Aggregate

Chubby

In safe cores we used to use a mineral known as “Zac” as the large aggregate. This was an abbreviation. Could any body, please, tell me the full name? I used to know but have forgotten.

Huw Eastwood

There’s big clues in the 3 letters chubby.
What colour was the aggregate? where did you get it? what exactly were you using it for? Answers likely to determine if it was zac or not.

Doug MacQueen

Zaccrete?

Chubby

We were using it to fill in deposit chutes in the top of some ministry safes. This was at COD Donnington. We welded in a piece of steel inside the top of the safe. That was probably IT100. Then standing the safe right way up, filled the resultant void with the mix, having put some mesh in. After drying time we welded over the top outside skin and generally made good.

I met a guy, whose name I forget, who was a manager at SLS which was just down the road from us. On the last Friday of the month we used to have a luncheon in the mess. I invited him as a mess guest. Over luncheon he agreed to sell us “a few bags of zac” for the purpose. Those we duly bought as a “local purchase”.

As to colour, I have no idea. I didn’t see the job performed

Safeone

Well this SLS safe sales brochure is full of Zac related stuff. You get Zacalum followed by Zacrete. In the same brochure you then have Zacallum featuring two letter ’L’s for some reason then Zacalloy gets a mention and finally Zac nuggets pop up. I am ‘Zacked’ as to the actually ‘Zacking’ meaning though!

safes-sls-cash-and-jewelry-safes.pdf

293kB

Huw Eastwood

SLS was the key there chubby, Zacrete was zac nuggets dispersed through their refractory concrete matrix, zacalum was zac cast in aluminium, and zacalloy was cast in stainless steel. Don’t think they adopted it cast in copper,, from memory the term was loosely applied for zirconium alumina ceramics /composites, that covered several and heat treated variants,, zirconia alumina silicate etc.
When you say ministry safes were they grade 1A’s ?

Huw Eastwood

Should have added that IIRC the top range stainless steel barrier used on bankers treasury, sapphire and gems was cast as ceramic needles ( I think)and not raw nuggets as in the cheaper grade zacrete matrix.
I made it sound basic in all three whereas SLS deserve credit in applying a lot of technology and investment to it back in the day.

Chubby

I don’t know whether anything with a deposit chute could have rated as a 1a. I don’t remember the regulations for a 1a. These had been rated as “sub standard” due to the hole. They were fairly good, from memory, but that is from 30+ years ago. They had a single dead aed located in the same spot on all of them. So I designed a simple live aed working off the lock bolt which improved things.

It was at a time when a particular branch was trying to do as much work as possible to justify their existence so everything that went in was very fully reworked. The guy running the branch aimed to send stuff out as good as new as a minimum standard. The best case scenario was to improve on new.

Redoubt

Hi Chubby.
I am pretty sure ZAC stands for, Zirconia Alumina Corundum.
It is one of the many hybrid refractory abrasives that are available.
As hard as aloxite, but tougher.
Hope that helps.