Saturday, July 6, 2013

Copper Kettle

A while back my friend Nate asked if I would be interested in making a sort of copper kettle for him.  He is into the whole slow pour drip coffee scene so he was looking for something to boil water in that would be able to pour a nice gentle trickle of water onto the grounds.  I thought about it for a while, said hey why not, and just kinda dived in head first.  Here's the finished piece, process pics after the jump.



Besides the pieces holding the handle on, everything on this kettle started as flat copper sheet.  The body, top and spout are 18 gauge, the bottom piece is 20 ga.  

Here's the piece cut out for the main body.  This shape, when curved around so the ends meet, will give me a tapered cylinder about 6 inches high.  The plan was for 6 inches diameter at the bottom, about 5 at the top.  Over all length of this piece was about 22 inches, so I had to buy a fairly sizable piece of copper to start with.  


Here I've filed a 1/4 inch bevel onto the edge so that the edges will lap over each other, instead of just butting together.  I then cut a series of slits into the bevel, and bend them either up or down, with matching cuts on the the other end of the copper.  This process is called cramping and helps hold the joint together as you are soldering it.  It also looks pretty cool and is a mark of a quality handmade piece.




Everything gets wired together so it doesn't come apart when I attempt to solder it.


This is what it looked like after my first attempt to solder.  The colors come from the copper oxidizing and occluding and interacting with the flux.  So at this point the seam is only tacked in a couple of places because I couldn't get the solder to flow nicely.  It would take a large amount of trial and error (mostly error) to get this seam to be perfect.  Unlike everything I've been doing recently, this had to be completely watertight, and I probably had to reflow the solder 5 or 6 times before I got it.  It definitely isn't beautiful, but it's functional and I'm happy with that. 

At this point I get to start working the form of the body.  I had a rough drawing and idea of where I wanted it to go, but for me this is a very open-ended process where I work the metal till the form looks and feels right.  It took a couple of rounds of raising and hammering to bring the neck into where I wanted it.




Now I round out the hard angles from raising on a stake with a curve that matches what I want.  Oh wait I don't have one of those.  What I do have is a random 1 inch section of train track.  Time to get the grinder out and put a face on it I can work with.



 This piece will let me get inside the copper body and give me something to hammer over.  

Here it is in my stake holder, into which it fit perfectly and very securely, no issues hammering on this.  Also it is double sided, allowing me the grind two different curves into the head for working different profiles.  I ended up using this for a ton of different parts, it was a real lifesaver.



Now I smooth the angles out into nice soft curves and also planish the entire surface of the kettle body.  That means every square inch is covered with tiny little hammer marks.  This is going to regulate the form and relieve tensions within the metal.  It is done with a planishing hammer with a slightly domem face.  Next I will repeat that process with the other side of the hammer, which has a flat highly polished face that will really smooth out most of the lumps, bumps, and irregularities in the metal.  



And here is the whole surface worked over.  This is as far as I am going to take the surface treatment, I want to leave these hammer marks and small amount of character in the surface.  This stage could be repeated until this surface is actually perfect, then filed, scotchstoned and polished to a completely smooth, uniform surface but thats not what I'm looking for.



Next is the spout, here's the flat form cut out and ready to be shaped.


I slowly bring the sides together and get everything to meet.  Then I'll wire it up and get the thing soldered.


At this point I realized that I didn't have any stake or mandrel to planish or regulate the form on, so I did what I could and just left it there.  In the future I'll have to get some little stakes that are used for working spiculums and other narrow tube shapes like this.

After this I cut out the piece that would be soldered onto the bottom of the body and bent the edges around it.  This let me push the form into the bottom of the body instead of trying the cramp or butt the pieces together.  After a lot of fusing I was able to get them to fit pretty well.  Alas, when I went to solder the joint everything kept moving on me.  I decided that I could rivet the base in place, and that would hold it real well while I soldered it.  




This was another seam I ended up having to go back and solder over and over again to get everything water tight.  Just another technique to practice and get better at I guess.

After the base the spout got soldered on, I domed a small circle of copper and gave it a lip on the concave side which would be my top.  I scrounged up a couple of pieces of rosewood to act as the handles, and got those carved and finished.  I then forged out two pieces of 6 gauge copper wire to hold the handle, and got those riveted to the body.  Before I attached the wood pieces for good everything got pickled, cleaned, and I gave the copper a wash with a liver of sulphur solution to give it a nice light patina.  Finally the wood pieces are fitted and riveted in place.

I had a lot fo fun making this piece and learned an awful lot of large constructed work while doing it.  It took a long time, probably around 30-50 hours, but a large part of that was the back tracking and redoing failed joints and such.  I would do this differently next time, but I was very happy with this as a prototype.  









1 comment:

  1. I am VERY impressed!!! Great job. No kidding; no negative comments. Making mistakes is part of the learning curve...IF you learn from them. Keep up the good work!

    Regards,
    John Cogswell

    ReplyDelete