Ursack Aluminum liner. Titanium replacement needed.

Shouldn’t be too difficult to come up with… just need to figure out what kind / guage the aluminum is and cross over to Ti…

Good idea, though…

However, realize that you’ll save a few ozs, and the cost may be prohibitive…

Be very careful here. SIBBG is very picky.

I suspect that if you change out the approved aluminum liner for something else, even if it’s the equivalent or better, you’ll no longer have an approved canister. that could ruin your day when the ranger hands you your ticket. Any change would probably have to be submitted to SIBBG for testing first in order to gain tentative approval, and it’s too late for this hiking year.

>just need to figure out what kind / guage the aluminum is and cross over to Ti.

In response to my query about the aluminum in a new Ursack (Thread:: Re: Re: Ursack Hybrid Conditionally Approved ON 12/20/2005) I got this:

thickness – 0.03 inches
dimensions – 8″ x 12″

>that could ruin your day when the ranger hands you your ticket

I doubt any ranger will notice the difference between aluminum and titanium inside an Ursack, if they even bother to open it up to visually inspect it. A quick rap of the knuckles to see if the shield is there is probably all they would do.

thickness – 0.03 inches
dimensions – 8″ x 12″

http://www.onlinemetals.com/merchant.cfm?pid=12626&step=4&showunits=inches
Grade 2

But Grade 5 (from mcmaster carr) is probably more appropriate (as the aluminum is probably a hardened grade)
9039K16
Titanium Grade 5 Sheet .032″ Thick, 12″ X 12″
In stock at $199.64 Each
9039K12
Titanium Grade 5 Sheet .016″ Thick, 12″ X 12″
In stock at $189.98 Each

“Grade 2 (40KSI-YS) Titanium
Not as strong as Grade 5, but easier to work with and has better chemical resistance. 99.2 commercially pure. Annealed. Can be readily welded. Use for parts that need maximum formability.

Grade 5 (6AL-4V) Titanium
High strength, commercial. Heat treatable for even more strength. Use for parts that need high strength under extreme heat and stress.”

You guys would go nuts at the Boeing (as in airplanes) surplus store in Kent, Washington. There are piles of titanium and aluminum and sold by the pound. I bought Swiss made seamless T4 aluminum tubing for $1.50 a pound. Titanium scrap is $3.00 a pound. I should make a trip down there and see what I can find for our DIY uberlighters.

“You guys would go nuts at the Boeing (as in airplanes) surplus store in Kent, Washington. There are piles of titanium and aluminum and sold by the pound. I bought Swiss made seamless T4 aluminum tubing for $1.50 a pound. Titanium scrap is $3.00 a pound. I should make a trip down there and see what I can find for our DIY uberlighters.”

WHAT?!?!? Holy Crap… I wonder if they do that in Wichita?

Yup, they do… Wow…

>Titanium Grade 5 Sheet .016″ Thick, 12″ X 12″

That’s expensive! Any idea of the ratio of thickness for Ti v. Al for equivalent tooth-size puncture resistance? Certainly a 25% reduction in weight won’t be worth $190, as with the 0.16″ Ti.

Aluminum is lighter than titanium, so if you use the same thickness as the aluminum shield, you will actually be adding weight.

There was some discussion on this on the pct-l mailing list last month. One member e-mailed the people at Ursack about a ti liner. Apparently, they can do it if you ask for it and the specs go like this (I hope it’s ok I quote from pct-l):

“I got another email back from Tom Cohen, who asked if I would be willing to pay $125 for a 12 oz (est.) total weight system (bag + titanium liner) vs. $75 for the current 20 oz system. My answer was yes, a weight savings of 8 oz would be worth that to me. If others feel the same, you could send corroboration to tomcohen at ursack.com”

Done. Email sent.

I wonder if anyone has tried a spikey container. Mother nature uses sharp spines to protect seeds from predation. An open mesh container with sharp projections could be really light and a thin plastic cover could go over the spikes to make it portable. I’m thinking of something that looks like a sea urchin, but a complete sphere. Yogi won’t sit on something like that to get it open :)

Yogi won’t sit on something like that to get it open :)

i’d pay to see that

I doubt any ranger will notice the difference between aluminum and titanium inside an Ursack, if they even bother to open it up to visually inspect it. A quick rap of the knuckles to see if the shield is there is probably all they would do.

I think you are correct, and the thickness and weight of titanium needed relates not to bear mastication, but rather to convince any Rangers that these are not the droids they are looking for.

I wonder if there is a plastic or carbon fiber that would serve the same purpose but be lighter? “Son, I have only one word to say: Plastics!”-The Graduate.

but of course another container will be needed to put the spikey one into!

but I really do think there may be a simple solution waiting to happen there

>>”simple solution”

Would a battery powered, low quiescent drain, and activated only based upon contact or noise signature recognition (via DSP and FFT’s) very irritating high-frequency emitter (possibly beyond the range of human hearing, so over 17KHz for most adults) – works against rodents and bears? Needs to be irritating enough so that bears can’t put up with it for the few seconds that it will take them to learn to disable it by biting or sitting on it. Perhaps if it was enshrouded and protected in a bulge in the cover? Need to do some research on what frequencies bears, even a hungry bear, don’t like. I’ve mentioned earlier sometype of chemical dispenser in the lid – a spray (bear spray or perhaps 4% acetic acid, i.e. vinegar) in the face if device is BOTH armed/activated and triggered by mishandling.

Anyways, probably another flawed concept and failed invention from Bad Ideas R Us – pj, president and chief creator of bad ideas.

” I’ve mentioned earlier sometype of chemical dispenser in the lid – a spray (bear spray or perhaps 4% acetic acid, i.e. vinegar) in the face if device is BOTH armed/activated and triggered by mishandling.”

Bears in an area could be conditioned with dummy containers (no puns please) that had some sort of negative reinforcement like noise, chemicals, small expolsives (aka firecrackers). Those containers would need a color, graphic pattern, or better yet, an odor that the bears would learn to avoid. That would be an odor that is non-offensive to humans. Then we would just need to use that same odor on bear sacks. It would get transferred to gear too, expanding the circle of protection. And this is all pure SWAG!

I still hold that some research pointed at finding a chemical with a taste/smell that bears find unpleasant would be the lightest way to keep them from snacking on our gear. A large garbage bag style container treated with the stuff could go around your food and/or your whole pack and could be easily stuffed away for travel on the trail. If the stuff is found and is really effective, it could be used in sticky patches to go on your gear. A ranger finding people on the trail not properly equipped could just slap a few stickers on them, etc.

Somewhere along the line we need to break the connection between people/hiking gear/food/bears to de-condition them from all the positive reinforcement the bears have gotten from being rewarded by getting into packs and bear bags– and preventing unconditioned bears from aquiring the habit.

The cover I had in mind for spiked containers would be something on the order of those clear plastic containers you get deli food in. A more engineered spiked solution might be like one of those expanding spheres they make for kids toys– you would pull on it, it would expand, and the spikes would pop out– “hedgehog” or “porcupine” would be good names for it.

I’ll keep dreaming.

For an Update:

I just emailed Tom at Ursack and ask him about the titanium vs. aluminum–his reply was:

We are looking into it, but don’t know yet

tom

> I think you are correct, and the thickness and weight of titanium needed relates not to bear mastication, but rather to convince any Rangers that these are not the droids they are looking for.

Well, not exactly…

The idea is, (black) bears have to have about a zero percent chance of getting food from an Ursack for this whole soft-sided bag concept to work. This requires that no one “cheats” by carrying an Ursack that, ultimately, a bear can get a “food reward” from, such as by puncturing or tearing a sub-standard ultra-light liner. Unfortunately, it doesn’t take many “cheaters” to ruin it for everyone–a little positive reinforcement goes a long way in the animal world.

As long as virtually *all* Ursacks work, in the sense that bears are unsuccessful in getting “food rewards” from them, they’ll learn to leave them alone, much as they don’t even bother with Garcia canisters any more. This “bear training” is more important with Usracks than canisters. A bear can go to town for hours on my Bearikade and I won’t care, since in the end the contents will be unscathed, and the bear has learned yet again that canisters–at least, black carbon-fiber ones–are not sources of food. Not so with the Ursack–even if the bear doesn’t get any food, the contents could very well be ruined by the attempt. The problem with unlined Ursacks seems to have been that, because food could be tasted through small holes made in the fabric, the “no food here” message was offset by the “…but something tastes yummy” message.

So…. the titanium liner is a great idea, but it has to work in the sense of preventing food rewards, not just in the narrow, selfish sense of avoiding fines. Otherwise, every Ursack user can look forward to bears continuing to test–and in the process pulverize the contents of–every Ursack out there in hopes that the bear will hit the Ursack jackpot.

(As for the whole odor-proof liner idea–yes, it’s a good idea to make it hard for the bear to find the food, but it’s very optimistic to think bears use only smell to search for food, or that you’ll never accidentally handle the Ursack, metal liner, or outside of the odor-proof bag with hands that still have traces of food, toothpaste, sunscreen, or something else that a bear might smell and take an interest in.)

I think that the intent of the statement was NOT that it’s ‘ok’ if it’s substandard from the bear’s perspective. What was meant was that any reasonable Ti alternative would be strong enough to stop the bear. Fooling a ranger with a lighter AND stronger substitute might be more difficult than finding a lighter Ti substitute that was as strong or stronger than the Al liner.

Tom Cohen at Ursack has not sounded optimistic about an approved titanium option for the Ursack liner anytime soon. The relative strengths of titanium and aluminum are no metallurgic mystery, and one would think it would be straightforward for Ursack to engineer and SIBBG approve a lighter and stronger titanium substitute. If SIBBG thinks it so vitally important that hikers maintain compliance with the use of the liner, SIBBG should eagerly facilitate any measures to lighten the liner, as ultimately compliance will be inversely proportional to liner weight.

Metal properties are a known quantity. The question is what weight of what type of Titanium will equal the puncture and resistance of the alumininum liner currently used. Then, we and they can judge if the weight savings/cost merits offering it.

In my opinion, we are otherwise moving towards the Bearikade option, carbon fiber and aluminum. This could actually do Tom, us and the bears a service.