Retained Heat Cook Box… 1st try failed

This year I have already had a lot of fun researching Solar Cooking, Solar Food Dehydration, Solar Energy, and now Retained Heat Cooking.

Have mentioned it before, but when I was a lad, I once overheard my Granny Davis describing a “hay box” she used during WW II which had the same general effect as one of today’s slow cookers/crock pots. Simply stated, she would partially cook a pot of food on the stove or fire, then seal the pot in her “hay box” to let it finish cooking over the next 2 or 3 hours, (not to mention staying hot). While researching Solar Cooking to expand my Outdoor Cooking repertoire, I was tickled to run across the same thing under the names “Retained Heat Cooking”, “Heat Retention Cooking”, “Haybox Cooking” and “Strawbox Cooking” – all of which boiled down to the same thing. Like Solar Cookers, there are quite a few different designs and recommendations – some include wrapping the pot in blankets while others are more modern, (including a design I found on YouTube involving use of a 5 gallon bucket).

For now, I am going to generally follow a design described in the 1999 November/December Issue of Backwoods Home Magazine “Try This Simple Slow Cooker” by J.D. Hooker. His idea is most easily shown by inserting a pair of his images from that article below:

Forming the base of the box

Forming the base of the box

Mr. Hooker chose to build his around an old stainless steel stock pot from which he removed the handles, (he did the same on the lid). I happen to like handles for messing around with hot items and will not be removing them, (nor will I be using stainless steel), but the general idea is the same.

Note that he used 2” thick Styrofoam insulation, construction glue, and a spray can of “expanding Styrofoam insulation” – I will be using a bit more modern materials, (again his article was written back in 1999). The idea, however, generally remains the same.

This is his diagram for how he handled creating the top of the box and forming it for the lid:

Forming the cover for the box

Forming the cover for the box

The pot, lid and inside of his double-thick cardboard frame were all coated with a paste form of car wax, (several coats), to prevent the sprayed in foam from sticking. I like the idea and will attempt to emulate it.

The Cookware I will be using with my “Retained Heat Cook Box” will be from my “Texsport Trailblazer Black Ice Hard Anodized QT Cook Set”. The largest, (outside), pot is just under 9” wide and its only about 6.5” tall – so the cook box will be formed to those dimensions and I will be using a Dremel tool to provide space for the handles and to carve out a pair of 3 finger sized notches on two sides to promote removing the pot. If I want to introduce one of the smaller pots into the box, I will simply wrap it in an appropriately sized cloth to reduce the air gap.

Guess I should show you what that black, hard-andodized TexSport cooking kit looks like:

Texsport Black Ice The Trailblazer H.A. QT. Cook Set

Texsport Black Ice The Trailblazer H.A. QT. Cook Set

Building the “Hot Box” – 1st attempt = FAIL – wrong foam

Lessons learned:

  1. Use paste wax on the outside of the form and leave the last, HEAVY, coat un-buffed. This will permit the form to release from the foam when it is cured.
  2. If using something light for the inside form, you will probably need to put something inside to give it enough weight to avoid “floating” up on top of the foam.
  3. The selection of “Great Stuff” foam was the source of this failed attempt. While it forms a skin on the outside, inside it is an “open cell” foam and would soak up water.  This is simply the wrong material – great for what it was designed for – wrong for this purpose!


This is the "Great Stuff" Big Gap Filler I am using for this little project.

This is the "Great Stuff" Big Gap Filler I am using for this little project.

Great Stuff – but the wrong stuff. 🙁

Note: I wore Latex gloves and eye projection while using “Great Stuff” – strongly recommend you do the same! Although the first attempt was ultimately a failure – those safety precautions resulted in no harm, no foul. Shooting the foam needs to be accomplished in a “well ventilated” area, with no flame sources still lit in the area, even if you ARE using it for its designed purpose.

Why am I doing this?

One of the severe limitations on solar cooking is that it must be accomplished while the sun is out and shining.  If you didn’t have power, you would need a means of completing the cooking of a meal, or simply keeping it hot until supper.  This is a means of doing so without the necessity of having a fire at night. 😉


This entry was posted by dave on Friday, April 29th, 2011 at 1:25 am and is filed under Uncategorized . You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

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