And this is what I did this evening - 359 Peterbilt AC

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In the middle of my neighbor's generator running gear project, a buddy of mine called in a panic and said he needed his AC brazed back together.  I told him I was in the middle of another project and if he could wait I'd be over in an hour or two.  He could and I did.When I got there he showed me his AC evaporator in photo 1 and said he had to cut it apart because the orifice tube had broken off and he couldn't get it out without doing so.  I informed him that AC stuff is typically silver soldered which I didn't have any of but his late grandfather used to do AC work and after hunting around his shop a little we came up with some old and questionable 'silver based' solder and some acid tinning/soldering flux.  I told him I'd give it a shot even though I hadn't silver soldered since the late '70s when I worked for a Detroit Diesel - Allison distributor that was also an authorized Carrier Transicold repair facility where I was the 3rd shift 'factory trained technician'.  So I cleaned the parts up better than what you see in the photos and the first attempt didn't go too well as the residual oil in the tube on the evaporator side boiled out and contaminated the joint.  A little brake cleaner and more acid flux later and photo 2 was the result.  Used his OA torches to do the job.We put it back in, hooked it up and pulled a vacuum on the system and when I left it was still holding and he was going in the house to get a bite to eat.  I'll know in the morning if it did the job and held up. Attached ImagesMM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110Save Second Base!
Reply:Looks like a great repair and not without a few challenges.Isn't it funny how these things time themselves. It was good that your buddy could wait. I'll bet it was easier/cheaper than trying to get an AC tech at the drop of a hat."One of the things we have to be thankful for is that we don't get as much government as we pay for." (Charles Kettering)Mitch 180 (NZ)Lincoln SAM-400-220 + ?-400 Fordson Major + 2 x Tractapac Humber 80 + Procut 40 PlasmaMiller Spectrum 375
Reply:I've never soldered anything but copper water pipe.  What's the difference between silver solder, and the conventional tin(lead I guess) type solder?  Is it a matter of strength, or interaction with the refrigerant?"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Great Repair Duane.  Your friend's probably singing your praises as we speak.Stress is nothing more than how you handle a problem.Learn to deal with it and you'll have less of a problem.
Reply:Originally Posted by farmersammI've never soldered anything but copper water pipe.  What's the difference between silver solder, and the conventional tin(lead I guess) type solder?  Is it a matter of strength, or interaction with the refrigerant?
Reply:"Cyclic"  Woo Hoo!!Doggone pros anyhow"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Are silver solder and silfos similar?"One of the things we have to be thankful for is that we don't get as much government as we pay for." (Charles Kettering)Mitch 180 (NZ)Lincoln SAM-400-220 + ?-400 Fordson Major + 2 x Tractapac Humber 80 + Procut 40 PlasmaMiller Spectrum 375
Reply:All those factory copper joints are "silver brazed" which takes a lot more heat then silver solder. Generally you use an acetylene and air torch and the material comes in long flat sticks. The way you can tell the difference is that solders (tin/lead, silver) are silver in color and the brazed joints are copper colored and much stronger.-DanOwnerDW Metalworks LLCMiller Trailblazer 302Miller 8RC FeederMiller Passport PlusMiller Dynasty 200 DX W/Coolmate 1Hobart Handler 135Hypertherm PowerMAX 30Smith O/A Torch SetPlus much much more
Reply:Originally Posted by engnerdanAll those factory copper joints are "silver brazed" which takes a lot more heat then silver solder. Generally you use an acetylene and air torch and the material comes in long flat sticks. The way you can tell the difference is that solders (tin/lead, silver) are silver in color and the brazed joints are copper colored and much stronger.-Dan
Reply:Depends.............I regularly fix cracked/pinholed steel tubing on my hydraulics with a bronze compression union fitting.  It works if you tighten the daylights out of it.  Nothing greater than 1/2 steel tubing.  That's pushin' it.  We're talkin' 2000psi.Not supposed to be done.  Hot day, broken down 3mi. from the house, in a very bad mood.  Do what ya gotta do.  Be da**** if I'm gonna wait on the dealer to send me 20 feet of tube because it's only broken in one place.Stainless steel compression fitting at the oilfield supply costs about $25.  Make do."Any day above ground is a good day"http://www.farmersamm.com/
Reply:Originally Posted by farmersammDepends.............I regularly fix cracked/pinholed steel tubing on my hydraulics with a bronze compression union fitting.  It works if you tighten the daylights out of it.  Nothing greater than 1/2 steel tubing.  That's pushin' it.  We're talkin' 2000psi.Not supposed to be done.  Hot day, broken down 3mi. from the house, in a very bad mood.  Do what ya gotta do.  Be da**** if I'm gonna wait on the dealer to send me 20 feet of tube because it's only broken in one place.Stainless steel compression fitting at the oilfield supply costs about $25.  Make do.
Reply:I definitely hear where you're coming from.That old baler that you've seen pictures of.  I had just gotten out from under the gate after oiling the floor chains, and the doggone thing dropped like an axe.  Was a pinhole in one of the lines going to the lift cylinders (This was an original hose dating back to manufacture.  Nylon cord, not steel.  Don't know if many people have seen the older hyd. hoses).  Use the safety catches nowDon't stand under anything that ya don't really want to become part of yer noggin'.You do the bandaid when you have hay in the field, and it's maybe gonna rain that night.I've become so pi**** at steel tubing, that when I built the loader, and have to replace a long run of defective tubing, I use modern two wire  rubber line.  Steel tubing is ok as long as it doesn't happen to run thru a place that collects trash/water.  Where the tubing is clamped is the worst.  It either collects trash and stays damp, or the clamp eats up the tubing over time because of the vibration.Rubber line has its drawbacks too.  It's susceptable to UV.Hydraulics are dangerous.  I wouldn't run a tractor without a cab.  Seen guys badly burnt from a line failure.  That oil will take your skin off if it's hot.  I like the line on the other side of the windshield or cab.I don't do any kind of fix, like I described, on anything that would pose an immediate risk to the ol' bod.You're 100% right."Any day above ground is a good day"http://www.farmersamm.com/
Reply:duaneb55 - The silver solder most likely would have been finee. I can't remember the exact reason why the HVAC guys use the solver braze but I think it is cleaner, less likely to get contamination inside the pipe from flux. An HVAC guy told that solver solder could be used but there was a reason for the silver braze. -DanOwnerDW Metalworks LLCMiller Trailblazer 302Miller 8RC FeederMiller Passport PlusMiller Dynasty 200 DX W/Coolmate 1Hobart Handler 135Hypertherm PowerMAX 30Smith O/A Torch SetPlus much much more
Reply:Sil-fos is actually a phosphorus-containing copper brazing alloy which is self fluxing on copper; it's high strength (40,000psi) and high temperature (about 1450*F) usually. The silver solders are lower temp. (~450*F) and lower strength (15K-20K psi) whereas the silver brazing alloys melt at about 1100*F on up. and have strengths up to 60K psi. Some have cadmium for wetting, some don't so are allowed on food-grade stainless. Many of the stainless brazing alloys are classified by the silver content. One common member in this class is Allstate No. 101, a general purpose 45% silver brazing alloy with a narrow working temperature and excellent capillary flow which is suitable for use on ferrous metals. Some alloys make good metal-to-metal bearing material, some have a wide 'plastic' range, some don't work on ferrous materials, others will join copper and aluminum (those usually have lots of cadmium), some have nickel for higher strength and are good for brazing on tungsten carbide inserts,  etc. I've used a number of these different alloys since I'm always doing something different, and I have a bunch of catalogs dating back three or four decades from which I've gotten lots of information.Almost forgot to mention; some are better at resisting vibration, as from refrigeration systems and such, whereas others are too brittle so will fail under those conditions. Also, some are better for tight-fitting joints while others will fill gaps better. Finally, a big difference in price  between some.Last edited by Oldiron2; 09-10-2008 at 12:21 AM.Reason: added material
Reply:Originally Posted by engnerdanduaneb55 - The silver solder most likely would have been finee. I can't remember the exact reason why the HVAC guys use the solver braze but I think it is cleaner, less likely to get contamination inside the pipe from flux. An HVAC guy told that solver solder could be used but there was a reason for the silver braze. -Dan
Reply:Originally Posted by farmersammI definitely hear where you're coming from.That old baler that you've seen pictures of.  I had just gotten out from under the gate after oiling the floor chains, and the doggone thing dropped like an axe.  Was a pinhole in one of the lines going to the lift cylinders (This was an original hose dating back to manufacture.  Nylon cord, not steel.  Don't know if many people have seen the older hyd. hoses).  Use the safety catches nowDon't stand under anything that ya don't really want to become part of yer noggin'.