FRH... Re-wired

[rattattoo]

Since I am basically a user and consumer of my MREs, I am always looking for ways to kick things up a notch.
I had some of that Mylar/aluminized bubblewrap from some sort of refrigerated gift food that someone had sent us over the holidays and I thought that using some might increase the efficiency of the FRHs. It would also mean that I could lose the cardboard box when I'm headed out, and just take along the meal pouch itself.

So, I took a standard MRE "brown bag", turned it inside out, cIlipped off the two bottom corners to make sure it would drain if there was any leakage, and slipped a secondary "bag" of the bubble wrap inside.
I cut the bubble wrap so if there would be a flap to fold up covering the bottom and another flap that could be folded over and tucked inside the MRE bag.
This is what the finished product looked like:

I added some duct tape to secure the two pouches together to prevent slippage.

Next is a filled FRH going in:

The results after 12 minutes on the timer: my meat thermometer showed 160°F.

While the FRH had quit "sizzling", there was still quite a bit of residual heat left. With the insulation, food could obviously be left for a much longer period of time, thus allowing the pouch to gain more temperature than it might otherwise.
As far as I'm concerned, hotter food is better food.
I wish I had thought to put a hot beverage bag in there at the same time...

This looks like pretty much a winner for very little effort, and at no expense at all. I'm going to try to make a second version using a used Tyvek mailer instead of the brown bag. It should be appreciably lighter.
My thought with the Tyvek envelope is that it would not only be lighter, but larger as well. Because the Tyvek is so tough, I think it would probably allow me to use it as a sturdy, leak-proof primary food container in my pack.

[housil]

Great idea and you are right, MREs are getting better as hotter as they become.

[noderaser]

Nice bit of "field engineering" you've got there! Have you tried using it with multiple items yet? It would certainly be nice to have both a hot meal and hot beverage at the same time.

[rattattoo]

I only had one old FRH sitting around upstairs. The rest of them are somewheres down with the meals in the "refrigerated storage" [ie. the cellar].
I did find a section of the Mylar aluminized insulation sheets though. They are reflective on both sides, and not as prone to tears or puncture as the bubblewrap. Of course, that means you can't sit there and snap the bubbles either.
I will probably use some of that when I try making one in Tyvek.
Once R&D is on Mk.1v.2, I will try will out the multiple items.

[RockyRaab]

Great idea, kind of a foldable oven. Here's another thought. I always wondered why we put the food pouch inside the FRH where it can get filthy if the heat packets leak. I've tried sandwiching the FRH between an entree and a drink bag but had trouble finding a container large enough to get all of that insulated. Opening the entree box and folding it around the three items leaves one edge exposed. And that thin cardboard doesn't provide much insulation to begin with. Your idea may be what I looking for.

[Name_not_found]

I like where you are going.

Think of this as a kind of thermos cooking, you get a fixed amount of energy and want to contain it to get max temp for max time, its all about insulation.

That means you want layers:
-The layer closest to the food and heat needs to be the least heat conductive as it touches the items(cotton batting for example, fluffy stuff)
-Then mylar for reflection
-Do step 1 and 2 again a bunch of times

In a pinch i have used my mittens in the winter to heat an entree to something near warm from pretty much frozen.
If you are really interested look at the insulated lunch bags and add layers to that. (even a small cooler can serve the same purpose for a group people)

[rattattoo]

Mixing a couple of threads here, but in light of the FRH failures I suffered up on the lake last weekend, I got to wondering if the bag is sturdy enough to pour in additional hot water?
Not necessarily boiling. But I'm wondering if the bag seams are sturdy enough to support the extra volume.
It would seem like, if an FRH fails to heat up, adding some hot water and slipping it into my thermal sleeve would work just as well. By my own habit I know I'm always likely to be heating water for a beverage anyways.

Has anybody tried this trick?