Cheap compact wort pump

JoeyChestnutFan said:

Ok, after some more investigation.... I opened up the tan pump which I bought this year. Inside the plastic coating was the magnet which has some sort of epoxy (I'm guessing) coating which filled with typical paint fillers (Ti/Al oxide). The magnet seems to be NdFeB, with what looked like some of the following: Ce, La, or Ba. All of those are pretty benign as far as I know, as with most REE. Most of the hazards are when handling the dusts (inhalation and/or explosion), or chronic exposures with large amount of bioaccumulation, both of which are not relevant here. Also, there was a brass (Copper/Tin alloy, no Lead) bushing after the magnet, and before the impeller.

I am putting this here in case others have gone down this same rabbit hole:

From what I can tell from browsing Alibaba, it seems that there are about 2 actual manufacturers that make the majority of these pumps. Shenpeng (swirl mark, dgshenpeng.com/spminipump.com) and ZKSJ (triangle mark, microdcpump.com). ZKSJ seems to use exposed ferrite based magnets on their rotors and their 3 phase pumps have an external box with circuitry. Their products seem to follow the following naming convention: DC10, DC20, DC30, etc. Shenpeng, seems to be the manufacturer of the tan pump, all topsflo pumps, and most of the other pumps I've seen posted on this forum. Their naming convention seems to be P25, P30, etc. For most of their pumps, and the TD5 pump, say they are using some imported magnet from Japan. The TD5 seems to be a custom version of Shenpeng P6017 pump (open rotor vs closed rotor). The magnet could be either just a normal NdFeB magnet with a coating, or an epoxy and NdFeB powder composite. NdFeB magnets will corrode without protection, so it seems that Shenpeng has tried to find a coating over the past years to do this. Because there was a user that had material flaking off, I am guessing they have not had much success in that regard, hence the PPS encased tan pump magnet. I do not have a TD5 pump, but I am guessing that they switched to an epoxy NdFeB composite, hence the food grade claims and seemingly not having corrosion problems. Or they finally found a suitable coating. If someone with a TD5 would take some close up pictures and some notes that would be awesome.

I'll probably add some more stuff later with an edit.

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augiedoggy said:

I have examples of the pumps mentioned in this post from all three companies including the black abs plastic pumps with the swirl mark logo and many tan food grade pps pumps with the encased magnets.
I also own a couple TD5 units (the ones specifically sold for brewing with the pwm speed controllers that brewpi sells and not the ones everyone ales carries which are meant for solar hot water applications with mppt optimizers built in that actually counteract the pwm speed control)
The TD5 does in fact have an exposed ferrite magnet. (as does the march made Riptide I own) Honestly if it wasnt for the size and power differences I would prefer the tan pumps because of this over the td5. the riptide is a nice pump but costly and has to be manually controlled as far as flow.

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JoeyChestnutFan said:

Are you sure the TD5 magnet is a ferrite? A ferrite is a specific class of material, basically iron oxide with another element. As I mentioned above, the tan pump used a neodymium magnet (not a ferrite, but an alloy of NdFeB). I analyzed it in a lab (I'm a materials scientist). Does the magnet feel like plastic or a rock?

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