[TCRA] useful info from QRZ
K9YLI at aol.com
K9YLI at aol.com
Sat Oct 24 09:27:35 CDT 2015
_RE: glue ?_
« Reply #12 on: October 06, 2015, 07:07:04 PM »
_Quote from: VK2TIL on October 06, 2015, 05:05:57 PM_
Australia may have more-restrictive environmental requirements than the
US; there are still a few acid-cure types but the majority are neutral-cure.
Considering the tiny quantity required to attach a small meter, it's
probably not too important for that application but it's good practice to avoid
I don't know the chemistry of copper -v- acetic acid; does anyone know
what the product of reaction is?
Warnings about acetic acid cure silicone seem to go a bit overboard at
times. First of all, gluing a plastic meter to an aluminum board using a
small amount of this type of adhesive would have zero risk of harming your
equipment. The acetic acid/water that results from the curing process, will
quickly dry and evaporate into the air.
Second, acetic acid is classified as a weak acid and copper is a fairly
unreactive metal. In fact, acetic acid will not dissolve copper without some
extra additions to the process (glacial acetic acid and heat). If you
drop a penny into some normal strength acetic acid, it will turn nice and
shiny, not because the penny is dissolving, but because the copper oxides are.
Note however, if the "copper" penny is scratched, it will turn black as
the acid starts dissolving the zinc that the penny is actually made of!
Of more concern is solder. Since even weak acids can dissolve lead and
tin, direct application of this adhesive on solder should be avoided.
Also, even non acetic acid cured silicone will smell like vinegar, so the
varieties are not easily determined by your nose. Look in the ingredients
for the curing agent used. I just checked an assortment at Canadian Tire
and none that I looked at were acetic acid cured.
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