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Sheet Metal Talk - Stainless Steel Soldering

pricer - Apr 20, 2004 - 02:30 AM
Post subject: Stainless Steel Soldering

Is it possible to solder stainless steel? I have information about soldering, but nothing on stainless steel. Is there another option to sealing a standing seam with some type of chemical based sealer, such as gutter seal or some type of polymer? I cut the template for the elliptical stainless steel tank for the water fall project today, among many other things. The wall behind the tank must be water proofed and many ideas have been tossed around. One was to cover the wall with EPDM roofing material, but I think the rubber would not react well with the adhesive that will be used to secure the granite to the wall and the fact that hanging granite on rubber is not a good idea to begin with. Lol

I was thinking in I were to build a multi sheet cover on the wall that will provide a flat surface for the granite to adhere to, that it would be my best option. The durability of the stainless steel and the contact with the water this should be a good combination. The granite is being removed from an old historic building downtown as we speak. The way I understand it is, they will be laid like tiles in the wall with a .125” clearance between the tiles. That means water will be able to travel between the seams of the granite.

What I proposed was to make a wall cover from 3 sheets of 18 gage stainless steel and seam them together using a one inch standing seam. The seams will run vertically incase water is able to get into the seam it will travel down through the seam and into the tank. Also thought about installing the seam horizontally with the female of the standing seam on the bottom panel to catch water as it may try to get through. The seam would be turned to the wall and a slot will be cut into the wall to accept the seam.

The seam it self will act as a deterrent for the water as well as the solder or sealer. Soldiering seems like to best idea. How would you do it? I have read some about soldering but I have never tried it as I have heard it described here. Any help at all will be appreciated.

Thank You

Pricer

pricer - Apr 20, 2004 - 02:35 AM
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Sorry , Ihave posted the same pdf some how.

pricer

steve2 - Apr 20, 2004 - 03:24 AM
Post subject: solder stainless

Pricer, what about a joint that looks like this one? Easier to bend and no cutting into the wall. Just something off of the top of my heae!

pricer - Apr 20, 2004 - 03:40 AM
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That is a great suggestion! We were concerned about how it may effect the granite. That would be a good way. I my just be counting hairs here, by the time they spread their adhesive it most likely will not mater any way. What do you think? They are going the glue the tiles to the wal any way. Lots of people turning away from this part of the project because of the liability involved. Go figure.

Thank You, Pricer

PS. I really like your drawing, looks like something I would do. I think I have turned into a CAD junkie! lol

steve2 - Apr 20, 2004 - 01:14 PM
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Pricer, In thinking about it, I seem to remember that SS expands and contracts more than steel. If this be the case, I would think about laying out the joints so that they would occur in the grout joints and then no tile would be spaning the metal joints. This would reduce the possibility of movement along the joint affecting any tiles. As for water in that joint, I don't think so. Hey as long as you are not ultimately responsible for the tile setters work, why shy away?

Steve

pricer - Apr 20, 2004 - 03:29 PM
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True it is. I just came back from a meeting with the owners, looks like we will cover the wall after all with the methods you had suggested. I printed your drawing, they saw it and choose the layer the stainless that way. Do you really think I would have a problem with expantion? The one detail I missed telling every one was that this water fall was in doors in a conditioned space. Once the water and stainless has reached room temp. and there are no apparent leaks the stainless should not move much is what i am thinking. The joints in the ss on the wall will overlap 6". Give me your thoughts.

Thank You , Pricer

steve2 - Apr 20, 2004 - 05:35 PM
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Pricer, Indoors-No problem with expansion there. If your decision on a six inch overlap is about the water, I wouldn't waste the metal. I don't believe I would overlap horizontal seams anymore than an inch or so. A horizontal seam like that is not going to wick mosture beyond the lap, especially if you incoporate some type of gasket or sealant in the joint. Vertical seams, where the water flow is going to run along the seam, would need a wider overlap and at least two distinct gasket or sealant lines before the water could reach the inside. Well anyway, I'm glad it is working out for you.

pricer - Apr 20, 2004 - 10:44 PM
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Thanks a lot for your help. What do you think about gutter seal. I am not reffering to any polymer but something that is solvent based, like the product made by Alcoa. It comes in a metal tube similar to tooth paste. I used 2 tubes of it today on my aluminum roof cap project which turned out quite well. I have to put some small flashing around it in the morning due to small elevation change. Thanks again for your help.

Pricer

Triple - Apr 21, 2004 - 01:17 AM
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Back to original question, We solder stainless all the time. Forget the name of flux (Stay clear I think) at the moment, but it comes in paste or liquid and we get it next door at CC Dickson Company, a HVAC supply house.

pricer - Apr 21, 2004 - 01:26 AM
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Triple wrote:

Back to original question, We solder stainless all the time. Forget the name of flux (Stay clear I think) at the moment, but it comes in paste or liquid and we get it next door at CC Dickson Company, a HVAC supply house.

What type of solder do you use? What size copper? You are dealing with a person who has never soldered much at all. What I had tryed was a misreble faliure! I bought a torch set once that came with a 1 lbs iron that attached to the torch body, would something like this work?

Grue - Apr 21, 2004 - 09:37 AM
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Pricer,

For mine 70% tin 30% lead and the biggest iron you can find others use the oxy torch for heat source see below, phosphoric acid based flux.

A tip I got from another source:

Quote
Stainless steel flux - Back when I did a lot of this (1980s), I used
Eutectic Castolin #157 for soft solder. The castolin website appears to
suck rocks, so I can't confirm the number or that the stuff is still
made now. Clean the metal well mechanically (brush, scotchbrite or
sandpaper) first, flux quickly.

An OA torch with a long feather (absurdly carburizing flame) works
nicely, as the long flame can be laid along the joint (stainless is a
poor heat conductor).

95/5 tin/antimony works well for solder.
End quote

Glenn

marky - Apr 21, 2004 - 04:10 PM
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what is the wall behind t he granite made of is it concrete if so this can be sealed with a bitumastic paint ,also how are the granite tiles being attached are these being bonded

pricer - Apr 21, 2004 - 08:43 PM
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marky wrote:

what is the wall behind t he granite made of is it concrete if so this can be sealed with a bitumastic paint ,also how are the granite tiles being attached are these being bonded

Water proof sheet rock is what will be behind the granite. That is why we think stainless steel is a good material to use . What is bitumastic paint ?

marky - Apr 23, 2004 - 01:12 PM
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bitumastic paint is a tar like paint used as a protection in water tanks [where the water is not drunk ]and below the damp course of concrete or brick buildings

pricer - Apr 23, 2004 - 06:20 PM
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marky wrote:

bitumastic paint is a tar like paint used as a protection in water tanks [where the water is not drunk ]and below the damp course of concrete or brick buildings

Thank you for the info. I will look deeper into the paint. Sounds like something that could have some alt. uses. Learn something new everyday! Thanks

Grue - Apr 28, 2004 - 08:54 PM
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I found a page of stainless info that may be a good reference for you
http://web.onetel.net.uk/~valdor123/bra ... l_stai.htm

Glenn

pricer - May 04, 2004 - 01:58 AM
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I need more help with soldering stainless steel. Someone that brazes alot at my shop tryed with 50/50 and it would not stick. They then used 45% silver in the joint and then capped the braze with the solder. It was a tough joint and did not break. I am going to try to solder the test parts in the morning. If any one would like to give me step by step details, now would be a good time. I have never had a successful solder joint and I must conquer this! Any help would be greatly appreciated.

Thanks,

From what I am reading from various sources, my problem of the metal not sticking together is from the material not being clean. The solder would only bead up in the joint. When removed from the clamp the pieces would fall apart. How should the metal be cleaned?

pricer - May 05, 2004 - 12:09 AM
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This is a picture of a solder joint made in 10 gage stainless steel. The solder was 50/50 and a flux caller rudy fluid. The metal was cleaned with alcohol. After the alcohol evaporated, rudy fluid was applied and heated. Once the heat was applied the solder was flowed into the joint. I was not there at the shop when this was done but, the joint was strong and the stainless had no discoloration. I am going to try it tommorow. Tell me was you think!
Thanks,

losso - Feb 01, 2005 - 01:05 PM
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i know this is a year to late..... but im only new here. we solder stainless shower trays with either 50/50 or 60/40 for flux we use killed hydrochloric acid ( regular plumbers hydrochloric acid from hardware store with smal pieces of galv droped in till it stops fizzing. Usually works a treat, sticking very easliy and seems very strong.
p.s. i know no one will read this cause youve long since finished your project. Sorry pricer

pricer - Feb 01, 2005 - 04:33 PM
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Personally, I re-read these post as needed. These forums serve me as a library of information. Welcome to the shop! This is very useful information, free free to share and exchange ideas here, they are greatly appreciated.

lisaf - Feb 16, 2005 - 02:39 AM
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losso: Re: A year too late. I happened to be searching the internet for some info regarding soldering to stainless steel and ran across this thread. Of all the postings, your "a year too late" posting was the one that solved my dilemna. I was trying to solder steel coax to a brass SMA connector (yeah yeah, I know "what's that?"...RF devices is what they are..in this case used in a very fancy adiabatic refriderator (don't ask)) Pretty far removeds from shower trays...but then since you solved my problem...maybe not so far removed after all. :) Anyway...thanks for your late posting!!! :)

Lisa F

lisaf - Feb 16, 2005 - 02:39 AM
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burninbriar - Feb 16, 2005 - 05:41 AM
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losso wrote:

i know this is a year to late..... but im only new here. we solder stainless shower trays with either 50/50 or 60/40 for flux we use killed hydrochloric acid ( regular plumbers hydrochloric acid from hardware store with smal pieces of galv droped in till it stops fizzing. Usually works a treat, sticking very easliy and seems very strong.
p.s. i know no one will read this cause youve long since finished your project. Sorry pricer

What do you use to deactivate the acid flux.Also,how well would the killed acid work on mild steel.

losso - Mar 28, 2005 - 12:50 PM
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gee i havent been back here for a while.

lisaf: glad you found it useful, and yes i was thinking "what's that??"

burninbriar: (sorry for the late reply) I usually use thin guage galv (.4mm or 26guage) to kill the acid, cut them up into about small pieces (about 15mm by 15mm) and drop them into the acid. I normaly use an old coffee mug about half full of the acid, and you will probably have to put in the galv till it is just below the acid for it to kill it quickly. Be a bit careful when putting it in though and do it outside, it smokes and boils violently. You should need to give it at least quarter of an hour, but half an hour is better. HERE IS A BIG POINT: the flux is only going to be good for a day, 2 at most. the longer you leave it, the more by product you get when you heat the stainless. I dont know what it is but it looks like some sort of beige crusty powder, and it makes it hard to stick the solder to it. So only make what you require for the job at hand. first time i used 3 day old stuff it took me forever to work out what was wrong with it, and it drove me nuts. Im not sure if it would last longer if you were to seal it in a bottle, i hae never tried, and for the relativly cheap cost of the ingredients, i always make a fresh lot when i need it.

Now i have never tried using this on mild steel, because ive never had to solder any. I have soldered galv before and for that i just used the hydrochloric acid straight out of the bottle (eek i hear you say) only apply a single stoke of acid to the surfaces your joining with a small brush, solder imedialty then after soldering wash the job of with water, you should see the acid start to bubble when you apply the acid to it. sounds a bit rough but has always worked for me, and if you dont use to much of it, you should be fine. So im not sure but if you wanted to you could try that on some mild steel, i dont see why it wouldnt work, and you wouldnt have to be so careful as there is no galv to burn off.

losso - Mar 28, 2005 - 12:53 PM
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"you should see the acid start to bubble when you apply the acid to it."

i meant to say you should see the acid start to bubble when you apply it to the galv, duhh

b_dog - Apr 12, 2007 - 03:33 PM
Post subject: soldering stainless steel

Pricer,
I have read thru this string and was wondering why there was no posting after the application was finished to share the results you achieved with others who may have a similar project to tackle.

b_dog - Apr 12, 2007 - 03:47 PM
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Pricer,

I have been surfing the web for sheet metal applications and soldering tips when I found this forum. I have read thru this string and was wondering why you didn't post a conclusion after you finished the application to share the actual results that you were able to achieve with others that may be facing a similar challange. The information provided may be history but it could still be helpful to others the same way that I found it. I would like to point out that the two most important aspects of soldering stainless steel (as shown in this string) is the proper flux and a very clean surface.

pricer - Apr 12, 2007 - 11:22 PM
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Well, I think we had everything tig welded in the feed tank above the waterfall and the sheets that were installed down the slop were over laped 6 to 8". I think everyone just abandoned the idea of soldering the stainless. It all worked out any way.

Since then, I have not attempted to solder any stainless. But it would be good to know.

rothalion - Apr 14, 2007 - 06:05 AM
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I thought I posted I comment but its gone so I apologize if this is a repeat. I solder Stainless all the time. We use a green flux called Allen Alsol I believe. Regardless it makes me very ill despite the fact that I wear a resperator; and wipes out my eyes. I just purchased a full face resperator with the filters attached behind me I hope this helps. When you speak of 'killed acid' does that mean that the flux is less caustic? I'm taking a TIG class next month in hopes of negating the soldering.

bordontn2 - Apr 16, 2007 - 02:01 AM
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rothalion.............killed acid is hydrochloric acid with zinc dissolved in it..mureatic acid is the same as hydrochloric acid
Can be purchased at some hardware stores..It's mainly used by masons to clean their brick..
Ruby Fluid is the same as cut acid (zinc chloride)
bordontn formerly from Ft. Myers,Fla.

rothalion - Apr 17, 2007 - 04:27 AM
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bordontn2 wrote:

rothalion.............killed acid is hydrochloric acid with zinc dissolved in it..mureatic acid is the same as hydrochloric acid
Can be purchased at some hardware stores..It's mainly used by masons to clean their brick..
Ruby Fluid is the same as cut acid (zinc chloride)
bordontn formerly from Ft. Myers,Fla.

Ok. Thanks! Is there a way to reduce the ill effects of using these products? We often solder hundreds of feet of stainless steel gutter, and other parts for days on end.... Is the killed acid less caustic? will the killed acid solder Stainless? Also; and this shows my gross naivete', where would I get the zinc from? Sorry to be so ignorant....thanks.

steve2 - Apr 17, 2007 - 04:16 PM
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The coating on galvanized steel is zinc. Zinc is also becoming more available (here in the USA)as sheet stock because of a resurging interest in it's use. I've never used galvanized steel to make killed acid but I think the soldering ability of the zinc coat on galvaized steel led to the idea that one could solder plain steel with killed acid. This I believe is not true.
Ruby fluid is zinc chloride which is what is created when you "kill" muriatic or hydrochloride acids with zinc. I however have never been able to effectively solder stainless with Ruby Fluid. Perhaps it's my technique!
As to the deleterious affects of soldering, I've soldered for days on end with Ruby Fluid, and if I have any ventilation at all I have no trouble. If I solder much at all with muriatic acid on galvanized I'm hacking and wheezing. Another reason for me to stick with the copper!

rothalion - Apr 18, 2007 - 12:01 AM
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Thanks! Amazing as well. I had an old time roofer who I used to work with come and borrrow some eqipment from us today, he told me to try exactly that: Drop galvanized into the acid. He said an old fellow he once employed did just that. It also helped wight down his flux jar.

Copper is not as bad for me, and oh how I wish the Govt. would go back to using it, but right now, possibly due to the Hurricanes everything in this area that is commercial roofing is specing stainless. In the past we would use copper for the gravel stops and such with a stainless cleat...

I have never been able to solder stainless with Ruby fluid, there is comething different about the recipie for the green flux and the Ruby. Seems that I did read it a while back on the MSDS' but I don't recall.

As for the galvanized we were told to drink milk before and after.

Thanks!

steve2 - Apr 18, 2007 - 01:22 AM
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One other thing, I've always been told that you need to remove the zinc after the acid stops actively bubbling. Leaving that steel core (if you use galvanized steel for your zinc) in the mix might cause the acid to do something. Perhaps that is why the poster above in this thread complained about the killed acid only lasting one day.

bordontn2 - Apr 18, 2007 - 02:17 AM
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Y'all...when I started in the bidness back in '61 we killed our acid by using mason jar lids..The threaded portion was zinc
and the top was a white glass..Knocked the glass out and cut up the rim.......I use borax in powder form for flux on silver....Might work on stainless.There is a thick liquid flux that is white that may be a borax base. Stay/silv or stay/brite, something like that...
bordontn

rothalion - Apr 18, 2007 - 04:09 AM
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Thank you! Its late so...I will look into this. Borax... Easy to buy and try. Mason jar lids. That's incredible, I wonder if they are still zinc? Geesh I was born in '61...so my respect for your knowledge is great! Its difficult to learn this trade in my area so to have found this site is a blessing! Thanks!

steve2 - Apr 18, 2007 - 03:11 PM
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No the lids are no longer zinc. The old zinc lids that I've seen are large threaded lids. More like a screw on cap with the white glass liner that 'ol bordontn mentioned above. The lids now are flat gasket like disks with reusable threaded rings that tighten down over them. I traced down some zinc sheet a couple of years ago but haven't gone looking lately. Any one doing restoration work has probably run across zinc used as flashings or ornamentation, even if they didn't recognize it. I've found the top half of step flashings made of zinc sheet behind dormer cheek walls more than once. Didn't last like copper, but most of the Victorian era houses I've been around didn't have copper flashings originally anyway. I can't just put it off to cost tho as many of these houses were not cheaply made. But lots of Terne coated and galvanized steel. And zinc. Maybe copper wasn't being produced enough in the last half of the 1800's. I lived for a few years changing out the flashings in slate roofed buildings as I stopped the leaks around chimneys and replaced valleys. Tore off 150 years of the next "best thing" from the flat roofs often at the top of some Mansard-roofed beauty and put down copper flat lock soldered tight.

Geez Bordontn, you've got me ramblin'!!

marky - Apr 18, 2007 - 04:54 PM
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Used to make our own killed spirits back in the dark days when i was a boy ,now i use Bakers soldering fluid ,i dont know if this is availiable in the U.S it may be the the U.K version of ruby fluid [is it red or just the manufacturers name ?]Bakers works ok on stainless. aw ra best Marky

steve2 - Apr 18, 2007 - 10:50 PM
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Both the color and the name Marky

rothalion - Apr 21, 2007 - 03:25 AM
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I made killed acid today much to the complete dismay of my two helpers. Both ran for the hills when the jar began bubbling and smoking...so brave they are!
I put some galvanized chips into a baby food jar about half full of Mureatic acid. Just as you all described it bubbled and smoked. After it settled down I brushed it onto copper and soldered a joint easily with 50/50 solder and a plumbers torch. It smelled pretty rank...I think it worked better than the Ruby fluid, sweated faster but smelled worse. I did not try to join any stainless I didn't have time. Tomorrow I will. Thanks for all the info. Oh and the Bakers I need to get some...so far I only found it on a European site...still looking!

LeadHead - Apr 21, 2007 - 11:34 PM
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For soldering stainless steel I use Stay Clean Liquid that I buy from the local plumbing supply house. It says on the bottle it is for stainless among other metals except aluminum. I use this stuff maybe once a year but when you need it you need it. All I use muratic acid for is galvanized stuff. Here is a link.
http://www.harrisproductsgroup.com/cons ... older_flux

pahrump - Nov 03, 2007 - 02:58 AM
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I always used muratic cut by adding chips of galv. iron to it (v notch dropping, etc) after about 10 minutes the acid worked great for SS and Cu.

bordontn2 - Nov 05, 2007 - 01:45 AM
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pahrump..........muriatic acid (hydrochloric acid) killed with zinc will give you zinc chloride a.k.a. RUBY FLUID.
We used to use zinc canning jar lids cut up and dropped in acid before commercially available Ruby Fluid...
bordontn2

rothalion - Nov 10, 2007 - 03:29 AM
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We found Stayclean and I love it. Thanks! Still get a litttle bit of sinus irratation but not the flu like sickness. We have wondered if the effects are worsened by high humidity. It seems that we all have more irratation when we solder during rain or just plain humid days.

MattM - Nov 13, 2007 - 01:48 AM
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You should be using a breathing mask (paper at least) if you have many fumes. There can be lead in that plume when you touch hot to acid/stay clean.

MattM - Nov 13, 2007 - 02:31 AM
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My apologies for 1. not finishing reading the second page and 2) not editting in 10 minutes.

I see that you are using breathing equipment. Good thing if you are in a poorly ventilated room. When you put the heat to stay clean/cut acid you vaporize zinc chloride which is a pretty mild toxin. If you use flux-core solder then you are probably getting a heavy dose of ammonium chloride in your lungs, another relatively mild poison. (Don't worry too much about their toxicity; either one can be found in a variety of products from foods to dental fillings.) Rosin-based fluxes (aka colophony) on the otherhand should be used much more carefully, their affects are felt in the lungs but also cause skin irritations.

If you are making the cut acid (aka killed spirits) in your shop then you are probably aware the discharge of the chemical reaction is hydrogen. Always fun for the geeks that play with fire.

DMNyankee - Feb 06, 2008 - 03:37 AM
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sta-clean or M-A stainless flux. Move quickly as ss heats very quickly and will buckle if you linger too long. 50/50 works great. I prefer it for its forgiveness in expansion and contraction to lead free solders. I'm on a huge terne stainless gutter and roof job now(250' built ins and 50 sq. standing seam). soldering it is a pain but it is strong and watertight.

rothalion - Apr 05, 2008 - 12:35 AM
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DMNyankee wrote:

sta-clean or M-A stainless flux. Move quickly as ss heats very quickly and will buckle if you linger too long. 50/50 works great. I prefer it for its forgiveness in expansion and contraction to lead free solders. I'm on a huge terne stainless gutter and roof job now(250' built ins and 50 sq. standing seam). soldering it is a pain but it is strong and watertight.

What type of Soldering Iron do you use? Thanks