How to roll photoetch into a circle?

[Hobbes]

I've got some photoetch that needs to be rolled into a circle. It's the mesh that forms the interstage:




I've been using a PVC rod as a dowel, and I've gotten the PE into a half-circle, but progress seems to stop there. Any tips on getting the PE to bend further, so I can install it without it being under too much tension?

[TomZ]

Use smaller diameter rod?

TomZ

[NARSES2]

I assume you've annealed it mate ? Even so it can sometimes work harden so might be worth annealing it again ?

Would it be possible to cut the mesh in half, roll 2 semi circles and then fit and glue them ?

[Old Wombat]

Very carefully!

On a more helpful note: You may find that simply sliding a curved rod (metal/plastic wood) backwards & forwards over the "inside" will get it to slowly curve into shape. It won't be fast but it may at least start the process.

[Hobbes]

I didn't anneal it (shows you how often I use PE). That helped, now to convert the rough oval I have now into a nice circle...

[PR19_Kit]

How DO you anneal PE stuff anyway?

I bet it's totally different to annealing ferrous metals.

[Hobbes]

I used one of the burners on my stove. Low flame, heat until the PE changes color. Then let it cool slowly.
One Youtube video showed using a blowtorch, but that quickly blew holes in fine PE mesh.

[PR19_Kit]

Thanks Harro, I'll note it. 

[NARSES2]

How DO you anneal PE stuff anyway?

I bet it's totally different to annealing ferrous metals.

Yes and no Kit. With copper, brass and other non ferrous material you can quench in water after heating it until it changes colour. Ferrous you have to let it cool naturally as you know. I tend to let brass etch cool naturally from habit.

The problem now is so much brass comes pre-painted which is great as long as you haven't got to bend it. then there's all these steel seatbelts that are appearing. Although I'm told they are so thin that they shape easily anyway. Haven't tried them yet myself.

[PR19_Kit]

Yes and no Kit. With copper, brass and other non ferrous material you can quench in water after heating it until it changes colour. Ferrous you have to let it cool naturally as you know. I tend to let brass etch cool naturally from habit.

So letting it cool down on its own doesn't harden it, like ferrous metals do when you quench them?

CAN you even harden brass, copper etc. by heat treatment?

[Hobbes]

From what I've read, brass can only be work-hardened.

[NARSES2]

From what I've read, brass can only be work-hardened.

Absolutely. Copper will work harden to an extent as well, which is why if doing a lot of bending and shaping of etch it's worth re-annealing.

So letting it cool down on its own doesn't harden it, like ferrous metals do when you quench them?

Nope, which is why we have a Bronze Age and not a Copper one. Bronze can be given an edge which it will keep for a while because it is a fair bit harder to start with, but copper ? Not really

I used to enjoy quenching and tempering steel in metal work at school. That and panel beating copper and aluminium to make bowls etc was one of the few things in that class I was reasonably good at.

Ferrous and non-ferrous metals tend to behave completely differently, although I'm not sure about some of the more exotic ones. Titanium, tungsten etc. We didn't cover that on my "Metallurgy for non metallurgy graduates" course all them years ago 

[PR19_Kit]

Ferrous and non-ferrous metals tend to behave completely differently, although I'm not sure about some of the more exotic ones. Titanium, tungsten etc. We didn't cover that on my "Metallurgy for non metallurgy graduates" course all them years ago 

And don't even THINK about heat treating Unobtanium!!! 

[Rheged]

Ferrous and non-ferrous metals tend to behave completely differently, although I'm not sure about some of the more exotic ones. Titanium, tungsten etc. We didn't cover that on my "Metallurgy for non metallurgy graduates" course all them years ago 

And don't even THINK about heat treating Unobtanium!!! 

Access to an active volcano is vital........actually, THE RING in Lord of the Rings may well have been forged from an unobtainium billet.

[jcf]

Annealing of copper and its alloys, silver and its alloys etc., can cause problems
if not done properly. Gentle heating and then letting it cool slowly is fine for thin
sheet and small gauge wire. However, with thicker materials if you accidentally
overheat it and allow it to slowly air cool, the metal reforms into larger crystals
internally, with very negative results in terms of workability/strength. The metal
looks the same on the outside unless etched with a mild acid solution which
reveals the enlarged crystal structure, it can look quite lovely and is useful for
purely decorative, non-structural, additions to jewelry and sculpture, however if
you're unaware of what's happened and go to form it via hammering, stretching,
raising, bending etc., the weakness becomes very apparent.