Round Coroplast BSFL Bin

Coroplast is not designed to be formed into a round tank but not impossible! Here's the result of the last three days head scratching, alot of thinking, plus a few finger burns from heat welding coroplast in positions not meant for the human body...

Wished about halfway into this project I had not ever started but once started one can't quit!  It was hard, I'm tired and I never want to make another round coroplast bin of any type haha!  Think if I were to make any more large BSFL bins I would just make a mold and use a hypertufa mix. Probably will just for the fun of making stuff. :)

Ended up 22" tall, 31" diameter.  Big enough for many thousands of BSFL.  That ramp looks steep but I checked and re-checked, it's 37 degree incline and they say BSFL can go up a 40 degree so it should be good, plus the fact the ramps are a silicone rubber surface instead of slick plastic.  My only concern is the 1" wide ramps may not be wide enough if alot of larvae try to migrate at once.  Guess we'll see how it goes. Pretty confident in the seam weld strength but just in case I installed a couple of hardware cloth wire mesh wall retainers on the outside.

Going to get some polyester felt, normally used as capillary mat in starting plant seedlings by sucking up water from a reservoir, cut two slits in the bottom for the ends of the felt to stick through.  I'm betting it will reverse the normal use capillary action and draw moisture away from the bin contents to the outside air to evaporate.

It's going to take lots of food to feed a BSFL population for a bin this size if it's maxed out.  Ladies at the local quicky mart are saving coffee grinds for me so there's a start. 

Not bad for less than $10 in materials so far.  Now for a lid... :)

Edit...

This drawing looks pretty dull and basic but it's exactly what one would see if they cut my bin open and laid the side out flat.  Ramps are nothing more than a triangle or in my construction, two triangles butted up on the edges.

Now about forming curves, there should not be anything really difficult given the material if one has a plan.  I'm trying to form an easy plan so people can duplicate this style if they choose.

So I think if one were to start out with flat material like shown it would be alot less difficult than my trial and error round bin. 

Some sort of flexible foam or sheet plastic might work for a bin.  We need to keep in mind when working with flat material that is to be curved to form a cylinder, we can't permanently attach the whole area of the ramps to the sides, just the centerline. This is because as we curve the material, the inside ( ends of the ramps) will need to slide as the inner diameter adjusts versus the outer wall material. If it were attached completely there would be severe wrinkling.

I would lay the wall out flat.  Attach the ramp material at the centerline.  Bend the wall material to form the cylinder, using a piece on the outside to overlap both edges to attach the seam so the inside would be smooth.  Attach the bottom and then form & attach the ramp material to the curved walls.

Another method one might use is the sand mold technique with concrete.  Ever made a sand castle?  Pile up wet sand and form a mold negative of what one wants the inside of the bin to look like. Surround it with a rigid plastic retainer wall like a big tapered tub with the bottom removed and oiled on the inside.  The bottom edge of the tub should be an inch or two taller than the "top" of your sand form, which will be the bottom of your bin.  When filled with cement completely to the top edge of your retainer and cured, the tapered plastic retainer should slip off easily, leaving you with an upside-down BSFL bin.  A big cement bin should have wire reinforcement.

Hypertufa is a lightweight material made of various aggregates other than gravel.  The standard hypertufa mix is 1 part portland cement, 2 parts peat moss and 2 parts perlite.  Fiber reinforced portland would be excellent for this type of project.  After a 28 day cure it is a fairly strong and very lightweight material compared to standard cement and also has excellent insulation qualities.  It is mixed "dry" as compared to standard cement and applied by hand to a tapered mold for easy removal and when dried could be sealed with a non-toxic epoxy coating.  Sounds like a fun project!