DIY "Stream" Style Pump

I hate you guys!!! another thing for me to dream about building and wrecking the entire living room with :/.

hehe j/k this is a good idea and simple I might try this one for the heck of it this weekend.
 
niko5 said:
I think iv noticed a problem.. The shaft seemed to be wobbling more than last night (was a very slight wobble) so i took it out and looked at it and the whole I drilled in the cover that normally holds the impeller in where the 3/16" tube came out has gotten bigger... When I first drilled the hole it was very close.. not snug but very close.. now you can see all the way around it so its like we need some kind of bearing or something in there to protect the seemingly soft plastic of the maxi jets.
Click to expand...
This is what I have been having trouble with too.

I actually did a slightly different mod, but only by accident. :p What I did was not glue the magnet to the shaft, I just let the shaft stabilize the magnet, and glued the 3/16" airline tubing into the magnet.

I used the regular maxi-jet cover (with a hole slightly bigger than 3/16" to accommodate the propeller shaft) and it ran for a few days. I took it apart and found the exact opposite of you niko - in my case the maxi-jet cover was wearing through the rigid airline tubing. It was almost all the way through, so I had to come up with a new way to stabilize the shaft.

What I did was first got rid of the maxi-jet cover, and used a ~1" length of vinyl tubing with an ID slightly bigger than 3/16", and an OD of 1/4". I then slid this piece of tubing inside another piece of tubing with a ID of 1/4" and OD of 3/8" of thereabouts. Anyway, from there I slid this into the opening of the maxi-jet to form a makeshift "bushing" that would fit snugly into the maxi-jet body, and also stabilize the shaft. (This way, it was not one specific point contacting and wearing away the shaft, but a 1" length of tubing.

Anyway, now that you mention it, my MJ1200 mod is getting louder each day. :( I am guessing that something is wearing away in the bushing I made, as it seems to vibrate much more than usual.
 
can you get some pics of that? sounds like a good idea... but waht about using a 1" piece of teflon tube rather than acrylic tube like you did.. the teflon would give it a nice smooth something to rub on... maybe.. .im sure usplastic will have soemthin ill check that later :)
 
Sorry, my "thing" is mounted in my tank with the guard epoxied in place, so no pictures of the bushing. Anyway, I think the point is moot as it is not holding up long term.

That is what I think is key here: long term reliability. This project is turning into a complete jury-rig. :(

Anyway, teflon tube??? What are you taking about? Also, I didn't use an acrylic tube, it was just the soft vinyl tubing that you get at hardware stores.
 
Ok the only snag I can find is what is said about teflon on the US Plastic site. "Nothing sticks with any strength to unheated surfaces."
So it might be an issue holding it in place...
 
I think you need to think of this on a design level. Think about a regular powerhead and how it is stabilized. A magnet spins freely, and an inner *fixed* shaft stabilizes the whole spinning assembly. The shaft then must be supported on both ends to work properly. I think maybe we need to get away from the whole idea of stabilizing a *moving* shaft, as it may just wear away in time not matter what you use as a material.

Maybe a high-grade titanium shaft the same size as the maxijets, only longer? Then you could replace the short shaft with a longer one that protrudes farther out of the MJ body. Again, this is only for stabilization purposes.

Then use the standard magnet and replace the impeller with a propeller. The titanium shaft would pass through this whole moving assembly and be stabilized on both ends just like a regular maxi-jet. You could then incorporate an anchor for the end of the rod in the protective housing (1 1/2"+ PVC) that would have a small strip of plastic going across the front.

Just thinking out loud here....:rolleyes:
 
good thinking, that is how it needs to work just not sure how to get the parts and most of all how to properly and securly secure the outer end of the rod without blocking off the prop.
 
I don't even know if it is worth it for me right now. :(

I failed to mention that on my version of this, I sawed off the top plastic piece that holds the impeller in place. I then drilled out the plastic in the center of the magnet about halfway through. The whole inside of the magnet, once drilled out, is exactly 3/16" so the rigid airline tubing fits in perfectly. However, I did this to a couple Maxi-jets, and while drilling out the center plastic, I cracked the magnet. Twice.

Right now the magnet has been super-glued back together, but only one of them has held together. I may just go back to a regular Maxi-jet for now.

As for my proposed plan, I might give that a shot someday too. You can get a 1', Grade-5, 1/8" diameter titanium rod from www.mcmaster.com for under $10. Also, the rod is only 1/8" thick, so I think that a 1/4" or 3/8" strip of acrylic over the front output of the gizmo to hold the rod in place should be enough. It shouldn't cut back on the flow too much, at least I hope.

EDIT: I'm not sure that the maxi-jet shaft is 1/8", could be closer to 1/16", might want to check that one. ;) Also, not sure if Grade-5 is the best choice. It says that its stronger, but says Grade-2 has a better chemical resistance, FWIW.
 
ejmeier,
Im looking at one of the shafts and im thinking its 3/16" can someone back me up here?
Also am I just stupid or missing something... MCMaster lists its rods at 1/16 then 1/8 then 3/16... 3/16 is smaller than 1/8" correct?

And if its smaller why is it $4 dollars MORE :)

Thanks
 
Hey good news my grounding probe that im never going to use happense to be the right size titanium rod :). Im going to fiddle with it iv got an idea in my head.. One question.. If i make the rod and everything about 1/2" longer than the prop/mag assembly will it allow the mag to come out enough to disengage and restart if its spinning the wrong way?
 
Haha ok so im stupid :P I was looking at the wrong thing stupid tape measure tricked me :P.... ANYWHO...

Iv got the Version 2.0 built :) with the titanium rod and I know it will work now :) The only problem is.. I opened it up and just like ejmeier the 3/16" tube was almost worn completely through errr... and to top it off I dropped the mag/prop assembly and it broke... nice... but iv got it it made anyway so all i need to do is pick up a new prop. So iv got the 1 1/2" pipe as the guard with a piece of acrylic over the end with a hole in it that the titanium rod sticks into and the prop/map assembly spins on that. See the pictures below.

http://www.nicksreef.com/images/diy/MJS/New assembled.JPG
http://www.nicksreef.com/images/diy/MJS/New Guard.JPG
http://www.nicksreef.com/images/diy/MJS/new prop.JPG

You may not be able to see it was hard to photograph but the piece of acrylic that supports the titanium rod at the end is filed to a point on the inside to try and help with the flow.. well see :)
 
Thanks :) I tried to take my time on this one. Normaly im trying to get the idea out of my head so quickly it comes out sloppy hehe Also I sanded the PVC pipe thinking maybe with it being alittle ruff that coraline would grow onto it faster.
 
Wow, that was quick. Just some random thoughts/comments:

Hopefully the little holes drilled in the guard won't choke the flow too much. I tried with small holes, and I didn't feel it gave enough flow, though yours looks to have more holes drilled than my original version did. I eventually went to 1/2" holes, and even then I can feel tons of suction on the holes when I put my hand near the intake.

Also, may I ask why you made an acrylic hanger for this? I guess some people just like doing stuff with acrylic, but to me, the MJ suction cups work pretty well and allow me to tilt the pump to different angles.
 
Well iv got good news and good news hehe It works great... it starts up going the right direction and if it doesent it corrects itself... The only problem I had is I ended up moving the prop back some AFTER I had drilled my holes in it so i was blowing water out some of the holes but I patched 1 row of them with hotmelt and it works great. The flows seems just as much as the first one so hopefully I have enough holes.

I made the acrylic mount because I like doing acrylic stuff and because with this modification you have to turn the maxi jet sideways and the suction cup mount for them has no where to hook to because the bottom is now the output plus the suction cups always let go i bet even more so with the flow this guy puts out :).
 
Oh also Just curious what size everyones Prop it? The one I have is 1 1/4" but I was looking online and they have a 1 3/4" one.. I was thinking about ordering that one... bigger prop more flow hehe any comments? Ied just have to make my guard out of bigger pipe.
 
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