Oh I get that. Comments based in fact aren't considered criticism by me and learning about that gasket material is enough to make me change course.
Oh I get that. Comments based in fact aren't considered criticism by me and learning about that gasket material is enough to make me change course.
Author of Midlana, Build this High Performance Mid-engine Sports Car. http://midlana.com/stuff/book
I came up with four ways to hold the screen ends together:
- - draw latches
- - cargo straps
- - large hose clamps
- - angle material drawn together with long bolts
The first three are convenient but don't address the springiness of the screen material; I worry it'll spring upward between hold-downs and allow a leak. The fourth method is less convenient for servicing yet ensures that the ends are drawn down when tight. It "shouldn't" have to be serviced very often, so if it takes 2 minutes to remove the screen versus 10 seconds, that's okay. Avoiding leaks is pretty high on the list and since all approaches cost about the same, 316 stainless angle material is being priced out.
Last edited by kimini; 02-21-2017 at 02:52 PM.
Author of Midlana, Build this High Performance Mid-engine Sports Car. http://midlana.com/stuff/book
Ordered the stainless angle and have the cut list for the outer housing... the last big "cha-ching" for this project.
Author of Midlana, Build this High Performance Mid-engine Sports Car. http://midlana.com/stuff/book
All the remaining RDF bits have been ordered. I updated the list of materials on the first page of this thread and it totals to around $2000 - a lot, yet not for what it is.
The idea is to have it ready to run before the new pond is filled, possibly even being swapped in to the existing pond system now. I like to compartmentalize changes, or said another way, changing one thing at a time to make it easier to deal with problems. Yeah, as I'm typing this I guess I've decided; the RDF will get swapped in as soon as it's done. Thanks for listening to my typing out loud, so to speak.
There's a fair bit of fabrication involved in the enclosure so there'll be plenty more updates, but the fussy hard stuff is done so it'll be more fun from here on out. The entire pond redo is finally past the money hump, with the only things left being the liner and possibly more retaining wall stone.
Last edited by kimini; 02-28-2017 at 09:34 AM.
Author of Midlana, Build this High Performance Mid-engine Sports Car. http://midlana.com/stuff/book
Really enjoying seeing your journey and the decisions you make. "The Beast" has been appropriately named. With the materials you are using, this thing is going to be solid....and heavy. You'll definitely need a few people to help you move it.
First off, the interim RDF failed over the weekend, the Rayon/Polyester filter fabric apparently weakening in the constant water immersion and/or being blasted with the sprayers. It was replaced, buying myself another 8 weeks or so to get this unit online. While I haven't written off filter fabric, this particular material obviously won't cut it. I could stick my finger through it anywhere and it was coming apart on its own right under each sprayer's centerline.
Mostly in the interest of time, RDF v2.0 will use stainless mesh, though I read it has its own issues, like microscopic burrs such that even when sprayed, retains some debris. Also, over time, calcium deposits gradually clog it. Not sure whether a phosphoric acid bath can restore such a screen, but at $200-$500 for a new screen, it's worth looking into. Anyhow, Dutch weave 60-micron screen was ordered but once the filter is up and running I want to more fully research filter fabric, as I'm sure there's something in industry that's far cheaper.
Regarding fabricating the new filter, the outer housing material arrived and the first end panel was prepared. Jogs and channels were added for the mating panels to make the unit self-jigging for welding. This will help the various pieces stay in position, which can be a real problem due to the material contracting as it cools and attempting to shift alignment, just like when welding metal. The triangular piece sticking up in the second picture is a test fit of one of the bottom slots, which forms the bottom of the tank housing.
Last edited by kimini; 02-27-2017 at 03:22 PM.
Author of Midlana, Build this High Performance Mid-engine Sports Car. http://midlana.com/stuff/book
As time allows, work continues and the enclosure end panels are basically done. A bevel was added mostly for looks but it's also functional because I learned the hard way that freshly fabricated HDPE can hold a surprisingly sharp edge, enough to draw blood. The fuzziness is the edge of the protective film.
With the end panels done, one half of the floor was placed in its self-jigging slot, which worked a treat as the Brits say.
The 60-micro screen showed up. A 48"x96" sheet of 304 was $200 from McMaster (who knows what shipping was... they hide that) and the equivalent in 316 is $457. I went with the 304 because:
1. I can't find any reliable data indicating that 304 will corrode in fresh water. None of the 304 fasteners in the currently-operating filter are corroding.
2. I still think filter fabric can work if I can just find the appropriate material.
3. I read that stainless screen eventually fails on its own (tearing or getting permanently plugged up). What's unclear is how long that takes and if it happens before the material corrodes, if it does at all.
4. If I'm completely wrong about 304 and it corrodes before it plugs up, replacing the sheet with the same material is still cheaper than the equivalent in 316.
Last edited by kimini; 03-02-2017 at 12:29 PM.
Author of Midlana, Build this High Performance Mid-engine Sports Car. http://midlana.com/stuff/book
Oh you have no idea until you have worked with PVC... That edge is wicked sharp and since it is a more rigid plastic it doesn't take much to draw blood. Just wait until you have to clean all of your joints with solvent before you weld them together. You will find every single small knick on your hands. I always have an orbital sander at all of my cutting stations to take the sharp edge off the cut as soon as i finish. I can't say I do it all the time, but when I do my hands are very happy
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Author of Midlana, Build this High Performance Mid-engine Sports Car. http://midlana.com/stuff/book
That is a wrong screen looks like Dutch weave mesh screen you need Plain Weave mill finish surface.
https://www.twpinc.com/325-mesh-woven-stainless-62
Zoran
There is no delight in owning anything unshared
"We believe .....that the person who says that "nothing comes for free"
knows absolutely nothing about the power and strength of human kindness"
< My album
"Plain Weave mill finish surface".... I mentioned in another thread of yours that my RDF screen was not stainless steel. Looking at the picture that Zoran posted and just now a couple of other post with pictures of the larger Profidrum units, I just may have stainless steel. Maybe I'll check with Koi Acres and Profidrum.
I like to say your design and fabrication skills are unbelievable, fantastic job!! How can you do all that in such a small space?
....."Never argue with stupid people, they will drag you down to their level and then beat you with experience.".....Mark Twain
Yeah I looked at the Profidrum manual PDF which referred to it as stainless.
I'm almost afraid to ask Zoran why Dutch weave is bad, fearing he'll have a really good reason. I picked it because of references that it was a better filter than plain weave.
Author of Midlana, Build this High Performance Mid-engine Sports Car. http://midlana.com/stuff/book
Zoran
There is no delight in owning anything unshared
"We believe .....that the person who says that "nothing comes for free"
knows absolutely nothing about the power and strength of human kindness"
< My album
Hey where are tall ordering your spray nozzles from. I am having a hard time figuring out the right gpm nozzles.
I got them from McMaster.com per Zoran's RDF thread.
Last edited by kimini; 03-04-2017 at 10:56 PM.
Author of Midlana, Build this High Performance Mid-engine Sports Car. http://midlana.com/stuff/book
Thanks kimini just ordered a set. Now hurry up and get here even though I still have a couple more pieces to the puzzle
Work continues with various edges being trimmed, unnecessary material being removed, and more self-jigging slots being added. Once this is done, actual construction will move along pretty fast, and the 1/4" material for the cover is showing up this week, so progress this weekend should be good. One thing I'm starting to think about is how to move the completed assembly, or more specifically, what can be done to make it easier to move. Handles, holes to slip pipes through for lifting, or something. Or, just put a couple slings around it and lift it slung below a long pipe.
Side note: Looking through the motors on Amazon and Ebay, I think I'd now recommend driving the drum with a direct-drive gearmotor instead of how I did it. Yeah the motors cost several hundred dollars, but that has to be weighed against what I did: chain, $100, custom gear, $180, DC gear motor, $70, nylon gear, $10, or about $360. You can just get the above gear motor and be done with it - though then the trick is adding a waterproof seal for the driveshaft through the side of the enclosure, and making sure any leaking water can't get into the motor and short it out. It's always something...
Last edited by kimini; 03-07-2017 at 11:43 AM.
Author of Midlana, Build this High Performance Mid-engine Sports Car. http://midlana.com/stuff/book
Slow progress but things are still happening. The fun part is just starting, as it's starting to go three-dimensional. The close-up shows one of the jigging channels which will help keep everything square and aligned during welding. The routing is nearly done and next up is fitting it all together and then a lot of welding and finish work. I love this sort of project.
Author of Midlana, Build this High Performance Mid-engine Sports Car. http://midlana.com/stuff/book