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Thread: Cutting shape out of tube stock

  1. #16
    Join Date
    Jan 2009
    Location
    SE MI
    Posts
    87
    Making progress! My productivity took a halt as I tried to work out the best way to proceed. For such a tiny project, you'd think I'd have this done by now...

    1) Switching to a ball-nosed mill eliminated any chatter, cuts are smooth
    2) Takes 30 minutes to mill each tube
    3) For whatever reason, I was having a terrible time making perpendicular cuts in these tubes. I purchased a small miter box (Zona brand) with a narrow kerf - plus a high TPI saw. No matter what I did, I could not keep the cuts straight. Using a jewelers saw with a #0 blade (in the same guide) and the blade wandered. I ended up designing a jig using angle iron and some 3D printed parts:

    IMG_0433_resized.jpg

    After cleaning up the end of the angle iron with a file, I was able to get square enough cuts.

    Anyhow, I have to cut some discs for the top, dome them, then I can move onto soldering then polishing, lacquer.

  2. #17
    Join Date
    Jan 2009
    Location
    SE MI
    Posts
    87
    Well, dapping/doming went well, as did the soldering. I used Tix "silver" solder with a butane pastry torch.

    IMG_0450_451_combined.jpg

    So... I'm not a jeweler, but from what I've been reading heating brass brings the copper to the surface. You can kinda see it in the areas where I heated it. This was my "first" complete soldering job (did some tests though), and learned a bit how to use less flame to get the job done. I'm really happy with the solder fillet on the dome, not so happy about the interior fillet... but it should be mostly invisible once I polish and finish the interior.

    Afterwards, cleaning was a multipart process - pickle in a warm vinegar/peroxide mixture to remove surface copper, then just vinegar to remove the darkened (but cleaned) surface. A quick scrub with scotchbrite:

    IMG_0459_resized.jpg

    Still a bit to do, but my goal is to have the lacquered up on Saturday as it takes about 5 days to cure. The scotchbrite I've been using is somewhat rough, so am going to have to figure out how to get rid of the "deep" scratches before final polishing.
    Last edited by John Pariseau; 12-06-2018 at 11:07 PM.

  3. #18
    Join Date
    Feb 2008
    Location
    E TN, near Knoxville
    Posts
    6,809
    Wonderful! Those are looking good. When you get all done, I'd love to see some real close photos - do you have a good macro lens for your camera?

    I haven't tried Tix solder - sounds good from what I just read about it - is it brass-colored like the solder some use on brass?

    For removing scratches and polishing I sometimes use the MicroMesh abrasives since I have some kits. There is enough range in the abrasives to remove almost any scratches. And the finest is so fine that after working through the grades metal polish is almost redundant. I like to use it on acrylics.

    Without micromesh, I'd probably use fine wet/dry sandpaper - I keep up to 1500 grit handy at the lathe and some on the shelf that go to 8000 grit. These are almost as fine as MicroMesh but the backing is not as nice.

    You can just use a buffing wheel but I don't like what it does to moderately deep isolated scratches on brass when you look at them real close. The little hard felt wheels that fit on a Dremel might be nice to get into the tight places around your joins. I usually just use some kind of polishing paste like Simichrome on a cloth and polish by hand.

    I once used MicroMesh to restore the windshield on one of our flying club planes, a Cessna 172. It went from being so crazed that landing into the sun was dangerous to crystal clear, just like a new windshield. (took me almost a whole day - the windshield looked bigger by the hour!)

    JKJ


    Quote Originally Posted by John Pariseau View Post
    Well, dapping/doming went well, as did the soldering. I used Tix "silver" solder with a butane pastry torch.

    IMG_0450_451_combined.jpg

    So... I'm not a jeweler, but from what I've been reading heating brass brings the copper to the surface. You can kinda see it in the areas where I heated it. This was my "first" complete soldering job (did some tests though), and learned a bit how to use less flame to get the job done. I'm really happy with the solder fillet on the dome, not so happy about the interior fillet... but it should be mostly invisible once I polish and finish the interior.

    Afterwards, cleaning was a multipart process - pickle in a warm vinegar/peroxide mixture to remove surface copper, then just vinegar to remove the darkened (but cleaned) surface. A quick scrub with scotchbrite:

    IMG_0459_resized.jpg

    Still a bit to do, but my goal is to have the lacquered up on Saturday as it takes about 5 days to cure. The scotchbrite I've been using is somewhat rough, so am going to have to figure out how to get rid of the "deep" scratches before final polishing.

  4. #19
    Join Date
    Jan 2009
    Location
    SE MI
    Posts
    87
    Quote Originally Posted by John K Jordan View Post
    Wonderful! Those are looking good. When you get all done, I'd love to see some real close photos - do you have a good macro lens for your camera?

    I haven't tried Tix solder - sounds good from what I just read about it - is it brass-colored like the solder some use on brass?
    Iíve been using my cell phone, but have a nice camera and lenses (including a macro) that Iíll use for final pictures.

    As for the color of the solder - it remains silver. It melts low enough for an iron, but the brass has so much mass I had to use a torch. Iím not worried about the color - it shouldnít be visible except on close inspection, and I kind of like the contrast. I read that there may be a way to colororize it, but fortunately it doesnít effect this project.

    Thanks for the tips on finishing!

  5. #20
    Join Date
    Sep 2016
    Location
    Modesto, CA, USA
    Posts
    2,046
    I would drill a hole with a drill bit first then use the endmill to cut full depth. Machinable wax is easy to make and can be reused many times. Just use paraffin wax not soy wax and melt polyethelene sheet into it until no more will melt. I get the poly from furniture stores.
    Bill D

  6. #21
    Join Date
    Jan 2009
    Location
    SE MI
    Posts
    87
    More or less done - everything is polished (went to the local jewelry tool supply store and picked up some compound/wheels) and lacquered. Waiting five days for that to dry/cure before epoxying the statues in.

    Are they perfect? Erm, not entirely After using the "rough" compound most of the scratches came out, but there were a few "deep" ones here and there. Not enough (quantity) to warrant deep sanding (and difficult to see), but the occasional scratch makes me deeply appreciative of fine artists and their craft.

    Pictures once everything is done and packaging is ready, probably this weekend if all goes well.

    I really had a lot of fun making these... I think my next project will be little brass robots, and maybe a rocket from the leftovers.

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