IPA versus IMS?

[Cleggy]

So, this doesn't answer the original question about Shellac, but just in terms of general cleaning of radio parts;

• DIY shed-meths is a bit of a risk (perhaps to both parts and people)
  
• ethanol is expensive because of the duty which needs to be paid
  
• IPA is king, and is probably no better or worse that ethanol anyway.
  

Earlier, someone mentioned pyridine being added to meths and that surprised me. Many years ago, I was told that it's a suspect carcinogen. Looking on Wiki, it seems that it's now regarded as a suspect carcinogen in animals, but there is insufficient data to classify it wrt humans. Call me a wimp, but with both pyridine and a bit of MEK potentially in the mix (and does it end there?), I think I'll treat shed-meths with deep suspicion in future.

[ken]

Alcohol is often thought of as a single substance but there are many alcohols and both their chemical and physical properties vary. Probably the most commonly used and most easily available are the alkanols. Methanol, ethanol and propa-2-ol (IPA) fall into this group. They are composed of a carbon chain, of varying lengths, and a functional group which in this case is an -OH group. Again the properties vary with the length of the carbon chain and the position of the functional group on the chain. Methanol and ethanol have the functional group on the end of the chain but propan-2-ol has it mid chain. Although all work as solvents each is best at dissolving particular groups of solutes. If the solvent used to dissolve Shellac is ethanol then the closest thing to pure ethanol (approx 99%) you can get is probably best. When I was working I had to have an excise license to buy pure ethanol. I also had to state a reason for it's use and it was very expensive as you had to pay excise duty. Clear meths is also probably difficult to get although as others have said it might be available via the internet. I think the most easily available is purple meths which as has been said can be around 90% ethanol. I seem to remember there were ways of removing the colour but this could be quite complicated. I would suggest trying purple meths with the Shellac in the hope that the Shellac will swamp the purple colour. If that fails try a drop of bleach in a small volume of purple meths. Ideally the bleach would be one that did not contain detergent. I have seen bleach tablets in pound shops which might produce detergent free bleach. Hope this is of some help. Good luck.

Ken.

[ppppenguin]

Not sure about mixing alchohol and bleach. If I remember my chemistry correctly you get something nasty. Looked it up and it's chloroform: https://sciencenotes.org/bleach-and-alco...nfectants/

[Cleggy]

Bleach is a potent source of chloride ions, which are just about the best species you are likely to encounter in the every-day world for initiating corrosion and keeping it going. That is to say, once you have chloride ions on a metal surface, washing them off is not straight forward; water alone is not very effective. I would never take bleach withing 10 feet of any of my radio or automotive toys.

[ken]

Not sure about mixing alchohol and bleach. If I remember my chemistry correctly you get something nasty. Looked it up and it's chloroform: https://sciencenotes.org/bleach-and-alco...nfectants/

Yes I take your point, however, it would take perhaps only a single drop of a dilute bleach solution to oxidise the purple pigment but I withdraw the suggestion.

@Cleggy

Bleach is a potent source of chloride ions

Most chlorine based bleaches, that you can buy over the counter, contain hypochlorite ions, however, they are still ions. Both chloride and hypochlorite ions are water soluble but again I would not use a method with which you are unhappy.

Regards,

Ken.

[Cleggy]

Chloride ions are very soluble in water, but they hang on to metal surfaces, and films of rust, tenaciously and you need repeated applications of something like an amine solution to work at getting them off. Scientists in Canada have published multiple papers on this, on account of their climate needing the use of so much salt on the roads in winter, the economic costs of damage by corrosion being enormous.

Chloride is the Devil's work  .

[ken]

Chloride is the Devil's work

Well I'm not sure about ions but I would have thought that if the Devil was keen on any element it would be sulphur.

[Craig]

Everyone thinks of hell as being hot, with lakes of burning sulphur etc.

It is actually a cool lake of sewage, with ever sinner up to their bottom lip. It is very very quiet, with the only sound being "don't make waves..."

[Radio Fixer]

Thanks very much for all replies and a chemistry lesson. Very weak subject for me. Can buy IMS on the Net but wont bother.

Gary