Friday, April 11, 2014

Expensive espresso cup

Well this is my first blog article in quite some time. I apologize for the long interval between posts. Lately I have been focusing on my Oxtoolco YouTube channel during the last few months building it up into a pretty good spot. So far so good. its taken off and surprised the heck out of me. If you like metalworking, tools and things mechanical then check it out.

This week I got to do a really fun job at work. Fun at work for me is a relative thing. Whatever it is it needs to be challenging and new and hopefully a little bit weird. The repair job I did for a materials researcher fits the bill to a teacup.
This is what I started with. Some sheet metal bits and a two different filler wires. What were looking at is a fairly large Platinum crucible. The body is drawn from a single piece of platinum and ended up approx .030 (.75mm) thick. The circular disc that will make up the bottom is a little thicker at around a 1mm. The two coils of wire are the filler rod for welding the two together.  Our materials group has the ability to recycle the material and make it into whatever form we require. Sheet, plate, rod and wire. Huge presses and wire drawing stands are right at their fingertips for just this kind of work.
I started by plannishing (smoothing by hammering) the body to round it up and prepare it for trimming. I'm using a soft faced hammer to lightly tap the ring without stretching it. A metal hammer against the metal mandrel would stretch the material and cause warpage and thinning. All I want to do is make it nice and smooth and round for the next step fitting the bottom.

The back story on the crucible is that it had been used to melt and fuse special glass compounds for research into energy efficient windows. The compounds being melted are hot enough to cause hot shorting in the platinum and failure in the original joint. Our materials department rolled a special higher temp alloy to use for the bottom of the crucible in the hope it will work better for this hot glass melting application.
Here you can see some cracking in the edge where the old bottom failed. Some of this is from me plannishing the material on the mandrel. I will be trimming it back to the lower blue line to make a nice clean edge for the new joint.
After I got the body nice and round the ends need to be made parallel. The side on the surface plate I just used some sandpaper to get it flat around the rim. I scribed a line at the correct length using sharpie as my layout dye. The rim was trimmed with the shears you see in the right side of the image. The band I trimmed off was probably worth a few hundred dollars. Incidentally the material behaves like soft copper. Not super plastic like but definitely soft.
The next part was a little tricky. The disc was irregular and not very round even though it looks pretty good in the picture. It was only marginally bigger than it needed to be with a couple divits that needed to be avoided. I taped the copper pad onto the surface to give me a place to scribe and place the divider point. Marking the platinum disc with scribe marks and a center punch was not on the menu.
Here is the circle cut out and fitted to the body. You can see I curved the body slightly inward to meet the disc. Better to have the fit in this direction that outward at all. This allows me to fit the corner and take out the curve as I go along tacking the the body to the disc and get a perfect fitup all the way around. Perfect fitup is the key to most welding problems.
Fitted up and ready for some tacking and welding. Later on I will even out the circumference and straighten the walls of the cylinder.
All welded up. The welding went pretty well. I used plain old TIG welding and DC current straight polarity to weld it. I did use filler in the joint because I planned on removing the weld buildup so the crucible would have a nice flat bottom.Yes I collected the filings when I removed the weld. All the scraps will be remelted and rolled into some other part later on. Incidentally Platinum does not oxidize at any temperature. You could almost weld this stuff without the Argon shielding gas. Notice the weld penetration shows zero signs of oxidation from lack of shielding gas.
Here is a view inside the crucible showing the weld penetration.

Here is the completed job. I missed a trick and should have made a cup of coffee to take a few sips out of as a joke. I ended up burnishing the outside to smooth small ripples in the wall and take out some of the curve near the bottom I mentioned earlier. Total weight of the finished crucible is just short of 90 grams. At the current spot price of Platinum that is about $4000 in material in the cup alone. 

I sure had fun working on it. It filled the bill for a fun job. The guy who brought me the job said he has another job for me this time in Gold. They need some reaction vessel for some crazy thing. He asked me if I was interested in looking at the job. I'll give you three guesses what I said and the first two guesses don't count. Thanks for looking.

Tom Lipton

29 comments:

  1. really nice job. thanks for sharing.

    ReplyDelete
  2. Replies
    1. Hi John,

      Thanks for the comment. I missed a trick and should have shot a picture of me drinking coffee out of it before I gave it back to the researcher.

      cheers,

      Tom

      Delete
  3. Nice job. Why not just make a mandrel and spin it on the lathe?

    ReplyDelete
    Replies
    1. Hi David,

      Spin it to round it up or to make the cup in one piece? I was given the ring and the new alloy disc for the bottom.

      Cheers,

      Tom

      Delete
    2. I was really just thinking about truing it up once the repair was made. Might also give it a bit of shape to keep it from deforming as much.

      Delete
  4. Tom,

    That is some really fine work. I realize some things cannot make your youtube channels, but I would sure have like to watch this.

    Keith

    ReplyDelete
    Replies
    1. Hi Keith,

      Thanks for the comment. I know what you mean. Its just too awkward to do any meaningful filming at work. Besides I was having way too much fun for a few hours to think about filming.

      Cheers,

      Tom

      Delete
  5. Tom,
    You really do have the coolest job.

    ReplyDelete
  6. Tom,
    Just wanted to say thanks for your blog & Youtube which I discovered only last week.- you are teaching me new tricks all of the time. I saw your tailstock tool tray and have stopped mid project(s) (you know how it is) to make one - I may even have it finished this evening. Do you work with Brits ? I ask as I didn't think 'scrounged' & a few other great words you use were in common use in the US ?

    Thanks again

    Tony - in the UK

    ReplyDelete
    Replies
    1. Hi Tony,

      Thanks for the comment. Glad you like the show. The tailstock tray is really a handy device you will wonder how you did without it all these years. I don't currently work with Brits. Not sure where I picked up scrounged from. Its pretty common here in the US. I always like James Garner in the Great Escape. His title was scrounger for the escape effort.

      Cheers,

      Tom

      Delete
  7. Thanks for the post. I like the YouTube channel but the Blog is great for getting a more manageable size update. Plus it is easier to find the posts, the videos seem to get lost on the YouTube channel and I am always at a loss of what ones I've seen and the ones I haven't seen.

    Thank you for sharing all the info you do, it is a lot of work but it means a lot to those of us that learn from you.

    ReplyDelete
    Replies
    1. Hi Lost,

      Thanks for the nice comment. You are correct that its very difficult to index the video's for exact content. There is just so much information in them it makes finding specific things difficult. Don't worry I'm not abandoning the blog. I have just been focused on the YT channel for the last few months since it get s much more traction with the viewership.

      Cheers,

      Tom

      Delete
  8. Tom;

    This takes me back to a summer job I had for U.S. Borax's research lab many years ago. U.S. Borax is owned by Rio Tinto Zinc (one of, if not the, largest mining companies in the world) and RTZ had purchased some mining leases in the southern part of Alaska (the part that goes down alongside Canada) and had assaying teams going in an pulling samples, which were then shipped south to the research lab for analysis of the various minerals. One of the minerals we were testing for was uranium and in order to do the testing we had to dissolve the ore samples in a complex acid solution and then boil off the acid. The only material that worked for the crucibles was platinum and each crucible weighed about 2 pounds. What I remember most is after working with these crucibles for a couple of days, one of the senior scientests called all of us summer interns together and had a very short talk with us. It went something like this: "I know you all have been looking at the platinum crucibles and I can tell you one thing. NO ONE has ever gotten out of the lab with one." End of conversation.

    The videos are great and I really enjoy learning the tips and tricks that you show.

    Regards;

    Ron Kluwe

    ReplyDelete
    Replies
    1. Hi Ron,

      Thanks for sharing your cool story. I heard they had a gold hemisphere as a door stop for a lab on the Manhattan project. Let me guess the time frame for your story. How does 1958 sound?

      All the best,

      Tom

      Delete
  9. Cool project Tom thanks for sharing it. Working on the $$$ stuff can be fun and nerve wracking at the same time. At my old job there were plenty of times working on things that were really expensive. Some of the things did not have a high dollar value, but the time it would have taken to make them again was pretty much out of the question.

    ReplyDelete
    Replies
    1. Hey Bill,

      Thanks for the blog comment. Looks like we might be doing some larger versions of these coming up. Looks like fun.

      cheers,

      Tom

      Delete
  10. Okay Tom, where do you work and what stuff do they do? Your always talking about the wacky and cool stuff "at work". Kinda making me jealous with all the cool stuff you do.
    .....and you get paid for it!

    ReplyDelete
    Replies
    1. Hi Andre,

      Thanks for the comment. My daycare place is Lawrence Berkeley National Lab http://www.lbl.gov/. They let me mess around with stuff like particle accelerators and superconducting magnets. Then I come home and do some of the same kinds of stuff at home.

      Cheers,

      Tom

      Delete
  11. Tom,

    Great to see a blog post from you, for some reason I enjoy them a bit more than the videos. I think it took me a week of bedtime reading to get through all of your blogs then I started on the youtube videos.

    Thanks for sharing your knowledge and keeping us entertained.

    Brian

    ReplyDelete
  12. Hi Brian,

    Thanks for the comment. I'll try to get some more articles up.

    All the best,

    Tom

    ReplyDelete
  13. yo tom, us guys that follow your blog have been starving for posts for a long time. Keep it up brother.

    ReplyDelete
  14. Very nice made in USA tool:

    http://serra-cabo.blogspot.pt/2015/06/f023-tesoura-para-chapa.html

    Regards
    SC

    ReplyDelete
  15. Hello Tom, do you know of any way to bend a Grade 8 bolt into an open eye-bolt shape? The size is 5/16"-24 threads per inch, with a total length of about 4-1/2"s long before bended. It may require heating to accomplish. Is this something you would consider doing for about 20 bolts or more? Thanks, Mark. My cell is (419)303-4409 anytime.

    ReplyDelete
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