Interesting topic. The manufacture process history I am familiar with relates to getting the Canadian production of the UC sorted out, including the issue of warping armour plate. British carrier production would predate Canadian by a few years. Does anyone know how warping plate was dealt with in England?

Also, did the same problem show in Australian and New Zealand production and if so, how was it dealt with there?

Might as well throw the whole bag of carrots out there for us to nibble on. T16 production in the USA. What did they do to solve this problem?

Possibly a common solution for each location. Maybe in Canada the problem was finding the right company with the proper equipment to handle the job rather than finding the technique?

David

I would say strike marks Bob. They vary in their concentration but not in the way they are done.
David, British carriers used armour plate that looks like the smooth pattern you might see on sand that is levelled by gentle water action. A fine ripple pattern that was easily hidden by a coat of paint.
The Australians I believe developed their own bullet proof plate (BP2) As i recall production was held up for a while with welding it. I think stainless rods were at least the interim fix. I think the need for stainless rods was overcome during the Australian and New Zealand carrier production. Hopefully someone more in tune with Aust. pattern carriers can verify this.
My British built and welded hull AOP carrier (mid 41) was welded with stainless rods.
The un answered question I have is that some British built armour, (the heavy daimlier armoured car as an example) is made with the Canadian style "axe marked" armour plate. How did this come about? Was Canadian plate supplied to British industry?

I think the same axe marks can be found on the ferrets, but I'll have to look again to confirm. Doubtful the UK would have emported the steel from us at that point, and as well there is no SDA markings.

Here are the three pages from the design branch records re bullet proof and armour plate development in Canada. If you open them in a new tab you can expand them to a readable level of magnification.

Tank u Rob

Hi Lynn,
After many years of being around British armour, I have noticed that those plates on Daimler hulls, Dingo scout car, Armoured Car and Ferrets, that have a cut out for a flap or visor, etc are those most likely to have the hammer marks. This I believe is because the plates were machined and cut before the hardening process and some distortion may have occurred. The plain plates with no cut outs do not seem to have the marks, generally.

The welding was done with Nickel Chrome rods, although stainless may have been used in later repairs. The process of welding armour was pioneered by Guy Motors for their armoured car, but this vehicle was later produced by Humber.

Nothing to do with Canadian steel manufacturers or lumberjacks wielding axes! :)

regards, Richard

Richard, Rob's post states the use of Austenitic rods. My understanding is that this type of stainless steel contains both nickel and chromium. To my simple un educated mind that is stainless.
I went to a chaps place some years back and he (along with a complete running Dagenham built AOP carrier) had the remains of another AOP carrier. It had been part of a sea wall. All he had was the spider web like welds of a silvery material that I would call stainless steel.
I could easily recognise the (some what collapsed) shape of the carrier welds.
Other Kiwis will know who I am talking about.

As an aside there were 79 of these Ford of Dagenham built Armoured O.P MkIII w (welded hull) carriers that came to N.Z. Later, 40 went to Tonga. I don't know if any of them returned. allowing for two other hulls we can account for 5 of them from that batch built in mid 1941.
What ever the welds are, I could not cut it with the gas but it certainly came away nicely with arc air gouging.

Interestingly enough my british Mk.III had been welded with non-austenitic rods - all welds are as rusty as the rest of the hull.

Petr, your carrier is later production than the ones that came to N.Z.
As you can see mine is T84991. My guess is that yours is from the T167892 to T168965 block of Dagenham AOP carriers (from Nigel's book)
I believe your hull does not have the two square holes in the rear plate.
The N.Z. ones came from an earlier batch of 3443 that do have those holes.

Yes Lynn, you are right, my carrier is one of the latest produced and definitely younger than yours.
I think that its most likely T30XXXX something, last contract from the Ford Dagenham, but investigation still continues.
I found this topic very interesting, so take this note just for comparison - how the building/welding of hulls possibly evolved during the time.
Cheers

Sda galt
 

This is an interesting topic and I have to reread the whole works to consider both composition, heat treating and straightening...but while I take time to do that - here is a slightly related / unrelated thought. Many years ago I talked to an old fellow who worked in Guelph at a foundry. It was closed down due to heavy contamination and possible liability issues related to the site. At that time Bill Gregg had the remains of an old WW1 tank ( no turret or duck tail. v8 engine etc) These were the tanks sent to Camp Bordan from the usa at the start of ww2. I was telling the old guy about this and he told me that several of these types of tanks ( hulls only??) were in fact buried on the foundry site because many of the vehicles were scrapped there after the war. The suggestion was that somehow the composition of the steel plate was such that it was difficult to melt or convert into usable scrap. Anybody know more about this??

Lynn,
We had a thread going on this armour plate welding rod subject about 3 years ago. I quoted then from a WW2 REME welding manual for repairing armour (even has details regarding German armour) and the rods were austenitic armour plate electrodes, comprising of 18% chrome and 8% nickel, the coatings contained special substances for welding armour plate. It is true that stainless steel rods are of the same percentages as above but to quote the manual " if armour plate electrodes are not available welding may be attempted with ordinary Stainless Steel electrodes."

So to answer you question there was a difference between Austenitic Armour rods and plain Stainless Steel ones when they were building these vehicles.

I heard the same thing about the dozens of FV432s that went through the wreckers in Regina Saskatchewan back in the 90s. The smelter next door did not like mixing them into the pot with other metal. This is just hearsay mind you, I did not talk to anyone at the smelter.

Attachment 73694

Attachment 73695

Attachment 73696

Attachment 73697


The Australian Ford Marmon-Herrington 'Dingo" Scout Car was made with Australian made armour plate and was fully welded with non stainless rods. I do not know what the composition was but here are some photos of mine (No.77212) for you to compare. It does have the armour test indentations in a couple of places.

Regards Rick.