Matchbox Tiger Moth RAAF Air Ambulance

[LSP_Kevin]

7 hours ago, airscale said:

 

 

Hi Kev - I use a dremel and a slitting disc for a surgical cut on guitar strings - works a treat

 

Great job on the cockpit by the way

 

Peter 

 

Thanks Peter. I did actually do some of the cutting with a disc in the Dremel, but it was quite a thick one, and didn't work well at all. I certainly couldn't cut flush with it. I'm not actually sure what a 'slitting disc' is, so I guess I should go check that out.

 

Kev

[LSP_Kevin]

I'm back with the promised update, which mainly concerns the rear spine part. I knew from the outset that this would be a troublesome aspect of the conversion, as the total length of the two resin pieces in my set seemed to come up short. I spoke with Uncle Les about this, and he confirmed that his examples were fine, so I'm not sure why mine aren't the same, but I suspect I might have been overly aggressive when sanding the ends, which would at least partially account for it.

 

Anyway, the upshot of all that is that I knew I would have a gap to fill somewhere, and up until yesterday, the plan was to have that gap be all at the rear of the fuselage, in front of the tail. With the forward piece already firmly in place, I could play around with the positioning of the rear piece, and I discovered that width-wise, it actually fit best when placed right in front of the tail. Placing it back-to-back with the front section would have meant I'd have a mismatch in the widths of the resin piece and fuselage in that position - and I really didn't want that!

 

So, down the back it went, which left me with a sizeable gap between the two resin pieces:

 

I had to trade better fit and less filling at the sides for this gaping hole in the middle! I originally planned to fill it with sheet styrene, and set about creating a new rear wall for the front hood from thin styrene sheet:

 

The interior side was painted in Foliage Green prior to being glued in place. It then occurred to me that I might be able to use a solid piece of resin from an old casting block to fill in the rest in one go, rather than having to glue a bunch of thin sheets in there. I eventually found one that would work, trimmed it to size, and glued it in with CA:

 

There's still a slim gap at the rear of the resin block, but I filled that with some more thin styrene sheet. After trimming and sanding, I arrived at this:

 

I back-filled the joins with a combination of CA and talcum powder, and sanded everything back. Since taking these photos, I've given the area a generous coat of Mr. Surfacer, and it tells the tale of more work to be done. I also managed to sand a slight depression into the area just ahead of the join, but I should be able to render that unnoticeable. It's an occupational hazard when sanding an area made up of different materials.

 

OK, back with another update when I'm done filling and sanding.

 

Phil Sand

 

 

 

 

[mozart]

Ha ha, well done Phil!  Proper bit of modelling there! 

[dodgem37]

Good show.

 

Sincerely,

Mark

[Anthony in NZ]

Great update Phil Sand, LOL

 

I like your 'fix' too.  I have a small-ish square of perspex for jobs like this (you probably have similar as well).  But for those who dont and get the same thing when sanding between different mediums.  I wrap emery paper around the block and sand at a diagonal across all mediums varying pressure to try and even it all out.  I am not telling you how to suck eggs Kev, as your skills are something I learn from and I've only ever found things out the hard way.  But it might help someone out there reading this.

 

As you say...Mr Surfacer will quickly tell you where your mistakes are! 

 

Who, knew all those years ago when we read those 'Mr Men' books ourselves or to our kids, there was a Mr Surfacer???  In fact a whole extended family.  Sometimes I feel like Mr Wobbly when I am trying to glue tiny objects 

 

OK, I shall move on....

 

Great update!

 

[LSP_Kevin]

2 hours ago, Anthony in NZ said:

I like your 'fix' too.  I have a small-ish square of perspex for jobs like this (you probably have similar as well).  But for those who dont and get the same thing when sanding between different mediums.  I wrap emery paper around the block and sand at a diagonal across all mediums varying pressure to try and even it all out.  I am not telling you how to suck eggs Kev, as your skills are something I learn from and I've only ever found things out the hard way.  But it might help someone out there reading this.

 

Actually, this is something I still struggle with. I do have wood blocks and the like for this kind of work, but find them clumsy to use, and generally I'm too lazy to drag them out of wherever I've hidden them! I end up relying too heavily on those skinny sanding sticks, which are great for what they're good at, but shouldn't really be used on large areas like this, as they do tend to produce localised depressions if you're not careful (and sometimes even if you are).

 

Anyway, I've been searching for a solution to this dilemma, but had forgotten until yesterday that I'd recently bought one of the SMS sanding plates:

 

https://www.scalemodeller.com.au/collections/tools-accessories/products/sanding-plate-w-pad

 

 

It's a stiff metal plate roughly 9cm x 2.5cm, that takes self-adhesive sanding pads. I broke it out last night to see if it would be effective in my scenario, and found that it was the perfect solution! It's far more ergonomic to use than a clunky sanding block, is much stiffer than a standard sanding stick (skinny or otherwise), but the sanding pad itself has a little bit of give to avoid any gouging effects. I'm sold! The main downsides are the ongoing costs of replacing the sanding pads, and the limited range of grits available. But it's still a very useful tool to have in your sanding arsenal.

 

Kev

[bdthoresen]

You might get away with using self adhesive sandpaper’s on the slab, Kev in certain scenarios. Cool tool.

 

Love the work so far. Keep it up, man!

 

THOR    

[LSP_Kevin]

OK, here's the result of all that filling, sanding, and priming:

 

 

Acceptable, but still a little bit of work to do. The forward section is hinged and has a slight overhang with the fuselage, along with a reinforcement strip along its bottom edges, so I still need to take care of those elements. I've been contemplating whether I should try to replicate the latches, but since I have no idea how, I probably won't.

 

Thanks to everyone for tuning in and commenting so far. More soon!

 

Kev

 

[mozart]

All’s looking very fine Kev, I’d be happy with that! I did some latches on one of my Tiger Moths using some lead foil, just a couple of pieces cut out and overlaid. 

[LSP_Kevin]

11 minutes ago, mozart said:

All’s looking very fine Kev, I’d be happy with that! I did some latches on one of my Tiger Moths using some lead foil, just a couple of pieces cut out and overlaid. 

 

Thanks, Max. I've actually got some lead foil on order, and have been waiting for it to arrive for over 3 weeks now! It's coming from NZ, but has actually been in Melbourne since the 11th of the month. Perhaps it's in quarantine.

 

Kev

[mozart]

8 minutes ago, LSP_Kevin said:

 

Thanks, Max. I've actually got some lead foil on order, and have been waiting for it to arrive for over 3 weeks now! It's coming from NZ, but has actually been in Melbourne since the 11th of the month. Perhaps it's in quarantine.

 

Kev

I love the stuff, it’s so adaptable and I’m pleased to say that the scoops I made from it which I reinforced on the inside with UV glue are very robust. 

[spyrosjzmichos]

That's some serious conversion work going on!

[Anthony in NZ]

Very very nice Kev!

[LSP_Kevin]

Thanks again, my dudes. Wasn't able to get much more done today, but I did turn my attention to the canopy once again, as this is the crucial area of this conversion, and the build overall. As you might remember, I've been delaying the decision about opening up the canopy until as late in the process as possible. Opening it up would make it easier to get a good fit, owing to fewer mating surfaces having to match up, but it would also expose the cockpit and hospital stretcher, and also require more detailing work on the opened canopy itself. So the decision was going to hinge (pardon the pun) on which was worse: the fit of the vac canopy (= open it up) or the my work in the cockpit and stretcher area (= leave it closed).

 

In order to arrive at my decision, I had to do some extensive test-fitting and adjustments to the various elements involved, including deepening the ledge at the front of the rear spine, judicious sanding of the vac part, and this:

 

 

I carved a recess into the forward fuselage for the new windscreen to sit in, as without it, it would just splay out and look weird. This doesn't exist on the real thing, of course, but was done in the interests of a better result on the model, and shouldn't actually be noticeable in the end. At this point in the proceedings I can say that I'm happy with the cockpit, but not so much the stuff behind it. So the tentative choice at this stage was to keep the canopy closed.

 

Let's do a final test fit after all the adjustments and see what that tells us:

 

 

Doesn't look too bad! You can see that I've already started to add some internal framing from styrene strip, partly to assist with adding more detail if necessary, and partly to make the canopy more stiff and robust. The clincher, however, is the view from the rear:

 

 

There's a fundamental mismatch in the shape of the canopy versus the shape of the resin part where they meet, and I eventually concluded that there was no way of fixing this. If you look carefully, you can also see how dramatically the clear vac part thins from top to bottom, which is why I had to add reinforcing strips to the bottom on each side; on one side, it was so thin it was buckling.

 

So, my final decision is that I really have no option but to open it up! It'll obviate this fit problem at the rear, at least. But another problem lurks, which I'm sure some of you have picked up on already: the clear vac part has the stepped striations from its 3D master evident in its own form, and I don't think anything I can do will make them less noticeable. There's a chance that having the canopy hood open will reduce the visual impact of the issue, but if not, I may have to try to cut the clear panels out and replace them!

 

 

Kev

[mozart]

Oh, ain't life complicated!!   Think of the smug, self-satisfied feeling at the end of the build though Kev.