Error Five Drifters Rescued - Hawaii Kai

[Scared Silly]

Plastic is hydrophobic, that's why it makes a great container for water based liquids. Signal mirrors are not laminate. A silver coating on one side is not a laminate anymore than the paint on your car. The sliver coating can come off from abrasion but that takes a lot of time and neglect for it to get to the point it's no longer useful. I'm starting to thing your posts are just trolling. I guess it's working...

Try doing some research on the subject before spouting off. Here is but one discussion regarding water absorption.

And yes signal mirrors can be a laminate. Here is but one example. Note the third image. See the yellow and silver layers? That is a LAMINATE. DAN replaced two mirrors that delaminated. That is one of them.

As for the rest of your post. It has zero basis it nothing more than insults and ignorance!

 

[Biotech Diver]

Try doing some research on the subject before spouting off. Here is but one discussion regarding water absorption.

And yes signal mirrors can be a laminate. Here is but one example. Note the third image. See the yellow and silver layers? That is a LAMINATE. DAN replaced two mirrors that delaminated. That is one of them.
View attachment 893516View attachment 893515View attachment 893517

As for the rest of your post. It has zero basis it nothing more than insults and ignorance!

Wow! I just deleted what I really wanted to say in my response to you.

Do you disagree that plastic is hydrophobic? LOL! You are trying to make the claim that a plastic whistle will warp from water absorption.For all practicality, the type of plastic used (maybe a TPE?) to make a scuba whistle is not going to absorb water. Why don't you buy a plastic whistle and put it in a container of water at room temperature for a year, take it out, blow on it, and tell us if it still works or if it's warped.

A coating of silver and a plastic sticker on the backside of a piece of glass is not considered a laminate material anymore than putting a decal on a glass beer mug is. If the mirror was made the same way as the windshield of your car with multiple layers of glass and a plastic sheet, then I would agree the signal mirror is laminate glass.

Also, since you are such a genius scientist/materials engineer, why don't you explain to me why my signal mirror and scuba whistle are still fine after hundreds of dives and hundreds of hours submerged under seawater and exposure to the UV rays of the sun when I let them dry out after rinsing them, in guess what, fresh WATER! LOL!

 

[Biotech Diver]

Try doing some research on the subject before spouting off.

As for the rest of your post. It has zero basis it nothing more than insults and ignorance!

I've actually done some scientific research, have you? Do you even know how to design an experiment? Have you ever read a scientific report on leachables and extractables? All you did was do a google search for key words to support your argument while ignoring anything to the contrary. I suspect you don't even fully understand what you are reading.

 

[Biotech Diver]

From the article you linked:

"The only polymer with zero water absorption is PTFE. Plastics with very low water absorption are polymers such as PEEK,PPS, PSU, PPSU, PEI, PVDF, PET, PPE, PP and PE. Furthermore, low water absorption is exhibited by POM, PA12, PC and ABS."

An AI answer to what kind of plastic a scuba whistle is made of:

"
AI Overview
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Scuba whistles are commonly made from high-impact polypropylene (PP). Some models may also include a SUS 304 stainless steel ring. Alternatively, some whistles might be made from high-impact ABS (Acrylonitrile Butadiene Styrene). "

As you can see from your own source, PP, if that is indeed what a common scuba whistle is made of, has a very low water absorption."


Is plastic hydrophobic?

"
AI Overview
Learn more

Yes, generally, many types of plastics are hydrophobic, meaning they repel water. This is due to the non-polar nature of many plastic molecules, which don't readily interact with polar water molecules.

Here's why:

• Molecular Structure:
  Many common plastics, like polyethylene (PE), polypropylene (PP), and polyvinyl chloride (PVC), are composed of hydrocarbon chains (long chains of carbon and hydrogen atoms). These hydrocarbon chains are non-polar, meaning they don't have a significant electrical charge distribution.
  
  
• Water's Polar Nature:
  Water molecules are polar, with a slightly negative charge on the oxygen atom and slightly positive charges on the hydrogen atoms. Polar molecules are attracted to other polar molecules, but they don't interact well with non-polar substances like hydrocarbons.
  
  
• Repulsion:
  The non-polar nature of plastic molecules causes them to repel water molecules, leading to the hydrophobic property. This means water will tend to bead up on the surface of a plastic, rather than spreading out and wetting it. "
  
  
• Applications:
  The hydrophobic nature of plastics is useful in many applications, including food packaging (preventing food from getting soggy), clothing (repelling rain), and biomedical devices (preventing protein adsorption). "
  
  I hope the parts about molecules and polarity don't confuse you too much.

 

[Scared Silly]

You are trying to make the claim that a plastic whistle will warp from water absorption.

I am only going to address one part of your diatribe. That is to learn to !@#$% read. Not one of my posts had to do whistles.

 

[Biotech Diver]

You were coming to the defense of the person who said a plastic whistle will absorb water and warp. I said plastic is hydrophobic, which is something you obviously have a problem with. Can plastic absorb a minuscule amount water? Yes, but it’s not enough to matter at all in this application. If you’ve ever been involved in an extractables and leachables study you will see that you can detect trace amounts of almost anything with the right equipment.

 

[tursiops]

For what it is worth: I carry two signal mirrors, one is laminated, the other is not. Not all signal morrors are alike.
I also carry a Hyperwhistle, which is (slightly?) louder than a Stormwhistle; both are the same pitch (2900 Hz). The Hyperwhistle is from 1 to 23 DB louder, depending on who you believe. Many whistles are in the 3000-4000 Hz range, which doesn't carry as well over a distance.

The Best Emergency Whistle for Outdoor Survival | TruePrepper

See our guide for the best emergency whistle, with a review of the loudest whistles from SOL, Fox, Storm, HyperWhistle, and more...

trueprepper.com

Small Topic: Safety Whistle

I want to develop the habit of always having a whistle with me while skiing. None of my gear has one built in. I have an ancient metal Acme Thunderer like your gym teacher had in junior high. You know, with the little cork ball inside? But I'd like something small, less sharp to fall on, and...

www.skitalk.com

 

[NW Dive Dawg]

I don't think the Storm whistle will fit into the Dryfob with the mirror and PLB......but based on the advice from DD, I just bought one that'll be here tomorrow and I'll see if it can fit.

If it doesn't fit then I'll attach it to my Class V PFD that I always wear when out on my boat.

Got the Storm whistle delivered. Louder than my other whistle but way too big to fit in the Dryfob with the ACR PLB 400 and mirror. Adding this onto my boat PFD and may even buy a few more for that purpose.

PS...Not at all worried about either the whistle or the mirror regarding water or pressure.

 

[Joneill]

Got the Storm whistle delivered. Louder than my other whistle but way too big to fit in the Dryfob with the ACR PLB 400 and mirror. Adding this onto my boat PFD and may even buy a few more for that purpose.

PS...Not at all worried about either the whistle or the mirror regarding water or pressure.

Like most plastics (I suspect the whistle is something like ABS), they will degrade and get brittle/crack with enough time and environmental exposure - but that will take quite a while, so inspect periodically and replace if needed (whistles and mirrors are cheap).

 

[Nick_Radov]

Plastic absorbs water, that absorption leads to the shape of the plastic changing, aka warping.

The other issue is mirrors are a laminate. The water degrades the lamination.

No, that's not how it works. I have carried the same whistle and mirror in a drysuit pocket for hundreds of dives. No damage.