New FB not shiny exactly

[Fil]

I needed a false bottom for the big new tun im building

circa £16 for 450mm circle of 3mm perspex
£4.45 on SS screws n bolts includung a M6 SS eyebolt (not arrived yet) for the centre..
(i had a bag of PP pipeclips for feet) £0

so circa £20 for the whole thing....

 

[Vossy1]

Nice work Fil I'd be tempted to put a lot more holes in it though.

 

[Fil]

I will be doing a drain test after my next 5 gallon brew when i will dump the spent grain in, possibly in a bottomless tomato pot to emulate the depth when its used..

the false bottom i copied has 1mm holes in a bigger than 1" square matrix..

the errors i made i fabricting this were

1) drilled 3mm holes (duh!!)
2) used a dril with a tierd battery (double duh!!)
3) didnt dril over a solid base (used the thermopot box uside down... not enough support (tripple duh!!!))

result- cracked exits on many a drill point, and one fracture bridging 3 holes

so this may turn out to be mark1 after all, but fingers crossed.....

good news is its not a long job, and sitting down with a bit of sand paper rubbing arround the edge whittled it down to an ultra snug fit in no time at all...

Its very strong supported me doing a push up.. so wil take any grainbill.. i aint petite...

The only unknown is how its gonna take 20l+ of prewraming water??? the thinner version i have regularly takes near boilling water when warming the tun, but its thinner, and has no started fractures????

just got 2 get the drain in and tap on so i can test it...

 

[Darcey]

Where did you get the perspex from?

I am about to order or make a false bottom, but I think this may bed a cheaper option for the moment.

D

 

[Vossy1]

I got polycarbonate ones from The One Stop Plastics shop they'll cut to any size :thumb:

 

[Fil]

ebay. :) just search for 'perspex circle', lots of sellers, many selling circles many selling sheet, i picked the cheapest on the day,
http://www.ebay.co.uk/sch/i.html?_nkw=p ... &_from=R40

id measured the diameter i wanted at 444mm and enquierd about a custom cut, that would have cost almost twice as much... so i opted for the stock 450mm diameter circle in 3mm perspex.

Im sure if asked they could also laser drill any hole pattern you wanted too.. but a fast fully powerd drill sharp drill bit and adequate support underneath you wont make the errors i did..

 

[Darcey]

Nice one. I have contacted afew sellers to see if they can custom drill them. If not Mr.s Darcey can get the tech department at school to do it for afew bottles of HB.

D

 

[Fil]

let us know the responses, i think it was about £25 for a 444mm undriled circle compared to the £16 for the stock 450mm, but i only asked the one supplier..

 

[Fil]

And the almost finished result...

need to support the valve feed a bit still and cop off the cut i made underneath after the final full volume leak test..

the SS eyebolt arrived this morning to finish off the FB

Now to consider sparge arms and automatic control :)

 

[Dieseljockey]

Looking good... :clap: that's got me thinking now, :wha: about changing mine...

 

[Fil]

cheers,, still got to test it for leaks at full volume, and check drainage thru the FB.. but so far so good :) but it can all be tweaked..

 

[Vossy1]

Now to consider sparge arms and automatic control :)

:P it never stops :lol:

 

[Cyclops]

just a heads up really when using perspex, polycarbonate can harbour bacteria when filed down around the edges, if you want a nice smooth edge, try and use a stanley knife or something just as sharp to run around the edge to make it smooth. :)

To be honest, i wouldnt be happy using polycarbonate in a mashtun with the number of holes you will need to make it quick draining and avoiding blockages, i cant see it being very strong to be honest. However give it a go and we can see the results :)

 

[Fil]

Thanks for the edging tip Cyclops, but the cracks i put in her using the last few gasps of power in my drill battery while drilling the holes will probably harbour more nasties than anywhere else, given the chance, i dont intend to give them much chance.. I tend to clean and sterilise everything on its way into the brewday and on its way out again too just as a matter of course.. and preboil cleanliness outweighs sterility attempts afaik.

strength wise i gave in doing push ups on it before it showed signs of weakness.. so a 15kg grainbill wont flex it an iota.

I share your concerns regarding drainage speed, but that can be adjusted with a full battery charge and some more holes...

My concern is the effect of the pre warming water on the thicker perspex 3mm especially now its peppered with flaws due to my dodgy drilling..

As i have made more than one error in the build its now a case of testing the concept, should it prove successful with the drain pumped thru a herms coil to return.. i will be happy and will consider investing another £16 in a fresh blank and cut n drill with my lessons learnt. its still a bargain.

 

[Springer]

Sorry to say Fil, but I think you are a thousand or two holes short. :) I tried polycarbonate, with holes and then more holes and then bigger holes and then some long fine milled slots and then some more slots..................it still didn't have enough flow rate :shock: Pump just ran dry, I then bit the bullet and got some proper stainless mesh, works perfectly. Although it still buckled without a center support. Working really well now though.
But you may have more success, good luck :)
S

 

[PD]

a stainless steel false bottom 30 cm in dia is available from one of our sponsors ...

http://www.thehomebrewcompany.co.uk/fal ... -1344.html
with some tubing affixed around its edge it makes an effective seal against in-comming grains... and allows the wort to flow perfectly...

It also saves on having to drill those numerous holes....

 

[Fil]

Sorry to say Fil, but I think you are a thousand or two holes short. :) I tried polycarbonate, with holes and then more holes and then bigger holes and then some long fine milled slot sand then some more slots..................it still didn't have enough flow rate :shock: Pump just ran dry, I then bit the bullet and got some proper stainless mesh, works perfectly. Although it still buckled without a center support. Working really well now though.
But you may have more success, good luck :)
S

I appreciate the benefit of your experience, was it only with a pump attached that you had problems, did it drain naturally all be it slowley? or did you get stuck mashes?..

If this scores 10 out of 10 out of the box and handles feeding a pump to recirculate i would be surprised, but fingers crossed :)

i have a cunning back up plan that may prove useless, but i have some #30 SS mesh which i believe is more open than closed, if i suffer a too slow drain, a layer of mesh above the perspex may solve that then again it may not ???

any pump tests will be on spent grain, i will start with a batch sparged brew in the new tun and as long as she drains eventually it will go down as a success :)


if a limitation is a slow natural drain, as long as its a total drain then its a 'feature' :) i can live with that... for now

 

[Springer]

Thats the sort of thing, that Pid shows.
Problem I had was that the pump just ran dry, i.e. there wasn't enough wort draining through the mesh into the bottom of the tun, so I had to continually try the pump off and on to allow time for wort to build up ready to be pumped. Doing this gives the PID, (no not him, :lol:) no chance of controlling the temperature properly HERMs flow rate needs to be about 2 litres a minute. :)
S

 

[Vossy1]

Fil, half the fun of brewing is doing stuff yourself but you know that :grin: There's an easy way to see what open area you have, measure the surface area of your fb and then deduct the surface area of you holes. If you're any less than 30% start to think again about using it with a HERMS, it might work by gravity though Another way round slow run off is to use an underback, do a search on the forum, unclpumple did a great build a while back :thumb:

 

[Fil]

im keepin me fingers crossed :) I hope to get a brew going in the smaller kit this week so will hopefully have some spent grain to play with, it will be a thin layer but may provide insight into how larger grain bills will perform..
if she drains slow with circa 5kg of grain, she will probably drain slow with a full grainbill so watch this space for triumph (ever the optimist )or me eating my words ( undertones of realism)..

fyi my current perspex fb has less than 1% of its area in drain holes?? a >1" grid of 1mm holes?? and is a snug fit.. < 1mm gap round the edge... is a great filter, but the last 4-5l do dribble out over about 20+ mins while the boil starts up...

so this one i may just have to learn the hard way.. :)