DIY "Stream" Style Pump

[thunt]

Currently modifying a Maxijet using a propellor to achieve a higher flow rate.

I glued the impellor to the shaft. Then, drilled out the plastic caps that either end of the shaft pushes into. Now, the impellor and shaft spin. By cutting down the impellor, so all I'm left with is mainly the magnet you end up with quite a long shaft at one end.

Instead of using the intake/outake that fits onto the powerhead, I've replaced this with some modified perspex, so now the shaft (that spins) sticks outside. So now you've got an underwater motor with driven shaft!

It's a maxijet 1000 impellor and I've tried it in a maxijet 1000 body and also a 250 body, with the same results from both, so maybe it's the impellor that governs the powerheads output.

Anyway, this thing really shifts water. Even in the MJ250 body its impressive. To descibe the output - if you have a powerhead running near the surface pumping end to end, you can see the narrow stream of water as turbulence at the surface.

With the propellor running, by half way across the tank, the entire width of the tank is turbulent.

With a powerhead, if you put your hand in front, you can feel the current immediatley in front but not to the side. Not so with the propellor - the current is very widespread. I'm using a performance powerboat prop!







Problems so far:

1. The maxijet does spin either way on startup, so its a 50/50 chance as to whether it'll spin the right way. My pond pump has a small ratchet inside that I assume is there to stop this, so thinking along the same lines.

2. The propellor comes with a threaded bronze insert that is not removable (already destroyed one trying). However, once you've screwed into the brass, there's about 0.25mm exposed so not sure if this will cause a contamination problem. I could always seal with glue or something.

3. This is going to need a good casing as the propellor spinning is far more damaging then an impellor - it'll slice quite nicely!

All suggestions welcome for any of the above.

Now, if I can do it, surely the guys at Maxijet can (are you listening?). That way, we'd all get a stream for 20 quid (30 dollars)! I'm going to email them this post anyway I think.

Tim

[dogstar74]

Amazing Mod! what a great idea. I will definately be trying this one out. Since they are only about 15 bucks per PH what have I got to lose eh? Nice

DS

[rcmike]

To get the brass inserts out of the propeller screw a bolt into it and heat the bolt with a small torch. Pull the bolt and insert out with some pliars when it just starts to melt.

Very good idea. I have made some of the reeftec things that kept burning out after a while. I am using some beckett pumps now and they seem to be holding up a little better so far.

[MarkS]

I'm assuming that "Perspex" is an UK brand name for acrylic? If not, what exactly is it?

What did you use to machine the Perspex?

[thunt]

Yeah, perspex is acrylic. The part is made from a ring and a disk glued together.

To machine it, I cut a square and then knocked the corners off to get an octagon. I then drilled a hole in the middle and screwed in a screw. I put the screw in the chuck of my electric hand drill and used it as a make shift lathe. Using a wood chisel I turned down the outside.

I made two disks like this. On the second one, whilst still running in the chuck, I cut near the outside edge to produce a ring. When I was almost through, I stopped the chuck and cut through the last bit with a sharp knife.

Superglue the disk and ring together and that was it. It doesn't lock in place yet (like the maxijet cover would), but I'm still prototyping at the moment.

Tim

[ReefVan]

thunt,

Nice DIY take on the the Tunze Stream, once you've got a nice guard and bracket attached, it'll be a popular DIY project.

Keep up the great DIY'in...

Van

[jjkahler]

about these pumps burning out as rcmike stated. what is the amp draw on the maxijet while running with this mod? maybe try different propellors to get the right amp draw so you dont keep burning them up.

[thunt]

I don't know what the amp draw is - haven't got the kit to test this. Only thing is, propellors I would have thought would slice through the water more cleanly than an impellor that just slashes the water and has no aerodynamics (if thats the right word for it?)

Tim

[cyrilp]

thunt,
what do you think about adding a couple of Teflon washers between the impeller and back plastic cap?

[Toast_Man]

Any news on this magnificent DIY Idea?

I was wondering if any off the shelf PVC fittings could be modifed to act as a gard?

[ReefVan]

As a guard you could use a PVC drain guard like this ...



It's 3" diameter so it will fit any DWV type pvc piping of 3", I use it as the base guard for the sponge to sit on in one of my calcium reactor designs ...

Van

[wedfr]

id like to see some more details on the acrylic circle thing you made. How did you get it to attach without coming off the pump?

[bergzy]

where did you get the prop?

[thunt]

Reefvan - that looks like a possibility. I'd really like to keep it as small as possible though as I notice people comment how hard it is to hide a "Stream". I notice Hagen and others make some decorative plastic rock and wondered if this could house it. If you can't hide it, camouflage it!

wedfr - at the moment its just a push fit and is held in place with cable ties for testing. Needs refining though.

bergzy - the prop came from an r/c model boat store.

I think I've solved the problem of the impellor sometimes running the wrong way. When it does this, it makes the propellor lift as the water is now pushing out the front. By placing a stop just in front of the prop it runs freely when the props going the right way. When the prop runs the wrong way, it lifts slightly, hits the stop and then starts spinning the other (correct) way. Make sense? All this happens in a split second. Needs to be incorporated into the guard/housing which is where I've got to at the moment.

Gotta say though, during test it really shifts the water.

Tim

[jjkahler]

Quick question thunt, what kind of glue did you use to seal the propeller to the shaft? Thx.

Jason K.

[tor101898]

just tagging along

[Foster]

tag

RC needs a subscribe button.

[wedfr]

they have one look directly below the RESET FORM button of the quick reply box and its right there

[niko5]

What if you just take a piece of PVC pipe that would be big enough to go over your prop (dont know the size that one is) then drill a bunch of holes in it to allow water to flow pretty freely...you really dont need to cover the end if it runs all the time.. nothing should swim/crall into a nigh speed thing.. I wouldent think... I may be wrong though.

[thunt]

I glued the shaft to the impellor using Devcon Devweld. Don't know if this is a UK product or if you have it in the USA. It's a 2 part epoxy glue.

The prop had a threaded bronze sleeve in it. Using 4mm tube that came with the CO2 bottle I use on my calc reactor, this was a tight push fit over the maxijet shaft. As the thread in the prop was 4mm, I screwed this onto the 4mm plastic tube, which then cut its own thread. At the same time, it pinched the tube tighter onto the shaft. There is a tiny amount of bronze still showing that I plan to seal with glue (to prevent contamination in the tank). Works well though.

Niko5 - yeah that would work. The "streams" have a fairly open fronted design. I know there's been some concerns if using with a wave device as the pump could switch off allowing fish etc to hide in there. When it then starts up again....well the results are obvious. But like you say, if its running all the time, then not a problem.

Tim

[cudaxtreme]

I'm interested to see how you are going to deal with the random propeller spin direction, I have DIY

[cudaxtreme]

I'm interested to see how you are going to deal with the random propeller spin direction, I have DIY a similar propeller but instead of pushing water, its sucking water in!

[thunt]

cudaxtreme - looks very similar. See my post above to solve the random spinning problem.

Just notice an error in my earlier post, so I'll retype:

I think I've solved the problem of the impellor sometimes running the wrong way. When it does this, it makes the propellor lift as the water is now pushing out the back. By placing a stop just in front of the prop it runs freely when the props going the right way. When the prop runs the wrong way, it lifts slightly, hits the stop and then starts spinning the other (correct) way. Make sense? All this happens in a split second. Needs to be incorporated into the guard/housing which is where I've got to at the moment.

Tim

[cudaxtreme]

sorry but I couldnt figure how its going to work, do you have some drawings or pictures?

[thunt]

No drawings, just the pictures already posted.

I allowed some slack in the positioning of the impellor. It can slide in and out by about 1/4". When its running the right way, its pushing itself back into the powerhead and so stays in place.

When it runs the wrong way, the propellor is trying to pull the impellor out. As I've allowed it to rise by 1/4", this makes the prop hit a stop, which in turns forces the powerhead to run the other way.

The vanes of the prop are also angled such that when it runs the wrong way, there's a leading edge that will hit the stop. When it runs the right way, it just glances of the stop and re-seats itself.

Hope that makes sense.

Tim