Variations of the Pop Pack

[Beta 5]

I've just been thinking about all the variations of the Thorn pop pack, does anyone know when the various changes happened?

I know the grey sided ones are from the 60's, when did they change to all white painting? Then the 70's design was dropped in 1980/81? for the oval ended version, then again in the 80's (when exactly?) the starter holder was changed from the square one and the turnbuckles became plastic.
Finally the most recent T8 design came about in 1991/92 I believe? Any further variations after that (aside from the cheapening down of materials etc.)?

It would be interesting to put together a rough timeline of what designs of it were around and when, and when changes were made.

[Slyspark]

There were some more subtle changes too. I think by the end we were on something like MK16 or so...

[Beta 5]

Yes I recall it was something like that, I guess another change was the fitting of ballasts on those clip brackets rather than screwing them in.

[Slyspark]

There were a lot of very minor changes, such as the inside of the spine on the later ones going from golden to white painted. Not all the different versions were that noticeable

[Beta 5]

I have some 2ft's from 1995 with the gold/green colour inside, will have to see what mk number those are too.

[fluorescent]

I have some 2ft's from 1995 with the gold/green colour inside, will have to see what mk number those are too.

I think they're Mk15 but not 100% sure, and I'm not sure they ever changed that version number despite all the revisions over the years. I think this version ran from about 1992 until they stopped making them.

They may be the most modernised/revised iteration of the Pop Pack line. Initially they were a dark green/gold colour inside with SB ballasts. Later the dark green became a lighter green/gold. After this they were white painted inside, still with the SB ballasts. They then switched to Tridonic ballasts followed by Tridonic ballasts clipped in & floating (terrible design), and HF versions were introduced at some point, initially with Thorn branded HF gear, then Tridonic. The spine remained unchanged throughout all of this although I think the metal is a tad thicker on the earliest versions. The end caps & covers are all interchangeable.

On a side note, I really like this version. Even at 30+ years old the lamp holders generally work fine, unless they've been abused of course, and the end caps can be removed & refitted without falling apart. The paint on the earlier ones is surprisingly resilient, I've seen ones that look knackered but with a bit of t-cut come up looking new. The metal is thin but it's some kind of high carbon steel so pretty strong. They look kinda goofy-but-great with T12 tubes fitted and suit T8s. The lamp holders can be adjusted to 'V' or 'H' orientation at any time.

[Slyspark]

Was definitely a MK16 - I have stock in my container with that version number inside. Think that was the very last tho

[RobTDCI]

My secondary school had a ROSLA (raising of the school leaving age) unit, a prefabricated building which was lit by grey sided pop packs with prismatic diffusers. That was erected in 1972, not sure if the grey sided pop packs were still being manufactured in 1972 or if it was old stock.

[Beta 5]

@fluorescent I quite like the original ones with the green colour inside and the SB/Thorn gear, they still look and feel like a proper Thorn product! I think it was when they started clipping in the ballasts they went properly downhill.
You are right about the paint, it seems hard wearing and I have noticed it never seems to yellow like the older ones. I think the metal thy use could actually be pre-coated before fabrication as they always have bare metal at all the cut ends and edges. The paint feels more satin on the later ones, the 1990's 2ft's I have are definitely very glossy while the newer ones with the clipped in ballasts look a little less so.

@RobTDCI, interesting to hear they still used grey siders into the 70's, perhaps they did just tip over into 1970/71, so were ordered for that building while they were still one in grey?

It is also interesting to note they switched to using the open frame chokes very early, I have an NOS Homelite (PP65 without a PFC) from 1973/74 which already has an open choke, and I know of some other NOS ones the same age posted here which also use them.
I am guessing they changed from the potted black chokes to white versions of the same when they changed from grey to white sides, but didn't seem to stick around very long before changing to open frame chokes.