How to solder (beginners guide)

[mampoer]

I have also read about ANTI-FLUX, but I've never seen it. I have found that rubbing the area with a soft pencil will often prevent it from taking solder. NB, I have only tried this with soft solder, not with hard/silver/brazing solder. Pencil "lead" is graphite, a form of carbon.

[miningcleargold]

Hi All new to posting but have been reading here for quite awhile. Really enjoy all the info you guys have banked here, priceless. Quick Question on brazing to SS to Copper. I got flanges made for my still 1/4" thick, what would be the recommended solder, brazing rod, and heat I should apply to to this thing. I read all the how to solder forum but either didn't really find that it didn't apply to what I wanted or maybe I just overlooked what they were using. Everything I found seemed to be very light material should I change anything when brazing the 2' copper to a 1/4 SS flange?

[Aces High]

Im trying to solder a 50mm (2") x piece of copper pipe onto a 50mm x 90 degree bend and I just can't get it to work. I'm no soldering expert, but this is my second still head, so i've done enough joint to know a little about it. I've cleaned it up properly and try and heat it up evenly using the instructions in this thread, but the flux keeps going brown and the solder just balls up (which seems to indicate not enough heat) its soo frustrating.

Im using a MAP torch which has been fine for smaller joints and also a couple 50mm joiners that I have soldered, but it may not have the heat for this.. but then why is it burning the flux when I am not applying direct heat to the flux ??

Any help would be most appreciated.

[Tater]

Probably not getting it hot enough sometimes helps if ya can disassemble any attachments to get less area that can draw heat.

[Aces High]

yeah i was thinking it was a heating problem too, but i couldn't work out then why the flux was turning to carbon.. maybe i was heating it wrongly. One piece is a 1' x 2" copper tube and Im joining that to a 90 degree bend that has a 2" to 1" reducer soldered in the other end, maybe thats too much for a MAP torch to heat. Whats the next step up from a MAP torch? Oxi ?, although thats getting a bit out of my league. I might have to find me a professional for that one.

[Husker]

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.

H.

[Aces High]

Thanks Guys,

I kinda knew it was a heat issue from my years of soldering circuit boards, I was just hoping there was a way around it.. For 1" and under this MAPP torch works great for me and I have managed to connect some joiners to 2" pipe, but the joiners heat up pretty easy. I guess its time to call in outside help..... dammit

[LWTCS]

I have had scortching (flux) issues when I used an older more dried out container of flux.

Certainly the the Homo Depoe sized version of the Burnzomatic set up may not be the best unit for the 2". But it is completely doable.

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.

[Aces High]

Thanks LWTCS good advice, the flux is starting to look a bit skanky.. i think i might replace it with a new batch and having one last go. I also read somewhere on here about a kiln effect. You put a bricks around and behind where you're heating so that the heat bounces back and is more efficient..

If that doesn't work..anyone know a good welder in the perth area?

[spumco]

Long delay for a reply, but for two of the above questions...

To solder stainless, you need to use stainless flux. This is an acid (liquid) that cuts through the chromium oxide passivation layer. McMaster Carr or some other industrial supply place should have it. Do not try doing Oxy-fuel bazing with this crap. Be careful with the fumes - they're icky. The 16oz bottle I have will last me three lifetimes.

Warm the area, then put the flux on. It'll boil and smell like industrial death. The sold will then wet out on the stainless.

To BRAZE stainless, you need to use Grade IV filler. Flux is the same (white borax paste). Use a slightly reducing flame and take your time.

For 2" or bigger equipment and you've only got a little torch - tin the pieces first. Clean everything as usual, then apply flux and solder to each side of the joint individually. Yo do not want big globs of solder. Just let it wet out the surface.

After both sides are tinned, sand down any globs, re-flux and assemble the joint. Heat and solder the joint as usual. Heating up the entire fitting or pipe until it's fairly hot (but not so hot you've burned the flux) can reduce the heat sink effect at the joint.

Good luck.

[Cong]

Hi guys,

I was just talking briefly to a commercial plumber and he informed me that if silver solder is purchased from a plumbing supply shop ( eg Reece) that they will only supply silver solder for food/water grade with no lead and little cadmium.

If you were to go to a Bunnings hardware or the like, then that is a different story.

He also told me that it was unlikely to need flux with clean copper as it has some fluxing properties already. With my background I always used flux. Maybe this is some modern type properties of the current silver solder, that I am unaware of?

Is anyone able to confirm or dispute this?

regards

Cong

[LWTCS]

My buddy brazes w/o flux.

But with only sparadic needs, I just stick with flux use.

[rad14701]

Cong, I think your plumber friend was pulling your leg on the lack of importance of flux... It is a very important part of the soldering process as it helps equalize the temperature between the pieces being soldered as well as helping to draw the solder into the joint...

I've had to fix joints throughout a house after a slather-assed plumber brute forced sweat joints with excess heat and no flux - by using proper heat and some flux, with no additional solder required... He ended up discounting the job due to his shoddy work and has since left the business...

[Cong]

Thanks Rad,

I always thought flux was the go, but what do you think about the statement that plumbing supplies will only sell the food grade solder? or is this a farce as well?

[rad14701]

Thanks Rad,

I always thought flux was the go, but what do you think about the statement that plumbing supplies will only sell the food grade solder? or is this a farce as well?

I don't know where you're located but I can't find solder that isn't lead free around here, not even at plumbing supply houses... I'm always snooping around to see if I find some but haven't found any... New York is pretty strict on lead in general...

[Cong]

A list of safe solders and brazes is a damn good idea.

I know of the following in Australia:


The SilBRAZE P is mostly copper with a small amount of phosphorous. The other SilBRAZE and all the Pro Silver are silver (2%, 5%, 15%) and copper, with a small amount of phosphorous. The phosphorous acts as flux for copper-copper joins, but copper-brass joins need a boron based flux.

In Australia Pro Silver is distributed by BOC Gas, and SilBRAZE by http://www.silbraze.com.au" onclick="window.open(this.href);return false;" rel="nofollow

Maybe this is what he is talking about

[Kirko]

It is impossible to solder or braze without flux. When soldering, heat the metal only until the solder is starting to melt, don't over heat it.
When brazing, heat the metal ahead of where you want the silver to flow, solder does flow toward heat. If your braze or your solder is beading up and rolling off, either the joint is dirty or the object not hot enough. As soon as some of the solder has melted and flowed onto the surface, watch that area and use it as a temperature guide, keep the metal just at the point where it looks like mercury, continue soldering but let the metal cool just to the point where the solder solidifies, then heat a little more, going between the flow and solidus point, back and forth between the two, this insures you are staying within a reasonable range. The 2 most common problems with soldering or brazing are over heating and joint contamination. You can't get a joint too clean.
Stop solder is a paste made of yellow ochre, you are better off not using stop flow because it is too easy to contaminate the area you want it to flow. A paste of brick dust or ground tripoli does the same thing. Carbon can actually act as a flux under the right conditions so carbon is not the best stop flow. It's best to just work clean, control your heat and make the solder or brazing material go where you want it.

[blanikdog]

... You can't get a joint too clean. ...

So very true.

blanik

[ibfestus]

I want to sweat a SS flange that is a firm fit inside a 2" copper column. I have a bit of "pre fluxed" silver solder and a Mapp torch. Is this doable? I am a rank amateur and can make ugly but solid joints sweating copper but this is all new to me. Any advice is appreciated as always.

[Kirko]

Stainless can be silver soldered but it's not easy. Use wire solder of 80% silver or better. The premixed solder /flux has a lot of problems and is really just a gimmick.Clean the metal with sandpaper and rinse it with alcohol and boric acid, mixed one table spoon of boric to one pint of alcohol. You can buy boric acid at the pharmacy, get the powdered, not granulated. After you have cleaned and rinsed it, do not touch the parts to be soldered. Map will do, use plenty of heat.
If the solder does not wet or tin the metal, scrape it or sand it clean and start again.

[ibfestus]

OK... I screwed it up. First I tried the "prefluxed" silver solder stick and couldn't get it to do anything. Then after looking all all over and 2 trips to town I found a piece of plain Jane silver solder and a tube of flux. After spending $6 for boric acid, $12 for solder and another $5 for the flux I decided to give it another try. I soaked both the stainless steel flange and the 2" copper in the boric acid/alcohol mixture then air dried them. The flux I wound up with was actually a clear liquid in a tube. It seemed to work pretty well, at least the solder was disappearing into the joint. I used all but a couple inches of the solder... of course some wound up on the floor but when it cooled everything looked good. Then this morning I did a vinegar water run and the damn thing leaks.

Do I need to start all over? Can I just reheat and add more solder? Any help is always appreciated.

[Kirko]

Just clean the seam up real bright with sandpaper and rinse it with alcohol, don't use the boric acid this time, just use the flux that came with your solder. Fill just the seam with a bead of solder, if you don't over heat it you should be able to keep it in the join.
What kind of silver solder is it?

[ibfestus]

I finally got it to quit leaking. As far as the solder I used, it came from Home Depot. I looked for a better grade at Lowes, Ace Hardware, NAPA, plus a couple of welding supply shops but (except for the prefluxed at the welding supply place), they all had essentially the same thing. The label says it is "lead free silver solder for non electrical use," but doesn't list the percent of silver/tin. The flux was in a tube and it's contents were listed as hydrochloric acid and zinc oxide. I think I got the stainless fitting too hot trying to melt the prefluxed which changed it's structure. Anybody else wanting to try this... good luck, I think you will need it.

[Kirko]

You were using soft solder. If the recommended flux is zinc acid, it's soft solder.
The zinc/acid flux is a soft solder flux. Soft solder is not silver solder no matter how much silver it has in it. The boric acid coating prevents soft solder from sticking. Never use boric acid or brazing flux to soft solder. The zinc acid flux is an etching, low temperature , soft soldering flux, it etches the surface and allows the soft solder to stick.
Boric acid and other brazing, silver soldering fluxes are essentially glass. They melt and flow at temperatures similar to glass. As these melt, they create a glaze over the surface that protects it from oxygen. When joining two pieces by brazing or silver soldering, the one thing stopping the two from becoming one is atmosphere, the high temp flux helps prevent oxygen from getting to the metal, that allows an alloy to be formed at the joint.
Soft soldering is a whole different animal, the fluxes for soft soldering are different and not interchangeable with brazing or silver soldering fluxes.
Boric acid and other brazing, silver soldering fluxes melt at temperatures far higher than soft solder melts. Brazing flux is a contaminant to soft soldering, any trace of brazing flux in a soft solder joint will prevent the solder from sticking.
A good place to buy silver solder and flux is http://www.riogrande.com/. They are a standard in the metal smithing industry, call them and request a tools catalog and a findings catalog.
A great book on metal fabrication is "metal techniques for craftsmen" by Oppi Untracht.
One more note on soft soldering. "silvaloy" brand "silver" soft solder and all the fancy, silver bearing soft solders are just soft solder. Don't waste your money on them. If you are soft soldering, buy a roll of lead free plumbing solder and a can of flux at the hardware store. It will be every bit as good. Silvaloy silver bearing soft solder was (imho) developed for looks, you can repair a piece of silver plated junk with it and (the repair) is not quite as ugly looking as regular soft solder. Regular lead free solder will work just as well or better. If you are having problems soft soldering stainless steal, try a different soft soldering flux, a higher acid content flux sometimes works better on stainless.

[ScottishBoy]

Okay. A few questions.
I made my first attempt at bonding brass and SS together. I kinda toasted it the first time, so I went lower temp and made sure I was heating from the inside. Then I got something that looked okay but it looked like a cold joint. I was using a cleaning brush, zinc chloride flux and basic lead free solder with 4% silver. In trying to get a good seal on both sides the solder would just run through the hole to the other side and end up on the floor. In the end I got a thin coating on the top which proved to be waterproof, but didnt like the stress of having a copper tube attached to it. The lid of my boiler is too thin.

Is there a preference to have the solder "kind of lump up" rather than seep into the holes?
I have been brushing the hell out the SS and Brass, then fluxing. They say to warm the metal up then flux. Should the flux hiss?
I feel like Im missing some crucial element. Soldering pipes was easy and I feel like if I watch one more YouTube video that makes it look easy, Im going to scream.

Hints?

[ScottishBoy]

Okay, after a brief ( hour long ) study of the problem, I came to the conclusion that I could make the joint,but that the lid was just too flimsy. So I dropped by the local bits store and got some washers that would fit the compression fittings I was using. I used brass for ther inside of the lid and steel for the outside making a sort of flange for it that I could seal up. I sealed it and then tinned the brass with silversolder to minimize exposure to brass surfaces. The washers were about an inch and half wide. Should have tightened them down a bit more. There is the ever so slightest leak between the brass and SS at the base when I use a thumper at 2 inches. Im happy with it for the first try though. Im looking to see if I can design an easy connector that is accessible to everyone with minumum solder skills.

SB

[Coyote]

I feel like it is time to weigh in on the novice soldering issue with a couple of things that will help. I also am a former plumber.
1. Bright and shiny before you dry fit, Emory cloth or fitting brushes do a very good job at this. Fitting brushes in the 1/2,3/4 or 1" size are a couple of bucks each at the local hardware store. The average homeowner will not wear one out in their lifetime.
2. Flux brushes They are .25 cents each or less. I bought a 200 count box for $ 8.99 last month. Short camel hair brush
Never touch the fitting area to be soldered or the flux with your bare hands, even dry skin can transfer oils that can cause a joint failure months later.
3. Husker is correct in the amount of solder needed for a joint, A 1" fitting will require an inch of solder
4. Heat slowly, starting away from the joint until you see the copper just start to change color - then move your heat to the BACKSIDE of the joint and HEAT EVENLY & SLOWLY
Test with your solder - when the joint is ready the solder will be sucked into the joint - even upside down.
5. The biggest mistake anyone ever makes soldering copper is (and we all do it) thinking that more is better- IT AIN'T
You are creating a bond between 2 pieces of copper and filing a very small space The Master Plumber I trained under would have me make a solid joint on a 1" fitting using only 1/2"of solder just to prove to me it can be done. Using more solder than is required only creates drips, runs and a big mess.
6. When you have made the joint quickly run a flux brush with a small amount of flux around the joint, followed by warm wet rag. This will give you a good looking and clean joint, removes the carbon and other garbage from the flux which is much easier to remove warm than cold.
7. PRACTICE PRACTICE PRACTICE You will find that ten dollars worth of 1/2 inch fittings from Home Depot and a bit of time will teach you a lot. It is a shame to see a well thought out project end up looking like a bad accident because you tried to save ten bucks

On another note:
I was unhappy with the connection for my pot still, so here are some thought and ideas that I have found work very well.

I was uneasy with the idea of attaching the tower to my keg boiler by bolting it down - if it can blow up or out I wanted a relief system
I cut the hole in the top of the keg with my plasma cutter, smoothed up the edges with a 4" hand grinder.
Using a piece of 1/4" copper plate I bought on line ( 4" X 12" X 1/4" was like 14.00) I cut a 4 X 4" piece drilled a centered hole to accept a 2" female adapter and 4 - 5/16" holes at the corners. I soldered the 2" female adapter into the 1/4" plate. Using a 1/4" food grade cork gasket I then bolted the new adapter plate to a heavy SS bowl inverted over the keg. Again using 1/4" cork I made a gasket to seal the bowl to the boiler. Now to my relief system the inverted bowl is held down to the boiler with a heavy black tarp strap
(bungie) This gives me a very solid base and IF I should ever have a blow out the bungie will give. It does not leak.

[46Ford]

It's worth the time to find a water soluble flux. It tends to brush on smoother and cleans up MUCH easier, with just water.

Everflux is a very strong/acidic flux which is water soluble.

NOKORODE® Aqua Flux™ is another good water soluble flux. It stays pliable in cold weather and is a little less aggressive of an acid. Great for novice soldering.



Tony the plumber

[Nightforce]

I guess I'm confused, is 95/5 tin/antimony okay to use in stills. One reply here seemed to say no and the other link seemed to say that it was only harmful if present in high levels of inhalation, unless I was mistaken.

[HookLine]

I guess I'm confused, is 95/5 tin/antimony okay to use in stills. One reply here seemed to say no and the other link seemed to say that it was only harmful if present in high levels of inhalation, unless I was mistaken.

Personally I would avoid it, especially as there are easily available and cheap alternatives that are some combination of tin, silver and copper. Should be able to find them at the hardware/plumbing or electronics store.