On 01/05/2017 05:13 PM, allison wrote: >> Freon TF works well on everything. Too bad it's not available. >> >> Is it still used for aircraft electronics? > No its been obsoleted. There are many other similar but not > fluorinated hydrocarbons that are preferred and also good old soap > and water.
No, it's been banned. "Obsoleted" to me carries the implication that there's something better. TF was banned under the Montreal Protocol not for its toxicity, but for the ozone-depletion characteristic of the stuff when it was released into the atmosphere. Same goes for most chlorinated refrigerants. HCFC-225 had been an adequate substitute, but that was phased out in 2015. Too bad--it was almost as good as a cleaner. Techspray (and NASA and a bunch of other outfits) have proposed some possible alternatives; https://www.techspray.com/t-ak225ban.aspx If these were my packs, I'd drop them a line and see what they recommend for the specific application. FWIW, I buy my denatured ethanol from the paint store--it's about as water-free as it's possible to get, usually with some methanol commonly added as a denaturing agent, although other substances can be used. This was a practice started in 1906 so that manufacturers could be exempted from alcohol taxation. During Prohibition, the government, responding to a higher moral standard, reformulated the denaturing agents, making them even more lethal. The result was dramatic--in 1928, 700 people died in New York alone from consumption of industrial alcohol. Oddly, the 18th amendment only forbade manufacture, sale and transportation of alcohol. Consumption was still perfectly legal. Paint-store alcohol is free of water because it's commonly used as a shellac solvent/carrier. Any appreciable amount of water results in a cloudy finish. FWIW, Chuck
