Brass Welding vs Brazing

[Prodigy]

Hi all

I'm working for a shop fitting company. every now and then we get Some 25x25x2 angle brass frames. Some of them are over 1.5m squared they can be really flimsy, i've had a couple of them come back from the polishers cracked.
I'm also having problems with porosity, i end up wasting too much time grinding and filling pin holes.
The way we are expected to do it is to tig weld it with regular brass filler, but the second i get a pool the zinc starts burning out of the metal,I get white soot over everything and spatter all over my tungsten. there must be a better way to do it.

I have thought about using silicon bronze filler and brazing it, but will it be strong enough? and will it show when mirror polished?

Any advice is appreciated

 

[nickk]

i used to regularly braize decorative brass [perforated strip] frames for a furniture maker,using flux coated 3.2mm rods with oxy acet' & would sand the corners never had porosity,however they were only 2' sq'.

 

[GrahamGKD]

I don't think you can use regular brazing rods with TIG (as you seem to have discovered). Try using something like SIFbronze No. 8.

http://www.weldability-sif.com/pages/view_product.asp?product_string=RO081225
http://www.weldability-sif.com/pages/view_product.asp?product_string=RO081225
I have never used them on brass though - just steel?

 

[hotrodder]

As Nickk oxy fuel and flux is really the right weapon for the job. Assuming the brass angle is CZ130 (aka cw624n) it's gonna be horrible to weld or braze with TIG regardless of filler wire as it's 40+ % zinc and also contains a little lead

Silicon bronze / copper silicon (CuSi3) TIG wire will be OK strength wise as would phosphor bronze (the SIF #8 mentioned) but won't fix the fume and porosity if my cz130 guess is correct. Both have a higher melting point than copper-zinc brasses (by ~ 100°C) and will result in a poor colour match too

 

[Shox Dr]

no8 will not to colour match to brass. I've used it on copper plumbing pipe it's bearly noticeable.

I've also tried unsuccessfully to tig brass, as HR points out. Zinc no likely

 

[Prodigy]

We have a oxy-acetylene set up for cutting, but i'm not sure if we have a gas welding torch. Would heat be a problem with gas brazing?

I want to get results like this guy, But my foreman won't order silicon bronze. he has done it for years with regular brass rod and doesn't have a problem.

 

[the snooper]

ive also always brazed with flux coated and OA perfect results every time

 

[hotrodder]

I wouldn't believe that egotistical waste of skin if he claimed the sky is blue. I can't face watching the vid but unless he specifically mentions the alloy of "brass" he's working with it's even more meaningless than the utter nonsense usually leaving his cakehole... some brasses are weldable, others not so much and some are truely horrible. There are LOTS of different flavours of the stuff and we don't know what you're working with, my guess of cz130 is based on that being one of the common ones for "brass angle"

CZ130 melts at ~890°C, very similar to 'regular' brazing rods (sifbronze #1 etc) that are also around 60/40 copper/zinc
Silicon bronze TIG wire melts in the high 900s - low 1000s °C range. So does phosphor bronze as both of them are mostly copper with a tiny bit of silicon or tin
Zinc boils at 907°C

Trying to weld or braze some 25x25x2mm with a cutting torch isn't gonna end well. With the right size tip in a welding torch it'd be fine but i'm thinking your foreman won't like that idea either unless the reason he won't get any silicon bronze is purely 'cause he knows it'll result in a poor colour match?

 

[Maxakarudy]

If welding isn't succesfull, try soft soldering or 2pk glue, make a little angle for the corners and backer for the flat, I make sign frames like that, same sort of thing you do, they are just decorative frames

 

[Richard.]

I wouldn't believe that egotistical waste of skin if he claimed the sky is blue.

Like wise.
Total tit in every sense of the word.
I watched one where he was talking through a 5G pipe root while the guy was doing it. Totally out of his comfort zone with no clue of the procedure. Made me laugh. He should stick to his poxy plates on a flat bench. Even then he just dribbles total s**te.

 

[WorkshopChris]

I wouldn't believe that egotistical waste of skin if he claimed the sky is blue.

Like wise.
Total tit in every sense of the word.
I watched one where he was talking through a 5G pipe root while the guy was doing it. Totally out of his comfort zone with no clue of the procedure. Made me laugh. He should stick to his poxy plates on a flat bench. Even then he just dribbles total s**te.

Problem is YouTube is full of them on all sorts of subjects, and unless you know otherwise they can sometime sound convincing.

Welding is not my main subject so i tend to stick to Jody with welding tips and tricks as although a bit to american he appears to know his stuff.
Would be great to have something maybe uk based with techniques and facts you could trust.
Same with machining videos i have watch a lot but only return to a very limited few.

 

[Richard.]

John (doubleboost) does some awesome machining vids. I've learnt loads of cool tricks off his lathe vids. Jody is loads better than that other clown as he's got the knowledge and he's introducing you to real jobs not scratty bits of plates that any wally can lay a weld down.

 

[hotrodder]

Good point that stuff like youtube can make sorting wheat from the chaff more difficult. It's not only technical content/knowledge etc but with video the character and confidence of whoever is presenting it can skew things lots too... a large part of my problem with the egotistical idiot is that the vids have a "professional" look to them being well fimed/edited, sponsorship etc despite the whole premise/format being mostly nicked/copied from others with less resources. That automatically adds some credibility for many people in much the same way as getting a book* published does. Except it doesn't always work that way... several welding books about by someone called Richard Finch that contain loads of nonsense about metallurgy mixed in with a few good practical tips

On the flip side there's a guy that goes by the handle Fieldres on youtube. One bloke (pipe welder from Alberta?), some welding kit and a camera, zero product placement/sponsorship/sales pitches from what little i've seen. Vid editing isn't great and he's got zero chance of ever getting a job presenting but the boy can weld which is pretty much all he does; gives a commentary while welding up various 6g test coupons on all sorts of materials including exotics.

 

[Brad93]

I follow Fieldres via instagram, have for years. He has about 60 tickets from anything in Aluminium to Zirconium, duplex, inconel alloys different processes etc. The guy really knows his stuff and has spent a lot of money getting to the stage he is at. He recently tallied it up at over $50k in training and materials.

 

[Richard.]

I follow Fieldres via instagram, have for years. He has about 60 tickets from anything in Aluminium to Zirconium, duplex, inconel alloys different processes etc. The guy really knows his stuff and has spent a lot of money getting to the stage he is at. He recently tallied it up at over $50k in training and materials.

Watching his Ti 6G looks almost robotic.
Probably one of the best tig pipe welders going.

 

[scott0031]

Silver solder, also known as brazing by some. Good colour match very little to clean up and should i think be a bit more flexible and forgiving than you currently have.

 

[Rrunnach]

I have tig welded a fair bit of brass when I was on the tools. It was sheet, so what follows may be no use to you?

I cut slithers from sheet being used for perfect colour match after polishing, maybe same could be done cutting slithers from off cut angle? Zinc paratroopers are always an issue, porosity was never an issue. I would always lean towards tig, first, quicker and, less heat input. One other point, we did our own polishing and lacquering, we were in control when handling client job. That said, though. Those are large flexible frames you and the polishers are handing.

 

[scott0031]

I would always lean towards tig, first, quicker and, less heat input

Don't agree. The set up for the job is the same/similar. No worrying about setting up the so you can access the joint without awkward torch angles etc. Clean it, flux it heat it touch of solder done, then a clean with a rubbing block. No build up on the inside of the angle which you could well get with Tig and is a pain to clean up, no risk of that with solder, clean up a lot easier than tig from my own personal experience. The heat input not an issue with brass, and silver solder average melting point is some 300 degrees below that of brass. Even so heat is not an issue with something like this.

The problem with silver solder brazing in general is people have little experience of using it and tend to stick with what they know. It's a very underused process and very often provides the best solution to a problem.

 

[Rrunnach]

I should have said, more localised heat input with tig = less scorch area. Cleaning off solidified flux can be time consuming, you miss a bit, discolouration at a later date, due to corrosive flux.

I have done loads of silver soldering brass/copper, too. Tig is quicker.

 

[DAPPH]

I should have said, more localised heat input with tig = less scorch area. Cleaning off solidified flux can be time consuming, you miss a bit, discolouration at a later date, due to corrosive flux.

I have done loads of silver soldering brass/copper, too. Tig is quicker.

I've done quite a bit of brazing & silver soldering in my jewelery classes & general engineering work life .

When you referred to " Tigging " brass strips , were you meaning strips of brass cut from the same material as the work piece ? ( I think you are )

Was that TIG AC or a DC TIG you were using ?

If DC TIG ( what I have ) what earth polarity do you use ?

What gas were you using ............ pure argon ?

Did you have to use a specific ground up point angle on the tungsten tip ?


Dave