Joining metal components

[Garrett44]

I’m looking for advice in joining small metal components, similar to the nut and bolt sculptures you see online (https://www.google.com/search?q=sculptures with nuts and bolts&ie=utf-8&oe=utf-8&client=firefox-b-m), but I’m using some slightly larger components e.g. hinges, brackets etc. The components are steel (not stainless), aluminium and brass. Some are old and corroded, others are brand new.

Cost is starting to be an issue as I’ve had a number of failed tries. So far I’m limited to using a soldering iron and a butane blow torch, what I had available and what was low cost, have tried soldering (does not adhere), tried brazing (cannot get a high enough temperature. Not sure if I should try silver solder, this is what tutorials for nut and bolt sculptures advise but given soldering had zero success I’m doubting this.

What will work? What is suitable? Do I need to go to welding? Is there some welding solution that is reasonable cost, small scale and can be used indoors (no access to a workshop or outdoor space)?

 

[Phil Pascoe]

If you can't get it hot enough to braze, you can't get it hot enough to silver solder.

 

[ChaiLatte]

You might do some research on the materials you are using. Steel is iron-based. Brass is copper-based. Aluminium is aluminium-based.

There is only one method which will join all three together, and that is glue.

Soft soldering will join steel to brass. Silver soldering will join steel to brass. Brazing will join steel to brass. Welding will join steel to steel. You can buy specialised low temperature solder to join aluminium to aluminium (confusingly called lumiweld). Joining aluminium to steel or aluminium to brass is challenging.

Every joining method you use will work better if the item is clean. A flux will prevent the clean items oxidising in the atmosphere while they are heating up to the temperature of the filler material. Try to shortcut by joining dirty, rusty, corroded, tarnished items, with no flux, and you will cry.

Please read some of the items here:

https://archive.org/search?query=soldering+brazing

 

[ChaiLatte]

If you can't get it hot enough to braze, you can't get it hot enough to silver solder.

In this area of joining things together, we tend to be a bit fast and loose with the terminology.

You could have a low temperature brazing material that melts at a lower temperature than a high temperature silver solder.

By and large though, brazing is a hotter process than silver soldering (look up the temperature for Easyflo and Sif Bronze), so what you say is not necessarily correct - you could quite easily be too cool to braze but silver solder adequately.

Traditionally, 'braze' and 'brazing' are used to refer to copper-based materials (brass, bronze), but 'silver brazing' is also a term of art.

 

[niall Y]

Given the disparate metals you are attempting to join then I would have to agree that a glue of sorts would be your best option,The body parts of modern cars are often glued together.

If the materials in question could all be silver soldered then starting with the highest temperature ones you can ensure that components stay joined whilst you attach others with progressively lower temperature silver solders.

Getting it right can be tricky especially if there are different metals and they are of varying thicknesses. I have often found myself applying too much heat and melting through thin parts whiles adjacent, thicker parts, won't take on enough heat to melt the solder.

Of course, if one is talking of brazing and soldering the parts have to be scrupulously clean. And, dipped in a pickle to clean off flux and discolouration, afterwards.
So, if one is hoping to use components because of their particular patina or corroded surface. Then this approach isn't going to work. And, using glue would be a better approach.,


Epoxy glues are probably your best bet, and they will come undone by applying sufficient heat, should the need arise .I believe there are also some polyurethane sealants that can be used to glue metal parts together.

 

[Spectric]

For stainless you can use a tin - silver solder but silver solder is a good all rounder for many applications. Another option could be rivets which with different heads could form part of the look of the item.