Hammering a lid out of a copper sheet

[Fredistiller]

After I posted the picture of my still, people asked my more information about the methods of hammering copper to make the lid of a boiler/thumper.

I thought about the best way to explain the techniques and decided to make a tutorial. If you like metal work, I truly hope this will spark your interest.

I made a step by step tutorial. Step "4-hammering" has different difficulty levels to fit anyone needs and ability.
Sinking copper on wood is not that difficult, raising on an anvil adds a bit of a challenge and raising copper requires some hammer skills. Although if you follow my advice it shouldn't be impossible for a handy Harry.

English is not my mother tongue, so please tell me if I don't make myself clear.



The Material:

A copper sheet around 0.7mm (0.028") thick. A torch, a metal shear, a hole saw, a compass, 1 or 2 "rounded face" hammer (you can grind an old flat hammer), a flat hammer, an anvil or any thick flat metal surface, a thick wooden plank (cheap pinewood is okay) with a cavity of diam ~130mm & ~10mm (5.1" & 0.39") deep.

1- Drawing:

Think about a shape you like (dome, elliptic,...) and draw it on paper or computer. Keep the inside diameter of your boiler (or adjust your boiler to your lid if you plan to make both, it's easier). Just bear in mind that the deeper/higher you go, the harder it will be. Also hammering a lid shaped like a plate/flat dome (right part of the drawing) will be easierthan a sharp cone. An ellipse (left part of the drawing) will need the use of the three hammering techniques (see further). In all case I wouldn't go bigger than a diameter of 400mm/11.8" and deeper than 35-40mm (1.4-1.6") as it gets difficult to handle.


2- Tracing:

Once your drawing is done, measure the length from the centre to the outside with a wire or a rope (or with your software) and report it on the copper sheet with your compass. Mark the centre with an awl/nail. Add 10mm (0.39") and draw a second circle, that will be your ledge. Then draw many circles, like you would draw a "target". And finally, draw a line from the centre to the outside. The face with the drawings will be the inside of your lid.

3-Cutting:

With your metal shear cut first approximately at 10mm (0.39"), then precisely on outside of your future lid. Smoothen the sharp edges!

And then, congratulate yourself and take a deep breath, you are now ready for the real stuff...

[Fredistiller]

4-Hammering:

Hammering copper is very satisfying. It has something meditative, because you have to constantly focus on every movement.
Follow these tips to make sure you make this challenge a success!
Hit the hammer with the same force every time but never on the same place. Hold the elbow of your "hitting hand" tight against your ribs. Start your movement from your elbow, through a flexible wrist, to the hammer head. Relax your fingers and move your index finger out on the shaft to aim correctly. Think your hammer is an extension of your arm, as a new limb. And always, always hit the metal gently!


4.1 -Sinking:

Sinking, also known as doming, dishing or dapping, is a metalworking technique whereby flat sheet metal is formed into a non-flat object by hammering it into a concave indentation (wikipedia).


4.1A -Sinking on wood: the first step,

Put the outside of your copper disc on the cavity like in the picture.

Hit the hammer at the same spot with one hand, while the other hand is turning the disc. Using the cavity to bend the metal.

You drew a line from the centre to the outside remember? Start hammering on the line, on the outside of the disc. Think of your disc as a watch dial, you have to hit at each "minute mark". Your "target lines" will help you to stay on the right diameter. When you're back on the line you know you've done one 360° rotation. Move a bit towards the centre and repeat the process. When you reach the centre, starts from there and go towards the outside. Go easy with your hammer.

My beloved one filmed the process:



After a while, the outside of your copper disc will bend because of the tension you created.

Don't allow this folds to grow too big as they will distort your disc. Flatten them on the wood regularly.


Your disc won't stay perfectly round, don't panic. Return the "bowl" on the table, so you'll see where the "straight lines" are. Take them into your index fingers and thumbs like you would to break a twig and bend those lines.

This is what you can achieve after 2 times towards to the centre and back.

If you are happy with the results, go to step 5. But if you want to go further:

[Fredistiller]

4.1B - Sinking on anvil:


This technique uses the same basic steps as on wood. But it's slightly different as you'll not use the cavity of the wood but the tinny space you'll make between the anvil and the copper sheet and hit just on this spot.

Use your sense of touch to "feel" that the metal is bending, you are NOT crushing it. And use your ears also, the metal should make a "thud, muffled" sound, not a "clinking" sound.

Look and listen this video:




This is an example of what you can achieve after 2-3 times towards the centre and back

After a while your copper will harden and will not allow you to shape it further. Instead it will distort your lovely rounded work of art. But you can use a magical trick to smoothen that stubborn rigid piece of metal: it's time to play with fire!

[Fredistiller]

4' - Annealing: the Side step


Mr Wiki says that :"annealing is a heat treatment that alters the physical and sometimes chemical properties of a material to increase its ductility and reduce its hardness, making it more workable". I couldn't say it better.


And here is how you do it: Turns the lights out and the torch on. Caress your copper sheet with the flame all over the place from a certain distance. Enjoy the colour changing patina as it eats. At once the colour changes and the copper turns black, pay attention and keep moving, you are almost there! Just behind your moving flame, you'll see the copper turning red, cherry red to be precise. That's when the magical occurs! Keep moving your torch until your copper piece has got this red cherry colour all over. Now take a second deep breath, enjoying this moment when you turned into the great metal wizard...you have changed an unwilling piece of copper into a very soft one!



Rinse under cold water and wipe the black layer off, and go back to your hammer.

After a while, you'll notice that sinking is not efficient any more. If you are happy with the results, go to step 5. But I you want to go further:

[Fredistiller]

4.1B - Raising


Mr Wiki says: "Raising is a metalworking technique whereby sheet metal is depressed in a stump or other solid object by repeated 'courses' of hammering and annealing."


Raising is the same than sinking but... the other way around. So in practice: put the inside of your now "bowl shaped copper piece" against your raising tool (see *) where you plan a steeper curve (see step 1-drawing), use your fingers to "feel " and keep the good position (see picture) as you hit the hammer,

and turn your piece at the same time just like you did while sinking. Hit the spot just above your raising tool so your copper has to "lean forward". Again, don't crush the metal between your hammer and your tool but "force" the copper to move forward. Use your sense of touch and your ears as you did while sinking. You're looking for that "thud, muffled" sound, not a "clinking" one.



Anneal every time your feel too much resistance, and go back to the sinking technique to push back any cavity and flatten the folds like in step 4.1A

* your raising tool can be any curved, round shaped, hard surface, of 10mm to 40mm ( 0.39" to 1.6") broad. A metal wheel, the straight peen of a hammer with smoothen (grinded) sides, a curved bar, etc. I used an old machine wheel. Likely you will need to weld some bar to work higher than your bench vise.

[Fredistiller]

5- the ledge:


Once your reached the desired diameter and shape with any of the above mentioned techniques, it's time to make the ledge. This will help to achieve a nice equal diameter and create a surface for your flour sealant.


In step "2-tracing" you already mark your ledge remember? If it disappeared, trace it again but don't use your compass this time.

Lean your future lid against the side of your anvil and use your finger to keep the position where you traced the line. The 10mm (0.39") ledge stands out. Use a flat hammer with a "half pendulum" move to bend the ledge. After a complete rotation, turn 180°and flatten the ledge on the anvil.

This video should make this clearer:


If the copper is too soft like in this video, because you annealed recently, you'll need to "sink" again the inside of your lid and this time it's recommended to crush the metal to make it harder (see strain hardening). Or to anneal again for the last time if the copper is too hard and makes "straight lines" instead of following your desires.

[Fredistiller]

6- Strain hardening: Almost there...


Work hardening, also known as strain hardening, is the strengthening of a metal by plastic deformation. (thanks Mr Wiki again).

Here you don't want to push the metal any more but to crush it. This process will harden the copper and flatten all the small imperfections while giving a dawn good looking appearance at your piece of art. You can work on the inside on the anvil with your rounded hammer. Or on the outside, on your raising tool with a flat hammer.

So this time use your sense of touch to feel the copper is placed between your anvil and the hammer, and you will ear that "clinking" sound you were avoiding until now.



PS: if you want to avoid to make deep marks on the copper it's better to have anvil and hammer "polished". I like to have some little marks, it gives "an antique look".

[Fredistiller]

7-the column:


Nothing difficult here. Use an hole saw slightly smaller than your column pipe and file the hole until it fits the diameter of your pipe (or make many small holes + file if you don't have a hole saw). Use the "easy flange" technique on your pipe so you have more surface contact and weld the pipe on your lid.



8-polishing: the final touch!!


To what extent you will polish your lid is your choice. You can just wipe the copper and leave it like that, or polish it until you can see the pimples on you nose. I like an perfectly imperfect final result. I used some copper polish paste and steel wool and gave a good brush to make this candle holder.

Please ask if you have any questions, and most important: Have fun while a flat disc of copper changes shape in your hands!

[Kansas]

This is great! Thanks for taking the time to put this together. Definitely one of the best tutorials I have seen.

[stillanoob]

Thanks you so much for taking the time to do this! I had a great time building my first copper still. With your tutorial above I learned a lot and am now encouraged to make an alembic as I have been dreaming of!

[jward]

It's always impressive how skilled hands make things look easier. Well done.

[Boozewaves]

amazing work , might have to try this , thanks for taking the time to make a tutorial

[Danespirit]

Excellent tutorial..!
It will be helpful to all novice metalworkers that wish to fabricate their own equipment.

[tombombadil]

Very cool! Thank you for sharing. Now how to convince my wife that I need more hammers and an anvil...

[StillerBoy]

This is great tutorial.. Thanks for taking the time to put this together...

Those are not pieces put together by beginner's hands..

It will certainly compliment the other copper work threads that are on HD..

Mars

[The Baker]

Very cool! Thank you for sharing. Now how to convince my wife that I need more hammers and an anvil...

For an anvil a heavy piece of H section steel does most things.

Geoff

[Chauncey]

This is awesome thanks man

[arentwejusthere]

Thank you! Is this in the running for a sticky in the build forum?

[LWTCS]

Thank you! Is this in the running for a sticky in the build forum?

It has been a sticky pretty much within 2 hours of posting
Really is one of the best if not the best tutorial on the forum.

[Fredistiller]

Thanks for all the positive reactions. I'm glad if I could help the community.

[LWTCS]

Thanks for all the positive reactions. I'm glad if I could help the community.

Don't rest on your laurels for too long.
Going to ask that you build us a copper robot coming up here in the near future

[Fredistiller]

Thanks for all the positive reactions. I'm glad if I could help the community.

Don't rest on your laurels for too long.
Going to ask that you build us a copper robot coming up here in the near future

as long as you'll polish it yourself....

[LWTCS]

Thanks for all the positive reactions. I'm glad if I could help the community.

Don't rest on your laurels for too long.
Going to ask that you build us a copper robot coming up here in the near future

as long as you'll polish it yourself....

Hmm,,,,nevermind

[JC973]

Beautiful, just beautiful. One of the best tutorials I have ever seen, like most anyone that Is comfortable with their art, you make it look so easy and it makes me want to try it, but I bet all I would make is a wrinkled copper plate out of a flat one, haha

[Fredistiller]

it makes me want to try it, but I bet all I would make is a wrinkled copper plate out of a flat one, haha

Give it a try with a small piece of copper. As long as you don't want to go too deep, and that you go easy with your hammer you should be safe.

[Danespirit]

+1 Fredistiller

Also, annealing is an absolute must for a good result as copper work hardens as you progress.
Every time you deform the copper in some way it will "harden up" and get more and more difficult to work with.
Quick heating (until it gets bluish) will make it soft and malleable again. It also prevents it from tearing and ripping.
Happy hammering...

[bionut]

Great tutorial!
Since we are on this topic how can one make a alembic swan neck vapour pipe?

[SassyFrass]

Awesome tutorial. Thanks for posting this.

[The Baker]

Awesome tutorial. Thanks for posting this.

Same here.

Geoff

[Fredistiller]

Great tutorial!
Since we are on this topic how can one make a alembic swan neck vapour pipe?

Best way for a hobbyist is to take a pipe, anneal one extremity and flatten it so you can solder it tight. Fill the pipe with DRY sand making sure you compress it as good as you can. Then solder the other extremity tight. You can now anneal and bend the pipe without flattening it. The sand inside will allow the pipe to bend without "crushing" and stay round. Cut at the desired length and remove the sand.

It's very important to use very dry sand. Otherwise the moisture/water will turn to steam when annealing. This will blow your pipe open and project burning grain of sand all over the place.