Soldering
freespirited wrote: After building several columns using SS ferrules. I have found that Lenox silver flux (lowes) and soaking the spot to solder in muratic acid over night works great. The hold is strong, I have no intensions of using expensive silver solder on my flute build. As for soldering large fittings, I prep as usual for soft soldering and then heat just below the joint with my oxy act torch. Takes 10 seconds as opposed to 20 minutes on a 3" fitting. Anytime I solder something inside a tube I prep the areas, make a ring of solder formed to the joint and heat from the outside. I only flux where I intend to solder. i also try to only heat just enough to get the solder to melt, then I walk the heat around til it has all melted. I usually jump from the first point of heat up to 1/4 way around the pipe to help from overheating the first spot. If I find I do overheat and the solder flows out of the joint, I then heat the pipe about 1" above the place I lost the solder and hold my solder (inside the pipe) on the flame (outside the pipe). The solder will run down and cool as it reaches the joint, filling the joint back in.
I think I have figured out that brazing this stuff together isn't needed, I think its pointless to achieve such a strong joint considering this will hold 0psi, I think I will soft soldering the rest of the build, just for shits and giggles I used some stay clean flux and plumbers solder on a piece of copper scrap and a stainless coupler and it is a strong joint, the solder had no problem flowing right up and adhering to the stainless, after cooling I tried to rip it off, I did succeed but all it did was tear the solder after folding the copper along the solder joint -
http://homedistiller.org/forum/viewtopic.php?f=17&t=28727&start=60
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Stainless - if your stainless is one of the 300 series you can soft solder it with 2207 but you have to use the matching liquid flux. Alternatively use a borax based flux and high silver 455, or if the stainless is of unknown origin use 449 as it also contains nickel. Both are cadmium free and melt below 700 degrees. both can be done with MAP. ONLY heat the copper on a copper/stainless joint.
For the copper/copper or copper/brass I tend to use a generic low% silver, lead free, plumbing solder for most things. Multi stage soldering requires harder solder. 455 is my favourite. Melts at 630-660 degrees and flows well. If it is only on the coolant side then cadmium is OK to use. 842 is 42% silver with cadmium and melts at 610 to 620 degrees. Very widely used. 440 is cadmium free and melts at 650-710 degrees. You can get cadmium free 424 but at 740-780 degrees you will strugle with MAP.
You can also get flux free copper-phosphorous. These are intended for refrigeration use and are not recomended for hot work. Can be fine on the outside of condensers though as the colour match is good on copper. There are dozens of alloys available but a lot are intend to be used at low temperatures and are not really suitable for boiler work. -
http://homedistiller.org/forum/viewtopic.php?f=15&t=22023
Brazing is also called silver soldering, or vice versa. The interchangeable terms is a source for much confusion. Soldering is the use of a low temperature metal to join two items. Silver soldering (or brazing) uses a higher temperature metal (still lower than the melt temp of the material to be welded) to basically weld two items. In soldering, you stick two metals together through adhesion. In brazing (or silver soldering) the filler material creates a new alloy at the joint, fusing the metals. Silvaloy brand silver "solder" and many of the other silver "solders" are not silver soldering, they are soft soldering. Even if a solder does not contain lead, it can still be a "soft" solder. A good quality silver solder will contain at least 80% silver, and melt at around 1700 F, the higher the silver content, the less oxidation of the solder while welding and the higher the temperature needed. All silver soldering (brazing) is done with the metal at or near red heat. Whether soldering or brazing, cleanliness is of the utmost importance. When soft soldering, clean the metal with abrasive, rinse, then detergent, rinse, then rinse with solvent. One fingerprint will ruin the flow, if that happens, re flux with a wire brush and scrub the solder in as it melts. With brazing, cleanliness is just as important but harder to maintain. You can't scrub it in because your brush will burn up, you can use a long handled scraper to scrape the seam as the braze flows but this is tricky, often necessary. Heat causes oxidation, oxidation stops the metal from joining, the key is to have everything bright (by scraping or sanding) and clean and work fast. The longer it takes you, the more the metal will oxidise. If you get half way through and build up too much fire scale (oxidation) stop, scrape the metal bright, pickle with sodium bisulphate, re flux and start again. The best way to avoid oxidation while brazing is "fire coat". Mix boric acid and pure alcohol 1 to 5 (one part boric 5 parts alcohol). Pour or brush this on your joints and immediately light it, the alcohol burns off and leaves a coating of boric (flux). A good flux is boric acid and borax 50/50 mixed with water or alcohol. Any commercial brazing flux should work. Silver solder will flow towards heat, it also will draw itself along a seam by way of capillary action. Learn to use the capillary action, learn to draw the solder with heat. If you are soft soldering, I have no advice except, don't do it. Silver soldering is also called hard soldering. Silver solder generally comes in 3 grades, easy, medium and hard, they are all 3 hard solders. I prefer to use hard silver solder on everything but it may be easier if you use medium or easy. All 3 melt at high temperature, the benefit of having 3 solders is you can join complex items by starting out with hard, going to medium when adding more parts, ending with easy for the last parts. This avoids earlier joins from coming apart while soldering later joins, not usually needed for still making. My main supplier for flux, pickle (sodium bisulphate, called Sparex ) and silver is Rio Grande, in Albuquerque NM, give them a call and ask for the tool catalog, everyone should have one of their catalogs, they are the standard for the industry. So: Clean it scrape it wash it rinse it fire coat it flux it braze it pickle it repeat as necessary. I may not have explained this as clearly as you like but I'd be happy to answer any questions. -
http://homedistiller.org/forum/viewtopic.php?f=15&t=4052&start=45
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I find that the cheap MAPP torches, the crappy burnsomatic things you get at the HW store, suck at doing 2". I have had problems like you, where the flux simply carbonizes up.
Since I got my oxyacetylene setup, I have been able to solder 2" super easily. The oxyacetylene flame is super tiny (thus, you can put it RIGHT where you want it), and super hot. It is very easy to heat up the pipe, and the fitting, and suck the solder right in there.
I have read of many forum members who had success at soldering with MAPP, but I have had nothing but heartache using it. For 1/2" or 3/4" water pipe repair, simple propane torch works wonders. For the larger stuff we build stills out of, I will use nothing but a good O2 torch, with a properly adjusted flame neutral flame. ++++++++++++++
Keep the heat applied to the female side of the joint and let the flame (thats bouncing off of the copper) turn green. Green flame is the key.
Once that flame is green you will only need to apply further heat every few seconds or so. Apply your solder to the joint and it will pull right into the joint quite nicely. Continue to apply heat and solder till you can conclude the joint is completely filled. Wipe around the joint with a balled up dry rag (while its hot) and your solder dribble and the like will clean right off. Or (while its hot) brush on joint surface some additional flux to allow remaining solder blobs to get sucked into the joint for a more tidy looking joint. -
http://homedistiller.org/forum/viewtopic.php?f=15&t=4052&start=60
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Hi Shaun, The Plumbers Solder is not "Silver Solder " at all. Real Silver Solder comes in very thin lengths of about a foot long and is used for soldering jewellery, rings etc. It is hard, not soft and takes much more heat to melt. It's not even silver in colour, its more of a dirty tan colour. Plumbers solder is just a form of soft solder. It is soft and easy to bend and melts at a fairly low temp. The next bit says basically the same but is an extract from the web site shown below text.
“If silver alloy is used, brazing can be referred to as 'silver brazing'. Colloquially, the inaccurate terms "silver soldering" or "hard soldering" are used, to distinguish from the process of low temperature soldering that is done with solder having a melting point below 450 °C (800 °F). Silver brazing is similar to soldering but higher temperatures are used and the filler metal has a significantly different composition and higher melting point than solder. Likewise, silver brazing often requires the prior machining of parts to be joined to very close tolerances prior to joining them, to establish a joint gap distance of a few mils (thousandths of an inch) for proper capillary action during joining of parts, whereas soldering does not require gap distances that are anywhere near this small for successful joining of parts. Silver brazing works especially well for joining tubular thick-walled steel pipes, provided the proper machining is done prior to joining the steel parts.”
http://en.wikipedia.org/wiki/Brazing -
http://homedistiller.org/forum/viewtopic.php?f=1&t=2670
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You do know, old stormy, that you only need to braze ('silver solder') when connecting dissimilar metals? That's pretty much only the boiler to column connection.
For the rest, connecting copper to copper, you can use regular, lead free solder, and it will melt easily with your torch. I prefer using acetylene-air to solder big stuff, but even propane will do if you wait awhile, I've done it. -
http://homedistiller.org/forum/viewtopic.php?f=1&t=1717&start=15