

The only compressor I have right now is apart in need of a new piston ring and sleeve. It's just a little 5hp oilless rig. I doubt it would do the job. A da sander is more than it can keep up with.
Plus by doing it the right way, I'd miss out on getting to build something neat out of junk.:D

turbo xtc
06-14-2006, 06:40 AM
i use to work in a new jeep dealership and back in 1993 and 1994 we had to replace a lot of condensors in these the just rotted away when r134-a first came out it was more acidic but i think they took most of the acid out of it and the jeeps started using different type of alunium in them that is probaly why it was believed that the old seals would deteriorate faster just a little info for retrofitters i don't know if this is any help or not but i hope it is i have done a few retrofits on chryslers and i have done a bunch more on gm's the gm's usally blew seals pretty fast not much problems with mopar i think a lot of the probs were the older type a/c units in the gm before 1986 although i have had some issues about the expansion tubes in the chryslers plug up but i have found out it is easier just to change them anyway if i'm going to retrofit them

ottawa rogue
06-20-2006, 06:39 PM
If you have an air compressor that has pretty good flow (like a painter's compressor), you can use one of those venturi-style vacuum pumps. That's what I have. It pulls a HARD vacuum and very quickly. I was totally shocked at how well it works. It was cheap...I think I got it from JC Whitney.

The key is keeping the input pressure above 90psi or so, which requires a good compressor that can not only keep up, but catch up to it.
i'll agree with you, those work really well. but you have to have a major compressor to run one, this one from snap on says 42 cfm :eek:

http://buy1.snapon.com/catalog/item.asp?P65=&tool=shop&item_ID=11447&group_ID=1523&store=snapon-store&dir=catalog
that's gotta be a typo, most of them i've seen are about 14scfm, still a lot of air

gkcooper
06-20-2006, 07:54 PM
You can put your filter/dryer in the oven and remove the moisture from the dissicant.

I have done this with different types of dissicant like those disposable in-line paint filters.

Here's a link.

http://www.moparmusclemagazine.com/techarticles/34460/index2.html

Greg K. Cooper
Huntsville, Alabama

gkcooper
06-20-2006, 07:59 PM
Here's the link I meant to post http://www.imperialclub.com/Repair/Air/refit.htm

The other one actually tells you not to bake it.

All I can say is that I have cold air from junkyard parts and it has been running for years with zero problems. Of coarse I did an oil-charge as well as the refrigerant.

Greg K. Cooper

ottawa rogue
06-21-2006, 11:24 PM
I got a flyer from the local snap-on dealer today and they have replacement Robinair filters for their recovery units for $20 i think it was.
it even has threaded ends so you could attach a hose on either side

Boogieman142
06-22-2006, 12:43 AM
my 93 still has r-12 in it from the factory, its nice when your boss has tanks of r-12 still lying around that i can use.

Tony Hanna
06-24-2006, 11:24 AM
Thanks for all the tips guys. I don't know if I'll ever get around to building the homemade recovery system now though. Matt (Darkwolf on here) loaned me a vacuum pump. All I need to do is either buy or build the hose to use with it.
Thanks for the tip about reusing the disecant. I may give that a shot, but more likely I'll replace the dryer since it's only about $20. I didn't realize they were so cheap.

87glhs232
08-02-2006, 10:26 PM
To bring back an old thread I found this vacuum pump (http://www.harborfreightusa.com/usa/itemdisplay/displayItem.do?itemid=92475) at Harbor Freight. Maybe not the best quality, but surely it would work for one or two vac/moisture pulls. For $16.99 (on sale now thru 8/9/06 for $11.99 plus I have a $2 coupon = $9.99) it would be worth a try.

Una
08-02-2006, 11:25 PM
Good price, but you'll need a GOOD compressor, as you have to pull that vacuum for 30+ minutes straight..

87glhs232
08-03-2006, 08:42 AM
Good price, but you'll need a GOOD compressor, as you have to pull that vacuum for 30+ minutes straight..

Well...I have one, so thats no problem.

Tony Hanna
08-03-2006, 07:59 PM
Just be sure your compressor is rated to flow at or above the requirements of the pump and you should have a nice setup.

Una
08-03-2006, 09:04 PM
Not just that, but most home compressors aren't meant for a 30 minute straight duty cycle.. Found that out once when trying to paint a car (ok, it was like the 3rd car on the same compressor, couple weeks apart) when the bearings started howling about halfway through the job.. hehe.. "What's duty cycle mean?"

Tony Hanna
08-03-2006, 09:13 PM
Not just that, but most home compressors aren't meant for a 30 minute straight duty cycle.. Found that out once when trying to paint a car (ok, it was like the 3rd car on the same compressor, couple weeks apart) when the bearings started howling about halfway through the job.. hehe.. "What's duty cycle mean?"
Right, I didn't even think about that. Better to have the compressor exceed the requirement of the pump so that it will cycle and allow itself to cool.

Tony Hanna
08-03-2006, 09:17 PM
Here's a neat link to how to make your own referigerant to replace r12.
http://www.vectorbd.com/peugeot/archive/General/2003/May/0010.html
I've been wanting to try this, but I'm having a hard time finding pure isobutane. All I've been able to find is large cylinders of the stuff from an industrial gas supply place. Overkill for anything I'd want to do.
Any thoughts?