The short answer is no, you cannot, but you can join them by using other welding techniques.
Brass is an alloy of copper and zinc. The percentage of zinc in each piece, will affect the melting point of the metal, so this will obviously affect a weld.
It also has a lower melting point than copper, so overheating it can cause a porous weld with cracking. If you want to weld brass to steel, the melting points are not the same, so this does cause a problem.
You can use a brazing technique to join them, or solder them
Brazing is a method whereby a filler rod is melted in to the joint and this creates the bond. A brazed joint is not the same as a welded joint, as the base metals are not melted, so they retain their physical properties.
Brazing metals is not a hard process, but it does need practice to get it right. You will be working at lower temperatures as you will not be melting the base metals.
- First you need to heat the base metals until they are hot, but not melting. Ideally the metals should be glowing red.
- Then, apply the filler metal. The heat of the base metals should melt this so that that it melts in to the joint without further heat being applied. If done correctly it should be drawn in to the metals by capillary action, and will flow in to the joint.
Once it has cooled, your joint is complete.
You can also solder the two metals together. The best solder to use is silver solder.
- Clean both surfaces thoroughly before you start. Use a wire brush or sandpaper to remove al traces of oxidization.
- Apply liquid flux, and clamp the two pieces together.
- Heat both surfaces.
- You will need to test the heat before you apply the solder.
- When the heat from the metal is enough to melt the solder, you can apply the solder stick. It should flow in to the joint.
As with brazing, practice this first, as overheating the solder or metal may mean you don’t have as strong a joint as you would like.
Welding always has it’s dangers, but when working with brass, you have to take extra precautions.
- When working with brass, you must remember that molten zinc can produce toxic fumes. Wear a helmet with good ventilation and make sure your work area is properly ventilated.
- Zinc also has a tendency to spatter, so you should wear protective boots and gloves as a minimum.
Frequently Asked Questions:
Is a brazed joint as strong as a welded one?
If completed correctly, a brazed joint should be every bit as strong as a welded joint. Just make sure that the zinc is not overheated.
Can you use brazing for other metals?
Yes you can. It’s an easier way to join together two metals which have a big difference in melting points.
Does brazing or soldering produce slag?
This is one of the good things about brazing. It creates a smooth surface which requires very little, or no, finishing. If you use the solder method, you may need to chop some excess solder away, but if you test the temperature as you go, it should flow smoothly in to the joint.
Welding different metals can be a problem, particularly with alloys and with metals which have a difference in their melting points. Brass must always be welded with caution, due to the potentially toxic nature of the zinc it contains.
Brazing and soldering are two safe and efficient methods which can be used with brass and steel, as well as other metals.
The main problem is making sure you have the correct temperature. You won’t be heating metals as you would with a weld, so it will take some practice to be able to braze or solder properly.
Although the temperature will be lower, please use the same caution as you would when welding, as they can still give a nasty burn.