Ultrasonic cleaners – should you buy one?
With prices coming down, we look at ultrasonic cleaners and how good they are for restoration at home. Are they the do-it-all solution?
What are they, how easy are they to use and do you need one? We look at ultrasonic cleaners and how to get the best from them
It seems a bit like magic. According to shed lore, an ultrasonic cleaner will take on the worst baked-on dried-up gunge from your bike's parts and remove it all. So, let's try it out. For this purpose, we used a Sealey SCT03 Ultrasonic Parts Cleaning Tank. It's the smallest and cheapest of the Sealey range of three cleaners, stainless steel and with a capacity of three litres. There are lots of cleaners out there, some of doubtful provenance, but the Sealey seems well-made, has a bunch of features you don't find on the cheaper items, and is covered by a warranty, which is more than you can say about something bought cheaply online. The Sealey SCT03 costs around £220.
It comes with a degas function to help improve the cleaning process. Degassing purifies the cleaning fluid and means you don't need to use distilled water. Using ultrasonic wave vibration, the cleaning action of the microscopic bubbles created by the ultrasonic generator, known as cavitation, can penetrate inaccessible parts to remove dirt and grime.
It has a 0-80°C temperature control, a timer setting which is adjustable from 1–99 minutes, and an LED display and memory function that saves your last settings.
The unit is the size of a posh toaster. Fitting large components is a no-no, but you can get individual carb bodies, brake calipers and pistons in the basket. Use the soft setting on some electrical components or on fragile items like jewellery or spectacles.
The instructions that arrived with the cleaner were basic, with no indication of what sort of cleaning
medium to use, apart from a suggestion for washingup liquid, so we proceeded by trial and error. I used plain boiled water at first, then tried a spoonful of bicarbonate of soda, which a friend recommended as he uses it to clean model aircraft engines, and this started the cleaning process. Then I tried a 10:1 mix of water and white vinegar, which produced passable results, followed by a good-sized squirt of washingup liquid. I followed this with a 10:1 mix of proper ultrasonic cleaning fluid bought from the internet (£25 for 5l). Interestingly, the washing-up liquid did almost as good a job as the proper stuff. The Sealey SCT03 costs around £220.
HOW TO USE THE CLEANER
First of all, don't treat it like a parts washer. Just slinging in mucky components will clean things but no more effectively than you can with a brush and some paraffin. It will just turn the water dirty. So degrease and wash off anything you are going to deep-clean first, getting rid of any major muck with a stiff brush. Then wash it off in water, especially if your degreaser is flammable, and put the item in the SCT03's basket.
Put anything to be cleaned with the most soiled area face downwards. If cleaning a carb, or a bank of carbs, break them down into their component parts and remove any rubber seals. Don't put too much in
the basket, as the unit needs space around things to clean them properly. Try to put alloy in with alloy, and don't mix alloy with brass if you can avoid it. Put the carb body in separately. Put small items that might fall through the basket in a small plastic bag, a heatproof glass container or a plastic cup with some of the cleaning medium, or put it in an old tea strainer.
Put on rubber gloves and eye protection. Now add hot water and your cleaning medium. Despite what you might see recommended online, don't use alcohol, petrol, acetone or other flammable solutions.
Doing so could cause a fire or explosion – use only water-based solvents. Set your temperature at about 40-60° for anything aluminium and 20° hotter for steel or iron.
Now turn on the degas function. This process turns the ultrasonic generator on and off every few seconds. It purifies the water and starts to work on the item to be cleaned.
Then, when the desired temperature has been reached, set your timer for five minutes, press the on button and set things going. Check it is all okay by lifting the basket out a few times. Once it turns itself off, check it all again and give it another five minutes if all is well.
It might not get things entirely clean at first, and giving a part-cleaned item a good going over with a toothbrush and putting it back in the tank won't go amiss. It softened the hard crud in the primary jet on one of my carbs but didn't get the dirt out, and it took a guitar string poked through to clear the worst of it. Give your hand-cleaned item another five minutes and all should be good.
Now lift the basket out and wash off everything in it thoroughly with cold water, then dry it very carefully to ensure all traces of cleaning fluid are gone. I used a hot air gun to evaporate any water I could not get at.
Reassemble anything you took apart. Don't forget that the layer of grime has been protecting what you have been cleaning. Exposure of the cleaned item to the air is likely to set off corrosion, so spray it with
Duck Oil or a similar protective lubricant.
The more I used the cleaner the better the results I got, so it is worth practicing on scrap items first. You should not leave the components in the cleaner to soak in cleaning fluid, as this may damage them.
Dispose of your dirty cleaning fluid carefully. If
using a proprietary cleaner, it's possible that it's dangerous or polluting.
HOW DID IT PERFORM?
I used it on two Dell Orto carbs, at a temperature of between 40-60°. I found one carb had less of a film of dried-up petrol inside than the other. The dirtier carb was also seized. It took a good squirt of Soudal penetrating fluid prior to cleaning to get it apart.
Using vinegar and following it up with washing-up liquid at a lower temperature did almost as good a job at removing the ingrained muck as the carb cleaning fluid did at higher temperatures. Twenty minutes in, the cleaner took all the dried-up petrol off the carb's internals.
There was a lot of success with the brake components. A Grimeca caliper came up beautifully. Then a corroded and seized Grimeca master cylinder was put in the basket for 10 minutes at 60°. This allowed me to take it apart, at which point I gave it another 10 minutes and it came out looking close to new. Given that I was about to consign it to scrap and would have struggled to find a replacement, the cleaner did sterling work.
Another 20 minutes in the cleaner did a decent job of removing some of the baked-on and ingrained carbon on an old XS650 piston, with a little wire brushing needed to get rid of the worst of it. I also used the cleaner on a pair of pistons from my Morini. This had both upsides and downsides.
It certainly cleaned off most of the baked-on carbon from one piston. On the other, the top ring had seized in its groove; half an hour in and the tank did nothing to free it. In the end I had to use a blowtorch. Cleaning the ring off once it was released showed that hard chrome coating had flaked off in places, revealing it to be no future use. The real downside was that the cleaning was so efficient at removing decades of grime from the pistons it revealed the amount of wear on them and it looks like a new set will be needed, and possibly an oversize rebore... all of which is not the fault of the cleaner, obviously.
The best result came from cleaning a plastic fuse box caked with dirt and grease, but five minutes on the soft setting brought it back to something close to new. Many parts have now been returned to a serviceable state with little physical effort, resulting
in a considerable saving on the cost had I needed to replace them. I can see myself using the cleaner on many other parts in the future.
WHAT ADVICE DO THE PROS OFFER?
We used water but Classic Bike Guide regular and chemist Steve Cooper recommends using a product that is more designed for the job you are aiming for.
Caswell Europe has created several solutions, some for removing rust, others carbon and yet others suited to different materials. Check out caswelleurope.co.uk for more information.
Our own Hutch and Chelley, of HTE Motorcycles, use an ultrasonic cleaner regularly for carburettors. They also suggest using specialised fluid for the task you're attempting, but if you clean the carb bodies and parts with brake cleaner/ petrol/ paraffin/ diesel and a toothbrush to remove as much crap as you can, then the ultrasonic fluid will last longer to do what you want it to – clean the inner passages you cannot easily get to. They also use their cleaner on a 40° heat and a 50% duty cycle – turn it on for 10 minutes, then off for 10 mins and move the part, etc.
SHOULD YOU BUY ONE?
An ultrasonic cleaner is not some magical cure-all.
It is more of a finishing-off device than an all-over cleaner and will get the muck out of places you cannot access.
The most common use is for carburettor cleaning, as the process can clean jets and drillings you cannot get to. Given that getting a single carb ultrasonically cleaned by professionals can cost upwards of £30, doing the Man Maths shows you've only got to clean six of them and the three-litre unit has paid for itself.
If you are considering such a purchase, get the biggest one you can afford or can fit into a space, with the highest wattage.
The SCT03 is a 100w unit. Sealey sells a nine-litre version with a 200w ultrasonic generator, and a 27-litre unit that has a 500w generator. For a club or group of friends, buying a bigger one together might be worth considering. Visit www.sealey.co.uk to check out the range.