Black Soldier Fly Forum

66 quart flushable, simple design
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Author:  RJG [ Fri Jun 12, 2015 1:57 am ]
Post subject:  66 quart flushable, simple design

I'm working on a second bin to expand my BSFL production capacity and have a few questions I hope Jerry or someone can help me with...
I like the simplicity of Gamba's ramp exit (from another thread in this topic), so that idea is in for sure.
Glue seems to be a reoccurring problem for folks... How do you seal around the PVC drain pipe where it exits the unit? I'd rather avoid having to buy a special glue gun.
Has anyone built a flushable unit larger than Jerry's prototype? Do I need several uprights on my drain line? what diameter PVC pipe for the drain line, or does it matter?
I'm excited to try velcro hooks as a barrier. I've been fighting past-vertical-wall-scaling larvae since day one. ugh.
I'm inclined to just let ants do their thing and not try to keep them out, but if I do... maybe keeping the legs of a stand in dishes of mineral oil? water will evaporate too quickly here.
I'm also contemplating using long pine needles as my bulking material.
I'd like to avoid the expense of a valve on the drain line. Anyone had luck simply elevating it, or do the larvae crawl out if you do that?
I'm hoping that the ramp will be long enough to avoid a problem I have with my current system--an angled 50gal plastic drum. If I put much food/bedding in the unit they drag it and lots of moisture (read, "escape traction") out with them as they exit. If I'm feeding them directly to my poultry that wouldn't be a problem, but sometimes I need to dehydrate them and grind them up to feed chicks, and for that I need them relatively (not perfectly, I'm not paranoid) clean.

Author:  jf371 [ Wed Jun 17, 2015 10:08 pm ]
Post subject:  Re: 66 quart flushable, simple design

I built a fairly large composter based on Jerry's videos - I would estimate it at 12 gallons total. I did not build any uprights into my drainage system. I have a single 1/2" PVC drain lateral with kerf cuts on the underside. I'm not sure I would do this again, but I used a fiberglass repair kit to anchor the drain pipe to the floor of the bin. I covered the base of the bin in one application, and then made fiberglass "straps" over the drain pipe while it was held in place with temporary weights. I scuffed up the bottom of the bin in hopes that the fiberglass resin would bond. It's holding still as far as I know, but I doubt it would stay if I really pulled on it, or flipped it over and thumped the bottom of the tub. It doesn't really need to be stuck - hopefully gravity will keep it tight enough to the bottom that no solids (or grubs) will get underneath.

To seal the drain pipe to the tub, I used a modified piece of a slip union (trimmed so the lateral will lay flat on the bottom) on the inside and a 90 elbow on the outside, using PVC cement, that hold the tub wall snugly between them. I sealed it with aquarium adhesive (not strong, but water-tight). In this way, the cemented PVC joints and fiberglass give it strength and rigidity while the silicone merely stops leaks.

Over that, I have a piece of plastic gutter cover trimmed to length and arched over the drain pipe (heat formed). The gutter cover is perforated with ~1/4" holes. It provides an air gap around the drain pipe of about 1/2".

Over the gutter cover is a trimmed piece of fiberglass window screen, which is an effort to keep bulk and larvae out of the drain (I gather from Jerry's posts that the larvae will not be stopped). It is neatly trimmed to fit, but loose - held in place only by the 3" layer of lump charcoal. On top of that is an expanded flake of coconut coir.

Once assembled, my composter held water perfectly well with the valve closed, and drained at a pretty good rate when opened. I was wetting the coir with a hose-end sprayer dialed to a cone spray, and I was not able to fill it faster than it would drain.

Unfortunately, I have not yet had any luck attracting adult flies, so my design is utterly unproven. I am reasonably confident however, that it will drain well enough that I can effectively flush it periodically - and I have maximum "floor space" for feeding, as well as a large amount of head room for bulky feedstuffs.

Probably more than you wanted to read - but I hope it helps :)

P.S. - good thinking on the mini-mineral oil moats. I did the same thing. Baby oil is cheap - and it's just perfumed mineral oil.

Author:  RJG [ Thu Jun 18, 2015 1:50 am ]
Post subject:  Re: 66 quart flushable, simple design

Thanks jf371! I never have luck attracting females without using some meat scraps, despite what everyone says about not introducing meat scraps until after the colony is established. That sounds like a good plan for sealing the drain. Did you seal the ramp exit the same way?

Author:  jf371 [ Sun Jun 21, 2015 1:12 am ]
Post subject:  Re: 66 quart flushable, simple design

My ramp ports will be installed the same way, with a union on the inside and 45 elbow on the outside, again with a short enough piece of tubing passing through the hole that the fittings will be snug against the wall of the tub. I probably won't cement the fittings or seal it with adhesive though, so they can be removed for cleaning/adjustment.

I bought some neodymium magnets (amazingly powerful) to use to support the ramps through the walls of the tub... I think I will rivet a small steel bracket to them to facilitate that, as the channels themselves are aluminum.

All inspired by various iterations of Jerry's composters... but I've had a lot of fun tweaking it and making it my own.

My larvae should be here on Tuesday, via our own Alfredo L... My wife can't understand why I'm excited about getting maggots in the mail :mrgreen:

Author:  Jerry [ Sun Jun 21, 2015 4:19 pm ]
Post subject:  Re: 66 quart flushable, simple design

Hi gentlemen.

I don't rely on glue for water tightness, I use o-rings with pvc plumbing/electrical fittings.

The drainage pipe uses standard pvc male/female threaded electrical pipe adapters to keep pressure on the o-rings.

The ramp exit uses plumbing pipe and fittings. The exit pipe goes through a tight fitting hole in the composter wall, and has an o-ring placed over the pipe from the outside. A connector fitting is glued to the outside pipe section, with pressure being applied while it sets, which takes about 30 seconds. It can be a little challenging to get enough pressure on the fitting before the pvc cement sets up, but it doesn't take much to seal this area. It's not an issue if you get a small drip since this connection is at the top of the waste and under little pressure.

Hopefully these photos will help, but please feel free to ask questions.

exit pluming detail.jpg
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water tight plumbing detail.jpg
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Author:  RJG [ Fri Jul 10, 2015 12:02 am ]
Post subject:  Re: 66 quart flushable, simple design

Thanks guys! I finally have my bin fully operational and in testing with a few mature larvae just starting to harvest themselves. I love the magnet idea (though I stuck with the PVC corner material).
Thank you for all the pictures Jerry, I found similar fittings.
Here are some pictures. The baby oil motes seem to be working well. I've installed them on my original unit as well and have no more ant losses (not so upset about them carrying off food, but they were carrying of the young larvae too).
One more question… When you talk about high temperature hot glue you aren't just talking about the kind you can get at walmart next to the low temperature hot glue in the craft section, are you? because that would be very easy and the glue guns for it are not expensive. I didn't really have the right tools for the job, so I cracked the container in several places and had to patch it up with the (low temp) hot glue gun my sister left. If it fails I will cross that bridge when I come to it. I still think this is going to be a great improvement.
Also… I feel somewhat honored by the mistake, but I am not actually a gentleman :) I am Mrs. RJG.

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