Owt or Nowt?

[Idris]

Let me start this post with a story which will put the question in this post's title into context.
A long, long time ago, I went round to Philip Bowdidge's house to buy a 27b from him (thereby completing my one-of-each mint and boxed collection). I think this must have been just after Lesney Products Ltd. had been decalred bankrupt and, somehow, Philip had acquired various bits and pieces (via Paul Carr perhaps?). Amongst them were a number of plastic versions of the American 'big rig' tractor unit bodyshells. I seem to recall him telling me that these were test mouldings from the tooling (presumably a modern version of the low-pressure test shots we are familiar with from various RW threads).
I was therefore intrigued when I saw an unpainted all-plastic matchbox Kenworth tractor units for sale, especially since it had a chassis and wheels. Pictured below, it arrived yesterday, and it appears to be, literally, a plastic version of the metal-bodied model. (I'm a bit out of my depth here, but i think this is a tractor unit which was only issued as part of the Convoy series rather than as a 1-75. However, I do have a pre-production version in white and have noted detail differences on the Lesney England baseplate.)
So, what my question means is, is this what I think it might be, i.e. a plastic test-shot on a pre-production baseplate, or have I wasted my money on something common as muck?

[GHOSTHUNTER]

I am, quite happy a 'Test Shot' model (from the Truck's time period, many were in plastic), on a 'Pre-Pro' chassis/base works. Maybe it should have been a full production chassis/base but none available, or...it exists out of the chance to asses both main components at the same time. This is not good practice because change one, you have to consider the other and/or change that which could spiral out of control and you end up with a model (test-shot/preproduction status), that goes nowhere!

Do the rivets have a full production finish.

Ghosthunter.

[Idris]

Do the rivets have a full production finish.

Nope, they're simply 'spot melted' to the baseplate (which is also plastic) with what looks like it was probably a pointed soldering iron.

[GHOSTHUNTER]

I am almost on the limit of my knowledge of Matchbox models of this type and from this period, but soldering iron usage to me does not sound right. The method of fixing bases to bodies is more likely to be by blobs of resin because as you are probably aware, applying heat to the types of plastic in use for these models will release harmfull gasses which I am pretty sure the workers would not appreciate!

Securing a body to a base will only be of benefit if the model is presented to the new products team at one of the regular Monthly meetings to give an idea (not the colouring) of the overal size ratio (could be too long, short or the wrong width).

If this model was obtained for a not substantial amount of Money, it is worth keeping for the very reason we are discussing it here and by using the process of ellimination, we should get close to something of actual fact...

Ghosthunter.

[Idris]

...applying heat to the types of plastic in use for these models will release harmfull gasses...

Melting a thermosetting plastic does not release harmful gasses.

[GHOSTHUNTER]

...applying heat to the types of plastic in use for these models will release harmfull gasses...

Melting a thermosetting plastic does not release harmful gasses.

OK Hugh, thank's for clarifying that, but do you think the workers doing this/these models could be trusted with soldering irons. Working in an industry where a lot of soldering irons were used (when I worked for a professional audio mixing desk company with components hand soldered to circuit boards), I know how dangerous they can be, seems too old fashioned for me.

Ghosthunter.

[Idris]

...applying heat to the types of plastic in use for these models will release harmfull gasses...

Melting a thermosetting plastic does not release harmful gasses.

OK Hugh, thank's for clarifying that, but do you think the workers doing this/these models could be trusted with soldering irons. Working in an industry where a lot of soldering irons were used (when I worked for a professional audio mixing desk company with components hand soldered to circuit boards), I know how dangerous they can be, seems too old fashioned for me.

We're talking about someone knocking up a couple of models in R&D, not a full blown production line. Furthermore, this is the early 1980s, i.e. no 'health & safety gone mad' - it was still possible to do a job without drowning in a sea of pointless administration whose sole purpose is to shift the blame for any injury onto someone/anyone else. As for '...could they be trusted...', they'd had access to axle crimping machines, used a chisel/screwdriver and a hammer as standard to close metal baseplate rivets and, I believe I'm correct in saying that Superfast axle ends involved some kind of welding/melting process. A small soldering iron would therefore not have been a big deal.
If you need to quickly secure two plastic components together, what better way than simply to melt the connectors?

[GHOSTHUNTER]

If it were just a couple of models being knocked up in R&D, then the soldering iron method is very viable. I do think R&D would have had a lot more to do besides getting a few Guys to knock up the odd prototype Matchbox model. I would have thought they were given a lot of projects to R&D on and would have at their disposal a number of curable fixing compounds. I may be totally wrong, we just don't have the insight of the workings from this period.

We do however have at least one member here that is more informed of the period, but not sure if he has posted recently, he is welcome to give us his views.

Ghosthunter.

[Idris]

I am almost on the limit of my knowledge of Matchbox models of this type and from this period, but soldering iron usage to me does not sound right. The method of fixing bases to bodies is more likely to be by blobs of resin...

Resin would be appropriate for securing a plastic bodyshell to a metal baseplate. However, when both components are plastic (as they are in this case), other solutions become possible.

[Idris]

I'm a bit out of my depth here, but i think this is a tractor unit which was only issued as part of the Convoy series rather than as a 1-75.

Research has revealed that this is actually a 41f.