38DD Mother of a Fermentation Chiller

In 1997 Ken Schwartz published plans for the Son of Fermenation Chiller, an ice & fan based chilling chamber for fermenting wort.

After building a Son of a Fermentation Chiller and using it for a while I found the following problems:
  • It would only hold one carboy
  • The analog thermostat sucked
  • It is a PIA to deal with the ice in deep narrow ice chambers
So I redesigned the controller first to use a digital remote sensing thermostat for under $25. Then I redesigned the Son of a Fermentation Chiller to hold two 7½ gallon carboys and two ½ gallon growlers for my blow off tubes.

This is the layout of the chiller with one side removed and the top and front removed.


From this top view you can see enough room for two carboys and two ice bottles


Cut sheet from a single piece of plywood foam:


Top closed:


Top open:


Front open:


The fan mounted in the right cooling chamber:


All three cooling chambers:


A tub full of ice in the central chamber:


Micah's version of the 38DD:


Awesome work, Micah!


All credit to the respective copyright holders.
- J Thornton
brant on 03/21/08 08:33 am writes
hey the link to the thermostat is dead.
Push Eject on 03/21/08 06:03 pm writes
Brant, you're right! It appears Thornton's entire site is gone.

I will contact him about hosting his sweet thermostat page here.

Cheers!
edit: Done!
Chad on 03/21/08 10:20 pm writes
Thanks! I was just composing an email asking about this. You rock!
Cheers,
Chad
Herb on 03/30/08 03:02 pm writes
Nice job but I have one question (so far). What size plywood? 3/4" ? or?
John Thornton on 03/30/08 05:12 pm writes
Hi Herb,

I used 1/4 plywood for laminating to the foam for the sides and top and I used some 5/8 ply for the base just because I had some on hand. Any size for the base from 1/2 up will be fine

John
John Thornton on 03/30/08 05:14 pm writes
Oh and I used some 1/2 plywood for the cooling chambers...

John
Herb on 03/31/08 08:11 pm writes
John, It appears from the pictures that the basic cambers from the diagram of the cuts on the plywood are surrounded by foam then inserted into another box.
Frank D on 04/21/08 11:08 am writes
Hi John,

Any chance you have the plans for how you cut the foam? If not no big deal..but if you did they would be nice. Great gadgets! Great Site! Keep it up!
John Thornton on 04/21/08 06:09 pm writes
Hi Guys,

The cut sheet is for the foam not the plywood. I cut and glued the foam together then skinned it with the 1/4" ply cut to fit as needed.

http://suburb.semo.net/jet1024/FermChill.htm

just scroll down to about the third picture

Enjoy
John
Push Eject on 04/21/08 06:29 pm writes
Frank, as to cutting foam there are a lot of options.

Craft stores have hot wire cutters (or you can make your own with a soldering gun), but I have found a big sharp chef's knife and a straight edge to work best!

Cheers!
toymaker on 04/22/08 10:25 pm writes
I made my own hotwire from a variable dc power supply hooked up to a .035 " piece of welding wire and a piece of 1/2" emt conduit bent into a U. I drilled two holes in the ends of the conduit. Then as insulators I used two ceramic wirenuts with the tips ground down till a tiny .036" hole appeared. then I fished the welding wire through the two wire nuts and twisted one end to anchor it the other end I used a small cable clamp. Then I hooked each lead of the power supply to each end of the wire. Next the power supply was turned on and dialed in to the correct voltage to generate the right heat. This will cut through the foam like a hot knife through butter.
My hot wire cutter is over 4 feet wide and will cut throug foam the entire length. So to cut through 2" polystyrene insulating foam (white blue or pink) which is 4' wide taakes about 2 seconds. the finished edge is better than the manufacturer's edge...
For more info google homemade hot wire foam cutters.
Rob on 04/30/08 10:46 pm writes
John,

Where can I find the foam? I have been to my local Lowes and they have the blue stuff but it is only about 3/8" thick.

Thanks,

Rob
Push Eject on 04/30/08 11:13 pm writes
Rob, if you can find the white 2" extruded polystyrene you should be okay. Both my local Lowe's and Home Depot have it.
Surfbrewer on 05/15/08 12:09 am writes
Nice site, how low will the temp get in your chiller and how often do you have to change ice packs.

I like the modifications that you made to the design and the final product is actually pretty good looking. It looks like you were able to do the whole thing with one sheet of foam is that right? Do you recall what the total price tag was for the build? Thanks.

Cheers
Baron Ken on 05/27/08 11:49 am writes
Where are you finding 7 1/2 gallon carboys? Most I've seen is 6 1/2 gallon.
John Thornton on 05/29/08 07:32 am writes
Surfbrewer, I built the whole thing with one sheet of foam. I had most of the wood laying about so all I had to buy was the foam and the trim. I don't recall the prices... and it would not be valid anymore with the rapidly changing pricing in materials...

Baron Ken, They are what is called acid carboys and they have a threaded top. These two were given to me and were found in a yard sale...

John
Beerinthe760 on 07/14/08 02:43 am writes
Hey John,

How low can you go with this? Is it possible to hit lagering temps? Wouldy post what the ambient temp was when you achieved your lowest temp? Also, have you used this going the other way to make the temp warmer during winter months? I like the idea (especially since it is cost effective).

Bluelou6 on 09/06/08 06:29 pm writes
Hey John,

nice build. I am going to attempt this weekend. I have 2 questions. What size fan did you use? What provides the structural integrity of the cabinet, the foam board or the plywood?

thanks,

Lou
John Thornton on 09/07/08 07:07 am writes
Beerinthe760, You could hit lagering temps but not with ice. You can place a small light bulb or similar as a heater to warm it up.

Bluelou6, The fan I used was a 100mm but I don't think it matters much what size. Just so it blows the cold air up the tube. The foam will hold up on its own as in the SOF. The wood provides even more support and beauty.

John

ben on 04/14/09 06:48 am writes
I am looking to build this in the next few weeks, and so have a few questions. One, how long does the ice last? Two, does this actively maintain the desired/set temperature?
Crowds on 09/03/09 06:48 am writes
Hi,
This looks great !
You say it can hit lagering temps but not with ice. What would you use instead if not ice ?

Jim
Goflyakite on 09/15/09 12:16 pm writes
How are others attaching the lower and upper door- I'm part way through the build- hadn't decided yet how to do the doors- I'm leaning towards dowling them for easy access straight on and off. Any ideas/input appreciated.

PS- the advice to use PL300 adhesive is appreciated (works great), I used white poly beadboard foam w/ foil on one side- looks nice (wouldn't recommend it- pia to cut and foam beads everywhere,) If I build another I'd use blue or pink closed cell board.
Tress on 10/26/09 07:40 am writes
Making clean cuts in 2" blue/pink foamboard (it is also called sheathing) is very difficult. If you do not have a hot wire or hot knife cutter, I would recommend (in order) an extended razor knife or a long serrated knife. I did not find out about the serrated knife's effectiveness until I already made a mess of a couple of the panels.
Rob on 12/07/09 09:43 am writes
Hey, is there any more descriptive plans available? The link to the original seems dead and I'm admittedly not super handy.
Scott on 01/29/10 06:41 am writes
What adhesive did you use to glue the foam board together and skin the plywood onto the foam?
John Thornton on 01/29/10 01:43 pm writes
Scott, I used yellow carpenters glue on the 38DD and it worked better than the high price glues I tried on the SOFC. You have to tape or pin things together so they don't slide around as the glue dries.

John
John Thornton on 01/29/10 01:45 pm writes
Rob, I'll have to fix the link...

John

Post a Comment

Categories

Archives

2009

2008

2007

2006

2005

2003