I’m an architect building a small house. Trying to solder the lap joints for some outrigger beam caps. These are in galvanized sheet metal. Having trouble getting a good solder joint. Looking for any advice on how to do this. I’m cleaning the metal with muratic acid first. Using 50/50 solder and a propane torch. (Didn’t want to buy an iron for the small amount of this work I have to do.) Even after fluxing and wiping down the surface with clean cloth, the solder doesn’t lay down everywhere, and I don’t get as much wicking action into the joint as I’d like. A second swipe of the acid then helps, but it seems like that shouldn’t be necessary.
Please tell me what I’m doing wrong.
Andrew
Replies
Good question.
What flux are you using? We use Ruby Fluid.
I THINK ya may be getting hot spots, and that will repell the solder. An Iron will give you vastly more control on getting the surface tinned, and moving the heat zone so the puddle will follow.
Edit: are the pcs actually TOUCHING with no gaps? A hammer to get them in contact, is VERY important. To get a good sweat, the pcs MUST mate. Apply plenty of flux. It too helps with the heat dispersion, and flow. If the parts are not in close enough contact, use copper poprivets to suck them together, or Copper nails. Both will help a lot.
Parolee # 40835
Edited 3/31/2007 11:59 am ET by Sphere
curiousity just bit me.Why copper rivets for galvy metal?
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Most other available rivits are alum or steel, neither like to be soldered. Alum is about impossible. And Brass is 3x the cost of Cu. in rivet fashion..afaik.Parolee # 40835
Andrew,
I use emory cloth to clean and scratch the joint. Use an acid flux and a rosin (acid) core solder. Pretin the joints and then melt them together.
Sphere is thinking you are doing copper. Don't use the copper rivets and nails.
KK
No I ain't. I know Galvy. Trust me, Copper is Noble higher up than zinc or steel, the rivets will out last the steel in the galvy, the zinc in galvy mediates the effect of galvanic corrosion, the lead and tin solder isolate that, unless under salt water.Parolee # 40835
Sphere,I am not going to join dissimilar metals if I can avoid doing so. I am looking at years of service. If it is ok to mix copper and galvanized why don't you use galvy nails on your copper tabs? Be cheaper.Off topic. I have extra birds eye pepper seeds if you want some. Also known as chili pequin. 140,000 scoville units.KK
I can't take the seeds, I have my beds layed out...I also can't market them..I am fiddling with Jamacain Hot Chocolate ( like a hab, but more flavor) and Fatali...death.
Galvy nails will fail, prior to Cu, thats why...Noble elements and such.
Altho'..I did a tear off where slate dust ate the valley away, and guess what? Galvy nails held the pans to rosin paper....all there was fine. 50 yrs of work.Parolee # 40835
You'll have to keep repeatedly fluxing with muriatic acid. You're burning the flux off with the torch. A soldering copper would make your life a lot easier, but....... Oh, and you know not to use copper rivets on galvanized.
http://logancustomcopper.com
http://grantlogan.net/
"We have enough youth, how about a fountain of smart?"
Thanks for all the advice. Sounds like an iron would help a lot, but for continuing with the torch, I need to concentrate on not overheating things. I'll also look to clamp my joints together tighter before starting. I've been fluxing, then clamping together, then soldering. I'll also try tinning the surfaces first and then just melting the joint together.I've tried several fluxes: muriatic acid, phosphoric acid, a bottled liquid flux (no info on the label exactly what was in it, and the paste flux I have for sweating copper piping. All seem to work about the same. Is that a typical experience. Or do thay all work the same for me because I'm overheating them all?Andrew
Zinc Chloride is your Flux, Muratic acid is your Prep solvent to get the cosmoline off.
Follow the heat with an iron, it will draw the puddle with you.
I can solder a verticle seam now, but it took a long time to get the hang of it.Parolee # 40835
Keep a wet rag handy and when solder isn't flowing let the joint cool and wipe all the residue off-then reflux with muriatic acid and try again.
Keeping things clean is a big plus with galvanized since the flux, solder, and the coatings all contribute to making lots of dirty residue.
As others have told you an iron would be better- you could heat it with your torch each time.
Walter
Been following this thread and have a question. Seems I remember a small "iron" attachment that fit over the burner head of propane torches. Is there any way the OP can make or buy something along those lines that would work for him?
I was in the gutter business for years, mainly galvinized steel and copper. Use steel rivets for steel, copper for copper to avoid electrolysis. Get you a soldering iron and file it down till it's smooth and clean looking. Then you tin your iron by heating it with charcoal or propane, but you have to be careful not to get it too hot. Pour you some ruby fluid on a piece of galvinized. Dip your iron occasionally in some ruby fluid in a small jar (large baby food ) to check the heat. It will sound like a loud scorching sound when ideal, then hold soldering bar up to the iron and let it flow all around and occasionally rubbing it around on the piece of galvinized tin with the ruby fluid on it. little or no noise indicates both , the iron is not hot enough or you have burnt it and you have to refile it to get the solder to adhere properly to the iron. When you have the iron properly tinned, you use a small acid swab ( looks like a small paint bush) and dip it in muriatic acid and swab it liberally on the two pieces of metal which should be laid as close as possible. You sweat the first pass while the iron is hot and this tins the metal, then as your iron starts to cool you kind of use the lower heat to build you a slightly thicker 'bridge over the joint. You really can't get too much acid on the joint. every time you make a pass to fill in or bridge what didn't get thick enough you have to swap with acid again and keep the iron not too hot so as not to melt what you've already got right but hot enough to keep the soder hot enough to work with it and make it adhere. Also anywhere you soldered this needs to be wiped clean and painted with an oilbased primer such as red or grey oxide or zinc chromate. I always use bonderized metal which is a dull grey color which doesn't have the oil on it like the 'bright iron' galvinzed which is very shiney and slick feeling. with a good coat of oilbased primer just liike you'd use on a house, you can go back over it with 2 light coats of latex finish paint and it'll last for years without peeling , no more till the rest of your house needs painting. Hope this helps.
By the way, the next best thing to soldering is using a caulk called vulkem. This comes in different colors and sticks better than anything I ever tried, but be careful about getting it on your hands it stains them and only half #### way of getting it off is with handcleaner and some serious scrubing. Use rivets for sure when using vulkem and most of the time when soldering too. This is also done anytime you're mating new metal to old metal, because you can't get the solder to stick to galvinized long after it's new and you'd have to sand the copper down so much it'd be wasting time since it may or may not stick anyway.
Oh , I keep remembering things after I've posted hehe! You don't need the acid core solder, best to use bar solder you buy at a gutter supply house, it's bulkier, and doesnt'have acid, get the 50/50 instead of 60/40. I don't think you could get as much solder as you needed it with the coil solder and the resin could interfere with the galvinized adhering to the solder. I think the resin or rosin is mainly for soldering copper wiring. If you were soldering copper to copper sheet metal you would swab ruby fluid or some water mixed with no corode powder in it in the place of the muriatic acid.
Thanks for the great advice.A couple of questions: I've been using the muriatic acid full strength. Is that ok or is it better to cut it a bit with water? I assume Ruby Fluid is a brand name. Any idea what's in it?I'll check my hardware store for a soldering iron head for my propane torch.Andrew
Andrew,
If you're using muriatic from the hardware store it should be a 20% solution already- there is no need to dilute it further.
Make sure to clean the joint when the solder won't flow- wash off the residue then more acid then heat and solder.
Walter
Ruby fluid is a brand name for zinc chloride (IIRC) which is the flux we normally use for soldering copper and tinning the soldering coppers.http://logancustomcopper.com
http://grantlogan.net/
"We have enough youth, how about a fountain of smart?"
This is veering off into the academic, but it sounds like some flux with muriatic acid and some use Ruby Fluid (zinc chloride). Are the two doing exactly the same thing? Surely there must be some difference in their chemical action on the galvanized. Is that difference significant in any way? Just curious.Andrew
Muriatic acid is a proper flux for Galvanized steel - there may be others. Zinc chloride (ruby fluid) can be used, but the galvanized must be cleaned with muriatic first, so I typically just use muriatic. Other metals take other fluxes.http://logancustomcopper.com
http://grantlogan.net/
"We have enough youth, how about a fountain of smart?"
Just to finish off this thread, I've attached some pictures of what I was able to achieve. With close attention to the temperature I was able to get watertight, serviceable joints. They look ok, but not beautiful, but the joint is on the inside and not visible so no worries. In many ways, the biggest hassle and thing that slowed the process down the most was trouble with joint #1 coming undone while working on joint #2. Best technique was to throughly cool joint #1 with water before starting on #2, and to attach a c-clamp next to joint #1 as a heat sink.Thanks to all for the help and advice.Andrew
Glad it worked out for you.http://grantlogan.net/
What are you clamping your joints with? A metal clamp may act as a heat sink and make it very hard to heat your joint evenly. Just a thought..
Rob Z
Wide mouth vise grips and small c-clamps. I thought of that too, but I don't think that's been an issue. Using a torch, overheating is more the issue than underheating I could pop revit, but don't like the looks of that. Guess I really need a spot welder!Andrew
Well, ya'll better tell us that about Cu rivets, in galvy....udderwise, we're gonna re-visit quite afew jobs in the next decade.Parolee # 40835
The metal has to be degreased before fluxing. Ruby flux will not work on oily metal. Galvanized frequently has an oil film on it.