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-   -   Cleaning a filthy/greasy amp chassis (https://www.vintage-radio.net/forum/showthread.php?t=135369)

martiR2R 1st Apr 2017 6:24 pm

Cleaning a filthy/greasy amp chassis
 
I have a pair of valve amps from an Akai M7, every nook, cranny, wire, cable, component, is coated in grease, gunge, muck etc. If I remove the pots do you think it would it survive a jet wash at the local garage (I don't have access to a dishwasher) or should I try and be a little more subtle.

Thanks
Martin

Boater Sam 1st Apr 2017 6:44 pm

Re: Cleaning a filthy/greasy amp chassis
 
High pressure washer will be a bit destructive and won't de-grease it.
A paint brush and white spirit will be more successful, and a quick wash with detergent will bring it back to new.
Remove any coils and pots first.

David G4EBT 1st Apr 2017 6:48 pm

Re: Cleaning a filthy/greasy amp chassis
 
I think that would be a bit drastic. I use brake cleaner aerosols with a small stiff artists' brush to agitate it, and kitchen roll to wipe it off.
It really loosens the dirt, and unlike WD40 etc, it evaporates quickly and leaves no residue.

Hope that helps a bit.

Omegaman 1st Apr 2017 7:03 pm

Re: Cleaning a filthy/greasy amp chassis
 
+1 on Davids reply with the brake cleaner. Marvellous stuff!
Poundland sell it, for a pound a tin, strangely.

mark_in_manc 1st Apr 2017 8:18 pm

Re: Cleaning a filthy/greasy amp chassis
 
Also very useful for starting recalcitrant lawnmowers (ahem, checks for mods) petrol generators.

What variety of volatile hydrocarbon it is, I don't know. I tend to use acetone (ordered from ebay and came by post, who would have thought it) as a cheap-ish general purpose liquid solvent, and even paraffin is pretty good if you can get it at a reasonable price. Folks more knowledgeable than me on here will tell you what tends to dissolve PCBs etc etc...

paulsherwin 1st Apr 2017 8:28 pm

Re: Cleaning a filthy/greasy amp chassis
 
Paraffin will leave a deposit unless you clean it off carefully. That may or may not be a problem. Personally I use ordinary white spirit / turps substitute for these jobs, but you still need to clean carefully afterwards.

More volatile petrochemicals like lighter fluid or ordinary petrol also work well, but need to be used with great care given the fire risk.

kalee20 1st Apr 2017 8:59 pm

Re: Cleaning a filthy/greasy amp chassis
 
Personally, I'd get an old household cleaner pump-spray action bottle, fill it with paraffin, and use that with a soft paint brush to sweep away the gunge.

Grease isn't water soluble, a jet wash will probably cause damage. But it is paraffin soluble, so you won't need forceful spraying.

As PaulSherwin says, it can leave a deposit, so a final rinse with white spirit helps. But this can loosen paint, markings, etc so use sparingly in such areas!

Peter.N. 1st Apr 2017 11:02 pm

Re: Cleaning a filthy/greasy amp chassis
 
Carburetor cleaner is very good as well.

Peter

Radio Wrangler 2nd Apr 2017 3:51 am

Re: Cleaning a filthy/greasy amp chassis
 
It's a multistage process.

A volatile solvent will be good for softening greasy gunge, and the run-off will carry some of the muck away, but not all. The grease dissolved in the solvent that remains to evaporate off of the chassis will be left behind by the evaporating solvent. But that leaves it greatly reduced and more amenable to a second go with a detergent which will chemically bind to the grease and render it water soluble for a final wash.

Acetone will dissolve some plastics (and polystyrene capacitors) and will take painted markings and coloured bands off of components.

Remember that it's liquid runoff that takes the unwanted grease away. Anyting evaporating off is just the solvent distilling off and leaving the unwanted material behind. This is why commercial degreasing baths work quite well. A garage workshop may be a better bet than the jet wash on the forecourt.

There are good degreaser detergent/kerosene mixtures like 'Gunk' and 'Jizer' (not to be confused with Tizer)

For cleaning electronics, I usually use lots of IPA followed by Electrolube foam cleaner.

David

Argus25 2nd Apr 2017 11:35 am

Re: Cleaning a filthy/greasy amp chassis
 
The perfect solvent, ideally, is carbon-tetra-chloride affectionately called carbon-tet. It was the mainstay in the past as it was "dry-cleaning fluid". Unfortunately chronic exposure in this industry increased the risk of liver cancer, so it got banned. It is also very good for cleaning oil off rubber parts, tape deck pinch rollers etc. It has the effect of "reconditioning rubber surfaces". It got replaced with trichloroethelene, for a while, but that has its own toxicity too. I remember they day I used the last of my bottle of carbon-tet, nothing was ever as good.

The common modern de-greaser solvents now are marketed as "contact or circuit board and switch cleaners". They have negligible residue and don't provide any lubrication either, so after cleaning potentiometers for example, some lubricant needs to be added. A typical product from CRC is:

http://www.radioparts.com.au/product...c#.WODNIvl96t8

(notice on the list of ingredients all the things it doesn't contain)

You can use this to de-grease the chassis, along with a brush is a good idea. It won't dissolve electronic parts or paint or attack plastics/insulation or circuit board coatings.

(There was a great episode of Lost in Space, in the mid 1960's, based around a bottle of carbon-tet. Dr.Smith, had left the lid off the bottle of Carbon-tet or used it up. With the help of an Alien teleporter machine, the young Will Robinson was able to travel to Earth and bring a bottle of carbon-tet back with him, the story is here:

http://lostinspace.wikia.com/wiki/Re...om_Outer_Space )

martiR2R 2nd Apr 2017 3:37 pm

Re: Cleaning a filthy/greasy amp chassis
 
Thank you one and all, good advice, I shall adopt the more subtle approach.

Martin

Guest 2nd Apr 2017 4:34 pm

Re: Cleaning a filthy/greasy amp chassis
 
I know the OP hasn't access to a dishwasher, a handy hint for those that do.

When cleaning a greasy oily thing in one pop an extra tablet in the body of the machine. This stops (almost!) the insides getting dirty during the first "non tab" cycle.


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