Brazing brass help

[TheoParticipant @theo]

Hi,

I'm new to the forum, but I'm struggling to find people in my area (Devon) that have experience brazing brass before, and thought a modelling community might be able to point me in the right direction.

I am in the process of fabricating a letter box (it's for a strangely shaped door) for our house, and I need the hinge components and a couple of nuts brazed to some curved 3mm brass sheet.

Would anyone be able to assist?

Thanks,

Theo

[TheoParticipant @theo]

[Martin KyteParticipant @martinkyte99762]

You can find a good tutorial here

**LINK**

regards Martin

[OldironParticipant @oldiron]

Hi Theo. Do you need instructions how to do it or a company or person to do it for you ?There are several large companies in Devon that advertise their services. Many garages have brazing facilities and might take on the job for a few £ if that is what you need.

regards

[TheoParticipant @theo]

I'd be happy to give it a go myself, but I suspect I'd be better off finding a company or person to do it as I don't own the right equipment for it already.

The companies I've spoken to so far haven't been keen to do it as they don't have much experience with brazing brass, which is why I thought a model forum might be a good place to look for the right expertise.

Can you recommend anyone?

[OldironParticipant @oldiron]

Not sure where you are in Devon but these might do it for you. I used to live in Newton Abbott and a friend had some brazing done on some car parts by them.

info@exeterengineering.co.uk tel:01392 344944

regards

[TheoParticipant @theo]

Thanks, I'll give them a call.

[IanTParticipant @iant]

Hello Theo and welcome.

Different people use different terminology in this area but to me "Brass Brazing" suggests high temperature brazing work with a brass filler. If you are planning to fabricate a brass letter-box – this will give a 'complete' (all brass) finish but it is quite hard to do – as the material being joined will probably melt not too far above that of the filler material. My point being that "brass brazing" brass components together is very skilled work, a skill that I certainly don't have (I use brass filler for steel fabrications only).

However, brazing using a silver braze material is far easier, as the silver will melt well before the brass. Some care is required to make sure the joint line doesn't show – or there will be a thin (silvery) joint line.

There may also be other alternatives to "brazing" , such as some form of screwed fixing (from the blind side) or the use of an adhesive. 'Soft' solder could also be a simpler (lower temperature) solution but it's also quite easy to make a mess with soft solder and once used, silver brazing cannot then be tried.

Just some thoughts that I hope will help – good luck with your project.

Regards,

IanT

Edited By IanT on 03/09/2020 20:37:22

[Speedy Builder5Participant @speedybuilder5]

Theo, As others have said. look at silver soldering, brazing runs the risk of melting the brass sheet before the brazing wire melts, also you will need a bigger torch. Brazing is about 850deg c and silver solder 650 degrees depending upon silver content. Some brasses melt at about 930 degrees.

[TheoParticipant @theo]

Hi,

Thanks all for all of the input. The 'brass brazing' as opposed to 'silver soldering' may be what has made it a challenge finding someone to do it.

The plan is to have it plated so it does not matter if it's not all brass. Here's an image of what I'm trying to achieve

Essentialy a nut, and the 'ears' for the hinge needs to be attached somehow. Do you think silver soldering would create a strong enough joint? I think usually these things are cast, but that would be far too expensive to fabricate that way.

[Dave HalfordParticipant @davehalford22513]

What scares the pro's is the chance of distorting the plate, though the curve may help and 6 loose items to solder.

You could look up your local model engineers club.

[TheoParticipant @theo]

Yes, the ears are very small and fiddly to all keep aligned. How else could I design it to be easier to fabricate?

[Neil WyattModerator @neilwyatt]

I'd suggest silver soldering, then bending. You can then keep it undistorted by clamping to a steel plate.

[larry phelan 1Participant @larryphelan1]

No expert I, but I see no reason why silver solder would no be suitable for that job.

I have used it for many jobs over the years and never had a problem with it.

Your job is not going to get knocked about [like some of mine did ! ], so, I think silver solder is the way to go and should be much easier to find someone local to do it. It,s no big deal.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, it is strange how terminology changes over the years, during my college studies from 1968 to 1973, brazing was considered as the joining of two metals that were the same or different, with a brass filler wire. With that in mind, brass couldn't be brazed because it would melt at around the same temperature, which was deemed to be indistinguishable and the filler wire would be totally fused with the parent metal and was therefore known as brass welding. However, brass could be brazed to other metals, but this and brass welding require a fair bit of practice and skill and is harder on thin sections. More recently thought, silver soldering seems to be classed as brazing rather than soldering, which can be accomplished relatively easy with a bit of practice, so in my mine it should probably be called silver alloy brazing to distinguish it from brazing associated using brass filler wires, but that may be better described as brass brazing to bring the two, into alignment and separated from brass welding. However maybe I'm just from the old school of thought.

Regards Nick.

Edited By Nicholas Farr on 03/09/2020 21:52:15

[Tim ChambersParticipant @timchambers76147]

Posted by Theo Cushion on 03/09/2020 21:07:38:

Yes, the ears are very small and fiddly to all keep aligned. How else could I design it to be easier to fabricate?

Could they be made as small blocks instead? Also I would use threaded sleeves to about half the depth of the door to give plenty of latitude when tightening up the screws.

[TheoParticipant @theo]

Nicholas, that makes a lot of sense to me. I suppose I could build it out of copper, and then braze with brass, but it sounds like the 'silver alloy brazing' / 'silver soldering' should be fine.

Tim, good shout on the threaded sleeves. I think I can source some m5 brass PCB standoffs which look like they could do the job. I suppose I could make the ears out of brass bar, or brass angle. It would certainly make it less fiddly, would it make soldering harder because a thin sheet would be being attached to a thicker block?

Sorry for all the questions!

[Martin KyteParticipant @martinkyte99762]

If I was attempting this job and had not got access to brazing kit I would seriously be thinking of joining the items by riveting using brass. If the lugs for the hinges for example had a couple of brass pins screwed and loctited in top and bottom with corresponding holes in the front of the letter box they could be attached by countersunk rivetting on the outside. Leave the pins long, rivet to fill the holes and then file off flush the same as you would when bushing a hole in a clock frame. Done properly nothing will show on the outside. Similar approach with the lugs on the flap and the nut and bolt arrangement could become a pillar with a flange and spigot again rivetted on the outside. The other end can be drilled and tapped to take a screw for fixing the inner leaf. It's basically nailing it together but with a little finesse.

regards Martin

[Tim ChambersParticipant @timchambers76147]

Having a bit more surface area would make it easier to solder, how thin is the facia panel going to be?

[BazyleParticipant @bazyle]

There will be some distortion during the heating so you will have to bend it back, and clean it. You need a jig to hold the position and curve of the plates as well as the lugs as the holes must be aligned. Can't do it flat unless you drill the holes after soldering. During the process you will need to put a substitute steel threadded bar though relevant holes with nuts holding the lugs, then that bar also needs to be long enough to locate in the jig to hold it.
Silver solder will be fine if you get a good joint and none of it is gong to show with that design. Else you could make the lugs bigger and use soft solder.

Again it would help to have some idea of where you are. It is a long way from Barnstaple to Totnes but there are several clubs around the county.

[SteviegtrParticipant @steviegtr]

I used to in my spare time as a maintenance electrician spend a lot of time making things. One was making brass outside lanterns. I always soldered them , but only where the join was not seen as your pic shows. 100% reliable & strong enough. I did not use a blowlamp. Just a large soldering iron , heated in a hearth. Warping was never an issue either. Cannot remember if i used bakers fluid or not.

Steve.

[TheoParticipant @theo]

Martin: That's an interesting idea. I've seen Clickspring on YouTube do that kind of thing with great success.

Tim: I'd planned on making it 3mm, mainly because it looks like you can get polished brass sheet in that thickness. Now I'm wondering if I would be better off using 4mm milled brass to make the parts slightly less fiddly, and provide a bit more surface area.

Bazyle: I'm based in Exeter. It looks like there is a club in Taunton, so I'll reach out to them. At the risk of sounding stupid, could the jig be constructed out of something like plywood (easy to cut the curve into several pieces of ply laminated together), or would it hit ignition temperature too quickly?

[Tim ChambersParticipant @timchambers76147]

I was thinking that you could probably form the curve just by tightening the screws when you fit it to the door. I am an ex member of the Taunton club ( I have been looking after my mum for the last four years, but now I have a bit of time on my hands)

[duncan webster 1Participant @duncanwebster1]

A bit off the wall perhaps, but if you're going to have it plated how about making it from stainless, you'll easily find a fabricator who will stick it together then

[Keith HaleParticipant @keithhale68713]

Clamps are used to support joints and allow for thermal expansion. Clamping will cause more distortion.

Clamping to steel creates a massive heat sink making any joining technique involving heat more difficult than necessary. The link to the tutorial is great and will point you in the right direction for making good, strong joints.

Have you considered adhesives. Once the letter box is in place what stresses are being put on any joints? Superglue a nut to a piece of sheet and try to knock it off?

Other adhesives are available 😀.

Keith

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