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Etching glass

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  • Etching glass

    Who/where can etch accurate circles on glass? Circle sizes (diameter) would be .224, .243, .308, and maybe a couple others.

  • #2
    Use the cartridge case of matched size and and chuck it in a drill press, indicate it staight, than a dab of valve lapping compound on the glass and spot the ring on with the case turning in the chuck.

    obviously this could be done more accuratly/repeatably with machined tubes.
    Ignorance is curable through education.


    • #3
      Tolerance is??

      a quick rubber mask and a $20 spot sand blaster from Hf?
      Excuse me, I farted.


      • #4
        I agree with Dave sand blaster with masked of areas you don't want touched.I have done this it's instantanious looks good .Alistair
        Please excuse my typing as I have a form of parkinsons disease


        • #5
          If you don't mind my asking, how can these be used to any advantage in ballistics, cartridge loading or any other use? I'd sure be interested to hear any new technique or applications.
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          Thank you to our families of soldiers, many of whom have given so much more then the rest of us for the Freedom we enjoy.

          It is true, there is nothing free about freedom, don't be so quick to give it away.


          • #6

            after getting high-pressure indicators on some reloads, I made a case length block out of steel. Not like the post for circles, but.. I had a target rifle with short chamber throat, the case on some rounds would touch the rifling and cause high pressure. After adding in the block to my setup rig on my reload bench I didn't have further trouble. I hand filed it to right size after milling it close.
            A lee crimp instead of using the taper crimp will tighten the group also. It make round crimps at the end of the brass, gives starting consistent pressure regardless of case length.

            Not sure what he is doing with the glass, maybe sorting unmarked ammo/yard brass? With the berdan priming of some cheap rounds, I quit picking it up.

            I bought 1000rds of Israelie wooden bullets, People laughed at me, but I got brand new boxer primed 308 brass. It tightened it up again. You should have seen the eyes on the guys picking up brass at the range. It had a hebrew head stamp. ONE clean bullet hole at 50 yards, a pretty flower at 200..
            Excuse me, I farted.


            • #7
              Stained glass supply stores sell a hydroflouric acid-based etching cream. the Glass is covered by a resist - paint, varnish, possibly parafin wax. Test what you have on a piece of scrap. The pattern is scratched in the resist and the cream is applied for a few minutes. Very fine lines are possible. Certain photosensitive resists are available for silkscreening and printed circuit work may be compatible for glass etching. The cream is acid based but I once watched a glass worker spreading it with bare fingers and suffering no visible harm. I wouldn't try it.
              Weston Bye - Author, The Mechatronist column, Digital Machinist magazine
              ~Practitioner of the Electromechanical Arts~


              • #8
                Well, I could do it for cost. I have an etching laser.
                Depends on the tolerance as the beam is focused at 0.003" 0.005". Also depends on how opaque the line needs to be. The laser doesn't work quite as well as a sandblaster where you can keep going over the mask to vary the density.

                If you need absolute precision and crispness of line edge.. like for using an eyeloupe... then I would draw a black mask at some multiple of the finished size. Like 4x or 10x. Then take it to a photo shop and have them make a reduced print on transparent material, emulsion side down. Use that to expose a photoresist that has been applied to the glass and chemical etch as in circuit boards.

                Or get a piece of artists frisket. Apply it to the glass. Use a compass with a sharp blade to cut the circles and use the chemical etching cream from the art store. You have to make sure the edge is burnished down well as it can creep under. It makes a very even etch, and can be reapplied to deepen the etch.



                • #9
                  The cream is acid based but I once watched a glass worker spreading it with bare fingers and suffering no visible harm. I wouldn't try it.
                  Don't even think of it. Hydroflouric Acid is a very bad actor. Contact with skin causes no immediate symptoms but it is easily absorbed through the skin. Nothing will be apparent until the next day or two. It works very slowly but will cause deep internal acid burns that often require amputation and can even cause death just by getting some on your hands.

                  Once the acid is in the body there are few treatment options. The only one that is effective must used early and is also risky. It involves upsetting the acid base balance to try and neutralize the HF Acid.
                  Free software for calculating bolt circles and similar: Click Here


                  • #10
                    Evan you can be so depressing at times.

                    Seriously, what else is this hydoflouric acid contained in? Want to make sure to give it a wide berth!!
                    Lynn (Huntsville, AL)


                    • #11
                      Seriously, what else is this hydoflouric acid contained in?
                      Nothing much else at the consumer level to worry about. It's used in the semiconductor industry to etch silicon and there may be other uses.

                      Here is some scary info:

                      United States

                      More than 1000 cases of HF exposure are reported annually. Actual incidence rate is unknown.

                      HF acid burns are a unique clinical entity. Dilute solutions deeply penetrate before dissociating, thus causing delayed injury and symptoms. Burns to the fingers and nail beds may leave the overlying nails intact, and pain may be severe with little surface abnormality.
                      Severe burns occur after exposure of concentrated (ie, 50% or stronger solution) HF acid to 1% or more body surface area (BSA), exposure to HF acid of any concentration to 5% or more BSA, or inhalation of HF acid fumes from a 60% or stronger solution. The vast majority of cases involve only small areas of exposure, usually on the digits.

                      • Local effects include tissue destruction and necrosis. Burns may involve underlying bone.
                      • Systemic fluoride ion poisoning from severe burns may be associated with hypocalcemia, hyperkalemia, hypomagnesemia, and sudden death.
                      • Deaths have been reported from concentrated acid burns to as little as 2.5% BSA.

                      Free software for calculating bolt circles and similar: Click Here


                      • #12
                        OK, here's the need:

                        In my shooting sport, a "plug" is used to score targets. The big flaw in using a plug is the paper tears, and can also be influenced by the condition of the backer (cardboard, or coroplast) and how shot up it is.

                        So there has been some talk of a reticle device, that is a magnifier and has different caliber circles etched on it. One would flatten out the paper, then align the circle on the punched hole.

                        The circle would have to be accurate to size, and relatively small and fine.


                        • #13
                          Viton O rings. at elevated temps they release hydrofluoric acid - this is a hazard with fires around mechanical stuff, IE engines. guys use O rings sometimes in steam engines, scares me away, because how the heck do you know if that O ring you pull out of a drawer is viton or not? (I know every super heated steam probably isn't hot enough, but who wants to chance it).

                          Its common use as a silicon enchant is interesting, I did some googling and found this from some U of Texas lab. while it is definitely nasty, the control point seems to be exposure time, although god knows what someone was doing using it without gloves. this refers to 49% concentration as per link at the end. something i plan on staying away from.

                          HYDROFLUORIC ACID

                          We use a 10% hydrofluoric (HF) acid mixture for etching SiO2. HF is EXTREMELY DANGEROUS, and we use it ONLY IN THE HF ETCHING HOOD. AT NO TIME IS ANY OTHER PROCESSING TO BE DONE IN THIS HOOD. One major problem with HF is the fact that it does not hurt immediately after exposure. When it does begin to hurt a few hours after exposure, it is too late. It will slowly eat through tissue over the course of several days, until it reaches bone, where it is neutralized by calcium. It is excruciatingly painful.

                          Although an HF burn is very serious, it is also very easy to prevent. Only when the acid is left in contact with the skin for an extended period is it dangerous. Our procedure is very simple: always wear the green gloves when working at the HF etch station, and rinse them with water frequently. When you finish, rinse thoroughly, and finally rinse your hands and arms. The etch station itself is designed to minimize the chance of exposure, but always be VERY CAREFUL. I have never seen a serious HF accident, but this is only because all the labs I have worked in treat it with healthy paranoia. Please do not break my record.
                          in Toronto Ontario - where are you?


                          • #14
                            HYDROFLUORIC ACID

                            I bought a 3oz. bottle of the etching cream. Have not had the opportunity to use it yet. There is no list of ingredients or strongly worded warning on the bottle about skin contact, although the poision control telephone number is on the bottle and references to hydroflouric acid-like symptoms and antidotes. (I don't have the bottle in front of me now)

                            The yo-yo that I saw spreading the etching cream with his fingers has been doing this type of work for years and his fingers appeared to be intact and not gnarled stumps. I make no judgement about his mental condition. I suspect that the etching cream is considerably diluted.

                            Nevertheless, I plan on taking precautions, especially in light of Evan's wonderfully distressing post of information on the subject.
                            Weston Bye - Author, The Mechatronist column, Digital Machinist magazine
                            ~Practitioner of the Electromechanical Arts~


                            • #15
                              That's some nasty acid in higher concentrates. I would imagine the hobby cream is probably 5% or less. It's used in food processing and putting the frost inside light bulbs. It's also used in some plating and metal treatment compounds. If you want to stay away from it, quit eating cereal and bread.