Tapered bottom IBC

Petesake

Hi All I was wondering if anyone has tried to stretch an inverted pyramid into the bottom of an IBC?

I was thinking of making a female base and fitting it between the steel base and the PE base then filling it with hot water to help it stretch into place.

boss

You can try it with a plastic milk container as that is a similar type of plastic. Wow, I imagined I knew a little about polyethylene from college, but after a quick search on the Web had I found this very informative site: https://www.creativemechanisms.com/blog/polyethylene-pe-for-prototypes-3d-printing-and-cnc
"What are the Characteristics of Polyethylene?
Now that we know what it is used for, let’s examine some of the key properties of Polyethylene. PE is classified as a “thermoplastic” (as opposed to “thermoset”), and the name has to do with the way the plastic responds to heat. Thermoplastic materials become liquid at their melting point (110-130 degrees Celsius in the case of LDPE and HDPE respectively). A major useful attribute about thermoplastics is that they can be heated to their melting point, cooled, and reheated again without significant degradation. Instead of burning, thermoplastics like Polyethylene liquefy, which allows them to be easily [injection molded] and then subsequently recycled. By contrast, thermoset plastics can only be heated once (typically during the injection molding process). The first heating causes thermoset materials to set (similar to a 2-part epoxy) resulting in a chemical change that cannot be reversed. If you tried to heat a thermoset plastic to a high temperature a second time it would simply burn. This characteristic makes thermoset materials poor candidates for recycling."
Brian

scotty435

boss wrote:

If you tried to heat a thermoset plastic to a high temperature a second time it would simply burn

I wonder if you could heat it underwater and reform it without burning that way. Might be interesting to try. It could give you a longer working time if you have a precise way to adjust the temp.

Petesake

I think Boss' statement reads "PE is classified as a “thermoplastic” (as opposed to “thermoset”)" so that means it is respondant to a limited amount of heat without degredation.

I read about IBC limitations somewhere stating that they can hold liquid at 80 degrees C for a short time and 60*C for a long time.
I imagine the bottom side walls would bulge out between the frames at higher temps so that might require a smaller amount of 100*C water say 100 lt then air pressurize or vacuum the base down.
Another thought was to use microwaved sand bags as they could get higher than 100*C and provide more weight... Hmmm not sure the Missus would agree to 200 Kg of sand bags going through the microwave. :think:

I filled a 2 lt PE milk bottle with boiling hot water and yes it makes it very pliable and even creates it's own dished bottom but it's so thin it seems there is bearly anything to stretch. The IBC is 3-5 mm thick so I'm hoping it won't tear.

boss

That's awesome. That description helped me a lot to understand the difference between thermoplastics and Thermoset plastics too. It's nice to learn more about plastics since we're surrounded by them. Did I see on one of your threads that you did reshape the bottom of an IBC?
Brian

joblow

Hi Pete,

Would a Commercial high pressure steam cleaner be any use? A heavy metal weight sitting on the bottom and steam. You could hire the high pressure steam cleaner.

Petesake

Yes Joblow I can see the problems in heating such a large area all at once, I thought to make the base out of timber (a better heat insulator than steel) and use some form of electrical heating device.

Yet during last Summer I had a spare IBC that I took out of the frame and stored it in my usable pile (no not junk to Missus). A month or so later I went to move it and noticed how twisted but rigid it had become from sitting in an odd angle.
So now I'm thinking of heating the base with fan heaters while having a heavy weight inside.
I've got another IBC I can try it on.

joblow

Yes some form of electrical heating device would work well, I've done a blue barrel using a heat gun, you can see when it's getting too hot and just pull the heat gun away without doing any damage. I didn't take it too far, just enough to get it to drain from the bottom.

If you're only looking for a slight concave in a small area you could use some dumbbell weights, they would also retain a bit of heat.

I'll be very interested to see how it turns out.

Petesake

As with most unusual things that I do, while I'm doing it I find an easier way to get the same or better result.

I mitre cut some 2 - 100 x 50 packing timber at 34" & 41" PPSS (point to point same side) and placed around the inside of the steel base. Dropped the IBC on top, fixed a brace over the top and used a porta-power to push the base down 3" 75 mm. Used heating fans under and over to de-stress the PE at 50*C for three hours. Placed plastic sheet over the IBC to retain some heat. Letting it cool down again.

Got a better idea not only to create but convert IBC to TBIBC (Tapered Bottom IBC). I'll think about doing that on the spare IBC in the fish house.

joblow

Gee that looks the goods, the porta-power is a great way to tackle it. :thumbright:

Terra

Got me thinking how about cutting long thin triangles out of the corners of the steel IBC cage base , dropping the centre and welding them "Cone shaped" then did the heat and press this would provide support after the reshape .

Petesake

Yeah lots of things swirl around in our minds when tackling something like this. It becomes easy to lose sight of the objective - which is to get the waste out of the corners and minimise the overall settled waste.

Since doing this I've been studying the performance of the SLO's in my IBC FT's 1&2 more so as they have different numbers and sizes of fish agitating the waste. Naturally the closer the waste is to the slo the sooner it gets sucked in, but that movement also drags further out waste to the close position.
Generally 50% of the distance to the edge from the slo is automatically cleaned so instead of trying to taper the whole surface I'm now going to try to taper just the outer 50%.

Terra

I played around with a short leg on the bottom of the SLO and found that pointing it in the right direction and sending the water flow in the right direction created a almost good enough result with build up in one corner only .

Tanks with corners are tanks with corners

Best result was when I got my "Floor Sweepers" (Tandanus Catfish) no crap in the tank then

Petesake

The deforming of the base seemed to work. There are two dinner plate sized excess bubbles in the middle of the long sides and close to the edges, they can be pushed through easily by hand either way.

Tonzz

well done you must be feeling very smart with yourself. Are you taking orders?

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