"Plastic Armor?" Topic

I found an interesting mention of "Plastic Armor" in a wartime evaluation of the effectiveness of the Wasp flame-throwing Universal Carrier:

"12. P.P.P. (plastic armour) has found to be a useful accessory to the normal equipment of a 'Wasp' MK II (C). The use of plastic armor gives added protection to the front and to the sides of the carrier as far back as the bulkhead separating the driver's compartment from the rear wells. This armor is a good defense against all types of fire up to 20mm A.P. and it will even stop, or prevent the penetration of 20mm A.P. at anything except point-blank ranges and normal impact. The armour can be used effectively on carriers mounting ‘Wasp' MK II (C) equipment for the reason that the 500 odd pounds of P.P.P. tends to balance the weight of the 80 gallon tank on the rear of that type of carrier. If the armour is used on the ‘Wasp' MK II, it makes the carrier nose heavy. Being very thick in appearance, P.P.P. also contributes to the feeling of security on the part of the driver and gunner."

I have never heard of this. Any idea what it is?

Scott Washburn
PaperTerrain

Being in the 40's I would have thought it was Bakelite--An early plastic, however I'm not sure how strong it would have been!!!

If it's the stuff I think it is, it was developed by the Department of Miscellaneous weapons development, in the Admiralty (who also developed, among other things, the Hedgehog ASW morter).

It was originally intended for the merchant navy as an alternative to concrete blocks, which splintered when ships were strafed.

It was a mix of crushed granite and mastic with a steel backing plate and was the only armour plate that would take a thumb-tack.

It was almost killed off as a project by bureaucrats who objected to calling it 'armour', so they renamed it Plastic Protective Plating (PPP)

Reference : The Secret War by Gerald Pawle

Cadwgan, that certainly sounds like the stuff! I wonder how it was applied? Could they just deliver sheets of the stuff and then cut it to fit, or did it have to be manufactured to fit the specific vehicle? The UC has a lot of angles on the front that are pretty unique. It was obviously pretty lightweight compared to regular armor plate (10 or 15 square feet of it and several inches thick to cover the UC as described and still only 500 pounds) but proof against small arms up to 20mm. In thicker amounts would it contribute any protection against larger AT guns? Was it ever used on tanks? I guess it wasn't used that widely or we'd have heard more about it.

It could be applied several different ways – either molded to shape or cut to shape and then applied – since it was partially made of mastic – you could use the same material to afix it to the armor in question.

Peel and stick!

Allen

Remember "plastic" can also mean a bunch of things related to shape, such as "plastic arts" (jewelry or sculpture), "capable of being molded," or "plastic surgery" (which has to do with reshaping the body).

So even something like the slat armor on the current Strykers could be called plastic, since its protective power comes from its shape. That's a stretch, but its a for-instance.

Crushed granite in mastic could be plastic in the sense that you could spread it over an existing steel component and increase its durability.

I suspect it was ablative, though, in the sense that it came apart during use.

Andrew

From the photos it looks like it was flat slabs bolted on.

There are two photos in the book, one showing the 'island' of a converted merchant escort carrier covered in the stuff and another of a landing craft from the Dieppe raid which had been hit with morter fire and survived, but the armour was shredded with great big impact craters.

The book describes that it was widely used in landing craft as well.

The main advantage of it was that it used road making equipment rather than an armour rolling mill. In Egypt they substituted porphory for granite.

The Wikipedia article on plastic armour is pretty good:

link

The mastic was tar/bitumen based, so it did not fare too well in hot weather – I rather suspect that it would have been an EXTREME fire hazard on the Wasp, but there again a big drum of napalm strapped on the back is also a fire hazard.

Bitumen isn't classed as a flammable substance it will burn but its nowhere near as much of a fire hazard as diesel for example