It may seem like a paradox, but one of the most important things you have to do to a 3D printer’s hot end is to keep it cool. That seems funny, because the idea is to heat up plastic, but you really only want to heat it up just before it extrudes. If you heat it up too early, you’ll get jams. That’s why nearly all hot ends have some sort of fan cooling. However, lately we have seen announcements and crowd-funding campaigns that make it look like water cooling will be more popular than ever this year. Don’t want to buy a new hot end? [Dui ni shuo de dui] will show you how to easily convert an E3D-style hot end to water cooling with a quick reversible hack.
That popular style of hot end has a heat sink with circular fins. The mod puts two O-rings on the fins and uses them to seal a piece of silicone tubing. The tubing has holes for fittings and then it is nothing to pump water through the fittings and around the heat sink. The whole thing cost about $14 (exclusive of the hot end) and you could probably get by for less if you wanted to.
[Dui] mentions that you don’t need a super powerful pump. We suspect too much pressure in the system would make it much more likely to leak, so this is a case where less is almost certainly more. In fact, [Dui’s] first few attempts had some leakage, so you’ll want to carefully test before you install everything back into the printer.
You might wonder if you need water cooling when fans work fine. Well, first of all, when has that ever stopped any of us? But second, apparently, as you increase flow rate — either for extrusion speed or to use a larger nozzle or both — you have to increase temperatures and this can tax the normal cooling system. That causes clogs and the water cooling is much more efficient.