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Old 01-04-2011, 04:55 PM   #1
Sep 2010
Upstate, NY
Posts: 41
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I'm retrofitting a coleman cooler for my mash tun. Please let me just drill holes in my CPVC manifold, I really don't feel like pulling out the hacksaw. What are the pros and cons? Also, if holes are okay, what size? Also, should I drill holes (or cut slots) on the shorter cross pieces? I heard somewhere that would increase the likelihood of channeling. Any truth to that?

Thanks in advance!

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Old 01-04-2011, 05:09 PM   #2
Dec 2010
Marietta, GA
Posts: 29

I just finished building mine so I think I can be of help. I started with a hack saw and gave up within a few minutes. I then fed my roommate a beer and had him hold the assembly steady while I went to town on the manifold with a sawsall (metal blade.) So, if you have access so a sawsall or a dremel tool I say that's the way to go. I'm not sure about drilling holes though, it seems to me that if the holes are on the bottom you're not going to get much flow.

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Old 01-04-2011, 05:44 PM   #3
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Aug 2006
Whitehouse Station, NJ
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The slots will keep more open area when grain is touching it. Grain particles, especially lopped off ends are like little round cones just looking for a hole to plug. I don't think for a second that drilling holes is any easier than making slots.
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Old 01-04-2011, 06:17 PM   #4
lurker18's Avatar
Mar 2009
Winnipeg, MB
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Beside the plugging part, I would think you would need quite a few holes. I would go with the hacksaw slots, especially if you are using the PVC, it should be nothing to cut into. I made mine of copper, put probably 50 slots into it, using a jigsaw, and it took me about 45 minutes. I think you would be faster putting 50 slots with a hacksaw than putting 200 holes with a drill.

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Old 01-04-2011, 07:02 PM   #5
cuinrearview's Avatar
Feb 2008
Delton, MI
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After I marked where they should go and fired up the dremel with a little cutoff wheel it took me all of 10 minutes to cut the slots in the copper manifold for my rectangular 48qt. MLT. Only way to go IMO. I shudder to think how long drilling would have taken! I also did put slots in the two short cross pieces in the center. Everything got slotted except the joints.
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Old 01-04-2011, 07:07 PM   #6
Oct 2010
Posts: 45
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I just finished mine this past weekend and cut and then filed the slots and ran a round file thru the center. It took a lot of effort, beer and time but I'm happy with the results. I did drill holes for the sparge manifold in the lid, which was much easier.
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Old 01-05-2011, 05:12 AM   #7
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Jun 2009
Aurora, IL
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Slits with a hacksaw are a pain in the @$$ ...... I gave up on that after about 5 minutes. I have some pics of the 2 mash tuns that I built over my almost 3 year brewing career (all of which was all grain). Since I didn't have a dremel I explored the hole route (I did have a drill). I used 5/64th's bit for the holes in both of my tuns.

This is my original tun. You can't see the holes very well on the picture but I only drilled 3 or 4 holes about every half inch. I never had a stuck sparge in this thing. It drained full bore and never even slowed. The only reason I built a new one was that the cooler didn't hold temp well. I ended up giving it to a buddy who still uses it

The new tun I went a little crazier on. I started with the slits ONLY (I borrowed a dremel for this build). I brewed two batches both of which stuck like crazy. Having never had to deal with a stuck sparge this pissed me off beyond belief. I spent half a day drilling holes between all the slits. No more stuck sparge.

I'm not saying that the slits suck (obviously I used to thin of a dremel wheel in retrospect). Just saying that holes work just as well. Never had a stuck sparge since adding the holes.

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Old 01-05-2011, 02:59 PM   #8
Jan 2010
Joliet, IL
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Yeast, that is a bad a$$ looking manifold.
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Old 01-05-2011, 03:59 PM   #9
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Jan 2010
Pineville, North Carolina, USA
Posts: 324
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I built 2 mashtuns with slots, a 5 and a 12 gallon. I had problems with stuck mashes on both. I didnt change any parts, I just got out the drill and punched a bunch of holes. I havnt had a problem since. So I say BOTH.

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Old 01-05-2011, 04:14 PM   #10
Jun 2009
Posts: 168
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I recently built a copper manifold and drilled holes, mainly because I have a drill and don't have a reciprocating saw or Dremel. It works great. About 5 batches with it so far and zero problems. Can't remember what size bit I used though. Something small enough that grain wouldn't have an easy time making it through, but large enough that a single husk wouldn't clog a hole.

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