Can you clean aluminium, brass and steel in one ultrasonic load?
Engine and pump assemblies, carburettors, fittings and fixtures often mix aluminium, brass and steel. Which of our solutions are safe on all three, how to load the basket, and when to clean the metals apart.
Yes, if the solution is safe on every metal in the basket and the aluminium does not touch the brass, copper or steel. In our range that is AquaVantage 1696 GD at about 5%, or AquaVantage 1990 GD. Both have aluminium and copper alloys on their data sheets. Most stronger cleaners are safe on one of the three metals and attack another, so the weakest metal in the basket sets the solution, the strength and the temperature.
Why mixed loads go wrong
There are three causes. Each one has a different fix.
- The solution suits one metal and attacks another. A strong alkaline degreaser that is fine on steel darkens aluminium and attacks zinc. Solutions with ethanolamine or ammonia in them attack copper alloys and can crack brass.
- Metals touching in the bath. Aluminium sitting against brass, copper or steel in a conductive bath can darken from a galvanic reaction.
- Copper already in the bath. Brass and copper parts put copper into the bath on their own. The next aluminium part can go dark even though nothing was wrong with the clean. Filtration does not remove dissolved copper.
Which solutions are safe on aluminium, brass and steel?
Read from each product's technical data sheet and our chemical compatibility matrix. The data sheet governs; a trial on your parts confirms it.
| Solution | Steel | Aluminium | Copper and brass | Zinc |
|---|---|---|---|---|
| AquaVantage 1696 GD | Safe | Safe, pH about 8 | Safe, the mildest in the range | Test first |
| AquaVantage 1990 GD | Safe | Safe, minimum 5% | Safe | Test first |
| AquaVantage 815 GD | Safe | Safe | Test first | Test first |
| CoreKleen HX | Safe | Safe | Time-limit and test | Safe |
| Desludge | Safe | Protected at working strength | Tarnishes, test first | Do not use |
| FX Degreaser | Safe | 5% max, 50 °C max, 5 min | Tarnishes, test first | Do not use |
| Alloy System | Safe | Safe | Test first | Safe |
| AquaVantage 815 QR-NF | Safe | Safe | Do not use | Test first |
| MetalTek 100 | Safe | Do not use | Do not use | Do not use |
| Descale | Time-limit | Do not use | Brass dezincifies, time-limit | Do not use |
| RegeniK | Time-limit | Do not use | Do not use | Do not use |
Only the first two are safe on all three metals without a time limit. The rest are the right choice for a load of one metal, or for the steel parts cleaned on their own.
How to clean a mixed load
- List every metal. Include plating, zinc die-cast bodies, solder and anything you are not sure of. Treat an unknown casting as the weakest case.
- Pick a solution with all of them on its data sheet. For aluminium, brass and steel together: AquaVantage 1696 GD at about 5%, data sheet range 3 to 15%.
- Set the bath for the weakest metal. With aluminium in the load, run 1696 GD at 50 to 55 °C. Below 49 °C it foams.
- Keep the metals apart in the basket. Use separate baskets or dividers so the aluminium does not touch the brass, copper or steel.
- Run short cycles and look. Typical parts clean in 1 to 5 minutes in 1696 GD. On a dual-frequency machine such as the MSX 30 (25 and 45 kHz), run most of the cycle at 45 kHz for soft aluminium.
- Rinse and dry straight away. Keep parts wet between stages, then dry them. If steel parts will wait before assembly, dip only the steel in Anti-Rust.
- Watch the bath. If an aluminium part comes out dark, stop and look at it dry. A bath that has darkened one part will darken the next. Drain it and make up fresh.
A mixed load is the worst place to over-dose. More chemical does not clean faster and it attacks the soft metal first. Under-dosing is no safer: on the alkaline products the inhibitor is what holds the bath off aluminium, and it falls below the level that protects long before the alkalinity eases. Run the dose on the data sheet, and see getting the strength right.
When to clean the metals apart
| Load | Do this |
|---|---|
| Light oil, grease, fuel varnish | One load in AquaVantage 1696 GD |
| Heavy baked carbon on steel, with brass or aluminium parts | Clean the steel on its own in a stronger solution such as Desludge. The brass and aluminium go through 1696 GD. |
| Rust or scale on steel | Steel only. Descale, MetalTek 100 and RegeniK are not for aluminium or brass. |
| Zinc die-cast in the load | 1696 GD at the bottom of the window. Test one part first. |
| Carburettors | Aluminium or zinc body with brass jets: 1696 GD at about 5%. See carburettor cleaning. |
More on aluminium in particular: does ultrasonic cleaning damage aluminium?
Questions we are asked
Can I put brass and aluminium in the same ultrasonic bath?
Yes, in a solution that has both on its data sheet, such as AquaVantage 1696 GD at about 5%. Keep the aluminium parts from touching the brass in the basket, keep the bath at 50 to 55 °C for the aluminium, and rinse and dry straight after.
Which ultrasonic cleaning solution is safe on all metals?
None is safe on every metal. In our range AquaVantage 1696 GD is the mildest: near-neutral at pH 7.9 to 8.3, with aluminium, titanium, copper and copper alloys on its data sheet. Zinc is not on its list, so test zinc die-cast parts first.
Why did my aluminium part go dark when I cleaned it with brass parts?
Usually one of three things. The solution was too strong for aluminium, the aluminium touched brass, copper or steel in the bath, or the bath was carrying copper dissolved from earlier brass work. A tank that has darkened one aluminium part will darken the next, so drain it and make up fresh.
Can I clean a carburettor with the brass jets still in?
Yes. A carburettor has an aluminium or zinc body and brass jets, so it goes in AquaVantage 1696 GD at about 5%. Strong alkaline degreasers clean faster but attack brass and zinc.
Will filtering the bath take the copper out?
No. A bag filter takes out solids. Copper dissolved in the bath goes straight through it, and topping up with fresh concentrate only dilutes it. Drain and make up fresh.
Can I use Anti-Rust on a mixed load after cleaning?
Only on the steel. Anti-Rust is not for aluminium, zinc, copper or brass. Take the steel parts out and dip them on their own.
Related: Matching chemistry to the soil · Cleaning chemicals · Chemical selector · Compatibility matrix
Send us a part
Tell us what the assembly is, which metals are in it and what is on it. We clean it and send back the result.