Building Metal, Conical Bottomed Fermernters.

[nabs478]

G'day fellas,

I want a massive (100-200 Litres) conical bottom stainless steel fermenter. I have seen the two commerically available items (can't remeber the brands) that are priced at around USD$1,000 for a fermenter with a volume of 100L or so. I think this is a resonable price, and if I were to buy one, then that would be great, except for the $1,000, but what happens when I want one that can do 400-500L?

What I really want to do is build one myself, and learn how to do it, so when I want a bigger one, I can just build it, and possibly sell me old one and re-cuop what I paid for it.

So here are the questions/discussion topics.

1. Does anyone know of any problems with building fermenters out of Aluminium? On this question, I would prefer is people only added info they have reasoning for, rather than just saying stuff like "that doesn't sound like a good idea to me".

2. Can anyone suggest any ways in which you could bend a peice of 1.6mm (this is the size people generally use I think) stainless into the conical shape. I understand you would construct it from a piece of a flat circle, but I would imagine that it would be far too strong for a couple of blokes to bend into shape and quickly tack is together? Do engineers have machinery for this? Any comments and ideas welcome!

I am considering just using thin enough stainless sheet that I can bend it into shape, but that brings two problems. 1. It will be much harder to weld it, and do a good job. 2. I dont want a flimsy piece of crap fermenter. I want one that is awesome.

I am in the dark here, so any info on this type of engineering stuff would be much appreciated.

Thanks

Pip

 

[ScubaSteve]

Dude. you gotta talk to Yuri. Look him up in the members list.

 

[KwaiLo]

A conical that size is much better made from SS. SS is easier to weld than aluminum is, and a lighter gauge can be used with superior strength. Take a look at a metal suppliers web site, many have strength of materials charts. Poke around at the Lincoln Electric site for comparative info on SS vs. aluminum welding.

For something that size, a multi part cone could be used, made on a roller. Trying to find someone who will either spin, or draw a piece of metal that size will be very difficult, and very expensive. Try to design everything with 4' x 8' sheets and smaller. Getting larger sheets is possible, but the price goes up too rapidly. Rollers can be purchased rather cheaply.

 

[fifelee]

Don't bother trying to bend sheet metal into a conical. You can buy a spinning much cheaper without the hassle.
http://www.toledometalspinning.com/products/hoppers/priceList.asp

 

[2ndstorey]

Either buy TMS's largest hopper and build up from there or have the cone bent for you by a shop with the capabilities to do this. Build them into fermenters from there. My brother had two made for him for a biodiesel project he is working on and I think he said they cost about 700 a piece. They are easily 200 gallons ea. Apart from a pump where a racking port should be they could easily be fermentors.

 

[nabs478]

That TMS site looks good, but I am in Australia. I guess I could have it shipped.

Thanks for your info guys, much appreciated. I might make some phone calls aorund engineering people in Melbourne.

Thanks again.

 

[Yuri_Rage]

I made mine from TMS hoppers.

Aluminum is easier to form, but it's also much easier to deform later.

Stainless is really hard to shape, so I recommend getting pre-fabbed pieces that you can weld together.

Remember to back-gas or use flux when welding stainless.

I'm building 21 gallon fermenters at the moment that I plan on selling for around $500 US. The price is subject to change, and I'm won't be ready to ship any of them until September or so. I have no idea what shipping to AU would cost.

 

[nabs478]

So I have done some investigations into these conical hoppers, and have found a place in melbourne that will supply 132L (35.2 Gallon) hoppers, much the same as from TMS for $AUD450 ($USD384) (+10% GST) if I buy at least 3.

Had a good look through Yuri's thread about his units, they look really good, well done Yuri.

I have a one question. Is there any reason in particular that you made your dump valves have that elbow in them? Is it because the bottom of the fermentor is close to the ground perhaps? Is there any problem with just have it straight?

Thanks

 

[Yuri_Rage]

I have a one question. Is there any reason in particular that you made your dump valves have that elbow in them? Is it because the bottom of the fermentor is close to the ground perhaps? Is there any problem with just have it straight?

Straight is just fine...I wanted mine to be able to sit closer to the ground (or a shelf). I figured the elbow would still work well even if the fermenter sat a little higher off the ground.

Thanks for the compliment...and good luck!