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Reviews > Stuff Sacks > Dry Bags > Watchful Eye Designs - O.P. Sak 2006 > Karl Fuderer > Field ReportField Report: Watchful Eye Designs O.P. SAK Polymer Bags
One of the small O.P. Saks has been selected for the sole purpose of containing my small collection of vitamin, mineral, first aid and personal maintenance substances, and this one bag has been subjected to an extended period of continuous pressure from inside due to my overfilling the bag. The Aloksak I was given has received the most usage over the last month, being opened and closed regularly to access the camera on my travels. This action has weakened the seal considerably, to the extent that I will seal it and put it in my pack and when I go to reach for it again hours later it is open. Puzzlingly, however, is that when controlled tests are conducted on the seal it functions as normal. I suspect the cause of it failing is due to the swaying of the pack when walking causing the other objects in the pack to adhere to each side and rub the seal apart.
It is my understanding that the marsupials of the Australian outback are reputed to have the smallest, sharpest, and strongest teeth of all marsupials in the world. Their ability to scavenge for food left by other carnivores is enhanced by their super sensitive sense of smell. On several occasions while hiking in Western Australia I have encountered the driven efficiency of these organisms to steal. For this reason, there is a massive difference between the testing of odor barrier bags around the home and in the bush. I intend to travel to campsites where marsupials are known to live nearby, and leave a reasonable volume of naturally occurring food (such as native nut and fruit products) out for them close to an O.P. Sak full of food. If their sensitive nose fails to determine there is food in the bag, and it is left undamaged overnight, I will know they truly work. In addition, I intend to answer the questions below, while being used in rough, punishing environments including the South West subtropical forests and the Northern deserts of Western Australia, and intense humidity of the Northern Territory. Over the next 3 months I will be mostly in the South West of WA, on the Bibbulmun Track and other tracks in the south west. Conditions are expected to be between 100 and 600 m (300 to 2000 ft) above sea level, on well-defined tracks in SW Western Australia surrounded by sparse trees and semi-dense low-lying shrub. Temperatures range from –14 C (7 F) on the coldest night to 35 C (95 F) on the hottest day, with averages ranging from 0 C (32 F) at night to 23 C (73 F) in daylight. As far as general use for my purposes are concerned, I will likely use one as a reusable temporary garbage storage unit, one as an all purpose food sack containing a collective variety of smaller Ziploc-like bags. Another I will use as my non-food consumables bag, to hold water reactive substances like matches, toilet paper and medical supplies. Another still will likely be used as a document holder for maps, reading material and reference charts. I am using an Aloksak to protect my camera; Otherwise I would likely add it to my documents bag. One of the small bags will be used to contain my snacks for the day, which I keep outside the pack when walking for easy access. Any others will be carried as spares and test subjects, like guinea pigs. Test Questions and Answers: Q: Are they really as good as the website indicates? A: The website clearly mentions that the O.P. Saks have a sort of expiration date. It seems from my usage that the system of expiration is variable relative to the treatment received and for how long. One or two of the seals from the bags seem to be failing well inside the mentioned expiration range, yet other bags (and their seals) that are hardly used appear to be in an almost flawless condition. Q: Are they odor proof; or is the barrier mostly effective? A: All tests so far are indicating that the seal is odor proof, however the hardcore tests are yet to come. Q: Can they safely accept such high pressures without popping? A: So far I have managed to apply about 3 atmospheres to a bag without incident, so it's looking good. Q: What actually happens when too much pressure is applied to the bag when filled with air? Does it pop, burst, disintegrate, or does the seal release before that is allowed, sort of like a safety precaution allowing the bag to be reused after it has failed? A: All preliminary tests indicate that the seal will release when too much pressure is applied. Q: Are they durable enough to withstand tearing, thrashing and pull tension attempts? A: The bag seal is susceptible to any rubbing of the two sides of the bag near the seal in a horizontal motion. Also, the bags are susceptible to large amounts of pressure being applied suddenly, whereas if pressure is gradually increased it may well reach 7 atmospheres of safe working load. Q: How easy are they to open and close? A: Surprisingly easy. Extraordinarily easy. See below for details. Q: How much time is required to properly seal them for odor proofing? A: Each bag size has a different length of seal strip, so the bigger bags take longer to seal. I estimate that it takes about 5 to 10 seconds to seal the small bag, 10 to 15 seconds to seal the medium size bag and 20 to 25 seconds to seal the large bag. The instructions for use recommend following the sealing procedure twice to ensure it is actually sealed, which means the most time reasonably spent sealing any bag should be well under 1 minute. Q: How quickly can they be unsealed? A: For the large size bag it shouldn't take more than 2 seconds. The smaller ones are easier and faster. Q: How much odor impregnation occurs over prolonged periods of food storage? A: Unknown as yet. Q: Are the instructions for safe use applicable, informative and relevant? A: This was another significant surprise for me. The instructions for general use, including how to open and close, are printed in bold, simplified English on the front of every bag. In addition, its exact length and width in inches and centimetres are also printed on every bag. Q: How easy are they to operate in the dark, or with one hand? A: Very easy. Given that the design is Ziploc-like, and I am well accustomed to operating Ziploc-like bags in the dark or with one hand, the difference to other brands of resealable plastic bags is negligible. Q: Can the bag be marked with a ballpoint pen? A: Yes. Normal pen ink will stick to the polymer similar to the way it sticks to plastic. Q: Can markings be removed? A: Yes. I tested writing a word on one of my bags and immediately after writing it attempted to rub it off with my dry finger. Then I wet my finger with saliva and after 1 minute of rubbing the opacity of the ink had reduced by 50%. The ink did not smudge of streak at any time during the test. Q: Will ink seep through the material over time? A: Unknown as yet. Q: Does the sealing mechanism jam or clog up? A: Only when foreign objects are wedged into the mechanism, such as sand. Q: Can the sealing mechanism be safely cleaned? A: Yes, by rinsing with water, or if the object is securely stuck a pin or needle can be used to prick it out. Previous experience with this situation when using Ziploc-like bags tells me never to use a cloth or sponge to pull it along the length of the seal strip in the hopes it will come out along the way. I will attempt to verify this answer before the next review. Q: How well does the sealing mechanism wear over time? A: Preliminary tests indicate that the seal wears faster when used then when not used. The speed of wear is thus a combination of age and use. Also, the seal will wear faster if substances such as powder or granules are wedged in the seal. Q: Does headlamp light reflect off the material at close range to see its contents? A: Somewhat. A significant amount passes through the polymer, but if it is held at close range at just the right angle the light reflecting off the polymer can be directed into the eyes which can be blinding. Q: Does headlamp light reflect off the material at a distance to spot it? A: Somewhat. See above. From a distance, that same blinding reflection would work as an effective beacon. This would reduce in effectiveness if the outer surface of the bag becomes dirty. Q: How easily are they to see in the dark from a distance? A: Impossible. The material does not glow in the dark, or create or emit its own light of any kind. It would be highly visible if something inside the bag were emitting light though, such as a glow stick or electronic device. Q: How small can the bag be compressed when not in use? A: Reasonably small. It is safe to fold the bag at any place, including the seams and seals, but is most effective when tightly rolled. Accurate measurements of size when empty to follow. Q: How much volume can reasonably be fit into the bag? A: On the Aloksak the exact volume in cubic inches and cubic centimetres are printed on the bag above the bag size. For some reason this has not been replicated on the O.P. Saks, much to my disappointment. See product specifics above for volume details. I filled each of the bags with tap water to the maximum I was able to with the bag fully sealed, then removed the water from the bag and measured it in a beaker. This method was successful in both the small and medium sized bags, but with the large the length of the seal strip makes it difficult to seal while full of liquid. I did manage to seal it eventually after losing considerable amounts of liquid from the top, and therefore can only estimate the volume to be about 30 L (1014 fl oz; 7.9 gal) Q: How much does the general appearance of the bag change after the first few times it is used from the "new" look? A: When new, the polymer material appears almost transparent, with no blemishes or striations. After using them in the bath test, and drying them on the clothes line, the appearance has changed significantly from smooth and crisp to rough and creased. Maintenance: After using for leftovers I would wash with warm soapy water, then rinse with cool clear tap water and leave upside down and open on the dish rack. After using in bush environments, if the stored product was dry I would brush out the particles with my finger tip, then shake it upside down and open. For anything else I would pour a small amount of clear, still water in the bag, seal, shake rinse, unseal, pour out and repeat till clean, then dry inside and outside with towel.
I have enjoyed having the O.P. Sak as part of my gear so far. It has proved to be helpful, boasting characteristics including durability, versatility, easy and simple to use, functional and well designed. The initial trends presented to me when testing it initially are proving accurate, including the tendency for the seal to crack when a sudden, sharp tug is applied to the bag near the seal. The material is also heavier than the average plastic bag, and some of the shapes and sizes could be redeveloped. After further examination of how the seal can be accidentally broken, I believe that any gripping of the two parallels of strip that form the seal can lead to a horizontal rubbing motion which then has the same effect as if someone were intending to open the bag. Due to the thickness of the material, any unclasped fold will spring back into the manufactured shape, so any attempt to fold the seal over in an attempt to use the bag to protect the seal from being rubbed must be secured down with something like an elastic band. This subsequently reduces the working capacity, adds to the weight, and means the bag cannot be used on its own with confidence that the contents are safe and secure. Perhaps this is the reason the bags have been designed as larger than needed for most objects. With the addition of an elastic band to the bag's working design, and if the bag is used to protect the seal as mentioned, the bag's contents are surprisingly safe and secure from any reasonable eventuality. After using a medium size bag to store leftovers, then eating the leftovers and going to wash the bag, I noticed how easy it is to clean the material, both inside and out. The polymer is somewhat non-stick, and the size of the bags and their openings make them easy to get into with a soapy sponge or cloth. Also, because the bags are at least somewhat odor proof (the extent of which has not been determined as yet) it means that if I want to take leftovers on a multi-day trip without dishwashing facilities, any smelly organic discards left in the bag will be contained till I return to a place where the bag can be cleaned or discarded. In one case, I ate noodles mixed with sundried tomato sauce, and the leftovers were eaten and the sauce remained in the bag, and after 2 days I returned to civilisation and almost fainted after opening it over the sink. After properly cleaning it I could not tell it had been used in that way. Pros: Easy to open and close. Informative labeling Airtight and watertight seal Tolerant to high pressure Appropriately sized for use in some situations Durable, high tenacity material Excellent reputation inspires confidence Custom size bags available Cons: Seal can be accidentally broken Heavy material makes me doubt the value of its durability Extra small size needed, but I am not prepared to order in bulk to get one There is no square shape, which could be a plus in some applications Read more reviews of Watchful Eye Designs gear Read more gear reviews by Karl Daniel Fuderer Reviews > Stuff Sacks > Dry Bags > Watchful Eye Designs - O.P. Sak 2006 > Karl Fuderer > Field Report | |||
