Aircraft Racer Part 1

These are two photos I found on Pinterest and they gave me a real use for many of my older aircraft  model kits where the plastic is brittle and the decals are shot. Subsequentally I have found a lot more, some where the fuselage is reversed just to be different. The idea of making an even vaguely sensible vehicle is new to me and as ork buggies do not qualify, I faced the dilemma of proper wheels and suspension, things I have taken for granted in the past.

This is an old Matchbox Bf109 in 1:32 scale so it is a good size and should lend itself to a nice level of detail. I did not count on the fragility of old plastic because when parts did not quite fit they decided to break, hence the large amounts of filler employed in the construction. The wings were cut off to stubs and the tail plane removed to be rounded off with car body filler or bog. One unfortunate thing happened in trying to get an overall impression of the car with its canopy in place, I bumped my arm and the 3 part canopy decided to separate with the only essential part, the front screen disappearing down the back of the largest, heaviest cabinet in my workshop. Oh great!

Forget this for a while, I can always empty the thing and muscle it away from the wall to retrieve the bit later, now however there is the problem of wheels. Even though the main part of this build is a kit bash, I do not have suitable wheels for a car of this size (lots of 1:35 tank wheels, much too small) and as I am a scratchbuilder by preference, my wheels would be made by me.

These show the process I used. I made a master wheel half, cast it then joined the halves to complete the wheel. The top pic is a circular screeding jig made to form a sausage of Apoxie Sculpt into half of a tyre and happily, it worked! Wonders never cease. A ring of copper wire was added to form a wheel rim and a central hub as well then the whole was cast in silicon rubber. In the lower pic the grey master, pink mould and white TC890 resin cast can be seen. From the shadow in the final cast you can see that there is a reasonable wheel well and this is adequate to hold the brake drum etc.
Two of these cast halves were joined to make a slick tyred wheel 52x13mm and all I had to do then was make 3 more.
Now came the bigger problem of suspension, that mass of struts, springs, rods and stuff that joins the wheel to the body.This would be so visible in the model that it had to be done well enough for my engineer friends to look at it and nod in the affirmative. I did a lot of research and became  thoroughly confused with the plethora of systems that have been employed over the years but, in breaking up a superfluous to requirements Tamiya Sd.kfz 222,( a small armoured car), I found a suspension that could do the job. The next three pics are of this arrangement and its main constituents are two large vertical springs partially enclosed in cylindrical supports.

 

 

 

 

 







Here is a sketch of the suspension to help me decide on what I had to build and the dimensions that would suit the size wheel I had.The resultant size was about four times the small model and so basically every dimension was doubled, giving a X4 ratio for the two measurements of length and breadth.

 

 

This shows lengths of copper wire resting on my sanding board (with strips of different grits of sand paper). I needed a strong flat surface to straighten the slightly bent wire and the board, when rolled over the wire on a hard substrate, converts it from the two bottom wires to the pretty straight top one.

 

 



 

Before I leave the sanding board which makes flat sanding so easy, I would point out that it is mounted in an old picture frame and that makes cleanup of sanding dust a lot easier. I can rub a cast resin piece on the three grits in order and get a nearly finished surface and then vacuum the whole board to remove the dust.

 

 Making the springs was easy with nice straight wire, a vice and a compatibly sized form to wrap around, in this case a steel punch.

While talking about the model with my artistic son-in-law,we got onto the fact that the wheels would look better with a tread pattern rather than the cop out slick look. So, this is my workbench at midnight after we explored every thing that could give a tread-like texture to my wheels. We finally decided on the knurled sleeve of an old brace and bit and even though I was tempted by some really cool mesh patterns, I did go ahead with it.
The photos below show the sequence of transferring the knurling pattern onto a strip of Apoxie Sculpt and the adhering of this strip to the wheel.

A rolling board with 1mm high sides was made long enough for the circumference of the wheel and marks for an appropriate width(one wide enough to cover the top as well as part of the sides ). A sausage of the putty was laid down the centre and a smooth roller (a piece of 1inch gal pipe) was run over the top, the 1mm side pieces assuring a 1mm thickness of putty.

Here is a sideways look at the knurled cylinder from the brace and bit doing its job of pattern transfer onto a well flattened strip of putty. Note the white talcum powder everywhere, this is to prevent putty sticking to the base board and to the rollers.

The purple lines define the width I deemed necessary to go over the wheel and drape down the sides and a thin steel rule cut the textured putty to this size. Now to get it off and onto a wheel.

Let's just say it didn't give up without a fight, all 1mm of it. I had to shimmy a knife blade under it for the whole length before very gingerly transferring it to a larger but smoothly rounded surface to cure a bit more before application to the wheel.

My electric jug on its side made a good resting place and I even remembered to powder it.

This is the jig I made to do the tread transfer and I'm pleased to say it worked! PVA was applied to the wheel and the strip draped and rolled on, just like that. The right side with the screws is removeable to allow the wheel to be mounted spinning on an axle that also carries two 1mm discs. These discs are what will terminate the overlapping putty and give a defining line along the side of the wheel.

 

 That operation is seen here with a fine tool gradually bringing the putty edge up to the disc edge.

 

After this was done and the putty fully cured, the disc will be removed and the wheel cleaned up and finally detailed. I will leave that to the next entry.

 

 

 

 

Robot No.2 Always at the ready

This is my second robot model based on the Ashley Wood pictures and using that stainless steel cistern float thingy I mentioned in the last entry. He sort of looks like he is at the ready, twitchy fingers, staring eye and all, so that's his moniker from now on.

Finally we get to see the steel float which has always looked like a potential robot to me, and together with the rusty gas tank I saw in Adelaide, I was destined to build a few metal men.

 



I made a mould of the float and cast various forms, the top pic being the one for this robot. The way the raised seam line came out was pleasing and gives some immediate character to the piece. A cast cylinder was ground down and glued to a plastic base plate with some other cast bits stuck on for good measure (the first of many).



 

Arms and legs make the model and I wanted the same basic form to do both jobs.This shows the master for the arm/leg piece together with the hands, a right and a left. Maybe later I will work out a way to use a single piece but at this stage I think the hands are so important at a detail level at least. I made another mould for the limbs as I would need eight in total and you can see that the half check built into the master allows two pieces to be joined as an elbow or a knee.

 



The fingers can be made many different ways and I have tried a few - all of them drive me crazy. This method where 3mm plastic is ruled up and a male/female system of grooves is sawed and filed, seemed to give enough basically equal sized joint segments for two four fingered hands. The file at the top was sharp enough to cut the female side while a razor saw dealt with the protruding male lug. That little soft jawed vice from Games Workshop has been invaluable. The bottom shot shows how the forearm casting has been cut off at the wrist and joined to the hand with a brass tube augmented with a wire connection. As the hands are separate, right and left, they have bulges that orientate the thumbs differently from the fingers creating a hand that may be able to grasp a tool realistically.

 

One of the main things I wanted this robot to have was some panel lines and to do this marking I needed a very hard, not necessarily super sharp, tool. My engineering friend had just the thing, a needle from a rust removal tool and allied with templates used in rescribing panel lines on plastic aeroplane kits, I set forth with a bit of trepidation. Resin is quite hard and therefore slippery and to scribe a good round corner without skidding past where you want to stop is tricky. I feel happy with the result but there aren't many on this robot, maybe I'll be more ambitious on the next.
Just cutting the groove around the top took a bit of planning and a lot of gentle sawing in a temporary jig.
The middle pic shows the tools used to scribe and finish the lines and grooves, a hobby knife, a dental tool and the hard sharp needle.
At the bottom is the robot laid out with arms and legs where they will end up.

Another side on photo I'm sorry but an important one. All my models are accompanied by pages of plans in my sketch books and this shows the thoughts behind the weapon that the robot will carry.
It is similar to a grease gun affair that an Ashley Wood robot held but mine was based on three cylinders combined for the major part with a flamer barrel and a more elaborate handle. Also on this page is the plan for his feet which I changed by using a casting previously made.

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These pictures show the stages in the making of the weapon and all the resin bit are cream while the white is plastic.The bands are copper and a brass rod strengthens the whole length of the thing.

 



And there he is, unpainted in all his fiddly glory. There are little bits of kit parts, cut plastic sheet, resin castings (especially at the joints), wires, tubes, brass bits,solder bits, anespecially tricky scratch built pressure dial and some homemade braided lines. I saw the "tentacle maker" that Games Workshop sells and decided to make my own, not too sophisticated but sort of useful. I particularly like his flamer and decided to provide him with a spare fuel canister hanging from his weapon rack.

 

 

This is what he looks like without the gun and building the rack to fit was one of the trickier parts of the project but also one of the most satisfying as it is crazily asymmetric and suits such a character.

 

The finished product resplendent in a hairspray blotched paint job. This is a paint technique where after a base colour is applied then sealed with a lacquer varnish, a layer of hairspray follows.Over the hairspray the top colour is laid and,being acrylic, is susceptible to water damage. That is exactly what we want, for by wetting the barely dry top coat, it can be removed with a toothbrush to allow the sealed base coat to show through. If your base coat were rust coloured then this is the colour that will be seen in all the areas where the toothbrush had removed the top coat.A clever technique which can be manipulated by varying the order of colours and the time of drying between stages. 

 

I enjoyed this build and have put the two robot images on my board "Things I have made" on Pinterest.