Building a Type 4 Ho-Ro, Part II

Type 4 Ho-Ro

Type 4 Ho-Ro

The gun was a challenge to make look appropriate for this vehicle. The Ho-Ro’s gun was based on

Gun barrel I used (note: the barrel has already been cut from the supporting resin-I forgot to take a proper “before” picture!)

Original sIG33 gun

the German sIG33 150mm gun. Now, I can do straight and angled construction fairly well – curved pieces just plain drive me crazy. So, I purchased a sIG33 sculpted by Mike Broadbent and available through JTFM Enterprises/Die Waffenkammer. The basic shape was what I needed though some modification would be required. First the recoil mechanism supporting the gun barrel was removed as it was not correct and was too big to fit through the shield. The extra bit sticking out of the rear was also removed. The supports that held

Gun in progress

the gun and hand cranks were removed for later use (I only needed the latter). All of the rough edges were sanded smooth. A rectangular piece of plastic was covered with another, slightly wider piece, set underneath the gun barrel and pinned in place. A tube was

Gun nearly finished

filed flatter on two opposite sides and placed perpendicular to the underside of the rear of the gun. A hand crank pinned to a rod would form one handle. The middle of the underside of this was filed with a round file to make a groove for the second handle coming directly back from the gun. The loading area of the gun was made by taking a hollow tube and covering it with sheet plastic and filing it to match the circle. A small piece of rod was glued to the back center. A piece of 0.3mm plastic was glued underneath the gun read edge and pulled around until it met the start. This glued into place easily and the extra lump of overlapping plastic on the bottom was easily filed flat. A piece of scrap rectangle was cut to match the shape of the hinge and filed to give it a rounded appearance. What looked like a periscope from the gun

Periscope detail from sIG gun carriage (note-the circular resin handle was cut off and re-used)

carriage of the model was cut and glued to the side of the gun. Again, trial and error were used to get this set up where the periscope piece could fit nicely on the side of the gun, look through the left front port and not interfere with the left handle. I did have to cut the left handle off, re-drill the hole and re-glue a shortened handle into the gun as the original set up looked crowded (the handle was in the way of the periscope). The lesson learned here is to

Finished gun in place

set everything up first, then glue it all at one time. This is a lesson I know I will forget. Details to the front of the gun recoil mechanism were made by drilling a plastic rod and inserting a pin for support and removing it before filing the cone end to give it a slightly pointed appearance. This was pinned into place. Supports on the sides were more “H” brackets converted to a “U” with a thin rod extending to the front; this was glued onto a triangle of 0.3mm plastic. Small Archer rivet decals were used for detail as well. Try as I might, I could not make small enough plastic bits to hold the rods in place so this was made with ProCreate; this putty was also used to fill the gap under the barrel. The JTFM gun was the best $12 I spent on this project. More trial and error was used to fit the gun into the crew compartment and the gun was pinned onto a piece of spare wood for security and glued into place.

Lateral vent template (note cut out near the muffler)

As with most projects I have done, I had several ‘oh my’ moments. These are times when I

Vent slots (later filed even though most of this detail will be covered)

realize I have absolutely missed something or, despite months and weeks of research, find something completely new. This happened after I completed the engine exhausts on the sides. A 3×5 card’s stock was used to make templates to match the shape of the sides of the engine top. These helped form the shape of the outside of the vents that were cut from 0.3mm plastic which had the center cut out and a semi-circle cut to accommodate a pipe going to the muffler. Looking at the top of the model’s engine, the exhaust vents are not made from flat but round plastic rods! This was a very neat way to make the side ports which worked very nicely. It was odd that several of the top down drawings did not show these ports; the 1/35th scale model also did not show them clearly. It was only when I found a clearer

Side vent covers

version of a blurred period photo that I realized there was a ‘wing’ of metal covering the ports! This would have obscured the ports’ view from above and made sense – venting hot engine gasses to the sides is an excellent way to not cook the live ammunition resting on top of the engine. This was confirmed by taking a closer look at photos I had on file. Sure enough, the ‘wings’ could be made out. By a neat quirk, the templates that were used to make the side vents worked perfectly to help shape the overhanging ‘wings’ on the sides of the engine.

While doing this the second and more annoying ‘oh my’ event occurred. A good look at the pictures showed that I needed to move the open crew compartment back another 2-3mm. Crap. I blew it off at first until, when gluing final pieces into place around the edges of the rear of the compartment, I realized it just did not look right. I had originally balked at making the change because I was worried about damaging the existing structures in place. Sigh. There was nothing to do but press on. I lined out the areas to be cut and drilled through the resin with my hand drill closely enough to use an X-Acto to cut from one hole to the next. The large metal file smoothed everything out rather nicely so it was significantly easier than expected, caused no damage and looked much better.

Japanese crew

The part of this entire project that vexed me the most was the construction of the inner crew section. If it was too shallow or deep the figures (the Company B Ho-Ni crew) would not look right and the effect would ruin the project. But how to determine the proper depth? I had to revert to the tried and true method of ‘hit or miss.’ After much fussing and positioning of figures on a flat rectangle of plastic supported on clay (that allowed adjusting by pressing down) I found the best depth (8mm from the base of the vehicle).

Floor supports

My small 6-inch ruler would not easily fit in the hollow of the SPG, so I cut a template from a 3×5 card to draw lines inside the hollow. More scrap was cut to make four 8mm ‘legs’ to support the floor. These were held together with a small clamp (more cool stuff available from Micro-Mark) and made level by drawing them over a large metal file. Glued in place, they

Underside of crew compartment, glued in place

supported the floor. Before final gluing, I tested the crew figures and was pleased with the final level. The rear part of the inner compartment would need to be constructed by hand with careful filing. I used a 0.4mm-thick piece of plastic for this purpose. It is just thick enough to be sturdy yet is thin enough to be filed easily and quickly. More filing, testing, more filing and testing happened before I was happy with the fit. Again, I used model glue to initially put it into place because I anticipated needing to slide it into position and Crazy Glue would likely fix too quickly; once the rear, main floor and front wall of the crew compartments were in place, this was used to permanently hold them securely.

The last non-rivet work needed was to the top of the shield, adding two handles and the scope thing. I used some left over straight pins, grabbed it securely in some old surgical clamps and bent one end to 90⁰ with the flat edge of a set of needle nose pliers (those are my little boy’s hands in the ‘posed’

Bending wire

photo). The gun shield was made by gluing a thin piece of plastic on top of a thicker piece of

Marking hole to drill

plastic. This gave a small groove to the edge of the shield to allow me to use the pointed part of an older knife (new knives will not work and simply break the new point) in a circular motion to make it easier to use a very small drill bit, another ‘gotta have’ item from Micro-Mark. Using a smaller drill bit to make the initial hole, I used a larger, more appropriate bit to finalize the hole and make it appropriate for the pin thickness. The wire of the handle was trimmed back to make the fit easier. I placed the pin into the first hole, saw where the second hole should be drilled and marked the spot with a mechanical pencil. The second hole was drilled like the first and the handle moved into place first before gluing (excess glue was removed with a rolled tip of paper towel. The process was repeated for the second handle. With the periscope glued on the top left of the gun shield, all the non-rivet work was complete. Well, almost complete. Looking at the gun barrel, the most forward part was too long. This was easily corrected by carefully cutting it off with a razor saw, filing the front edge flat and drilling out the gun tube. Easy stuff.

Straight pin wire handles x2

Hand drilled rivets-very neat and pretty looking!

I learned something neat and new for making rivets. Instead of cutting and gluing individual rivets on each surface or using decals to put them into place (with the risk that they may be rubbed off): use a hand drill and drill a hole into the resin. Cut and place a cylinder of plastic into the hole; sand/file as appropriate. Glue in place with liquid glue (model, not Crazy Glue) which will round the edges of the cylinder to make it more rivet-looking. That is a really cool trick!

The final part of construction included placing rivet decals on the sides and above the upper view port. I marked out lines where

Finished front-note the shortened front barrel

the rows of rivets would go; cross lines showed where the decals would specifically go on the model. Because the rivets on the sides of the gun shield look a little bigger than those on the hull, I used some plastic rivets I bought from a railroad shop. I These I glued in place with Crazy Glue and then moved on to the rivet decals. Archer makes an awesome set of decal sheets with rivet designs. They really work well and look good though I do wish they made some that were a little bigger. As with all decals, these stick best on a gloss surface; after a light gloss coat to protect the model, I cut three decals from the page very closely to the edge of the decal for use on the upper view port. These moved into place nicely, however, I failed to put a second level of gloss protection to hold them in place and two were knocked off, likely brushed off while handling the vehicle. I hate having to do things twice. I lifted the front on a piece of clay to get a better view of the front gun

Side view-rivet details, shortened gun barrel

shield and blocked the back of the SPG with another piece of clay to stabilize the vehicle before applying the decals. Cut individually and dropped into water (I used an eye dropper to fill a spare paint lid with 2mm of water), I patiently waited until each looked ready to go (I staggered the time when I put them into the water so I had a steady supply to apply). Picking the decal up with either the point of an X-Acto or damp paint brush, I placed the decal near where I wanted it to go and slid it off the paper. A wet paint brush works nicely to move and reposition decals. Those that are nearly but not strongly affixed can be re-worked by taking a wet paint brush and loosening the seal to allow repositioning. I did the entire side of the SPG, let the decals dry and sprayed it lightly with clear gloss paint before working on the other side (28 decals placed per side – it sounds like a lot but it was a straight forward and simple process.) The final decal rivets were placed on the thin plastic strip to the rear of the crew compartment, gloss protected and the project build was complete – yay!

Four views of the finished Type 4 Ho-Ro self propelled gun

The next part of this project will include airbrushing and painting though I might need the garage to warm higher than the current 35⁰F before I can get to that. This was a project that I worked on and off for several months, putting in a hard push to get it done for the initial issue of the Historical Minis Dot Com website. Once finished, I figured that if I made two more I would have about as many as the Imperial Japanese Army fielded in action in WWII!

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