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Old 5th Sep 2019, 9:20 pm   #1
ribbonmicsrus
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Default Cleaning AR88 Gearbox

I have just repaired an industrial ultrasonic cleaner, runs at 33kHz (no, not putting watch crystals in it!), but would like to use it for degreasing and cleaning my AR88 gearbox.

In the old days at work I used Arklone, this is now of course banned.
Can anyone recommend a suitable solvent I could use in this tank, it can be heated by the way to about 90deg C if required.

73
Andy
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Old 5th Sep 2019, 10:00 pm   #2
g4aaw pete
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Default Re: Cleaning AR88 Gearbox

I have a Maplin cleaner which I use occasionally.
The agent I use is Sea Clean :

https://www.bestultrasonic.co.uk/sea...500ml-10-p.asp

Though I didn't get it from that supplier.
Seems to give reasonable results.
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Old 5th Sep 2019, 10:26 pm   #3
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Default Re: Cleaning AR88 Gearbox

There has been an enormous push towards using water-based cleaners over the last 30 years and while some are very effective, the risk of corrosion lurks in the background. Quite a lot of the products are fairly alkaline. Others, while apparently pH-neutral could encourage corrosion if dissimilar metals are present, especially if you start pushing up the temperature.

I used ultrasonic baths a lot at work, but the weirdest result I ever saw was at home when I put a salvaged B7G valve base in to a neutral aqueous cleaning solution. Leaving it for ~15 minutes, I returned to find it had turned in to a "right mess".

I imagine that an AR88 gearbox is quite a valuable object, probably made of a number of different materials. Immersion in an aqueous solution is probably not the safest way to go. I wonder if a paint brush and a drop of paraffin might be a simpler and safer approach? You can bet that the gear box was not ultrasonically cleaned at the point of manufacture.

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Old 5th Sep 2019, 10:42 pm   #4
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Default Re: Cleaning AR88 Gearbox

Thanks Pete and Bazz

Just been speaking to neighbour who has a lot of jewellery and she uses Sea Clean along with her husband for some of his mechanical stuff and say it is very good so have taken plunge and ordered a bottle. I shall finish cleaning with de-ionised water. I am going to fit new bearings all round and have the correct grease as supplied by a local company

Andy
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Old 6th Sep 2019, 1:13 am   #5
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Default Re: Cleaning AR88 Gearbox

I've just been looking at the website of James Products, who make (or distribute) Sea Clean. The data they offer does not say anything about pH but says it can be used with "most solid metals (not for use with plated metals)".

They offer another product called UltraFX which they say is OK for "all industrial metals and plastics".

I've no idea what an AR88 gearbox looks like, but one day I may think about removing the 76 year old grease on my HRO gearbox. Hope you'll let us know how it works for you Andy.

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Old 6th Sep 2019, 2:11 am   #6
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Default Re: Cleaning AR88 Gearbox

The AR88 gearbox has anti-backlash gears using pairs of wheels sprung apart.

Grease gets trapped between the plate gears which have to slide face against face. Sticky grease and weak springs = backlash.

I'd strip the box and clean the parts individually. No dissimilar metals in contact this way. You may want to replace tired springs.

David
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Old 6th Sep 2019, 2:15 pm   #7
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Default Re: Cleaning AR88 Gearbox

In the past I've cleaned AR88 gearboxes by soaking them in Diesel for a week or so - it's sufficiently penetrative to get into the grease between the meshed gear-segments, and no worries about aqueous 'solvents' being left behind in any places where they may corrode (I'm particularly thinking here about the ball-bearings-running-on-steel-shafts: such surfaces can develop surface-rust in minutes if left exposed and damp).

Dunk in a tub of Diesel - swish it about a bit every day for 10 days or so, turn the gears through their full travel each time - then at the end dry with compressed air.

Relubricate the gears using a thin oil - I use ATF automatic-gearbox oil, and something like the semi-fluid moly-grease used in Land-Rover steering-swivels for the ball-races.
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Old 6th Sep 2019, 2:26 pm   #8
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Default Re: Cleaning AR88 Gearbox

The thought occurs to me that if such an assembly is immersed in water you'd probably need to be able to put in inside a vacuum oven to get all the water out. Several days in the airing cupboard might also do it, but that sounds like a risky way of doing it.

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Old 6th Sep 2019, 3:07 pm   #9
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Default Re: Cleaning AR88 Gearbox

The original was probably 'Lubriplate' an american grease designed for instruments etc and to not go walkies.

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Old 6th Sep 2019, 4:42 pm   #10
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Default Re: Cleaning AR88 Gearbox

Well, I obtained some Screwfix driveway degreaser as recommended by another forum, water soluble, 3 capfuls to 3 litres, the capacity of my ultrasound tank. Gave it 20 minutes and all grease gone etc. Thoughly washed in clean distilled water.

Took gearbox apart, having done an earlier one was aware of the pitfalls of springs, sandwiched gears etc. Baked all parts in oven at very low temperature for 1 hour. Let it cool and replaced both types of ball bearings and new grease. Springs were good, once degreased, the operation of the meshed gears was good. Used some sewing machine oil for the end float bearings.

Re-assembly took me about 45 minutes, if I ever do this again will make a jig to hold the plaates with the shafts otherwise its a balancing act.

Appear to work like new now, very smooth, no lumpiness and no backlash!!

Andy
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