How to get a 100% strong bond when bronze brazing

[@Xynudu]

Note: Bronze filler achieves it's maximum strength at it's thinnest thickness. Always use the least amount of bronze possible for complete coverage of the joining faces. Cheers Rob

[@Grahammon]

It’s been a while since I did brazing but one tip that prevents the brazing melt from going everywhere is to rub a pencil (as if you were shading a picture ) around the border say 3mm 1/8” bigger than the finished brazed joint. There are commercial products about, but a quick shade with a pencil can help contain the flow of braze when it matters. You’re better than me as I’d often get the fluxed rod pick up the light part! A grr moment, thanks Rob

[@Xynudu]

Hi Graham, thanks for the tip. I will try that next time. Makes sense for sure. Good one. Yes, brazing small stuff sure checks out your nerves ;) Cheers Rob

[@EverettsWorkshop]

I enjoy watching your videos about brazing techniques and now that I finally got a torch setup (still need the gas bottles) hopefully I can try some of your ideas. I've brazed at work before using standard flux-coated brazing rod but you've got some cool techniques I want to try for small projects.

[@sophiestabilitronics]

Thank you for the guide and technique on how to do brazing properly. I am new in brazing since I only tried when brazing copper pipes in HVAC units. But also I would like to try brazing to bond 2 pieces of steel and also the capillary action works well. I tried once to put flux powder before firing up and the filler do not stick well. Then I imitated this and worked pretty well. I strongly agree about having "control" when doing that. I use MAPP Torch for brazing. Greetings from Philippines!

[@Xynudu]

Hi Sophie. Glad it helped. You must put the flux on with the metal hot. I add it while the job is heating up to near brazing temperature. It will go clear when it's melted. That gives it time to clean the job before adding the bronze or silver solder. MAPP is quite OK for most small heat loss work. Greetings from Oz. Cheers Rob

[@sophiestabilitronics]

@@Xynudu Sir, how hot? would it be cherry red? red orange? or in between? or i would rely on giving silver filler rod with flux while i see those colours on workpiece indicator? I agree about that since on sheet metal (mild steel or GI) or even on metal tubings like in reception area of offices (took me a minute). But also i tried rebar (bars used in construction) and took me 5-7 minutes before reaching cherry red and tried your technique and finally the filler with flux adhered, provided i used metal brush to the bar prior brazing. It was rusty, then when i brushed, there were some shiny parts that can be used for brazing so the filler will adhere. I do not have "oxygen" tank to partner with my humble mapp torch yet (which hoping will speed up the process) but overall though it looked bit messy, the durability is good and even a chubby person can support the visitor chair that was brazed. I agree on what you said since the thicker the metal, the more it acted as heatsink. ^_^

[@Xynudu]

Hi Sophie, sorry for the delay in replying. As soon as the job goes dull red it's OK to add the flux. The heat will allow it to adhere and melt. The metal must be clean - no rust. Cheers Rob

[@mcmillanfarms]

Thanks! I learned something useful today. I have probably always used way too much rod.

[@Xynudu]

It's a common mistake. Doing it this way (when possible) you can keep the bronze filler to a minimum and be sure of complete coverage. Sometimes you just have to use capillary action and that usually means some of the rod is wasted - flowing elsewhere ;) Cheers Rob

[@howder1951]

Nice job, Rob very similar to tinning in soft solder, and as you demonstrate, it is always wise to go over every step prior to the job to keep surprises from interfering with execution, cheers!

[@MrBuddysAdventures]

Great tip. For those who don't have an oxy/acetlyne or the bullfinch torch but want to be able to do this sort of thing I use Silver solder and a cheap hand held propane torch (not even MAAP) for small parts like that. Very strong and pretty much the same exact concept/techniques as Rob has shown on his channel. Of course, for bigger projects you need more heat so for that I use silicone broze with my TIG welder or MIG it etc depending on the metal.

[@berniesr]

ALways instructive Rob

[@MrUbiquitousTech]

Great tip there Rob, thanks for sharing!

[@RetroSteamTech]

Thanks for this Rob, I always enjoy your brazing videos, gives me confidence to do my own. Cheers, Alan.

[@Xynudu]

Hi Alan, this approach will give a much neater end result and also allows butting together irregular broken faces (as on cast iron) which don't capillerate very well. Most times gravity is sufficient to allow the two faces to come together during the re-melt if everything is lined up correctly. Cheers Rob

[@RetroSteamTech]

@@Xynudu As you say, it's very much like soldering where you tin both surfaces before joining. Cheers, Alan.

[@marynollaig4124]

I would have left the hole in the plate until after the brazing was done. That way the hole would be perfectly aligned. Well explained.

[@Xynudu]

True, but the hole was the alignment indicator for the job. Cheers Rob

[@rayfalcone6897]

nice video and tip .thanks Rob,see you next time

[@TrPrecisionMachining]

very good video..thanks for your time

[@pcka12]

Capillary method does work well, BUT you have to clean both surfaces very carefully then apply a paste of flux powder mixed with water and preferably wire the joint tight together before heating in order to be certain of the braze fully penetrating the joint (capillary action works best in very narrow spaces).

[@Xynudu]

Hi Pat, Capillary works fine with freehand. Flow paths and gaps are going to be the same. I've only ever seen paste used with a furnace. That's how most factory production brazing is done. Cheers Rob

[@pcka12]

xynudu that is how I was taught to do it decades ago, I am not sure that I saw a pre fluxed rod until at least 10 years later, as for capillaries and ‘capillary action’, well I went on to become a biologist & that is how most plants 🌱 raise water up their stems (tall trees have a bigger problem), but it is the very narrowness of the plant tubules which facilitates the capillary ‘draw’ which pulls the water up the plant against gravity, it is related to the ‘meniscus’ around the edge of your cup of coffee!

[@Xynudu]

Hi Pat, coated rods are rubbish from my experience. You have no control of the flux. The rods sold in tool outlets from my experience are total junk and it's no wonder newbies often struggle with brazing. I only use BOC rods. They are the best, as is DA 303 dipping flux, from my long experience doing this. Cheers Rob

[@pcka12]

xynudu yes with the coated rod you have to heat the flux and allow it to flow down into a joint which all the while is being heated whilst not being protected from oxidation, with the two methods we have outlined (I would call your method ‘tinning’ the joint from soldering practice) the cleaned surfaces are protected from oxidation as they are heated to the melting point of the spelter.

[@gregwilson9035]

So “keying” can be considered like tinning when soldering?

[@Xynudu]

Hi Greg, yes. The only difference is that you don't add additional rod when melting the parts together, as is often the case when soldering. Cheers Rob

[@shawnmrfixitlee6478]

Great job man , ENJOYED .. That will hold up very well

[@jefffisher5021]

Thanks for your excellent videos. How important is the cleanliness of the joint when brazing? I seem to have difficulty in getting the bronze to run or bond - not sure if it is preparation of the joint or something else. cheers

[@Xynudu]

Hi Jeff, it's extremely important to have clean rust/corrosion free surfaces when brazing. You must also use the correct flux, or the molten brazing rod will bead and not adhere to the job. If the rod is not melting it indicates that the rod is poor quality, wrong type, or the gas torch flame is not hot enough for that rod. Never buy cheap no name brazing rods as they usually have extremely poor melt and flow capability (from my experience). Borax based flux as required, is a type of cleaning agent, but use one specifically formulated for bronze brazing. This will also do silver solder - the code in Australia is CA-303. Make sure your rods have a high manganese content for easy flow and melt characteristics. I hope this helps. Cheers Rob

[@jefffisher5021]

@@Xynudu Excellent - thanks Rob. I bought the rods and flux from the big green shed, and I'm using one of those small mapp/Oxy kits (expensive to run) but I think it is hot enough. Yes, the bronze appears to bead - will double check the flux to make sure I picked up the right one. thanks again - from Adelaide!

[@Xynudu]

Hi again Jeff, as you are in Adelaide the rods to get most definitely are BOC Profill Manganese : www.boc.com.au/shop/en/au/boc-profill-mang-bronze-gas-welding-rod-grmb-112 The small packs are more expensive per rod. I use 1.6 or 2.5 mm depending on the size of the job. Smaller are easier to handle. The last lot of brazing flux I bought came from Hampdon Gas in WA. Free postage and cheaper than BOC: www.hampdon.com.au/CA-Flux-Copper-Brass-Flux-250g-303-OXY-LPG-Brazing I haven't used it yet, but it is CA-303 code/mix same as the EZIWELD 303 which is no longer made. Cheers Rob

[@garyc5483]

Great job m8. I always wonder what all the fuss is about on the forums over brazing. ie (cant do this cant do that gotta be done this way or else). I have been doing it since I was a teenager 60 years ago and always found it easy to do. Clean base makes a big difference but even on some ropey materials it still usually works OK as the heat does a lot of the clean up. Thanks for sharing. Stay safe stay well. regards from the UK .

[@Xynudu]

Hi Gary, yes some people seem to make a big deal out of what is a simple process. Provided you prep the job, use the correct flux and a decent quality rod all is easy. Cheers Rob

[@mickellis8747]

Hay Rob, I have a really neat product I use very sparingly because I only have a small amount of it. It's a flux with powdered silver solder in it. It works brilliantly on jobs like this. Don't ask me who makes it, the container has no markings and I can't remember where I got it. It may be a Utectic product, I don't know.

[@Xynudu]

Hi Mick, I haven't seen that one. I have seen quite a variety of specialist rods over the years, some quite expensive. Most do what they say. Bronze rods are definitely not all the same. Many different flavours. Cheers Rob

[@ChrisB257]

Good tips Rob :)

[@juliusvalentinas]

So what it the nozzle size of bullfinch brazing torch? They claim it's smaller so 0.3m or 0.35mm, my torch has 0.4mm

[@Xynudu]

I have no idea what size it is. That isn't really the reason it works so well - it has more to do with the gas mixing venturi in the burner nozzel, Cheers Rob

[@kevclar]

Another great video! Excuse my ignorance, but what type of metal is the bent wire that you use to push around the bronze blobs?

[@Xynudu]

Piece of steel fencing wire.

[@harrybond007]

I wish I could find a gas torch that heats like that, usually I can't get things hot enough to braze correctly

[@JoaoFerreira-df9wm]

Hello, Please let me know what kind of torch you use. Can you send me a link from a suplier of a torch like yours? Do you use oxigen? And gas, is propan? Thank you.

[@Xynudu]

Hi Joao, the torch is made by Bullfinch in the UK. This is the kit I use: bullfinch-gas.co.uk/blowtorches/autotorch-brazing-sys/autotorch-brazing-kit-detail It runs on standard LPG or propane. No oxygen cylinder required. You can buy it off of Ebay in some countries. It is NOT sold in the USA or Canada, but units sold in Australia will fit the USA gas cylinder POL fitting. The UK POL fitting will not fit many overseas cylinders (including the USA), so check compatibility. This company will ship overseas: www.hampdon.com.au/bullfinch-lpg-autotorch-brazing-and-welding-kit Cheers Rob

[@JoaoFerreira-df9wm]

@@Xynudu Hello Rob Since I live in Portugal it is easier for me to buy to Bullfinch-gas in England due to the proximity. Thank you very much for your precious information Regards Joao A Ferreira

[@Xynudu]

Hi Joao, you are welcome. Just make sure that the UK POL thread will fit your cylinder as the kit uses a high throughput gas regulator, which you don't want to have to replace. Apart from that aspect you should have no issues. The torch is not cheap, but is a quality unit and quickly pays for itself in gas savings. I put a couple of end screen links on that recent video linking to other earlier videos about the Bullfinch system. It has it's limitations and can't equal any oxygen boosted gas torch, but is excellent for smaller job use - a bit better than MAPP gas. Cheers Rob

[@JoaoFerreira-df9wm]

@@Xynudu Hello Rob I'mm thinking of buying only the torch without regulator or hose because I have a home cylinder of 13 Kg propane gas that already has the regulator. Yes, the equipment is very expensive. Thank you for your attention Regards Joao A Ferreira

[@johnsweda2999]

Can you use bronze rods in arc welding

[@Xynudu]

No. You can however use arc welding rods for torch welding provided you have a hot enough gas torch (oxy acetylene).

You use to be able to get a carbon arc rod attachment for brazing. A gadget with two carbons that is adjustable to get an arc. Here is a picture of the gadget with out the carbon rods.www.mig-welding.co.uk/forum/threads/carbon-arc-heating-brazing.17798/

[@Xynudu]

Hi Tony, a mate of mine bought one of those kits a long time back. I checked it over, but never saw him use it, although he did try and reported back that it was difficult to strike and maintain the correct arc gap between the two carbon tips. I had not heard of it being used to arc to the job ground as stated in that link. That would erode away the job pretty quickly I would expect. It wasn't very good. Difficult to see and use as well. Pretty lightweight construction. It looked the same as in the link photo. One of the brass rods slid in and out. The other was fixed. The principle was sort of like a poor man's TIG. It also went through carbon rods at a fast rate. Probably in the scrap bin by now. Cheers Rob

[@thosoz3431]

You can TIG bronze but it is a different form. It is silicon bronze.

@@Xynudu I agree with you. I have one and yes it will braze but it is not easy and not worth the bother.However like all the junk I keep it may come in useful one day.

[@mrsonic5663]

thanks video

[@pgs8597]

G’day Rob, you make it look easy. Cheers Peter

[@Xynudu]

It is easy Peter :)