We had this already I think, but its so easy and I made some pics:
The parts:
Finished:
I didnt solder, but used epoxi 2-component glue. Took one hour, most time was searching my tools. Oxydro - 19-10-2004 at 11:12
You say you used epoxy instead of glue; was that for convenience or is it better for some reason?
Looks nice by the way. I wanna build one now .... maybe I will.Organikum - 19-10-2004 at 12:03
Quote:
You say you used epoxy instead of glue; was that for convenience or is it better for some reason?
I didnt solder because I am lazy and better with the epoxy-tubes than with the soldering-iron
Makes no big difference, the epoxide stands the temps at the condensor with ease.Al Koholic - 19-10-2004 at 12:51
Nice looking final result and more efficient result than equal length glass versions due to Cu's higher thermal conductivity no?chemoleo - 19-10-2004 at 17:07
Well it's true except the resistivity of Cu vs glass - the latter is altogether a lot more inert.
Plus- not to put you down Orgy - what I like about glass condensers is that you can actually SEE how condensation etc is proceeding. While a copper or
any non-transparent condenser is more or less a black box.Organikum - 20-10-2004 at 02:49
Copper is actually a rather inert metal. The condensor will be favorably used in solventstrippings, benzene and ether synthesis but not only.
The heattransferrate is VERY good it beats glass by magnitudes.
The argument of "you cannot" watch is nonsense as this is no column and no reflux condesor (although it can be used for both if desired, but
it wasnt buildt for this purposes).
Voyeurism maybe a nice hobby but its not really necessary except in first small experimental runs.
The function of this device is to transfer compounds which are non-corrosive to copper from the gaseous to the liquid state, and this it will do with
excellence, as already the plain coppertube with water running over it was much better in the benzene synthesis than a glass-Liebig condensor which
eventually broke - something what wont happen to this one.
I have good reasons to replace glass with iron or copper whereever possible. I will add earthenware as soon I have access to a kiln.
There are reactions which call for glass and small-scale trials are favorably done in glass, almost always. But scaling up calls for the use of metal
whenever possible.
yep?JohnWW - 20-10-2004 at 15:04
The use of the epoxy resin glue (Araldite) may not be appropriate, because it softens and then melts above only about 60ºC. Solder melts at about
190ºC. The best way to join Cu woiuld be brazing or gas-welding, using brass rods and an acetylene flame
John W.Organikum - 20-10-2004 at 15:09
Epoxy resin is favorably cured in the oven at 120°C to 150°C to reach maximum strength. It hardens out finally. I somehow doubt that it will melt
at 60°C.
Thats at least what is told on the box of my epoxide.
I guess you confuse this with something else.
Never heard of "Araldite", will avoid it though.JohnWW - 20-10-2004 at 15:23
Araldite is, in fact, the largest-selling brand of epoxy glue, at least in this part of the world, coming in "regular" (takes 24 hours to
cure at ordinary temperatures) and "5 minute" (cures in less than 10 minutes) varieties. I once tried hastening the cure of the
"regular" type by placing it in a domestic oven at a bit under 100ºC, but it simply melted away.
working temp.
HRH_Prince_Charles - 20-10-2004 at 15:33
70 Celsius seems pretty standard for the maximum working temperature of epoxy resin. Maybe there are some special high temp. versions.
If you are passing cold water through the copper condensor, it won't get hot anyway.Tacho - 20-10-2004 at 16:09
I have worked a lot with many kinds of epoxy resins.
Epoxy resin does not "melt" under high temperature.
If it looses some of its properties above 70°C, its clearly not enough to prevent it from being used as Organikum did.
Epoxy resin is (at least was once) sold in US as cold solder for copper tubes used in hot water instalations.
I have used epoxy pieces under boiling water for long periods with no change in its shape or appearance.
Many electronic IC chips are packed in epoxy. Try to melt those with a flame.
Do a google search to see how hard it is to "dissolve epoxy resin".
AFAIK, only very hot GAA or very nasty solvents can afect its structure.
Beautiful job Organikum.Twospoons - 20-10-2004 at 19:17
Typical 2-part epoxy glue turns to jelly aroung 60-70 C, but regains its hardness on cooling.
Epoxy putty is somewhat better as it is usually reinforced with something else, like steel or copper powder.Organikum - 21-10-2004 at 00:09
I have two epoxide resins by hand, one is professional, a local brand for use with glassfibers or as glue and is rated -40°C to +160°C, the other is
household 5 Min. epoxy adhesive which is rated -20°C to +120°C. The brand is ALTECO.
Cured Epoxide should melt never again, when it gets too hot it discolors and at temperatures over 180°C to 200°C it starts to carbonize.
The "melting" will be a misinterpretation of the fact that epoxides heat up and get more liquid whislt curing, an effect which is often
mistaken for melting and often leads to the impression that the epoxide is still workable when it actually started hardening already, a non-intuitive
property of epoxy resins which made them less usable for the layman but more a tool for professionals.
You will find information on this on the web at every epoxide manufacturers webpage - for professional use not the household products thats
understood.
I lookes for this US-brand and found only one temp. named, 45°, what was Fahrenheit as I guess and names the min. temp. needed to cure.
Actually I am quite sure that nobody is able to make epoxy-resin which so lousy properties as melting at 60°C, I believe this being almost
impossible. Epoxy resin is not thermoplastic when cured, at least this what we talk about here is not.
[Edited on 21-10-2004 by Organikum]vulture - 21-10-2004 at 01:53
Copper condensor...?
Why limit yourself?
Copper catalytic reactor? (with bad surface area though, but still)
Nice job.Hermes_Trismegistus - 26-10-2004 at 10:38
epoxy/resin melts at 60 deg C???
Better run out and tell all those guys with fiberglass boats to get them out of the water before the weather warms up and they drown!!!
(but seriously though, resin is resin, hardener is hardener, mix them together and a chemical reaction occurs, never again to un-occur, the result is
a hardened epoxy)
there is a "working temperature though, that is the temperature beyond which you do not want to work with the epoxy because the high temperature
will cause the reaction to happen too fast and leave you with ..... a mess? .... a bucket full of very expensive paperweight material?
Working Temperature
HRH_Prince_Charles - 26-10-2004 at 15:03
is operational temperature, not curing temperature.neutrino - 27-10-2004 at 13:11
Epoxies are usually thermoset plastics. That means that, unlike thermoplastics, they can't be heated and molded. Thermoset plastics usually start
to decompose before they melt and even this happenes at high temperatures.Organikum - 23-6-2006 at 12:52
FYI
We have now 2006 and the condensor is still in use, the epoxy being no problem even not when removing residues/stains with acids or lye. Looks not so
new now of course....
/ORGevil_lurker - 23-6-2006 at 21:22
Yeah the catch with epoxy on that condensor is that whereever there is a joint, its pretty much water cooled due to the thermal conductivity of
copper.
And since I've soldered one, I can say without a doubt that its a hell of a lot easier using epoxy.
.... maybe I will.