To anneal, or not to anneal ?

[figworthy]

I'm about to start my first loco kit build (in 4mm), and having read the instructions before I started, it says that the boiler etch should be annealed before rolling, which it suggests can be done using a socket bar.  As I've got a set of the GW models rolling bars, do I need to anneal ?.  The etch is 15 thou brass.

 

If the considered opinion is that I do, what is a suitable tool for doing it.  I've seen suggestions for putting it on a gas hob (which I don't have), or in a frying pan (which I suspect is unlikely to improve the flavour of my snorkers).  I'm assuming some form of small gas torch, perhaps the sort of things that cooks use ?.

 

Thanks

Adrian

[Brassey]

I have successfully rolled a number of boilers, both kit and scratch, with my GW roller bars without annealing.  I followed the practice of Geoff Holt as per his series of books on loco construction published by Wild Swan.

[Theakerr]

In theory Yes, otherwise there is a risk that you may get small surface tears, especially if you have to roll it to a small diameter and do a complete tube. Also, by annealing it should be easier to get a true round profile although the use of rolling bars instead of a Heath Robinson set-up will help.   However at 15 thou I suspect you will be OK.  Do you have enough of the etch that you can do a test roll?

[figworthy]

47 minutes ago, Theakerr said:

In theory Yes, otherwise there is a risk that you may get small surface tears, especially if you have to roll it to a small diameter and do a complete tube. Also, by annealing it should be easier to get a true round profile although the use of rolling bars instead of a Heath Robinson set-up will help.   However at 15 thou I suspect you will be OK.  Do you have enough of the etch that you can do a test roll?

 

Thanks.

 

Unfortunately, there will be very little fret left over for me to use for testing, which is a major reason for asking.

 

6 hours ago, Brassey said:

I have successfully rolled a number of boilers, both kit and scratch, with my GW roller bars without annealing.  I followed the practice of Geoff Holt as per his series of books on loco construction published by Wild Swan.

 

Thanks.  Sounds like I might need to add to my library.

 

Adrian

[Brassey]

Does the boiler have etched boiler bands? If so you should protect them with some paper from being squashed when rolling 

[figworthy]

10 hours ago, Brassey said:

Does the boiler have etched boiler bands? If so you should protect them with some paper from being squashed when rolling 

It doesn't, but thanks for the tip.  It might come in useful for future models.

 

Adrian

[Simon Moore]

I never anneal a boiler or smokebox wrapper when it goes through the GW roller. Utterly pointless as the roller works its magic so its pointless weakening the metal when it does the job so well.

[Jol Wilkinson]

Brass generally doesn't usually need annealing, However it does work harden if repeatedly worked so is then worth annealing. .012" brass the norm for 4mm kits so it might be worth annealing your .015" if the boiler diameter is small and needs several passes to get it to the right size.

 

.015" N/S on the other hand does benefit from annealing for rolling, even in a GW rolling mill. Having rolled some test etches in .015" N/S it definitely helps.

Edited April 4, 2021 by Jol Wilkinson
Additional text

[Shed Driver]

I would never recommend annealing brass for a boiler.  It makes it far to soft and creases very easily.  It may be harder to roll a hard brass boiler but you will get a far better result.  Also if you try heating a large boiler sized sheet with a small flame it will buckle.  The temperature for annealing brass is about 370 degrees C , Does a frying pan get that hot.

 

Norman Blackburn

NB Models

[michl080]

I don't anneal my boilers before rolling, but I recommend to roll them packed between two layers of cardboard. The rollers should grab the cardboard first, the metal should follow some 10mm behind. This helps to avoid flat zones at the first 10mm of the rolling.

 

Michael

[drgj]

I have a thread on building a Comet Stove R going at the moment. The tumble homes on the sides had been formed at an angle and annealing did help to make the job of fixing this easier.

 

i too wouldn't recommend annealing unused material.

 

Dave