19 May 2011

Realistic Tow Cables for Armored Vehicles - Part 1

This post is going to show how I made realistic tow cables for my current build of Tamiya's US Army M1A2 Abrams Main Battle Tank. 

The boxart for the Tamiya 1:35th scale Abrams M1A2 Main Battle Tank

What inspired me to replace the kit offering is two-fold. One, it is very difficult to remove the mold seam from a detailed plastic part such as a tow cable without creating flat spots or eradicating the fine detail. Two, I broke the plastic cables while I was removing them from the sprue. While repairing the breaks is possible by using solvent cement or super glue (cyanoacrylate), I would still risk further damage during the clean up after the repair was made. 

With this in mind, I set out to find a way to add more detail by using other materials I have at hand. I remembered a demonstration at an IPMS Niagara Frontier meeting conducted by Master Modeler Joe Szczygiel where he used common picture-hanging wire for a variety of modeling super-detailed parts. I scrounged through my garage and found a small spool of said wire and went about seeing if the scale was correct for what I wanted to do...and it was.

Parts needed to modify broken kit parts to rebuild wire rope tow cables. Clockwise from the top: (1) broken plastic kit cables; (2) spool of twisted strand picture hanging wire; (3) Kit plastic tow-eyes dry-fitted to the wire; (4) Kit plastic tow-eyes ready to be mounted to the wire. Note how the wire has a more natural and realistic look to it than the plastic parts.
To begin the modification, cut the tow eyes from the kit parts by using nippers, a razor blade or fine saw. My preference is to use a standard No. 11 Xacto blade. Sand the butt end of the eye flush. Take the tip of the Xacto blade and press a divot in the plastic. Make it in the dead center of the butt end. This is going to be the pilot hole for drilling into plastic kit part with micro drill bits. Using a small micro drill bit in a pin vise, start drilling out the plastic. Be careful not to go through the part and keep the bit centered. It should be as straight as possible. Use progressively larger diameter drill bits and test fit the wire cable ends periodically. Stop drilling when the wire can be easily inserted into the tow eye. If you see the close-up in the photo above, this is what you're trying to achieve.
The end result of micro-drilling into the end of the tow-eye to accommodate the end of the wire cable. Test fit periodically to ensure the cable is a tight fit. Keep your drilling as straight as possible and do not drill through the part.

The next step is to test fit and cut the cables to the proper length and then secure them into the tow eyes. On the Abrams, the tow cables are mounted to the sides of the turret along the lower edge. I have inserted the cable into the eye and secured it with thin super glue (not pictured, but is at the far left of the picture, out of view). That end was tacked in its proper place per the kit instructions and the cable laid along the base of the turret. Take the other tow eye and place it where it belongs on the turret. You can accurately measure the length needed with ruler or use your eye to guesstimate the length (that's what I did). Mark the cable where you want to cut it. I use a fine point Sharpie marker. Cut the cable and insert the second tow eye. Secure it with a drop of super glue.

Here the modified cable is being held against its mounting point on the Abrams turret to test fit its proper length

Marking the cable with a black marker to indicate the proper cut

Here is the finished product. The tow eyes were removed from the broken kit parts and any mold seams cleaned up. The sockets for the wire were made by drilling holes with progressively larger sized micro drills until a firm fit was obtained. The cables were inserted into the tow eyes and rotated until they were aligned properly for mounting to the turret of the tank. Finally, the cables were secured into the sockets with drop of super glue applied with a fine wire applicator.
Finished modified tow cable ready to be mounted to the Abrams turret

The Abrams MBT is equipped with two sets of tow cables, mounted on either side of the turret. Even though I broke only one of the kit parts, I still replaced both of them with the above described methods. I did this to ensure both looked the same. To me, the twisted wire cable looks far more accurate than what is provided in the kit. The total extra time I spent scratchbuilding them was about an hour. This is about the same amount of time I would have spent trying to scrape and sand the mold seam off of the plastic kit parts, but yielded a far more accurate product.

In my next installment, I will show how I reproduced the ferrules (the metal sleeves at the base of the tow eyes to prevent unraveling). on the cable and how to mount them to the turret using brass wire.  A 21-gun salute of thanks goes to Master Modeler Joe Szczygiel of IPMS Niagara Frontier for mentioning the picture hanging wire as a means of scratch-building many things in miniature.