Cue the 2001 Space Odessy music!

[Tony]

Now at least I know what the apes were excited about!  Naturally wet paint is a fly and rain magnet though...

[greasemonkey]

Hmmm........... Shiney.........

[Tony]

The tanks were dated 1996, so getting on a fair bit now, one is perfect and the other had a bit of pitting at the bottom but nothing to really worry about now it's painted and will be used inside.

They came from a garage that shut down a while back, one still has a little fresh engine oil in, the other old engine oil.  So the fresh one (on it's side in the photo) I don't even need to clean out to use as a biodiesel storage tank, the other will have the top sliced off and will be a settle tank, better give that a glyc rinse!

Probably should weld some angle around the outside to stop the sides bowing out when full of liquid, if the top is removed.

[greasemonkey]

Cool. They should never rust.

Putting a frame around the one that you cut could be a good idea, maybe do it before you cut the top, although I guess it doesn't matter either way. They can loose their structure a bit when a panel is cut off.

[knighty]

can you not just leave an inch of the top on around the sides, and then fix the angle iron inside under that ?  it would keep it nice and tidy and stop it getting in the way ?

love from

angle iron al

[greasemonkey]

Aye, or even leave 4 inches around the sides, and maybe not need to put any reinforcing at all.

[Tony]

The only problem with height is somehow getting the accumulated solid soaps out of the bottom, but if anyone has any ingenious ideas then I'm all ears!

I was only going to cut it a bit down from the top in order to give myself a fighting chance of getting a shovel down into it to get soap out.  Maybe I could keep the height and use something like this:

http://www.ebay.co.uk/itm/FENCE-POST-HOLE-DIGGER-FIBRE-GLASS-HANDLE-FENCING-DIGGING-TWIN-SPADE-SHOVEL-/281061740708

Be a bit tedious and unwieldy though!

[Tony]

Actually I've just remembered something that RM suggested a while back - put a tray in the bottom that can be lifted out.  I believe I have just the thing in steel!

I tell you that man is a bloomin' genius.

[Julian]

The only problem with height is somehow getting the accumulated solid soaps out of the bottom, but if anyone has any ingenious ideas then I'm all ears!

I was only going to cut it a bit down from the top in order to give myself a fighting chance of getting a shovel down into it to get soap out.  Maybe I could keep the height and use something like this:

http://www.ebay.co.uk/itm/FENCE-POST-HOLE-DIGGER-FIBRE-GLASS-HANDLE-FENCING-DIGGING-TWIN-SPADE-SHOVEL-/281061740708

Be a bit tedious and unwieldy though!

Great minds .... just went to post this and got a warning that another post had been made ... must learn to type faster!

I've pondered on this problem a while back, but did nothing about it.  The best I could come up with was a liner for a barrel that could be partially lifted when the barrel was empty and suspended so the bio drained back into the barrel leaving the soap in the liner.

You sound like you're operating on a far larger scale, so how about bread trays lined with Terram or similar with wires for lifting.

If you want to get really elaborate, I worked on a machine to clean engine blocks at Jaguars.  The machine washed swarf out of the blocks and into a skip shaped tank.  A slow conveyor belt of mesh ran along the bottom and up the ends of the sump, collecting the swarf as it settled and transporting it into a container at one end.  That should keep you busy for a while!

[Jamesrl]

Great minds .... just went to post this and got a warning that another post had been made ... must learn to type faster!

Yeah,  about 7 years faster, that's when I suggested a lift out bottom to GL himself.

[Tony]

Not sure I'm quite up for building the conveyor system!  Or an Archimedes screw (though I am wondering if a mono would be able to shift soap).

I've gold an old hydraulic oil tank, which I could weld chains to either side to lower in, and weld hooks to the top so each side could be lifted a bit at a time (it's reasonably heavy empty, without being full of soap!).  Ideally the chains could go around an axle with a handle a bit like a well. Or I could just make the tray shallower and empty more often.  Might have to experiment and see what is practical to lift.

[julianf]

How hard does your soap set?

What about filling the setling drum with hot bio, then comming back some hours later, and opening a wide bore valve in the base?

I settle in clip tops - the fall-out is too thick for my mono pump, but if i turn the drum up-side down, it slids out as a paste, rather than a block - im sure it would go through a wide bore valve if warmed and with enough bio on top of it.

[Tony]

I did wonder if it would heat the soap below enough to do that.  The trouble is I tend to do batches in evenings and typically finish quite late - don't want to have to come out at 1am just to drain some soap off   That said with the bigger batches coming up, I'll likely have more opportunity to do them at weekends.  Hmm.  You think 1" would be enough?  It has a 1" port at the bottom already.

[julianf]

I doubt it would be enough, however, what have you got to loose by trying?

Is the tank sealed at the moment (well, semi sealed?) -

You could connect up an airline, and give it some mild pressure insted of the bio - then just leave it as long as is needed.

I dont know about others, but i do several batches before worrying about soap build up.

[Tony]

It's not a tight seal, as it has a lid that just rests on top.  Maybe I shouldn't be hasty about cutting the top off.  Perhaps I should weld in an immersion element, or arrange a halogen heater underneath?  I wonder if an old hob induction heater would work?