SimonD’s workbench

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simond

simond

Western Thunderer
Thanks Nick,

on further inspection of my photos, I could agree that the headers - ie end-on bricks - are blues, certainly on the ends. But I think the normal bricks are painted. This seems to be the case for the ends of the Didcot furnace, but the Banbury one in Lyons does not appear to have the dark area at the end, only on the side facing the rails. I’m going to search for more photos.

(and I haven’t forgotten the iron bodied loco coal wagons - it’s in the queue!)

cheers
Simon
 
simond

simond

Western Thunderer
So the other Lyons book shows two, and Griffiths shows a few more, including Didcot two months after opening, with the darker lower walls.

But IMO not dark enough for blues…

IMG_8492.jpeg
And Merthyr

(Very tight crop from Griffiths “Sheds in Camera” plate 153 (c) Matthews & Caddy for illustration only)
 
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Pencarrow

Pencarrow

Western Thunderer
simond said:
So the other Lyons book shows two, and Griffiths shows a few more, including Didcot two months after opening, with the darker lower walls.

But IMO not dark enough for blues…

View attachment 203049
And Merthyr

(Very tight crop from Griffiths “Sheds in Camera” plate 153 (c) Matthews & Caddy for illustration only)
Click to expand...

Agree that's nowhere near dark enough for engineering blue brick.
 
Pencarrow

Pencarrow

Western Thunderer
magmouse said:
But is the top half dark enough for red brick? Just playing Devil's Advocate here...
Click to expand...

I'm comparing the lower section of the building with the black colours elsewhere in the shot. I think if the lower section were engineering blue brick, it would be closer in shade to the black. Looks much lighter to my eyes.
 
simond

simond

Western Thunderer
The row of bricks below the sand hatch is definitely blue brick. I do not believe the rest are, though I could be convinced that alternate rows are, but even so, there’s something like a wash over the other bricks.

Anyway here’s a view with the lights on
image.jpg
Contrast is a bit hash, need to turn them down a bit…

Atb
Simon
 
simond

simond

Western Thunderer
BrushType4 said:
Simon I think a stove pipe type chimney is possibly missing from the build.
Click to expand...
Yes, there are photos in the books I quoted, and there is a drawing in Lyons. I had intended to get the printer going tonight, but that’s not going to happen, I’ve got several hours’ CAD to do, of which the stovepipe is the simplest part,, and then everything needs supports etc, so maybe tomorrow.

once I’ve done it, I’ll send you the CAD.

looking through the books I have, the chimney on this style of furnace is a simple stovepipe, the earlier generation are massive brick-built edifices, of epic “brick outhouse” proportions, and with a level of detail & ornament that would befit a civic crematorium, rather than a simple sand furnace.
 
simond

simond

Western Thunderer
Sorry if my post was not clear, that photo in post 1003 is Merthyr, and here is my interpretation of the stovepipe

1701555768187.png

and my interpretation of Didcot based on scaled dimensions from Lyons' book

1701555840475.png

I rather fancy the fancy one...

on the bricks front, Abercynon does not have the dark lower courses at all. the photo is a bit in the shadow on the long side, but the end is clearly the same all over.
 
Osgood

Osgood

Western Thunderer
Going back to your own photos of the Didcot sand dryer, Simon - I am 100% certain these show naturally coloured unpainted bricks.

Many engineering bricks came out multi-coloured - it looks as if the bricklayers selected the darkest blue ones for some courses as seen in your photos.
The colour variation would be influenced by clay quality and firing temperature - engineering bricks being fired at higher temperature than ordinary bricks and invariably using higher quality clay.
I’d imagine the colour variations here is caused by temperature variation in the kiln.

Safe to say in this case some of the engineering bricks are more ‘engineering’ than others :D
 
Osgood

Osgood

Western Thunderer
The same variation can be see here - the builders of this MR bridge must have known the darker the brick the stronger, so chose blue for the arches - the remainder being a right old mixture!
The coping and plinth bricks appear to have been subjected to more consistent firing.

Waltham1.jpgWaltham2.jpgWaltham3.jpg
Waltham6.jpg
 
Overseer

Overseer

Western Thunderer
Osgood said:
The same variation can be see here - the builders of this MR bridge must have known the darker the brick the stronger, so chose blue for the arches - the remainder being a right old mixture!
The coping and plinth bricks appear to have been subjected to more consistent firing.

View attachment 203099View attachment 203100View attachment 203101
View attachment 203102
Click to expand...
It’s not that simple. The builders of the bridge would have purchased the bricks specified by the engineer. The blue bricks are probably Staffordshire Blue Brindles. It looks like the reds in the parapets were specified as face bricks, to get a consistent colour the bricks are stacked hard together in the kiln to stop the combustion gases contacting the face. The other side of face bricks usually have kiss marks showing how the bricks were stacked in the kiln - ideally there needs to be enough spaces for the heat to reach all the bricks at the same time so they are fired the same amount but some will be over burnt and others underfired - the underfired bricks will be softer and less durable so should only be used in internal walls. The fuel used to fire the bricks also changes the colour. Coal fired red bricks tend to turn blue if exposed to the flames, clinker, due to high carbon monoxide levels. Oil fired bricks can have a yellow to brown slightly glazed appearance.

The centre of the bridge in the photos has been repaired with later bricks which do not match the original Brindles or red bricks. The blue brindle arches would have been complete between the piers when built.
 
simond

simond

Western Thunderer
Thanks guys,

There seems to be some conviction regarding the darker bricks. It would seem more logical to use stronger bricks for lower courses, but it’s a sand furnace, rather than a bridge, and it has steel framing too. Why would the builders feel the need to use higher quality (higher cost?) bricks in a low level, low stress structure? Would the fire have something to do with it, and they just made it consistent all round at Didcot, but not elsewhere?

anyway, I’ll apply a coat of something, at some point. Would have been easier before I assembled it :(

(regrets, I’ve had a few, but then again too few to mention :)) )
 
simond

simond

Western Thunderer
Fraser,

thanks for your post, which crossed with mine. What is your view of the bricks in my photos from Didcot?

cheers
Simon
 
Overseer

Overseer

Western Thunderer
simond said:
Fraser,

thanks for your post, which crossed with mine. What is your view of the bricks in my photos from Didcot?

cheers
Simon
Click to expand...
The lower brick courses are definitely a different colour brick to the rest of the building. Is this building a reconstruction? It looks like it could be and they have used reasonably close matches to the original bricks from what was available at the time. The lower plinth courses should probably be more consistent blue bricks while these bricks look like more recent bricks with manganese added to the clay to produce the darker colour. The original specification was probably the same as Swindon workshops. It is common practice to use better quality, harder, bricks in contact with the ground, especially when the walls are built of orange coloured wood fired bricks.
 
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