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  • Stop Using Ferric Chloride Etchant!  (A Better Etching Solution.)

    I haven't made PCBs in probably 30 years, but in the old days I used either ferric chloride, which was awful and permanently stained anything it touched, Sodium Persulfate, which was expensive, or Ammonium Persulfate, which was expensive AND slow. Needing a couple of small one-off boards I looked for an alternative online. There are quite a few similar instructional pages and videos out there, but this one had the clearest explanation, simplest ingredients, and the result photos looked very good. I wanted to slow down the aggressive HCl reaction on first use so I dissolved a few inches of copper wire in it and then etched all the metal off a 3/4 sq/in waste piece of board to judge the etching speed, which was about 5-7 minutes. Satisfied I etched this small board in less than ten minute...

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    I haven't made PCBs in probably 30 years, but in the old days I used either ferric chloride, which was awful and permanently stained anything it touched, Sodium Persulfate, which was expensive, or Ammonium Persulfate, which was expensive AND slow. Needing a couple of small one-off boards I looked for an alternative online. There are quite a few similar instructional pages and videos out there, but this one had the clearest explanation, simplest ingredients, and the result photos looked very good. I wanted to slow down the aggressive HCl reaction on first use so I dissolved a few inches of copper wire in it and then etched all the metal off a 3/4 sq/in waste piece of board to judge the etching speed, which was about 5-7 minutes. Satisfied I etched this small board in less than ten minutes and I'm extremely happy with the result. There is some pitting on the track surfaces, but that is an issue with the toner resist permeability, not the etchant. Although light reflection from behind in this photo makes the board look tinned already, it's not... just bare copper.

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  • 100 Lb Propane Tank Homemade Air Compressor

    Great project. Couple of suggestions...1. Draw a hard vacuum on the tank to evacuate any remaining propane. Ebay/Amazon have a plethora of affordable pumps for A/C and degassing tasks which are capable of pulling a full bar of vacuum, which should be enough to render your tank safe.2. Fille the tanks to the brim with water. This is the accepted method of purging any remaining propane before repurposing a tank.

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  • MartinG40 commented on bfoz's instructable Pressure Cooker Vacuum Chamber9 months ago
    Pressure Cooker Vacuum Chamber

    Mainly so you can see inside under vacuum. If you are degassing glue or epoxy or drywall mud you want to be able to see when the bubbles stop. Also, the safety valve in the lid is designed to hold in pressure, not vacuum. Unless you somehow sealed the safety valve you wouldn't be able to draw vacuum.

    Great project. A few suggestions...First, skip the 3/4" drill bit and use a step drill bit instead. Not only do they cut near-perfect circles, which is difficult to achieve with big standard bits, but they are easy to use in a handheld drill. Just drill a small starter hole large enough to get the first step into it, then step your way to 3/4".Second, every similar project I've seen mounts the vacuum fittings onto the acrylic top instead of into the pressure cooker. Several advantages to this... the pressure cooker is still usable for its intended purpose, the hole is not cut into a curved surface, making the seal more reliable, and acrylic is much easier to cut a big hole into than steel. Also, you can mount the brass fittings directly onto the acrylic and skip the copper tub...

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    Great project. A few suggestions...First, skip the 3/4" drill bit and use a step drill bit instead. Not only do they cut near-perfect circles, which is difficult to achieve with big standard bits, but they are easy to use in a handheld drill. Just drill a small starter hole large enough to get the first step into it, then step your way to 3/4".Second, every similar project I've seen mounts the vacuum fittings onto the acrylic top instead of into the pressure cooker. Several advantages to this... the pressure cooker is still usable for its intended purpose, the hole is not cut into a curved surface, making the seal more reliable, and acrylic is much easier to cut a big hole into than steel. Also, you can mount the brass fittings directly onto the acrylic and skip the copper tubing from the valves/gauge to the chamber.Finally, I got my vacuum pump along with an A/C manifold set. If you have one of these the set will have pressure-safe flexible hoses, with female 1/4" SAE fittings, so if you put a male SAE fitting onto your setup instead of NPT you can use the nice flexible hose from the pump to your chamber.Just suggestions, and your project is terrific.

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  • MartinG40 commented on pfred2's instructable Make an Acme Tap10 months ago
    Make an Acme Tap

    I realize this comment comes 5 years after this article was published, but I'm confused why you would call this an ACME tap? ACME threads are trapezoidal, which the threaded rod you made this from is not.

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  • MartinG40 commented on solelord's instructable Brick Barbecue10 months ago
    Brick Barbecue

    Fantastic project!!! I must point out though that a "lentil" is small legume often used in Middle-Eastern cooking, and a "lentel" is... who knows. The word you were looking for is "lintel".

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  • MartinG40 commented on tomatoskins's instructable Make a Wood Tap From a Bolt1 year ago
    Make a Wood Tap From a Bolt

    "Would a stardard [sic] tap for tapping metal work in wood? I'vs never tried it."Yes, but wood tapping is easiest using a cordless drill. Standard taps have square shanks which won't fit the drill chuck. If you don't want to make your own there's a YouTube creator (The Wood Whisperer) who's selling an excellent set of round shank wood taps... https://www.youtube.com/watch?v=QC6p5SSUSW4

    "Coat the threads you cut with 2 applications of superglue to harden them."Was just about to comment the same thing. For best results fill the initial hole with low-viscosity cyanoacrylate glue, then tap the hole when completely dry. Refill threads with glue and tap again. The resulting threads are almost as hard as metal ones.

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  • MartinG40 commented on Josehf Murchison's instructable Rebuilding Keyed Drill Chucks2 years ago
    Rebuilding Keyed Drill Chucks

    PS... forgot to mention that I have never needed to lock up the shaft using this method. If you strike the end of the Allen key sharply, the inertia of the armature, shaft, and chuck body is all the rotational resistance you need for this method to work.

    Yeah, that's what I have always done too, with reliably good success. The bigger the Allen key the better, as long as it will fit in the chuck, since you want maximum rigidity. Of course, we are talking about the traditional "L" shaped keys here. Chuck the short end into the chuck and whack the end of the long arm with a metal hammer, not a rubber mallet, since you want the shock of impact to break the thread grip. One strike is usually all it takes and if you leave the key in the chuck it is easier to spin the rest of the way off.

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  • MartinG40 commented on Aleator777's instructable Apple II Watch3 years ago
    Apple II Watch

    The best part is the AWESOME floppy disks and drives. They look EXACTLY like the real thing.

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  • MartinG40 commented on Mrballeng's instructable The Only knot you need to know. 3 years ago
    The Only knot you need to know.

    Great knot. I guess everyone has their favourite. The one I have used more often than any other in my nearly 58 years of life is the horse hitch. Supposedly used by cowboys to tie their horses to saloon rails, pulling on one (the horse) end just tightens the knots and won't give, while gently pulling the other end completely unties the knot. Cowboys could mount their horse with the long loose end in hand and release the knot "remotely".I have always used it for mooring small boats for the same reason. It is absolutely slip-proof when tugged from the "boat" end, but you can embark first and release the knot with the loose end once safely aboard. This knot often goes by other names, especially historically, such as the mooring knot (for obvious reasons), or the slipper...

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    Great knot. I guess everyone has their favourite. The one I have used more often than any other in my nearly 58 years of life is the horse hitch. Supposedly used by cowboys to tie their horses to saloon rails, pulling on one (the horse) end just tightens the knots and won't give, while gently pulling the other end completely unties the knot. Cowboys could mount their horse with the long loose end in hand and release the knot "remotely".I have always used it for mooring small boats for the same reason. It is absolutely slip-proof when tugged from the "boat" end, but you can embark first and release the knot with the loose end once safely aboard. This knot often goes by other names, especially historically, such as the mooring knot (for obvious reasons), or the slippery knot.

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  • Van Turned Dorm Room, Complete With Bed and Desk

    When I was a teen we called these "shaggin' wagons". In those days though the most popular conversion was a panel van.

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  • Solar powered air conditioning unit.

    @drzcyy - Ummm... no. For any given cooling capacity traditional A/C technology is more efficient. While you do away with the compressor pump when using peltier coolers, you still need a very large fan on the hot side for house-sized cooling (bigger than for a comparable A/C unit), and the peltier slabs themselves are notoriously inefficient. Their greatest advantage in some applications is the ability to be be converted for heating just by reversing the current direction.For instance, those few-inch square peltier blocks you find in portable drink coolers are completely outclassed by the efficiency of compact drinking fountain refrigeration modules.

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