Build Log of Hobby Boss “Dora” railway gun in 1/72 scale
Part 1
By Richard Geraci
This kit (fig 1) was released in 2010 and is one of 3 models of this weapon available, The other 2 are a 1/144 version from Soar Art which I have previously built (fig 2), and a 1/35 scale monster also from Soar Art which is in my stash. I intend to build this model OOB but will be adding a wooden base, some Preiser figures, and a pair of Hobby Boss BR57 locomotives (fig 3). The Dora was actually assembled at the firing site and not towed there however it was 'nudged' to aim it. With a range of about 37 Km it took very little movement to change the line of fire. Since a fair amount of clear track space is available on the kit base I chose the BR57 locomotive rather than the larger armored BR86 which were used to transport many of the large parts to the site. Neither is historically accurate as the mover per the book Deutsche Eisenbahn Geschutze (fig 4) which I am using as a reference but I want less empty track on the base and the BR86 is too long with the tender attached. Also, a BR57 is shown on the box art so it may be acceptable. Throughout this article I will be noting the cumulative Dora kit parts count thus [#] so you can get some idea of the size of this project.
The Dora build begins with assembly of the track base. This is because about a third of the way thru construction you are to mount the eight rail cars to the track and complete the rest of the build on top of that. I will be building and finishing the base as a separate piece and intend to complete the main part of the gun and later add it to the base and rail cars. The base has parallel tracks and consists of 7 sections plus 2 end pieces (fig 5). Overall size is just under 44” long and 8.25” wide (fig 6). And this is at 1/72 scale! As reference, here is a shot of a rail car wheel, a Preiser figure, and a US Jeep (fig 7). Note the rails themselves are not the correct scale but are much stouter (actually larger than 1/35 scale rails!). The gauge is correct however. You might want to replace the rails with 'OO' (1/76 scale) if you are concerned with accuracy. Also the wheels are too thick on the back side of the rim. You can sand down the back of the 4 end wheels on each rail car to be more accurate (you can't see the others anyway) but you will have to shim out the axle to make up the difference.
And while we are talking about accuracy, there are a couple of rather glaring errors in the kit. First, the axle spacing is off by about .8mm each, 8mm total each side making the rail cars too far apart. You can correct this somewhat if you want by re-drilling the mounting holes 8mm further back and cutting off some of the inside end of the inside rail car body. The wheel spacing will still be wrong but the car placement under the bridge will be better. Also, the barrel is off – way too long. In fact it is an EXACT copy of the Soar Art 1/144 model barrel which is itself incorrect. There are a couple videos on the internet showing where to cut and how much to remove if you are inclined to attempt this. Lastly, while the railings are beautifully molded they are too tall by from 2 to 4mm depending on the location. Keep this in mind if you plan to place any figures beside them. I will not be making any of these adjustments to the kit but I am mentioning them here in case you want to. I am using the box art as a reference for figure placement as well as a photo of Hitler inspecting the weapon.
The base sections fit together nicely but I added sheet plastic gussets underneath across the side seams for more strength there. For mounting to the wood base later, I made a 2” wide strip of 1/2” foam core board about 40” long and glued it underneath the center of the base. Here are the steps I will use for finishing the base:
1.Spray paint the entire base Rustoleum gloss Sand
2.Sponge mottle with light gray, dark gray, brown, and tan acrylic paint. (fig 8)
3.Spray seal with gloss acrylic.
4.Wash with Raw Umber oil paint. (fig 9)
5.Seal with Dullcote.
6.Mask between ties using 5mm x 6” strips.
7.Mask all gravel areas leaving only the ties exposed. (fig 10)
8.Paint the ties Rustoleum gloss Khaki. (fig 11)
9.Lightly wash ties again with Raw Umber oil paint. (fig 12)
10.Seal with Dullcote.
11.Install rails and joint plates. (fig 13)
12.Mask on either side of rail tie plates. (fig 14).
13.Paint rails and tie plates Rustoleum Soft Iron with a light overspray of Rustoleum Rustic Mist.
14.Remove all masking and spray with Dullcote. (fig 15)
15.Highlight top of rail with a silver Sharpie and lightly dull with pencil lead.
Note the sleepers are not dark wood and the base gravel is not gray. Going by color photos of the time (poor quality at best), the base was more like river stone and the sleepers were new wood as the tracks were laid especially for this weapon and therefore would not be aged very much and certainly not creosote treated. The model railbed is actually a good bit darker than the photos indicate. I'll try to do better with later pictures
The wood base is made of picture frame molding, 1/2” maple plywood (fig 16) stained with Minwax English Chestnut, and sealed with two coats of Minwax Satin Polycrylic (fig 17). [61]
The Dora build begins with assembly of the track base. This is because about a third of the way thru construction you are to mount the eight rail cars to the track and complete the rest of the build on top of that. I will be building and finishing the base as a separate piece and intend to complete the main part of the gun and later add it to the base and rail cars. The base has parallel tracks and consists of 7 sections plus 2 end pieces (fig 5). Overall size is just under 44” long and 8.25” wide (fig 6). And this is at 1/72 scale! As reference, here is a shot of a rail car wheel, a Preiser figure, and a US Jeep (fig 7). Note the rails themselves are not the correct scale but are much stouter (actually larger than 1/35 scale rails!). The gauge is correct however. You might want to replace the rails with 'OO' (1/76 scale) if you are concerned with accuracy. Also the wheels are too thick on the back side of the rim. You can sand down the back of the 4 end wheels on each rail car to be more accurate (you can't see the others anyway) but you will have to shim out the axle to make up the difference.
And while we are talking about accuracy, there are a couple of rather glaring errors in the kit. First, the axle spacing is off by about .8mm each, 8mm total each side making the rail cars too far apart. You can correct this somewhat if you want by re-drilling the mounting holes 8mm further back and cutting off some of the inside end of the inside rail car body. The wheel spacing will still be wrong but the car placement under the bridge will be better. Also, the barrel is off – way too long. In fact it is an EXACT copy of the Soar Art 1/144 model barrel which is itself incorrect. There are a couple videos on the internet showing where to cut and how much to remove if you are inclined to attempt this. Lastly, while the railings are beautifully molded they are too tall by from 2 to 4mm depending on the location. Keep this in mind if you plan to place any figures beside them. I will not be making any of these adjustments to the kit but I am mentioning them here in case you want to. I am using the box art as a reference for figure placement as well as a photo of Hitler inspecting the weapon.
The base sections fit together nicely but I added sheet plastic gussets underneath across the side seams for more strength there. For mounting to the wood base later, I made a 2” wide strip of 1/2” foam core board about 40” long and glued it underneath the center of the base. Here are the steps I will use for finishing the base:
1.Spray paint the entire base Rustoleum gloss Sand
2.Sponge mottle with light gray, dark gray, brown, and tan acrylic paint. (fig 8)
3.Spray seal with gloss acrylic.
4.Wash with Raw Umber oil paint. (fig 9)
5.Seal with Dullcote.
6.Mask between ties using 5mm x 6” strips.
7.Mask all gravel areas leaving only the ties exposed. (fig 10)
8.Paint the ties Rustoleum gloss Khaki. (fig 11)
9.Lightly wash ties again with Raw Umber oil paint. (fig 12)
10.Seal with Dullcote.
11.Install rails and joint plates. (fig 13)
12.Mask on either side of rail tie plates. (fig 14).
13.Paint rails and tie plates Rustoleum Soft Iron with a light overspray of Rustoleum Rustic Mist.
14.Remove all masking and spray with Dullcote. (fig 15)
15.Highlight top of rail with a silver Sharpie and lightly dull with pencil lead.
Note the sleepers are not dark wood and the base gravel is not gray. Going by color photos of the time (poor quality at best), the base was more like river stone and the sleepers were new wood as the tracks were laid especially for this weapon and therefore would not be aged very much and certainly not creosote treated. The model railbed is actually a good bit darker than the photos indicate. I'll try to do better with later pictures
The wood base is made of picture frame molding, 1/2” maple plywood (fig 16) stained with Minwax English Chestnut, and sealed with two coats of Minwax Satin Polycrylic (fig 17). [61]