My roommate shops at Trader Joe's a lot and asked me if I could use his empty container of Organic Hemp Protein Powder for any kind of camping purpose (he knows I do a lot of MYOG type projects). As I looked at the container, I instantly thought of a Fosters Can Sheath. I discovered that the fosters can fits inside very well, not too snug, and the container provides adequate protection for the can.

Upon further thinking, I pondered if I would be able to put boiling water inside this container, safely, for my dehydrated meals/coffee/tea...etc.
On the bottom is the recycling #2 along with HDPE (which stands for High Density Polyethylene) which is used for food grade containers. That was great and all but I still didn't understand the effects of boiling water to this type of plastic so I did some research and this is what I found....

HIGH DENSITY POLYETHYLENE:
Excellent resistance (no attack) to dilute and concentrated Acids, Alcohols and Bases.
Good resistance (minor attack) to Aldehydes, Esters, Aliphatic and Aromatic Hydrocarbons, Ketones and Mineral and Vegetable Oils.
Limited resistance (moderate attack and suitable for short term use only) to Halogenated Hydrocarbons and Oxidizing Agents.
Maximum Temperature: 248°F 120°C
Minimum Temperature: -148°F -100°C
Autoclavable: No
Melting Point: 266°F 130°C
Tensile Strength: 4550 psi
Hardness: SD65
UV Resistance: Poor
Translucent
Rigid
Specific Gravity: 0.95

Given that 212°F is the boiling point for water and 248°F is the Maximum Temperature of this material (along with the Melting Point being 266°F) then, in theory, this should be completely safe to put boiling water into. Pop a cozy on this thing and it's good to go!

Any objections or comments would be much appreciated. Also, any ideas for a lid? The lid in the pictures does not fasten on in any way but I was hoping to solve that.

Check out the pics!

Edited by Superfluous_Grizzly on 03/22/2012 15:02:50 MDT.

Yes you should be able to pour boiling water into and not have it fall apart, however I would caution against using an MSDS as the sum of all scientific knowledge on a material. My first thought, is there BPA in it? That would be more likely to leach out when in contact with a high temp liquid.

Possibly not a relevant question for you because there is most likely BPA in the lining of your Fosters can and your using that to boil the water.

HDPE is BPA free...at least from the sources I know about. The can lining probably does contain BPA though.

HDPE (at least nalgene's bottles) is rated to about 250 F

Ben,
Thanks for the concern about this. I'm not sure what I think about BPA. Many arguments say that is leeches in such small doses that it wouldn't necessarily affect an adult; Babies and small children are a different story. However, research is still being done.

HDPE is BPA free and is safe at high temperatures. It does not leech and is recommended for water storage. The MSDS was just a quick reference. I agree with your caution towards them.

I don't drink soda or eat many canned foods (like fosters, the liners contain BPA) but I do use my fosters can about a dozen times a year on backpacking excursions.
Do you think, even at this minimal of exposure, that BPA is harming my body? I say this curiously because, like I said, I don't know what I think about BPA.

Also, do you know if BPA leeches more at higher temps? I understand that more acidic things, like preserved fruits, would aid with the leeching of BPA. A beer can should be okay in that aspect

Sorry for my long-winded nature.

Daniel:

Yes, BPA would leach more at high water temperatures. Whenever I repurpose any container, I run it through the dishwasher a few times. Whatever might leach in use would be reduced by the temps and (more so, due to complicated factors in the diffusion of chemicals through a solid) because of the detergent in that hot water. I am NOT saying it makes it totally safe, only that it removes some of it and I'm comfortable with the remaining risk. You probably got more BPA exposure from the last receipt the grocery store clerk handed you.

HPDE is good stuff. I sometimes go dumpster diving at the recycling center for HDPE containers for all sorts of purposes - BP storage, bowl use, portable one-tank refueling for pre-mix fuel for my chainsaw, etc.

HDPE is used in water storage containers, gasoline storage cans and has a wonderful temperature range. It is used in "tupperware" sea kayaks, even more river kayaks, and as sled runners in the Iditarod (which get banged around at -50F). You can heat weld it, saw it, sand it, or use a sharp knive/plane to form it. Some plastics get brittle at cold temps (especially PVC), but HDPE does not. LDPE is used in some food containers as well, but isn't nearly as solvent/fuel resistent so I don't bother with it.

My favorite plastic-fabrication trick is to take a strip of any HDPE container, light it on fire at one end and let the molten plastic drip onto the surface being repaired. I've fixed ski kayaks while still on the beach, downhill ski bases, and once, a bear-chewed nalgene using that technique. Sure, a hot-air plastic welder is more controlled and leaves no soot, but is not nearly as fun and you can't do it at 12,000' or on a remote island.

David,
Thank you for your insight. I'm going to have to try your tricks, especially the melting of the plastic as a quick weld job for plastic. I have a broken Bike pump that I could fix.
Dan

Daniel:

It's like hot glue without the glue gun or electical cord. Go ahead and try to repair the bike pump if it's also polyethylene. For an even tougher patch, try this:

Wrap the area with a open weave of fiberglass (super cheap and readily available option: drywall joint tape (mesh, really) at Home Depot). Wrap one layer, then dribble the molten plastic on to create a fiber/plastic composite.

Some HDPE containers are very slick and can be tough to open with cold hands. You can dribble molten bits on the outside to make bumps (I think of them as "pleasure dots") so thay you can grip a large-diameter container (HDPE coffee can, for instance) in order to screw / unscrew. It might also slightly decrease its tendency to slide all the way down a snowy mountain, but probably not by enough.

Most of all, play with it some day. Get a sense of what you can do, and break a few things you've welded to test their strength. Then when you need to do a field repair you'll have a much better sense just how smooth, moist or dirty something can be and still be weldable.

The research is definitely still out on BPA. I may be over reactionary. What concerns me is your body appears to treat it like a hormone. It doesn't take much hormones to have a significant affect on your body and we've literally been exposing ourselves to this chemical our whole lives.

As Dave noted above, the diffusion of most anything with increase with temperature. How much of an affect it has I cannot say. As you note acidic things have been shown to leech more BPA (try finding tomato paste in a glass jar :( ). I doubt they have done much research on cooking with BPA plastics. I am sorry for not providing much more information. We will probably find out in the years to come. I am just playing it safe until then.

As far as the BPA discussion... I'm probably going to play it safe as well. But this tip has definitely got me thinking of other containers that could be reused/recycled for outdoor activities.
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Edited by rcaffin on 03/27/2012 14:48:07 MDT.