DIY "Stream" Style Pump

That thing looks pretty nice. It's interesting how your threaded piece detaches closer to the base, whereas mine detaches at the front. I guess it accomplishes the same thing, just a little different method of getting there. :)
 
niko5 said:
Also ejmeier, you said you did not want to put SS in your tank well i always though the maxi jet rods were titanium but they aren't its SS.
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Where'd you hear this? I did a search and couldn't find anything conclusive. One site describe the shaft as "steel", but it didn't look too official. :rolleyes:

The reason I ask is because most of the stainless steels are magnetic. There's an easy way to check that out, see if it sticks to the impeller magnet. :p SS does (tried with a knife), but whatever the shaft on my MJ1200 is made of, it isn't magnetic.
 
Ok you have a point there... SS should stick to the mag... I guessed it was SS just because of how shiny it was. I know its not titanium because I held my titanium rod that was twice the length and IT was lighter than the maxi jet rod AND when I grind on the titanium rod i get a white spark but the maxi jet "metal" I get the normal yellow spark.... HUMMM it weighs to much to be aluminum.. but i cant think of anything else that isn't magnetic...
 
Maybe a different grade of titanium?

Anyway, I just hooked up Version 4.11b and tried it out, and I have mixed results.

Some of my concerns are:

Enough flow coming in through the sawed out slots.

Slots too big to allow snails into prop area. (Slots are about 3/8" wide).

Too much flow restriction on the end with the eggcrate in place.

Prop stop won't reverse direction of propeller.

Any other weird or unforeseen problem.
Click to expand...
Positives:

Tons of flow getting to prop via the slots.

Epoxy appears to be working like a charm in reversing the direction of the propeller. It worked at least three times that I saw, all in a fraction of a second. The only time it didn't work was one odd incident when it started up in reverse, and kept spinning in reverse, but didn't pop out. I have no idea why it did this that one time, but for the most part the epoxy is working.

Amazing flow coming out of the front in a very wide cone. It is a much wider distribution than what I seem to have remembered in the past.

Negatives:

Doesn't start spinning everytime. :confused: I have no idea why this is, but sometimes I have to give it a hand-start. Maybe the prop is slightly too large for the MJ to get going at startup.

The front plate is, well.... junk. :p I think it has to do with the fact that I couldn't get the shaft perfectly on center, so it makes it even harder for the MJ to start spinning the prop. It also seemed to cut down on the "dispersion" factor of the flow as well. It was probably the eggcrate that did it.

Anyway, the nice thing is that even without the long top shaft in place, the unit still runs very smoothly! :bounce1: So I am currently running it without the front cover. And since I can remove it and just thread it back in later, I think I'll rework it and leave the rest of the unit running in the tank for observation.

That's it so far...:)

Wait, one last note. I was actually going to use the 2" pipe fittings for the guard, but found that the overlap was too big and conflicted with the suction cups. So, if anyone else ever wants to try this, if they want to use the suction cup mounts that come with the MJ, I wouldn't go with anything bigger than 1 1/2" guard. Anyhow, it still gets exceptional flow with the smaller pipe.

Okay, another thought: Maybe a 1/16" titanium shaft wouldn't be such a bad idea? The shaft fits very precisely in the magnet. Perhaps with the added glue and gunk that has fallen all over the parts, the shaft just plain can't spin smooth enough on startup. A shaft that is only 1/32 of an inch smaller might do the trick. Maybe.
 
Well i tested my version 3 and my slits just dont let enough water into it. I think im just going to pick up some more fittings like waht i got and drill holes but ill try and do them neatly...

ejmeier, If yours is running and you put ur hand close to the output will it stop and try and run backwards or just restart?

I have the same problem with this one with it just not starting sometimes and sometimes it runs backwards and wotn stop itself.. hum...
My version with the 1 1/2" pipe with holes zip tied to it is still running strong and had non of thease problems.. im starting to think it was the prop.. if you look at it (its the red one) its a basic cheepie prop its not a sharp and angled as the new ones I have and ejmeier is using.
 
Well i swaped my super blue prop for one of the old red ones and im sitll having the not wanting to spin the right direction issues and there is deffenlty less flow with the red one. once it starts spinning it works...
 
niko5 said:
ejmeier, If yours is running and you put ur hand close to the output will it stop and try and run backwards or just restart?
Click to expand...
If I put my hand over the output, it just makes a weird noise but still keeps spinning the right way. All I know is, he sounds mad when I try to block the flow, so I'm not messing with this guy. I'm gonna keep him happy. :)

niko5 said:
Well i swaped my super blue prop for one of the old red ones and im sitll having the not wanting to spin the right direction issues and there is deffenlty less flow with the red one. once it starts spinning it works...
Click to expand...
Do you have any epoxy putty? Trust me, a little glob of this in the right place will work wonders. Look at how the prop spins and then make sort of a triangle shape. Check out my third picture over on page seven. :) It is much nicer to have the prop always start up in the right direction. (That is, if it starts to spin at all.... :rolleyes: ) Next time you are at the hardware store, get some epoxy putty. :D
 
Well i glued a piece of acrylic onto the acrylic support on the end that will hit the blade if it spins backwards adn i plug it in and it just pops.. cause it spins backwards stops spins backwards stops.. etc.. hehe
 
Hmmmm, maybe it is not close enough to the blade? When it is running straight, you can see how the magnet sort of settles down into the lowest spot in the MJ body. Use that as a reference point as to where to position the stop.

You don't want the prop flying too far out; if it starts spinning the wrong way, it doesn't take long for that thing to rise up. You want to try and hit it the moment it starts going backward.

Good luck. :)
 
well i screwed it down alittle more to get it closer and it seemes to work. It kept stopping on me for no reason but i think it was not getting enough water so i drilled some more holes (now my guard looks REALLY UGLY) and it runs now.. so ill pick up some more parts tommorow and nake a new guard... now should I do the slit like yours.. or carefuly do some holes.. hum....
 
Niko5, is it me or is your "super blue" prop on backwards??? I though it was suppose to be "flat side" of blade to cut through the water and force it off the back of the prop to get a vortex?? More vortex better stream...?.:confused:
 
No i beleve I have it on right It has alittle slit in the prop that hookes onto a bar in the shaft of an rc boat adn that part goes toward the boat and away from the spray and thats how I have it setup on the stream. I always though you started with the smaller sharp end to cut through the water... im no expert though
 
Well I turned the prop around just to see what happense... and it starts up and runs now with the flat side as the leading edge. I still think this is backwards... maybe Im not sure but the flow feels the same. Maybe the maxi jet isent powerful enough to use the prop the right way because it would push so much? Im not sure...
 
ejmeier said:
Doesn't start spinning everytime. :confused: I have no idea why this is, but sometimes I have to give it a hand-start. Maybe the prop is slightly too large for the MJ to get going at startup.
Click to expand...


Here's my experience with that sort of thing:

Symptom: Shaft rotates without prop, just sits there with prop attached.

Action: Get out some scissors and trim the ends off the prop.

Symptom: Prop now 'flutters'. It moves around but never makes a complete rotation. I attached a piece of string to see what was happening because the prop was moving too fast to see. The string makes squiggly lines all around the prop.

Action: More scissors work. (Arrgghh!! Look at what I've done to my beautiful prop! :sad2: )

Symptom: Even with a small 'stubs' left the prop still moves a ton of water!!!

It seems that the difference between a 'high flow' powerhead and a 'lower flow' powerhead is the impeller. I've not tested if that really makes a difference on the size of prop that you can drive.

Some of the props that I got where quite large.

It appeared to me that that a thicker prop with shorter blades moves more water than a thinner prop with longer blades. I tried cutting a prop in two vertically, and trimmed the blades to fit using the method above. The blades where slightly longer than the unsliced prop, but didn't seem to move as much water.

Some sites of interest for those having a hard time finding props locally (I did at first, but eventually found a hobby shop semi-locally that does carry them) :

http://www.finedesignrc.com/octuraprops.asp

http://www.mackproductsrc.com/props_p3.htm

http://www.funrcboats.com/Store.htm#Props (Polished carbon props for the aquarist that demands the very best!) :lol:

http://h1070299.hobbyshopnow.com/se...Detail.asp?strProd=&strInCategory=BPP&tag=dir

http://www.hobby-lobby.com/boatprop.htm

http://www.dumasproducts.com/cgi-bin/dumas.storefront/405b25ad07217f60271d40d409680623/Catalog/1040
 
DonJasper,
Good info :) I really think ( i may be wrong ) that the key to this is not having a pro racing prop... i think the key is to get a prop like or trim it like the red ones I used or the one ejmeier used. My blue prop works every time now that I trimmed it down alittle.

DonJasper do you have a picture of your prop after trimming? :)
 
Hey guys,

I found this thread last week and this is my 1st rev. I used a 1.5" strainer for the guard. I am also using a 1.25" prop on an old mj750. The the flow pattern its very wide, I tried to show that in the last pic. I would like to get an old mj1200 and see how much it will improve.

Rev0.1
 
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