Casting Lead Sheet

Had a really interesting day this week: a few of us from the church were invited to the yard of our contractors (Norman & Underwood in Leicester) who are doing a lot of stone repairs/replacements on the church (thanks to our HLF grant).

Apart from seeing the stonemasons at work on our stone, and having a go ourselves (see right - with one of our finished stones in front), we also saw lead sheet being cast (even though they are not doing our roof as it's not lead). This casting is done largely in the traditional manner on sand and N&U say that they are the only people in the country who still do it in this way; they can re-cast the lead from a particular roof and so send back essentially the same material as was removed from the roof, which pleases the heritage-minded.

The casting process is called a "throw", although that seems an odd word for such a carefully done process.  It requires a sand bed to be prepared, about 6m x 1.4m, which has to be done from scratch for each casting, obviously with great skill to get it perfectly smooth and level. This photo shows them aerating the bed first.  There is a wheel on a track on either side of the bed which helps as they run various wooden tools along it as part of the smoothing process, which is then followed by a final go by hand with upturned copper trays about a foot square.

 

The furnace at one end is lifted up and tilted to produce a river of molten lead (right) which goes into a trough and then they wait for the temperature to come down slightly to the desired figure (330 deg C, we saw). 

Then it is released and flows along the sand (too fast for me to take a picture!), and the two workers take the wooden tool sitting on the wheels along the bed at the right speed, with a bow wave in front (photo left), any surplus lead going off the end into an old bucket on wheels. Done!

Edit: I was also given a DVD by the company, which I watched last night (it was a bad night on TV).  I learned that the said wooden item is called a strickler, and to my surprise the verb "strickle" is in my dictionary.  It means (in general terms) exactly what the two men were doing with it!

The thickness of the sheet is controlled only by the speed at which the workers move along the molten lead. Here the lead has just been poured and they are about to do this critical run along the bed.









Then they cut off the edges and ends, and cut the product into separate sheets and roll it by hand, with all the still warm surplus going back into the furnace for the next go. This produces about 5m of sheet about 1.25m wide, and each go takes about 25 minutes so they can do 16 casts in a day. We saw the sheet cut into four bits, each weighing about 50kg (it was Code 6, I think).

I wouldn't want that job as it looks really physically tiring and I bet they have back problems. There is no doubting their skill at producing such a product but I have no idea how much it costs!

NB N&U did the lead casting for the inscription on the coffin of Richard III.  We saw a copy of this which I think is destined for a museum,














and they did an imprint in the sand from the original for us!

A really good day!

Using a Scaffold Tower

I have been very busy this last week.  I hired a scaffold tower for the whole week, as the fire alarm in church needed a servicing; they need a tower to get up high enough for their long pole to reach the detectors in the ceiling.  As this is an annual task, it had to be done in July, and so I had saved a set of other tasks that would be done at the same time.  These included a repair job to the CCTV camera which is mounted high up, the replacement of some high light bulbs, and the removal of the string from balloons which has got wrapped around the fans in the ceiling of the church hall.

At this stage I will vent my anger at the church architect who told my precessors what to fit in the church without a thought for the subsequent maintenance or the running costs.  The uplighter bulbs fitted five years ago are halogens and I have proved that switching the uplighters off saves about £50 per month.  The fire alarm is overly complex, and is wireless even though you could have hidden cables in the roof structure without them being noticed.  The CCTV camera (also fitted five years ago) had a wonderful pair of devices which allowed the video signal and the control inputs to share the same cable.  Great idea, but it's another two components which can go wrong - of course one did, probably in my view because of the known dampness under the suspended wooden floor.  Guess what? These boxes are no longer made so we would need two new, bigger ones at vast price.  However, we fixed that issue by laying the extra cable instead so now there are two less components to go wrong.

Anyway, there was a need to remove the tower from the church for Sunday and, as the hall was also in use, I brought it over to my house for "storage".  It seemed sensible to make use of it so this weekend I have:
a. Refitted the stuff in the gutters that prevents leaf build up (and they are now held in by some wire)
b. Fitted tingles to hold the three slipping slates in the area of the vent slates in the roof (done poorly as they were an afterthought...)
c. Tackled the poor pointing and defrassing on the west wall - there was thin cement over the pointing in some places, and spalling stone elsewhere, plus some large holes which I had blocked temporarily three years ago...
d. Then I had to tidy up the bits and dust all over the path below!

The aluminium 6 metre tower is a wonderful design.  It has three pairs of frames, with easily fitted clip-on bars in two lengths - one for the horizontals and one for the diagonals. Every item is very light; there are four stablisers, and wheels on the bottom of the frames.  On Saturday, Jane and I erected most of it in about 20 minutes; the difficult bit is positioning the top platform at the right level, but I found that the height was adequate at the top of the second frame which avoided that difficulty. I actually got her to go up it once just so she could agree that it is safe when you are up there (and so stop worrying!).  On Monday after doing the wall I took it down on my own and moved it to the church hall, all in about 45 minutes.

Then in the hall on Tuesday we attempted to remove the string from around the fans in the ceiling.  This string is the residue from balloons released by hirers who think it's funny to watch them going round! Sadly, this was one job we couldn't complete, although we did remove the balloons which surprisingly had been there for over three months with no sign of deflating.  The reason we couldn't fix the string was that the tower was too low with two sections and too high with three.  It turns out that we should have had some half frames which would have been just right, so that job will have to wait until next year.

On Wednesday the tower was taken away at last, and I have to say that it has been a most tiring week! I lost count of the number of times I went up and down the tower - at least I should be a bit fitter!