It's finally time to look at the plastic elements of this build, meaing those parts of the original Airfix kit that are retained in the combined Airfix + Masokits design... and there aren't many of them! Aside from a couple of tiny pieces - tank filler cap, for example) this is all that's used:
The solebars have already had their plastic v-hangers and other protruberances removed (aside from those central electrical boxes) but the eagle-eyed will see that the circular moulding marks are still there. They're not easy to get at without damaging neighbouring rivet detail or the channel sides, but with patience they can be reducd, eventually to the point where they won't show:
They're then reinforced on the inside surfaces with plastic card, otherwise not only are they a little flimsy but there's not that much of the plastic in close-ish contact with the brass underframe, for glueing purposes:
Two strips of plastic card are provided in the kit for this purpose, but they're quite a bit thinner that the gap between the main solebar lengths and the brass, which may be because there were different iterations of the Airfix parts at different times. I initially decided therefore to use slightly thicker card - here's a view showing the two thicknesses, the one in blue being that supplied by Masokits, the one in green being my slightly thicker one, where you can see the larger gap afforded by the thinner card:
After glueing the small pieces in place at each end of both solebars however, I couldn't help thinking I might/must be wrong. I started doubting my idea that the Airfix solebar mouldings might have varied in thickness at different times in the kit's production history and If there's one thing I've learned from building this kit, it's the Michael Clarke thinks things through very thoroughly! The only reason I could think of as to why the reinforcing plastic strips should be that thin is to allow for more epoxy to sit between the plastic solebars and the brass frame, giving a stronger bond... so, I used the strip supplied with the kit for the remaining sections!
One other slight issue is the raised circle round each bearing hole on the plastic solebars:
If left in place, they cause the solebars to splay outwards when the rest of the plastic is brought flush with the brass - as shown circled here:
Unless I can think of a reason for their retention, they'll have to go!
In any event, I was finally able to put together plastic and brass elements for a test fit, which was quite exciting!
There's also some hole filling to be done on the tanks, where the plastic walkway supports would have gone; I followed the suggestion in the instructions to use plastic card pieces:
And while all that was drying, I took a look at the buffers. Finding suitable looking ones was a bit of a quest, but the kind folks at Dart Castings came to my rescue with some GWR ones, plus some larger buffer heads to substitute. These are of a type I've used from them before, where the steel buffer heads are moulded within the white-metal housing, a very effective method that also allows the heads to be swapped should the need arise, but the use of suitable gripping tools and a bit of oomph! Here you see the housing, with the smaller diameter head removed and the larger one next to it:
I can't decide whether to solder the white-metal housings to the buffer beams before or after putting in the new steel heads. Putting them in before soldering adds material that might act as a heatsink (where I want to be in and out quickly, soldering such small white-metal items to a relatively much larger brass assembly) but OTOH they'd perhaps be nicely seated if they're there before heat's applied, plus there's then no chance of blocking up the holes through the housings... If anyone's tried that both ways please let me know what you found.
In the meantime, the solebars have had their reinforcement pieces added and the filler pieces in the tank halves have been filed back, a slightly awkward operation as I didn't want to mark the otherwise very smooth and shiny tank surface around the where the pieces are glued in place:
Looking again at this last photo, I think the question of removing those rings round the plastic bearings should involve checking clearances for the sprung bearing carriers with the plastic solebars in place: do the outsides of the brass bearings poke through and interfere with the plastic?