[jtybt]

Boat project. I am making railings from 1 1/2" SS tubing(304?)

I want to add pole holders to the open ends of the vertical tubes. The bases have tapered/hex receivers that I cut and ground to fit the open end of the 1 1/2 OD SS stanchions.

The question is how to 'weld these things together. I haven't been very successful brazing brass before or even touched the oxy/acet for anything other than cutting. Can this thing be TIG brazed somehow?


I watched the 'welding brass' video but couldn't find anything about joining bronze and SS.

Thanks guys/Jody


Charlie

[Otto Nobedder]

Have you considered soldering it? A good cleaning, a good flux carefully applied only where you want solder, a good silver-bearing (lead-free) solder, and a hand-held air/propane or air/MAPP torch will due just fine, especially if your fit-up is good. If you've ever sweated copper plumbing, you have all the skills you need. Keep a wet rag handy, and wipe off the excess immediately.

edit: Pre-heat the heck out of the bronze before you put heat on the joint itself.

I've never attempted using TIG to braze; I think the heat is too intense for metals with such dissimilar melting points. Someone here recently mentioned a MIG-brazing method, but I suspect the results will be unattractive on boat handrail.

Good luck.

Steve

[jtybt]

Hey thanks Steve! Never thought of soldering. I'll give it a try. I'll make the next fitting a slight taper fit and open the end of the tubing. Should work great.

[kermdawg]

If your going to solder it-

1-Your fitup has to be -very- tight. Solder doesnt work like welding, it reallys on capillary action which only works if the gap is very tight. Again, think of soldering copper tubing-look at the gap between the cup and the pipe. Your max gap will probably be in the area of 1/32 of an inch.

2-Im not sure I would use a regular lead free silver bearing solder. Not saying it wont work, but that solder is designed for copper and bronze/brass (both of which are copper alloys) soldering. Not sure if it will work with the stainless, but you might be able to find a solder that will.

3-Be sure your flux is non-corrosive. Acid base flux (like johnsons) is -not- water soluble, and it will eat the hell out of copper/brass/bronze (again, not sure about the stainless, never used it on that). Likewise, water soluble flux will likely burn up before your stainless will reach a temperature to melt the solder. Remember, the heat of the metal needs to melt the solder, not the flame itself.

I think you'd be better off brazing it. They make filler rods designed for dissemilar metals and the like and also have many differant types of flux. Im sure you would have better luck finding something that would work with brazing rather than soft solder. But, who knows you might stumble onto something Whatever you do, good luck and let us know how it goes.

[Otto Nobedder]

Kermdawg,

Consider the application. Rod holder in 1.5" OD vertical stanchions. Rivets would suffice in this application. If the fit is good, soft solder should be more than adequate. Common fluxes will have very little effect on 304 SS, and even less if it's 316. The shear mass of the bronze component (whittled down to fit the SS tubing) suggests corrosion there will be insignificant.

I agree that brazing is the absolute best option, but with careful and sparing application of the flux, this solution is a closer fit to the OP's skill set and comfort zone, and should outlast the rest of the boat.

Respectfully,

Steve

[kermdawg]

Found an article on soft soldering stainless steel. Been a plumber most of my life so soft soldering anything besides copper or brass is pretty out there to me Turns out it can be done. Had no idea. God I love this website, I learn somethin new all the time. Thanks Otto

[Otto Nobedder]

The main reason I enjoy participating on forums like this is the opportunity to learn something new. I learn something almost every day here, sometimes from Jody, sometimes from you good people, and I'm glad I can occasionally share something someone else can use.

If we all just bragged about how good we are, this would be a pretty dull place. (And there are sites like that. )

Steve

[Otto Nobedder]

Hey thanks Steve! Never thought of soldering. I'll give it a try. I'll make the next fitting a slight taper fit and open the end of the tubing. Should work great.

Let us know how it works out!

BTW, scuffing the inside of the SS tubing w/ 80 grit will give the solder more "bite".

Steve

[jtybt]

Well Dang! Didn't take a careful look at the stanchions but cut and fitted the bronze base to a 'scrap' piece of tubing. Tried the fit up on the boat and forgot about warping, so I'll have to fit each piece individually.

In the mean time, with one of the cutoff pieces of bronze base plate laying around, I tried brazing to a piece of SS. Worked like a charm. May end up going that route. It didn't need as close a fit-up.

[Otto Nobedder]

Brazing is probably your best option, if you're comfortable with it. The strength of the finished joint will be higher.

I suggested solder because you expressed a lack of comfort with the oxy-acetylene. Either method should suffice, but you are correct, brazing is more forgiving of the fit-up. It also requires more heat, so be prepared for more distortion and more cleanup/polishing.

Steve

[jtybt]

Yup, surprised myself...and polishing is a PITA.

[Otto Nobedder]

So...

Are you going to post a picture or two when you're done?

Steve

[kermdawg]

Question for you (mainly otto)-

If he did braze this joint, would annealing be a problem? Ive had a lot of experience with brazing copper and I know after we're done you can actually take a piece of 4" copper and bend it with your body weight into a worthless piece of scrap.

[jtybt]

I whacked the little bronze end tab with a ball-peen. It only bent slightly at the thinnest where the mounting screw was cut off. The bronze base will be fit and brazed to the ID so it would reinforce the SS tubing. I'll try to keep most of the heat at the thicker bronze center. Should be OK.

[Otto Nobedder]

Question for you (mainly otto)-

We're not talking copper tube/pipe here. jtybt keeps referring to "bronze", so the alloy is similar to brass. The annealing should not be an issue, as it would be with copper.

This is closer to brazing a brass valve body to SS in process piping.

Steve

[kermdawg]

Cool. I was just wondering if it would have the same effect on the SS. I figured if the SS was thin enough it might be an issue.

[Otto Nobedder]

kermdawg,

I misunderstood your question.

The heat cycle should have almost no effect on the SS; Brazing is well below the temps that would harden/embrittle the stainless. (For 304, you have to approach the temps that would "sugar" a weld to significantly affect the properties.)

There are alloys of stainless where this could be a problem. I think Jody has a video on SS alloys that touches on this.

Steve

[ogorir]

another option for this situation would be 'hard' silver solder. it's technically brazing, but you use a liquid or paste flux and need tight fitups similar to soft soldering. an 'easy' solver solder would be the best bet. I've done some jewelry work before and it's a pleasure to work with, but the price of silver right now makes it somewhat cost prohibitive. it's damn handy for attaching carbides to things, though. I think I learned that trick from someone on this board, too.

[Otto Nobedder]

ogorir,

Now that you've said that, that's how I connect brass valves to 304, with hard silver solder. Almost brazing, but not quite. Fortunately, this has been at work, and I didn't have to buy the rod. Seems to me the last batch we bought was well over $50/pound.

Steve

[ogorir]

try about $50/oz for silver solder pure silver is trading around 38 bucks/oz right now. and not to nitpick, but AWS refers to joining metals together above 800f but less than the melting temp of the base metal as brazing. I still think of it as solder because it works like plumbing solder.

[Otto Nobedder]

I knew it $50 something. I didn't realize "per OZ". As I said, my employer bought the stuff. I just turn half of it into useless droplets.

I agree with you. It's solder. I don't nitpick those definitions, either. To my mind, brazing involves a copper/zinc/etc. alloy filler.

Steve.

[kermdawg]

Lol Im a plumber brazing to me is silflossing :p