The "Hitchhiker's Guide" to the Maxi-Stream mod

[ejmeier]

<a href=showthread.php?s=&postid=6752310#post6752310 target=_blank>Originally posted</a> by dhnguyen
Here are some new photos of a 1.75 Dumas mod on a MJ1200. This thing puts out some serious flow. The housing is about 1.5 " in length.

After tinkering a bit, I've found that pretty much any housing is going to limit flow to some extent VS running w/o housing. (Though it is still TONS of flow.)

But one thing that I think that has been overlooked is the opening AFTER the prop. As soon as the water exits the prop, it wants to SPREAD. I believe you can get even more flow, and much wider flow, by opening up the front end of the housing, almost to the point where the front half of the propeller is exposed, and only the back (suction) side of the prop is protected.

So, for instance, in the pic above, you could almost completely remove the first front opening, leaving just the sides to hold the stabilzer bar.

Here's a lousy paint pic I made of what I'm talking about. (The red is the part to remove.)

I think this will open up a wider flow pattern - a little bit goes a long way.

 

[dhnguyen]

So... I've gotten quite a few questions from people on this mod. Here is a list of FAQs that some will find helpful.

Q: How can I prevent the propellers from spinning in reversed?
A: You'll need to fashion out a stopper that will stop the impeller when it spins the wrong way. When spinning in reversed,
the whole magnet impeller assembly will pull out of the MJ body where the propellers will hit the stopper, stop spinning,
and allow the magnet to be sucked back in into the MJ motor and correct its spinning. This will happen very quickly upon start up.
On page 1 of this thread is a photo of how I made a stopper for this which is nothing more than just a little piece of acrylic glued underneath the cross brace.

Q: Why won't my mod spin correctly or at all under water when it spins fine outside the water.
A: Either you have too few of the inlet holes and/or slots on your housing or that they are too small.

Q: My mod is extremely noisy, what can I do about it?
A: Chances are you don't have the impeller and rod centered.
This is causing excessive vibration and possibly the magnet might also be hitting/rubbing against the inner wall of the pump.
Take the cross brace out and try to re-center it.

Q: When using a 1.5" SCH80 pipe or PVC test cap to connect to the MJ body, I can't seem to make it fit.
A: There is a black rubber O-ring gasket on the port hole of the MJ motor, try removing this O-ring to get your housing to fit.

Q: What does OD and ID mean?
A: OD=Outside Diameter, ID=Inside Diameter

Q: Can I use aluminum rod found at the hobby shop instead of the carbon fiber rod?
A; No. Aluminum will corrode in saltwater. The alternatives to using carbon fiber rod is using 3/32" stainless steel or titanium rods.
You can probably find 3/32" stainless steel rods in a welding supply store.
Some people have reportedly used bicyle wheel spoke for the rod as well.

 

[dhnguyen]

<a href=showthread.php?s=&postid=6763372#post6763372 target=_blank>Originally posted</a> by ejmeier
After tinkering a bit, I've found that pretty much any housing is going to limit flow to some extent VS running w/o housing. (Though it is still TONS of flow.)

But one thing that I think that has been overlooked is the opening AFTER the prop. As soon as the water exits the prop, it wants to SPREAD. I believe you can get even more flow, and much wider flow, by opening up the front end of the housing, almost to the point where the front half of the propeller is exposed, and only the back (suction) side of the prop is protected.

So, for instance, in the pic above, you could almost completely remove the first front opening, leaving just the sides to hold the stabilzer bar.

Here's a lousy paint pic I made of what I'm talking about. (The red is the part to remove.)

I think this will open up a wider flow pattern - a little bit goes a long way.

Interesting idea. Almost like you're adding an eductor to the output so to speak.

 

[dhnguyen]

<a href=showthread.php?s=&postid=6763372#post6763372 target=_blank>Originally posted</a> by ejmeier
... As soon as the water exits the prop, it wants to SPREAD. I believe you can get even more flow, and much wider flow, by opening up the front end of the housing, almost to the point where the front half of the propeller is exposed, and only the back (suction) side of the prop is protected....

You're absolutely right. This is why I opted to make my housing as short as possible so to let the water spread out more. But your idea does seem plausible. My only concern here would be that the opening might be too large and allowing fish to swim through and get turned into sushi puree

D.

 

[dwdenny]

Never mind the PM I sent you. lol Will be getting so PVC parts real soon. WIll be running by the hobby shop this afternoon.) Just to look that is(I hope)

 

[dhnguyen]

<a href=showthread.php?s=&postid=6763574#post6763574 target=_blank>Originally posted</a> by dwdenny
...Just to look that is(I hope)

That's how it starts :lol:

 

[Critter]

Just a side note here... After adding a new fish, he found out what the pump was all about by getting chased too close to it.. he actualy got sucked up against the housing where the slots are... good thing for him, he was able to flick his body and get off the housing. There was also no visiable damage. man I just about leeped out of my seat when I saw that happen.
So this story does promote having somewhat of a solid area at the end of the housing where the prop spins.. just in case a fish gets sucked up to it they won't lose a fin.

<a href=showthread.php?s=&postid=6763500#post6763500 target=_blank>Originally posted</a> by dhnguyen
You're absolutely right. This is why I opted to make my housing as short as possible so to let the water spread out more. But your idea does seem plausible. My only concern here would be that the opening might be too large and allowing fish to swim through and get turned into sushi puree

D.

 

[marm64]

I wonder if you couldn't cut out the sides for better flow and just glue in a couple of cross braces to keep the fishes from being puree. I am working on making one more and I might give this a try on the next one.

 

[ejmeier]

<a href=showthread.php?s=&postid=6763633#post6763633 target=_blank>Originally posted</a> by Critter
Just a side note here... After adding a new fish, he found out what the pump was all about by getting chased too close to it.. he actualy got sucked up against the housing where the slots are... good thing for him, he was able to flick his body and get off the housing. There was also no visiable damage. man I just about leeped out of my seat when I saw that happen.
So this story does promote having somewhat of a solid area at the end of the housing where the prop spins.. just in case a fish gets sucked up to it they won't lose a fin.

Hehe, notice I said ALMOST have the front part of the propeller exposed.

What I mean is, immediately after the prop, it is pushing water AWAY and outwards, in all directions. By opening up the end of the housing - AFTER the prop, I think you could increase flow/spread. IMO there is little chance that this would pose a threat to a fish because - again - it is pushing outward, not sucking inward.

Critter - if it were sucking inward, it must've been before the propeller, right? I don't mean to cut an exposed section in this area. Heh, yeah, that'd be bad. But I bet that fish of yours learned his lesson quick, and he doesn't let that happen anymore.

 

[crypto]

Great thread.

FYI - Instead of rigid airline & soft airline tubing you can purchase carbon fiber tubes from the hobby shops as well. The nice thing is that the 0.157" CF tube has an inner diameter of .098" which is the size of the CF rod. You would need to glue the tube to the magnet but that is really easy.

 

[Jabbajaw]

I was ready to go home last night and start the build and low and behold I forgot to turn off my RO before I left for work. Enter me in the aquarium idiot hall of fame. I was squishing around all night. Lesson learned don't do anything in the mornings.

 

[jrcastro]

<a href=showthread.php?s=&postid=6763788#post6763788 target=_blank>Originally posted</a> by crypto
Great thread.

FYI - Instead of rigid airline & soft airline tubing you can purchase carbon fiber tubes from the hobby shops as well. The nice thing is that the 0.157" CF tube has an inner diameter of .098" which is the size of the CF rod. You would need to glue the tube to the magnet but that is really easy.

Thanks for the info I seen some of those CF tubes at my local HS.
?'s for you:
Does the .098 CF rod fit nicely through the 0.157 CF tube?
Do the props fit through the 0.157 CF tube?
Or do you still have to drill them out?

I have a hard time drilling them out.

 

[Critter]

And not right before bed as well lol.

<a href=showthread.php?s=&postid=6764113#post6764113 target=_blank>Originally posted</a> by Jabbajaw
I was ready to go home last night and start the build and low and behold I forgot to turn off my RO before I left for work. Enter me in the aquarium idiot hall of fame. I was squishing around all night. Lesson learned don't do anything in the mornings.

 

[crypto]

the .098 fits in the 0.157 quite well. make sure the end of the .098 is clean (no burrs or bits hanging off). once it is in the tube, the graphite of the tube and rod make it spin quite well.

i had to drill the props out (from 0.125 to .157) but that was only about 3 or 4 drill sizes, then a little steel wool on the tube. I found a fairly easy way to drill the prop.

1. use the smallest drill size first on the prop, this is pretty easy.
2. then drill with the same bit into a piece of wood (all the way through is best).
3. take the drill bit, push it into the block of wood so that only a few mm's stick out.
4. put the prop on this, to keep it aligned with the drill press.

now step up in drill bit sizes but just dont drill all the way through. the first bit will keep the prop aligned. once you get to the final size and drill partways through, you can remove the small drill bit that was aligning the prop.

all of this was done on a drill press, with the block of wood clamped down, so the center never moved.

(note, you could try sanding the tube down to 0.125. an easy way is to put the tube in the drill and then use sandpaper or a file. but becareful because the chuck will squish the tube easily.)

 

[shelburn61]

<a href=showthread.php?s=&postid=6171304#post6171304 target=_blank>Originally posted</a> by dhnguyen
Again measure and mark the center of the brace so that you can be assured that the rod will be perfectly centered.

Measure and mark the center of the brace

I am confused on how to get the brace perfectly positioned so it is at the equator of the pipe. How do I measure to be sure it is online?

 

[dhnguyen]

<a href=showthread.php?s=&postid=6766382#post6766382 target=_blank>Originally posted</a> by shelburn61
I am confused on how to get the brace perfectly positioned so it is at the equator of the pipe. How do I measure to be sure it is online?

Very simple really. Take a measuring tape and measure the outside circumference of the pipe. Then mark the starting and halfway points.

 

[marm64]

An easier way to find the center is to take a piece of paper and wrap it around the pipe and mark where the paper overlaps. Now take the paper off and fold it in half using the mark as the end. This will give you the two points across from each other. You can just keep devide the paper in half again if you want quarter. This is pretty easy since there is not any math involved.

 

[shakestheclown]

props (no pun intented) to all of you who contributed to this design...about 2 hours of reading & planning + ~3 hours of work = tons of money saved (wife is extremely thankful)....thanks everyone

 

[dhnguyen]

Don't forget to spread the wealth so to speak so that others may know

D.

 

[Isayso]

what m'I doing wrong????????
I did the MJ 400 mods
beatifull it took me more or less 1 hour..
BUT BUT BUT ............
the propeller always turn the opposite side..even if I install it up side down
the sucker turn the opposite direction..and when I manage to turn in the right direction it freezees
I havent touched it in a month due to work... but now I 'm back and wanna fix it.........
BTW should I try with a Mj 900..or 1200?
thanks