I would like high quality tools when it comes to saving my life. Rust on a blade is one thing, but most cheap shears use a rivet which tends to rust first and is the most likely point of failure. If we're talking about the difference between $3 for cheap shears and $20 for something better (performance, durability, even convenience), I don't really mind.
Dunno. That's possible, but have been using the same set for years and have never seen that. Especially if you just replace them at regular intervals, it should be fine.
The DGX titanium coated shears are interesting. They have only 1 review, so I wonder how rust resistant they are in practice. Does anyone have them? There's a number of titanium coated shears on Amazon, many with poor reviews. Apparently opening/closing the shears wears the blades and they rust. Similar thing happens with the black coated shears. Still it's probably better than no coating, assuming the metal under the shears is stainless. The DGX shears do look different (gold color) from the other titanium coatings.
I think that you may be overthinking this. The rivet is one thing - that's a reasonable concern. But being worried about the long term rust resistance of a $6 set of shears is probably overkill. Worry about your hoses, worry about your o-rings, worry about reg maintenance and service - but don't worry about a bit of rust on your shears. Just buy a box and replace them when the color bothers you.
The DGX sheath is friction fit, is that really DIR? Seems like if it snagged on anything, the shears could be lost. Probably a loop of webbing through the shears handle with some velcro could make it more secure, but I'm not exactly a whiz with a sewing machine.
I like the 3.5" shears I linked above for their size. Those seem to be the only 3.5" trauma shears available, all the others are 5.5" or 7.5", with 7.5" being the standard size (which is huge). The 3.5" still cut a penny, so it seems like they'd work fine. I'd preemptively replace the rivet with one that won't rust (as fast). The only issue is how to mount them. I'd probably have to make my own sheath, which may be possible. I'd have to solicit my mom's assistance!![]()
Are you saying "is that really DIR" because if it isn't specified in the GUE equipment guidelines you think that it would be unsafe, or because you are planning on doing Fundies and want to have the correct equipment for that agency's course? If the latter, I guess you had better ask the instructor. If the former, I can tell you that the fit of the DGX sheath is snug and fine, and has never accidentally dropped the shears in my experience. Also, it makes them very easy to deploy and replace.
If you look on the page with the kit, you can see that it also comes with the blunt steak knife which I believe IS standard DIR cave diving issue (maybe someone who knows something about this agency can chime in here). They also offer a sheath with that velcro holder that you want, if you prefer that (I don't).
---------- Post added September 14th, 2015 at 11:10 AM ----------
So far I like the 3.5", then the 5.5" Prestige, then the 7.5" DGX.
The 3.5" looks very small, which would be a big disadvantage if you are diving with heavy gloves. You don't get anywhere near the same amount of leverage with one finger (as in the 3.5) compared to three fingers (as in a standard trauma shears).
You don't say where you are diving, but unless you are diving gloveless, I would pick the standard size model. And even if you are diving gloveless, I would pick the standard size model. Tiny things are easy to drop underwater.