Mk1 gun carrier scratchbuild

[Model Mate]

Hi folks…!

 

Well the dust has thoroughly settled on my Pierce Arrow AA truck, and so it’s time to consider the next project. I had a bit of a palate-cleanser in the form of the Vickers gun crew that I bought to provide a decent machine gun to clone for the last scratchbuild. I stuck the two chaps and their weapon together and mounted them on a little round base made from a piece of insulation foam stuffed into an olive jar lid as a figure painting practice more than anything, and rather enjoyed it, though I still seem to be struggling to improve my figure painting skills.

 

 

 

So the stash is empty and I admit that I can’t really get myself excited about kits – it needs to be another scratchbuild. Trawling the Landships II website, I came across this vehicle….

 

 

The mighty Mk1 gun carrier. Based loosely on a Mk1 tank, it was intended to be the first self-propelled gun, carrying either a 6” howitzer (as above) or a 60 pounder. The 60 pounder was too ferocious a weapon to fire in-situ, so had to be demounted for firing, but the howitzer could stay on board while it did its damage. Strategically the opportunity never really came up for these vehicles to fulfil their intended role, so they were converted into supply tanks, recovery vehicles and ad-hoc troop carriers it seems.

 

Panzerart do a kit (a whole series of them covering all the variants in fact) but it’s very expensive, and pretty hard to get hold of. Also, being resin, not terribly appealing to me. I seem to have developed an allergic reaction to superglue, so too much of it during a modelling session and I sneeze for days and my eyes are streaming. This doesn’t promise an enjoyable build experience!

 

It’s a beast of a vehicle, slab-sided and covered in rivets – yeah! So ripe for scratching!

 

The Landships II site contains a good bit of background info and more importantly, an excellent and very detailed cardboard model template and instructions produced by Clifton W McCullough. He’s provided both the vehicle itself and the howitzer, and just building the cardboard model would be a considerable challenge and should produce an excellent and highly detailed model, including interior detail and engine – really impressive stuff.

 

Of course I’ll tweak his cardboard instructions and template to get the thing constructed from plastic.

 

I kind of have a kit after all with these excellent templates, so time to assemble the other necessary ingredients. I ordered 5 A3 sheets of 0.75mm plasticard plus a number of A4 sheets of 0.5mm and 0.2mm. The rivets on my last couple of projects went pretty well using “nail caviar” – small decorative balls intended to be glued onto one’s digits. I’ve got these in 0.6mm, 0.8mm and 1.0mm, but the 0.6mm ones are rather irregular in both size and shape. For the Pierce Arrow I used 0.8mm which are much more consistent, but really way too big when the finished model is compared to photos. A search on ebay for “0.4mm balls” came up with solder balls – ah-ha! I ordered some 0.2mm and 0.4mm. The 0.2mm are unbelievably tiny – more like dust than visible balls, so I don’t think I’ll have much use for these, and the 0.4mm are really the smallest I’ll consider for rivets. I’ll order some 0.6mm as well. The consistency of these solder balls seems to be absolute – 0.4mm really is 0.4mm. To go along with these, I ordered a bunch of drill bits – 0.15, 0.35, 0.7 and 0.9mm – 10 of each, as they’ll snap as soon as look at them. The idea is that the balls sit in/on holes slightly smaller than the balls’ diameter. A slosh of Tamiya extra thin creates a tiny crater, and they’re held in place that way. Talking of which, I also ordered a bottle of Tamiya airbrush cleaner, which I’m led to believe is exactly the same stuff as extra thin cement, but much cheaper.

I inserted the template images into CAD software and re-scaled them up to 1/35 (the originals are intended to produce a 1/48 model), tracing over most of the major detail to get nice, sharp images. The parts were re-arranged to make best use of the A3/A4 size and they were printed out – here’s a typical sheet:

 

 

As usual, these will be spray-mounted onto the plastic, drilled for rivets and cut out, and so it begins!

[Bertie McBoatface]

Ohh this looks interesting. Good luck with the project!

[Model Mate]

thanks Bertie - It's going to be a long journey! I'll be referring to your excellent Mk V build quite a lot I imagine.

[Courageous]

Gotta love a scratch build.

 

Stuart

[APA]

This is going to be interesting. Just hope you don't get riveters wrist 😉

 

Andrew

[ColonelKrypton]

I will be following along looking forward to how this build of such an interesting vehicles develops. 

 

cheers, Graham

 

[Bandsaw Steve]

Great subject. Will be watching closely. 

[Model Mate]

Off to a slow start….

 

In an effort to avoid complete mental collapse, I’ve decided I need to find ways to reduce the rivet count in the build-up of this beast and so my first thought was “what bits can I cast in resin?”. When there are only two or three similar parts I tend to scratch each one, but where I have smaller items that repeat more than this, I consider breaking out the silicone and resin.

 

For this one, there don’t appear to be too many components that are repeated unfortunately. There are the track links, which are a no-brainer for casting, and “trolley” wheels/rollers for the gun frame (which I’ll need to research a little to determine quite what they look like in detail). There are also, in the cardboard-template kit I have to work from, a number of applique rivetted strips – 3mm wide with either single or double rows of rivets. 

 

After splurging out on my new tiny, tiny balls and even tinier drill bits, I’ve actually come to the conclusion that the 0.8mm nail caviar I used for my last build is appropriate for this vehicle after all. 0.8mm scales up to 28mm in real life, which doesn’t seem unreasonable at all for a heavily armoured tank like this. A bit much for the thinly armoured Pierce Arrow, but fine for this I think….. anyone out there know what size WW1 tank rivets are/were?

 

Track links first: I cut a strip of 0.5mm card the correct width of the tracks, marked out positions for the (flattened) rivets with a pin and drilled holes using a 1mm bit. Lengths of rod were pushed in and set to a regular height by pushing it face-down onto the world’s simplest jig of 0.2mm card to get the penetrations regular – the aim is to get them just proud of the plate. A slosh of TET and snipping off the back bits and (almost) done. They just need sanding at the back to remove the stubs, adding the leading curve and cutting into individual links. When I first tried this track-link casting for my Whippet, I only made 4 prototypes, so had to cast at least 50 times (50% success rate), so in order to reduce the number of casts, I’m making up 12 links this time, with 8 of them in a strip, and 4 individuals. Say 160 links at 50% success should mean no more than 26 castings which is a big improvement.

 

 

Next up, the applique strips. I cut (3mm wide by 0.5mm card) and drilled (0.7mm holes) the first one at a random (but longer than the longest needed) length. The whole strip was glued down onto a slightly wider 0.2mm card strip and the balls were glued into place. The idea of the 0.2mm backing is to provide a guide in sanding them down to the correct thickness. I’ve found when using a single-face “open” mould, that the resin will need sanding back, so this “flash” should give a guide as to when to stop. I’ll use the same plan for the track links.

 

 

[APA]

Quality start MM. Could tell me where you got what your tiny balls are called please? 

 

Andrew 

[Model Mate]

1 hour ago, APA said:

Quality start MM. Could tell me where you got what your tiny balls are called please? 

 

Andrew 

search ebay for "nail caviar" or as I've recently discovered (also on ebay) "solder balls". Both are available in a variety of sizes, though 0.8mm seems to be the smallest size of reliable nail caviar - solder balls go right down to 0.2 which are all but invisible!

[diablo rsv]

Fascinating stuff. I enjoy your scratch builds so I shall watch this one with interest. There is always something to learn from you guys. 

I wish I had the patience/ time to attempt one.

Wayne

[APA]

1 hour ago, Model Mate said:

search ebay for "nail caviar" or as I've recently discovered (also on ebay) "solder balls". Both are available in a variety of sizes, though 0.8mm seems to be the smallest size of reliable nail caviar - solder balls go right down to 0.2 which are all but invisible!

Thanks MM. Just did a search and found some solder balls 0.06mm I'll try not to sneeze 🤣

 

Andrew 

[ColonelKrypton]

7 hours ago, Model Mate said:

anyone out there know what size WW1 tank rivets are/were?

 

An excellent question and one to which I have not yet found a reliable answer.

 

In case you were not aware, rivet sizes are given to the diameter of the shank - not the diameter of the head.  I knew that when I was thinking something like pop rivets ( i.e. blind rivets ) but never made the connection to the larger steel construction type rivets.

 

I recall reading somewhere about the construction of the Eiffel Tower where a list of rivet sizes and their cost per 100kg was given - the largest size was 25mm. So, a 25mm rivet with a 25mm shank would have a head diameter of about 44mm not quite twice the shank diameter. That 25mm / 44mm diameter relationship comes from a document I found describing button head rivets and their sizes where a 1 inch rivet ( shank diameter remember ) would have a head diameter of about 1-3/4 inches.

 

I have searched through various model railroad forums for rivet information. After all, many early armoured vehicles where built by locomotive builders, for example Montreal locomotive works, Baldwin locomotive, etc. I have not yet found a lot but I did find this interesting online magazine published by Model Railroad Hobbyist where their August 2011 issue has an interesting article on rivets:

 

http://macrodyn.com/assets/files/MRH11-08/MRH11-08-Aug2011.pdf

 

All of their back issues are available online and they are all free: https://model-railroad-hobbyist.com/magazine/back-issues

 

I like trains but I am not a model train enthusiast. However these model train magazines do contain a great deal of interesting stuff which is applicable to all genres of model making.

 

I quite like your use of the nail caviar for riveting and I have been playing around this technique for some time. I have also worked out a way to make rivets using jewellers beading tools and cup burrs.  Once I get organized I will post some more on the later. 

 

Here is a teaser:

 

 

on the small grey piece on the right, for reference the brown rivet heads are Tichy Train rivets of 0.020" (0.5mm), 0.0.25" (0.6mm), and 0.030" (0.75mm) smallest on the bottom, all of the others were made using the jewellers beading tools and the large rivets on the idler and drive wheels are bout 1mm.

 

Gonna stop now lest you think I am trying to hi-jack you WIP.

 

cheers, Graham

 

 

[Model Mate]

That’s some great info, and lovely looking rivets, thanks Graham!

[Model Mate]

I completed the track sections, adding 1mm rod leading edges/curves and rounding off the corners a little. I then glued them back together in a row of 8 and as individual links.

 

These were stuck onto 0.2mm “flash” strips and in turn onto a piece of HIPS foam board (slightly squishy 5mm thick plasticard). The same was done for the applique rivet strips, and both were boxed up ready for silicone mould creation.

 

I also knocked up 26 roller wheels for the gun carriage/sled from pieces of plastic tube and rod.

 

And onto the bodywork; slightly more exciting!

 

I drilled out the rivet holes and then cut out and scored the template for the driver’s (left hand) side cabin. I've learned with these sratchbuilds to drill the rivet holes before cutting out the panels to avoid trying to drill right next to a cut edge which can be very tricky. Also, not to add the balls until later to minimise the amount of "ball-loss" (nasty).

This thing is full of hatches – left, right, front, rear and top – and from what I can see in photos, they were often open. I guess it must have been particularly hot and/or noisy in these tin coffins. I didn’t cut the inside-facing hatch out as it was all looking a bit fragile.

 

I then swiped the pieces with a touch of white spirit and the paper (spray-mounted) slid off nicely. I had a particularly dull work meeting (on Teams) so took the opportunity to glue it all together.

 

I guess I got a bit carried away, because it now occurs to me that detailing the interior could be a little tricky… also, I’ve concluded that the roof hatch is unlikely to be open, so I could stiffen the whole thing up a bit if I didn’t bother cutting it out. The rear hatch frame is also tremendously delicate so I may re-make this whole unit with just the front and side doors cut out. One of the benefits of scratchbuilding is that if it doesn’t go to plan, you can always re-do it!

[APA]

So

 

 

 

many

 

 

 

rivets

 

 

 

 

😳

 

 

Andrew

[Model Mate]

I’ve decided I need to step back and approach this a bit more methodically rather than dash in and start cutting and gluing with abandon – this is a really large and complex job, so needs a bit more respect.

 

I assembled the various bits I need – various rod and tube stock, my rivet kit, and a re-printed set of plans that make more efficient use of the plastic sheets. I also ordered some hexagonal rod to form bolts and nuts where I need them. I did a little trial piece to test these out, along with the two rivet sizes (0.8 and 0.4mm) that I plan to use.

 

And so I started by re-making the cab, although I tackled the right hand side one first this time. I cut out the parts and decided to cut out the hatches after all. The paper plans show these exactly same size as the hatches themselves, so I cut them slightly smaller to give a bit of overlap which made it all a little less fragile. I then glued one side together and detailed the interior with the thin support frame/straps and 0.4mm rivets before fixing the final panel in place.

 

The outside rivets will be stuck on a bit later. From photos it’s clear that the cabs were constructed from lighter steel than the main body of the vehicle, so I’ll use 0.4mm rivets for most of it. I’ve found that these will stick nicely into pin-gentleman's parts holes, so that’ll avoid having to drill the tiny 0.35mm holes on the other cab at least. Once together, I glued a 0.5mm roof hatch in place with hinges added from 0.2mm card and thin rod.

 

With that drying, I started the gun sled. This went together ok, with 0.8mm rivets on the bottom rails. There’s a hinged shoe/blade type arrangement fixed to the front of this, for which the card instructions use four supporting “feet” made from multiple thicknesses of card to get up to the required overall width. Looking at some other plans and photos, these appear in reality to be relatively thin plates, with a flange running around the outside and a collection of webs and gussets inside. I cut these from 0.2mm card and some lengths of plastic rod. The bottom plate was made from 0.5mm card which was scored and bent front and back to create the necessary curves. Lengths of very thin plastic rod were glued into the scored cuts, slathered with extra thin cement and then sanded smooth.

 

[Model Mate]

On 25/01/2022 at 20:22, APA said:

So

 

 

 

many

 

 

 

rivets

 

 

 

 

😳

 

 

Andrew

yes - it's a pig. I've refined my technique(s) though, so althought it's time consuming, it's really not too difficult, and I'm getting pretty consistent results now.

[ColonelKrypton]

3 hours ago, Model Mate said:

I’ve decided I need to step back and approach this a bit more methodically rather than dash in and start cutting and gluing with abandon – this is a really large and complex job, so needs a bit more respect.

 

Well stated. I tend to dash right in whenever I just feel like I want to just get started building something in spite of having learnt over the years that a bit of planning makes for a better and less frustrating build.

 

We don't thank those who post work in progress ( WIP ) builds enough for all of the effort required to post such topic threads. Thank you, it is a real treat to able to read your WIP and benefit from your discussion on how you have approached your build and the many techniques and ideas used.

 

I have done some more messing about with the nail caviar that you have been using for riveting. I have some of the 0.8mm size in silver and gold coloured and also found some nearly clear type in sizes from very small ( 0.4 to 0.5mm ) up to about 3mm that were all mixed up in the same lot; 100g for only a few dollars.  I have been using a dollar store salt shaker to separate the large from the small to make them easier to sort by eye.

 

Your use of Tamiya extra thin cement does let you fix them in place well enough but as you have found does not really cement the balls in place as if you where cementing two pieces of styrene together.  With that in mind I tried over a half dozen other types and formulations of common plastic solvent cements but nothing would touch these nail caviar balls. I got to wondering just what they are made of.  I couldn't cut or nick them with a sharp blade and a file barely marked them. They are advertised as Acrylic Nail Caviar or Acrylic Nail Art or use similar wording the implication being that they made from acrylic.  I am thinking that while they are being correctly being describe that in reality they are simply being described as something for use with Acrylic Nails.  To cut to the chase, acrylic plastic will melt and burn with the application of flame ( small butane torch ) but these nail caviar balls do not burn instead will turn red hot and can then be squished. I am now quite certain that these tiny balls are made of glass and not of any sort of plastic or resin.

 

cheers, Graham

 

[Bertie McBoatface]

4 hours ago, Model Mate said:

I’ve decided I need to step back and approach this a bit more methodically rather than dash in and start cutting and gluing with abandon – this is a really large and complex job, so needs a bit more respect.

 

I wish I knew when to be methodical and when to be abandoned!

 

This build is astonishing me, as is the thread. You have MY respect if that's any use to you. 😁

[Model Mate]

2 hours ago, ColonelKrypton said:

 

Well stated. I tend to dash right in whenever I just feel like I want to just get started building something in spite of having learnt over the years that a bit of planning makes for a better and less frustrating build.

 

We don't thank those who post work in progress ( WIP ) builds enough for all of the effort required to post such topic threads. Thank you, it is a real treat to able to read your WIP and benefit from your discussion on how you have approached your build and the many techniques and ideas used.

 

I have done some more messing about with the nail caviar that you have been using for riveting. I have some of the 0.8mm size in silver and gold coloured and also found some nearly clear type in sizes from very small ( 0.4 to 0.5mm ) up to about 3mm that were all mixed up in the same lot; 100g for only a few dollars.  I have been using a dollar store salt shaker to separate the large from the small to make them easier to sort by eye.

 

Your use of Tamiya extra thin cement does let you fix them in place well enough but as you have found does not really cement the balls in place as if you where cementing two pieces of styrene together.  With that in mind I tried over a half dozen other types and formulations of common plastic solvent cements but nothing would touch these nail caviar balls. I got to wondering just what they are made of.  I couldn't cut or nick them with a sharp blade and a file barely marked them. They are advertised as Acrylic Nail Caviar or Acrylic Nail Art or use similar wording the implication being that they made from acrylic.  I am thinking that while they are being correctly being describe that in reality they are simply being described as something for use with Acrylic Nails.  To cut to the chase, acrylic plastic will melt and burn with the application of flame ( small butane torch ) but these nail caviar balls do not burn instead will turn red hot and can then be squished. I am now quite certain that these tiny balls are made of glass and not of any sort of plastic or resin.

 

cheers, Graham

 

yes, I think they're glass, and the solder balls I'm now using for the smaller rivets are well, solder, so metal. Thankfully the extra thin seems to (usually) be enough to hold them in place at least for a while and if some do pop off, they're easy enough to replace. I don't generally like to prime my models, but using Halford's automotive plastic primer really helps to add the final grip before I start painting.

[Mike]

Very nice work.  I've always wanted to do a Mk.9 Pig, the first real APC, but never seem to get the time to attack it.  Accurate Armour do a few different sets of WWI British tank tracks in resin in case you wanted to save yourself the hassle of casting more for any other projects

[Model Mate]

20 hours ago, Bertie Psmith said:

 

I wish I knew when to be methodical and when to be abandoned!

 

This build is astonishing me, as is the thread. You have MY respect if that's any use to you. 😁

thanks Bertie - high praise coming from you. I'm really glad you're enjoying this thread.

[Bertie McBoatface]

4 minutes ago, Model Mate said:

high praise coming from you

 

That's very flattering but I'm not really in your league as a modeller - not yet!

[Bullbasket]

Wow!! Just catching up on this (hence all of the likes), and my gob is well and truly smacked. I like a bit of scratch building and some riveting, but you've taken this to a whole new level. It's a master class. Keep going (at least until the men in white coats come calling!)

 

John.