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Slots Or Holes

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OOlsen

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Just finised making (all except for the holes) a manifold out of copper pipe for my mash tun. I am nearly set to start all grain...

Wondered if anyone had thoughts on holes (say 1/16" dia) versus slots cut using a fine hobbie saw (.6 mm kerf).

Unless there are problems using holes, I was thinking of drilling a series of holes around the manifold. I am considering the efficiency of the mash and the relationship of just how many holes to have. I am thinking more is not ness. best.

Perhaps ideally the collective area of the holes should be approximately the same area as the internal pipe dia.
My rational is that the internal dia of the pipe can carry X amount of fluid at a certain pressure/flow rate. If there are too many holes then the mash will fill freely from near the exit of the manifold, so the flow rate from the furtherest point from the exit could effectively stop???

Or have I got it completely wrong, as I type this I'm thinking maybe the pressure in the manifold from the head pressure of the tun will regulate an even flow throughout, given the overall slow flow rate during sparging???

If I wasn't going to work tonight, I'd have a beer and think a bit more about this. I think I could waste a whole drinking session pondering this problem.

Any help on the matter would be greatly appriciated...

Regards O.
 

pint of lager

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With any sort of drain system in a mash tun, it is actually the husks of the barley that do the filtering, and the slots or holes hold most of the husk particles back.

At the start of sparging, some particles come through, and the first 10-40% is recirculated back through the mashtun, till the wort runoff has no visible particles in it.

You may find the hobby saw blade too thin. One member suffered this problem recently. A regular hacksaw blade works well in copper.

Don't get too scientific with your theory about the ratio of area of manifold holes to the output port. There are all sorts of edge effects and non-laminar flow happening. Do make sure you have a tap in the outflow, so that you can control the runoff flow rate.

The holes in the false bottom of my mashtun are approx 1.5mm across. The false bottom has many many of these holes.
 

Aaron

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I found two hack saw blades together on the saw worked really well. Seems to give a really good flow in my mashtun. The design of my mashtun is pretty ordinary and doesn't have a lot of surface area at present but I still get a good flow with the double blade slots.
 

OOlsen

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Thanks for the Info. I think I'll just get busy with the drill....
 

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Oolsen

As POL points out, the husks do the filtering, the manifold just has to keep most of the husks back and let liquid through. From that point of view, slots are better than holes. I design groundwater wells for a living, and the screened casing is always slotted, not drilled. Holes are too easily plugged by a single grain of sand/gravel or in this case a husk, whereas a slot always leaves a bit open. In the case of a false bottom this is overcome by having a huge number, but you cant do that on a pipe. So holes will work but slots are better. And a wedge shaped slot, which has a narrow entry and wide exit (on the inside of the pipe) is actually the best. Thats what the most expensive wellscreens look like.

And at the rates you sparge, there is almost no pressure loss due to flow through the pipe, so there is an equal pressure pushing flow into the far holes, as there is pushing flow through the close holes. By which I mean as long as you arent letting husks through, and you havent completely damaged the strength of the pipe, you can never have too many holes or slots.
 

Batz

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And then there is a braid :beerbang:





Batz
 

Brizbrew

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Batz said:
And then there is a braid :beerbang:





Batz
[post="71726"][/post]​
Eh, Batz is that a thermometer probe I see sticking through the wall of your cooler? Does it give you an accurate temp and how did you seal the hole?

I too have a braided manifold, yet to be broken in but I am sure this is the way to go.
 

Batz

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Yes that's the temp. probe , I find it very accurate as does Dicko using the same , I have heard brewers say thiers was out.

I seal it with a small dab of 'selleys' aquarium silicon , this is food grade and only $6-00ish a tube , handy for other AG sealing jobs as well.


Batz
 

sosman

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Didn't we have a poll on something like this a while back or am I just getting old?

Maybe it wasn't slots vs holes, more like false bottom vs braid vs copper manifold.

Anyway, braid rocks.

 

Batz

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Briad....copper manifold

Beersmith.....promash


Valleymill....barleycrusher.....crankinstien


the list goes on hey?

each to there own , what ever works for you :beerbang:

Batz

PS. dare I mention March pumps :blink:
 

Boots

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Oolson,

i used one of those mini hobby hacksaws ( i think it's called a junior hacksaw) with the really thin blade. I made sure I did a lot of slits (no more than 10mm apart) due to the added risk of blockage that would come with thinner slots.

It works really well for me, I never have to recirculate more than a litre before i get clear runoff and have never had it block up on me.

Having said that, I've seen a manifold with the slits cut with an angle grinder and a standard cutting disk, and it's made a more high quality beers than mine has. Don't look as purdy but :)
 

pint of lager

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Batz says, Braid....copper manifold

Beersmith.....promash


Valleymill....barleycrusher.....crankinstien


the list goes on hey?

each to there own , what ever works for you
Very true Batz. The answer is, it depends. Whatever you can afford or have lying around or have access to.
 

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sosman said:
[March pumps suck!

:ph34r: :ph34r: :ph34r:
[post="71779"][/post]​
Actually, from the ones I have seen in action, they seem very prone to airlocks and dont suck well at all.
 

Hoops

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:eek: you March pump haters

O
I have a slotted copper manifold which I just used a hacksaw to make.
You're welcome to check mine out if you want or I can bring it to the next club meeting if you want?
Braid seems to be the way to go though - easy, ready to go with no cutting or drilling......and stainless steel :rolleyes:

Hoops
 

Borret

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Hoops said:
easy, ready to go with no cutting or drilling
[post="71816"][/post]​
I think I need to stay out of this one....
What about putting a bit of thought, originality, ingenuity and passion into your setup. The results can be very satisfying.

Borret
 

OOlsen

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Thank you all for the ideas offered. I think I've changed my mind, I'll do the slotted manifold, and I'm thinking that somewhere in the not too distant future I'll get me some of that you beaut braid...

hoping to do my first ag within a week...

thanks again

O
 

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