Posts by Linghunt

    3 D printing is really kool, How is it for strength? I assume it is less than a typical piece of ABS Plastic. Assume you are using ABS.


    Just thinking, but sound run a test of a 3-d Part compared to a ABS Part made in conventional way. Something like a Tensile Test.


    Tensile test and Stress-Strain Diagram [SubsTech].


    I don't understand the T-slot and Mounting. Might be something trick you do there. Maybe a bolt to add friction from below.


    Would you 3-D print the threads, or cut them afterwards with a tap?


    I have a small Plastic Injection Machine, got a good deal on it, and couldn't pass it up. Still looking for something to make with it.

    Looks Good, Are you going to plastic inject this part?


    It might make the mold a little more complicated, but a couple of O-ring groove on the inside of the big ring to take compression and snug up the part from rotating. I understand the need to want for a hinge.


    The bolts are more work to remove, but stronger in the end I would think. You might be able to beef up the hinge for strength. If you are going with the hinge, get rid of the bolts on the other side, perhaps some type 1/4 Turn Cam and use a Quick acting Thread.


    These take a surprising amount of thrust. you could thread the plastic and then put on of these in there.


    Item No: QA-3 [Quick-Acting Threaded Insert]


    Anyway, just some ideas out of the box... -John

    CLEANING with Steel wool In CARNAC comments: That references the many customers, I have had that requested a NON anodized Pole spears and they just wanted to clean up the dings and scratches with some 0000 Steel wool.


    That's what they want, that is what I made. Called custom, made your way. -John

    When I asked Carnac permission to Post his work I got this comment from him. Carnac is not a Diver like us, but he does know material Science... Carnac wanted me to make sure you all knew some other items when he realized I wanted to Post to SpearDiver.


    CARNAC Says


    " John,


    Feel free to post provided you put my response in the proper context. Namely, the comments about saltwater corrosion are off the top of my head and not a well researched answer. For example, calling an anodized coating porous is a relative term encompassing things like pinholes and the manufacturing process. See for example the comments on "barrier anodization" here Yahoo! Groups or 7075 Al here Pin hole corrosion in 7075 Aluminum I've got anodized products laying around that don't even stop a volt meter reading the underlying aluminum, so there's definitely a difference in the galvanic protection of the different processes. Any weak spots in the coating will simply fall back on the protection of the natural oxidation process.


    This also brings to mind a comment I heard a few weeks ago that the carbon fiber/Al honeycomb construction used in the America's cup yachts will quickly fail from galvanic corrosion if seawater gets into the honeycomb. This might be something to watch if aluminum tips are put on carbon fiber shafts.


    The comments on tight binding oxides providing corrosion protection are pretty standard, and one can look up sources for that, but I can't give a source for Ni being a good glue layer. That's a model I came up with during work on protection of PVD metal films that were failing due to atmospheric sulfur leaking through holes in a thick protective overcoat and splitting the metal from the substrate by attacking the bond with the underlying substrate. Adding a thin metal layer (a few atoms thick) of the right type under the metal layer had a dramatic effect on the protection and also changed the growth of the metal layer making the crystal size much smaller which showed up in measurements of the metal conductivity. This also fit very nicely with later work done on surface roughness which showed a sharp maximum when the metal layer was deposited on top of a metal whose work function matched the deposited metal. Changing the work function of the glue layer to either higher or lower than the deposited metal produced smoother films with smaller crystal size. The theory being that the deposited metal atoms would hit and stick due to oxidation from the glue metal which prevented lateral movement on the surface leading to island growth and large crystals. Presumably a low work function metal like Mg would also work as a glue in that sense, but data from other metals suggest it would actually make the joint easier to attack because the top layer gets more electrons which are then gobbled up by oxygen. The role of MgO or MgF2 min preventing that issue muddles things. I suppose one could look at the corrosion of the superplastic Al alloys containing Mg to get some sense of that issue.


    Another thought popped to mind when you mentioned cleaning Al with fine steel wool. I would have thought one would want a thick, clear anodized layer there for the same abrasion resistance in cookware, but more importantly, that steel wool leaves a surface contaminated with iron. That type of surface contamination from tools is one of the arguments I've heard for needing to passivate SS. Have you seen the current citric acid passivation products? Stellar Solutions - Citric Acid Passivation I went looking for a paper the other day (unsuccessfully) that compared the pitting from both citric acid and nitric acid passivation. The nitric acid surface looked much more etched which I suspect is generally a bad thing. The reviews seem to be swinging to citric acid passivation which is something to consider if your audience is cleaning their stainless with steel wool. The stuff can be found at places like the rust store The Rust Store - Solutions for All Rust Problems "

    CARNAC SAYS


    "John,


    I'll give my two cents on anodizing and corrosion.


    1. Anodizing provides a very thick saphire (Al2O3) layer that provides abrasion resistance. I doubt it really does much for corrosion enhancement in low wear applications as it's a porous layer. Just ask the makers of wear resistant cookware why they anodize. It makes things easy to clean and allows cleaning/cooking with things not made of soft plastic.


    2. Corrosion resistance is a fairly complicated thing. As described in the link, it would sound like SS is corrosion proof because of the Cr2O3 passivation layer. But put it in a marine environment without oxygen, such as under a bolt or encased in epoxy, and it will corrode just fine. The passivation layer makes things corrosion resistant, not corrosion proof. They key for passivating layers to work is that there is oxygen around to keep corroding any freshly exposed layer, and that the oxidized molecule is smaller than the metal molecule it replaces so it doesn't flake off. The small molecule is why both Cr and Al can form passivating oxide layers while large Fe oxides will flake away.


    The second half of passivation requires oxidation in the chemical sense meaning the oxidizing atom steals electrons from the metal atom. In that sense, turning Ca into CaO or CaF2 is an oxidation reaction in both cases. This broader type of oxidation reaction provides both another avenue for protection and an avenue for attack. To prevent flaking of a thin film layer, one can pre-oxidize the bottom of the layer with an adhesion layer. For example, Ni has a high work function which allows it to steal electrons (ie oxidize) other metal atoms which makes it a good candidate for a glue layer for metals. Once it steals the electrons, that top layer is both electrostatically bonded to it giving good adhesion and it makes the other metal inert to further oxidation, so if one tries to attack the boundary with oxygen, oxygen has to steal electrons from nickel which is both hard and makes a fairly small oxide. The point of this being that protection of the grain boundaries from attack by things like chlorine and sulfur is also a key part of corrosion prevention. I suspect an anodization layer will help here because it may be that one doesn't clean all the microscopic crevices of things like salt. Anodizing might help here by protecting the underlying metal grain boundaries from full exposure to all the nasty stuff in sea water.


    I'm not readily seeing anything that says anodizing greatly improves aluminum corrosion resistance in sea water, but I'm also not seeing much talking about repeated dip then dry cycles. This review article does say that salt facilitates the galvanic corrosion of aluminum structures near the ocean, so one does need to be a little careful if the spear has parts made from other metals http://www.sheetpileeurope.com…s)/aluminum_corrosion.pdf


    By the way, the superhydrophilic coating people advertise marine protection against corrosion because their coating keeps water away from the surface. I know they advertise marine paint for hulls, but I've yet to find any place selling it, nor can I think of anyone providing a durable coating. "

    Wood Guy, Very good.


    I kind of Cheated on this Question / Thread: I wanted to get a thread going for all to read and get an idea on some of the material issues we have with Spear guns, Pole spears and the such.


    Material science is a big part of what we do and design around.


    The Anodizing questions was a "Starting point". There is also different types of Anodizing to consider.


    I got a good friend that is a great resource on Technical issues of all sorts. I'm an Electrical Engineer and my other Buddy a Mechanical Engineer (JoeP) call him our own " Carnac the Magnificent" . Our term of endearment for him.


    Anyway Carnac commented on this topic for this forum. Next Post: Comments and dialog welcome. -John

    I thought this might be a good thread.


    I've seen divers and manufacturers take both sides of this issue. Spotted one Pole Spear Manufacturer in Florida that had a write up to why it is NOT needed.


    His poles spears are expensive and are NOT anodized.


    From a non Technical perspective, if it is not need for corrosion protection and just a trick way to add color, why are there so many anodizers across the world.? Why are there clear coat anodizing processes.


    I think it is an add advantage for reduced corrosion possibilities, what say you? -John

    Welcome to Spear Diver....


    Your in MN, That's cool , My mom's family is from the Stillwater area.


    What are your "Fish and Feather" (game and fish) laws for Shooting Pike up there?


    I've been hit up to make custom tips for shooting those guys from divers in Montana and also our friends Over the Northern border.


    Montana looked pretty open in some areas. It sounds like a good vacation to shoot some Pike and maybe an Elk in Montana.


    Anyway options for getting wet and bringing home some grub for the family.


    -John ( Linghunt )

    Dan, As we talked about this in offline dialog, It sure does seem that the jardon of "16mm threading" on various Dive gear sites is misleading and confusing.


    History:


    I made a batch of a couple 100, 16mm - 1 - Adapters for an Australian Dive store, in the mean time as the slow boat traveled to the "Land Down Under". I sent some to Dan to sample and we combined efforts to try to determine what the hell was wrong with these not fitting into a Muzzles calling for "16mm threading"


    The Parts made it and were tested to fit Gun muzzles with a true 16mm-1 thread spec.


    The Beuchat Muzzle, I bought with this product description "16mm threading" was measured to be 14mm-1 by me with gauges in hand.


    Why would a manufacturer produce a 14mm-1 thread hole and a callout of "16mm threading".


    This Term is wide spread..... Thanks again, Dan for your time and help on this.



    For those of you wanting to go deeper into Metric threads and Classes, Here is a good Web link.


    METRIC THREAD -- EXTENDED THREAD SIZE RANGE

    Hey Everyone, My name is John and I am the owner/builder of KOAH spearguns. First off let me say I really like the forum, seems to have more contribution with minimal drama. Sad to say I didn't know it existed until George pointed it out to me, and I would like to contribute with fish posts, gun builds, sponsorship and whatever else I can if that works for everyone else.
    Now as for the guns, to make a long story short, I never really intended to sell spearguns years ago. I own a dive/spearfishing charter and I constantly experimented with gun builds for years and when I finally got one the way that I wanted it, I used it for some time. Well, one person on a charter would use it and would ask me to build him one and over time another and so on. Eventually I gave it a website, went to a few expos and sold a few. I will be the first to admit the first series were not pretty, and over time they evolved in shape, performance,ballasting, coatings ext. to the gun they are today. But two things all series of Koah guns accomplished was tracking and accuracy. They look better today and I do recess the wood for the length of the handle mainly to utilize the auto-return on Josh's mechs while keeping a thinner profile (pic). I also like how the lines run with the gun on a side profile.I started doing this 60-70 guns ago, but I have to admit I really like some of the DIY uhmw handles posted on this thread. My only question is how do they work on a standard rear handle where the mech sits above the handle and a push rod isn't used, while keeping the integrity of the handle strength? I just need to know if the mech is cut into the handle or are they strictly built for remote trigger applications.


    The good news is only one handle out of many guns has come close to sheering off and this was due to the user shooting a grouper with three bands at a range of about 3 feet in a hole, with nothing but rock behind the grouper. I did use #8 screws for some time in both 3/4 and 1in, but as of late I have moved to #10 1in, with both alexander and neptonics handles. As for linghunts gun, it was before i did any countersinking and it is regrettable. I would be happy to rout out and countersink the handle (either style seeing as its not an auto-return mech) while upgrading the screws if he can get the gun in my hands for no charge. As for the saftey, Josh has refined his euro style saftey and I think he has it looking pretty good. I plan on offering it as an option starting with the next mech order, which will be in a couple months. I'm open to any questions/opinions and I look forward to putting fish reports ext. on the board.


    John , (Gruper reeper), I so meant to get back with you sooner and Started to Just send an Email , But thought I better to add to Forum Dialog. I can drop the Gun in the Mill and Add reess for Handle, It would be easier than Boxing the Gun up and Worries of it in Travels.


    The Recess is still the way to go, but I am still as concerned as before. The failure of these screws has to be more than what is seen. I'm getting my head above water for work load so I will take a look at it again.


    You made me one NICE Gun, I have some picky ass folks out here and all liked the quality of that Gun. I moded it for Safety. ( We were throught that already) and the recess, I might go bigger screws in 18-8 or something else,


    You buy be a Beer, or give me and guest VIP on your Boat charter, we can call it even. -John (Linghunt)


    Calculations to come as promised.

    Andrew, good idea, I should go through my stuff and see what I do not use. Only thing I got you might want are stringers.


    Dan has some as well (you might want to contact him), he thinks my welding was a little rough, I have to agree. I never was a good welder for cosmetics, but doing it every 2-3 years doen't help. If you want a different size stringer or something I can bend it up as needed, 3/16", 1/4", 5/16" 316L stainless rod. I have a couple different rod benders in my shop. I'm going to sub out welding to a long term friend who retired, side work will help him on limited SS checks.


    I do offer Spearboard Discounts....


    I didn't see Polespear on your wish list. I finally got my new design done. It turned out pretty good. Shipping out a few poles tomorrow to folks waiting for over a year.


    Feels like Christmas, so I don't have to come up with reasons why I'm behind. Dog ate my notes didn't work so well in time... lol


    Dan, how about a spring cleaning Gear swap Category, might be a good idea.


    -Linghunt -John

    If the material is 316L or 304 SS testing not required, I would think.


    But is it really 316L, 304, 303.


    The Salt water spray is better method vs submersion. Raising the Temp should help with corrosion test I would think.


    I will poke around and see if I come up with anything. 316L is rated the best for saltwater corrosion.

    Seems to work with Ling cod here on the Northern Coast of California. Remembering years ago out scuba diving it seems the first one down to the achor would get a Ling, (the knock of anchor on the bottom was the thought) not always but seemed to be a trend line. I've had them swimming away from me and I would tap my spear into a rock, and it would turn them around.


    Was planning a tapiing noise maker for a while, most laughed at me and thought I was crazy.


    Had a torsional spring, that you would wind up like an alarm clock. Looked like it would have worked. Needed a longer dwell in it as I recall. Bringing back memories...


    I remember the laughing the most. :laughing:


    Prey Fish maybe, non- prey. probably not.


    that's my 2 Cents

    Welcome, you got some nice water to dive.


    You will need to post some pictures of the area to make the rest of us jealous.

    That is one disadvantage. But the alternative is unacceptable, it simply doesn't hold well.


    Got it, I had to think a little as we are talking a Single flopper close to the tip.


    If it was a double flopper close to the tip, "the Spinning off" factor would be reduced.


    If the floppers were longer, then it would reduce spin off as well.


    if there were 3 floppers then it would reduce it farther.


    (all floppers reference to the same point on spear shaft.)


    -John

    How big of a fish we talking? 3 oz to 1 lb, 1 lb to 5 lb. 5-10 etc.


    What if you have a back stop (ROCK) that is close or shooting into a hole.


    If the flopper is to far back then it will not make it thru the target?