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Discussion Starter · #1 · (Edited)
Eheim 2217/2215 Impeller Shaft Emergency Fix Using a Bamboo Skewer - Field Test

Hello everyone,

Introduction:

I thought this field test of mine would be of interest to some as I have seen a few discussions in the cyberverse regarding attempts to find alternatives for the notorious Eheim ceramic impeller shafts of the Classic model line. Prone to breakage, it would be nice to have a quick fix as we know from Murphy's law that these breaks will happen at the most inopportune time. Buying some time until you could get an official replacement would be of value at least.

Most of the discussions I found were not current and were not comprehensive or complete. So since I picked up a used 2217 that needed a shaft replacement, I wanted to try this and see if it is a viable stop gap.

I have seen basically four options for fixing the broken impeller shaft issue:
1) Buy the Eheim replacement part
2) Buy stainless steel rod, cut to length
3) Buy carbon fibre rod, cut to length
4) Use a bamboo skewer, cut to length

The bamboo skewer option intrigued me as I had some on hand and would basically cost me nothing and would take me 2 minutes to cut to size and install. My main concern was 'How long would it last?'. So I decided to add to the wisdom of the cyberverse and perform a field test and post the results.

Hope you find this useful.

Background:

A common 'wear and break' part for the Eheim Classic series is the ceramic impeller shaft. The replacement part is available at a cost of about $20 CAD online plus or minus a few buck for shipping, and taxes if applicable.

I have been buying used Eheim Classic series since restarting my aquarium hobby and I have been very happy with them. I have six of them now.

Even though the sellers report generally operational filters, they often qualify that the unit may be a bit noisy for unspecified reasons. So it is a buyer beware scenario, but I have not had any unresolvable issues with the six that I have bought so far and I have been getting them at well below the price of new so it seems worth taking a chance. As long as the motor turns on when plugged in, I take it.

The Field Test:

So my latest used purchase was for a 2217. The seller was selling it for parts and I basically got it for free when buying another from him as well. He told me it was making noise and would not generate any suction to pump water. I took it because the casing and seal ring were good. For free, the price was right. When I got it home, I opened it up and confirmed what I suspected, the shaft was broken. The impeller was fine, the bushings were fine. So what to do about the shaft...

I read online that a bamboo skewer was the same diameter as the ceramic shaft for the 2215/2217. So went to the kitchen and I looked in my utensils drawer. Sure enough I had a bundle of the standard 10inch long bamboo skewers. I took the broken shaft and compared it to the skewer and it matched up very well. From the naked eye and finger touch, they basically matched in diameter. I took the impeller and inserted the bamboo and it fit perfectly.

THE SPECS:
Now here is where I hope I am adding new usable info...I did not know the exact length required for the DIY shaft. The broken one was actually missing a piece of itself so I could not reconstruct an approximation after the fact. Nor could I find it in the cyberverse. Eheim seems to not reveal measurement specs otherwise their replacement kits would not sell ( I assume ). So here are the specifics you need in imperial and metric measurements (measured from actual replacement shaft which I happen to have on hand from another used buy where the seller gave me any spare parts they had...love bonus parts!!).

Length of shaft:

3 3/8 inches
87 millimeters

Shaft diameter:

1/8 inch - CORRECTION - 1/8inches will be too thick to fit...use the 3mm as the spec for the shaft diameter
3mm

I chose a skewer that was as close to perfectly straight as possible and did not show any major fibres splintering along the length that would become the shaft piece.
Test straightness by rolling the skewer on the kitchen counter top. If it rolls without humping up and down, it is good.
With a sharp pair of scissors, cut the shaft to length. Trim the ends carefully to remove bamboo splinters and insert into bushings (my bushings were still fine).
Install the impeller, reassemble the cover and locking bracket.

I tested it in a bucket of water and it worked perfectly without any extra noise, vibration or anything. I was very happy.

I ran it for about ten minutes and then disassembled the impeller housing and took a look at the bamboo shaft to see if there was any obvious wear. I could see a bit of black residue from the impeller rubbing old slime onto the shaft, but otherwise I did not see any damage to the bamboo. Given this observation, I thought this might be viable for a while. For how long is now the magic question.

I started running the filter on Dec 31st 2016 at 12noon.

Just a side note: This is running on a tank that has a gravel substrate, so sand abrasion issues be a non-factor on the results. For those that have sand, the durability of the bamboo may be affected.

This test is being done on a tank that already has another filter running, so if this bamboo breaks and the filter stops, my fish will be fine.

Result Log: (will be updated with periodic status)

Dec 31st, installed bamboo and started the filter without issue
Jan 1st, 7am, 1st check no issue detected from a basic flow and noise check.
Jan 2nd to 30th, no issue detected from a basic flow and noise check.

Jan 3rd, 8pm inspection - Some black smudging but NO wear on shaft. (see picture)
Jan 30th 8pm final inspection - marginal wear showing on the bamboo

Picture attached of the (bottom to top) original broken ceramic shaft, unused bamboo, used bamboo after 4days.

So I will be checking sound and flow twice each day and will do a weekly inspection until i see or hear a change in operation or see definitive wear or it fails.

Check back for updates. I will keep it running like this as long as it lasts!

If you have any questions or suggestions about this field test feel free to voice them.
Cheers!

Field test extension!
On Amazon.ca I found a seller of 1/8" diameter stainless steel rod. I ordered one and will be making them into replacement impeller shafts. I will be testing them once I have them and see how they perform in terms of any heat buildup. Will let everyone know what I experience. :)
ETA for the stainless steel rods to arrive is late January.

UPDATE (Jan 27): received the SS rod shipment yesterday. Will be cutting and preparing it to be the replacement shaft. Once installed will report on its performance.
 

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Thanks for sharing this. I never thought of using a skewer as an impeller shaft. Even if it were to only last a day, it could be a lifesaver. I wonder how the Fluval shafts compare.
 

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Discussion Starter · #5 · (Edited)
Thanks for sharing this. I never thought of using a skewer as an impeller shaft. Even if it were to only last a day, it could be a lifesaver. I wonder how the Fluval shafts compare.
I am happy that I am able to share some real-life experience for this hobby.

I looked online for options just because I was anxious to try get the filter going ASAP and it appears to be working great.

Now I can't wait until I get the stainless steel rods to work with. Those will last forever.

I won't go back to retail once I learn how to do it myself with these DIY options :)
 

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Regarding easy availability of rods of the right diameter, knitting needles work really well. . .:D
 

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Discussion Starter · #7 · (Edited)
Regarding easy availability of rods of the right diameter, knitting needles work really well. . .:D
Interesting...in an emergency sure why not. I don't knit so didn't have anything like that on hand. But knitting needles would rust wouldn't they? plus the painted coating would potential come off. I was thinking of checking a basic wire hanger also, but those would rust up almost immediately too.

Well the bamboo continues to work flawlessly at day six! :)
 

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Interesting...in an emergency sure why not. I don't knit so didn't have anything like that on hand. But knitting needles would rust wouldn't they?
Most are aluminum, so, no.
 

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Discussion Starter · #10 · (Edited)
Final Results

So after running my 2217 for a month using a bamboo skewer as the impeller shaft, I conclude that it is a very viable substitute for the ceramic original.

The diameter matches very closely and the wear-and-tear on the bamboo is minimal.

I attached a picture of the bamboo after the 30 days.

As for the stainless steel rod experiment, unfortunately it is a no-go unless further work is done. As it turns out the 1/8 inch diameter SS rod is too thick. In metric it is 3.18mm and is a tight fit in the impeller hole. Not sure if I can somehow sand it down a bit to make it work. Or I will look for a 3mm SS rod. Curse the precision!!! Should have known that a non-US manufacturer would be using metric instead of imperial standards. LOL
If I try it at a later date, I will post my results.

In the meantime, Eheim 2217/2215 owners should keep a couple bamboo skewers handy in their aquarium supplies box. :)

Cheers!
 

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Interesting thread. I just wonder if you would be able to use a TIG welding rod, of 3/32" diameter. Unless the Eheim shafts are actually designed to contact the impeller, I would think they might work. With Fluval/AC impellers, the shaft doesn't contact the impeller. There is supposed to be a layer of water between shaft and impeller, that acts as a lubricant and coolant.
 

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Discussion Starter · #12 ·
Interesting thread. I just wonder if you would be able to use a TIG welding rod, of 3/32" diameter. Unless the Eheim shafts are actually designed to contact the impeller, I would think they might work. With Fluval/AC impellers, the shaft doesn't contact the impeller. There is supposed to be a layer of water between shaft and impeller, that acts as a lubricant and coolant.
The 3/32" would be too thin I think. The rod in the eheim does have some space for water lubrication and but is "tight" enough to keep the magnet from wobbling too much and touching the sides of the impeller hole housing. Plus then you would not be able to use the existing rubber bushings as the holes would be too big....too much wobbling all around.

If TIG SS rods come in 3mm, then we're in business! :)
 
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