Saturday, May 19

1:72nd scale Mercury Atlas / Mercury Redstone - Gary's Build Report in Full

Gary has been sitting on this one for a while, but not as you might think - his long-awaited finished build of the Horizon Models Mercury-Atlas / Mercury Redstone in 1/72nd scale is our story for today. See what this kit is made of and what he made of the kit in his full build guide...

Mercury-Atlas / Mercury Redstone - Build Report
Horizon Models (#2002 / #2004)
Scale: 1:72nd
Started: March 2018
Finished: April 2018

From Horizon Models
In 1959, the race between the United States and the Soviet Union to conquer space was heating up and NASA awarded the contract to build the Mercury capsule to the McDonnell Aircraft Corporation. The Mercury was to be the spacecraft that would fly the first American astronauts
The initial sub-orbital Mercury flights (Shepard and Grissom) were launched using the less powerful Redstone booster with the remaining four brave American Mercury astronauts (Glenn, Carpenter, Schirra and Cooper) achieving earth orbit with the increased power of the Convair Atlas SLV-3D booster, a derivative of the successful SM-65D Atlas missle.
The Mercury space capsule was designed to carry supplies of water, food and oxygen for about one day in a pressurized cabin. Mercury flights were launched from Cape Canaveral Air Force Station in Florida where the capsule was fitted with a launch escape rocket to carry it safely away from the launch vehicle in case of a failure.

The flight was designed to be controlled from the ground via a system of tracking and communications stations. Small retrorockets were used to bring the spacecraft out of its orbit, after which an ablative heat shield protected it from the heat of atmospheric reentry. Finally, a parachute slowed the craft for a water landing. Both astronaut and capsule were recovered by helicopters deployed from a U.S. Navy ship.

After a slow start riddled with humiliating mistakes, the Mercury project gained popularity, its missions followed by millions on radio and TV around the world. Its success laid the groundwork for Project Gemini, which carried two astronauts in each capsule and perfected space docking maneuvers essential for manned lunar landings in the subsequent Apollo program announced a few weeks after the first manned Mercury flight.

GENERAL THOUGHTS - Horizon Models 1:72 Mercury Atlas / Mercury Redstone (#2002/#2004)
Horizon Models is a relatively new Australian kit manufacturer, which for me is quite a novelty. Being local would be enough reason for me to try out their kits but when the subject matter is Real Space flight then they definitely got me hooked. To date, Horizon has released four kits, each of which is related in some way to the NASA Mercury program. One kit is dedicated to the Mercury capsule itself (of which you get two in the box), two of the kits are focused on the Atlas launch vehicle (the Mercury version and the ICBM version), and the last kit so far is, of course, the Mercury + Redstone launch vehicle combination.
Once you crack the seal on the box of any of these kits it quickly becomes apparent the high level of effort the folks at Horizon have undertaken to ensure they deliver the most detailed and accurate space kits in 1:72 available today. Included in each kit are injection moulded plastic sprues, photo-etch detail frets for the Mercury capsule and launch vehicles and of course a decal sheet printed by Microscale in the US. The assembly instructions are logically laid out and more than gives enough detail to allow you to work out which options are appropriate for the particular Mercury mission you select to depict.

Of course, no kit is perfect and I found a few areas that could benefit from extra detailing but everything I did was not to correct inaccuracies in the kit rather to enhance. I found the fit of the kits to be excellent, the parts layout and general engineering to be sensible. In fact, the biggest challenge for the modeller will be in the painting. Natural metal finishes and white can be a bit daunting so make sure you are comfortable with your weapon of choice (I am an Alclad man for NMF and Tamiya Primer for White finishes) before taking on these subjects and you should have no troubles. I tackled both these kits at the same time as they are relatively simple with low part counts and because the mercury capsules are basically identical between the two models which makes it quicker when building and painting them together.

Horizon provides everything you need in each of its kits to build any of the Mercury missions, including the unmanned and boilerplate flights. As I planned to build the very first Mercury flight (Alan Shepard in Freedom 7) for my Redstone model I thought it would be interesting to select the very last Mercury flight (Gordo Cooper in Faith 7) for my Atlas build. In this way, I could nicely bookend the Mercury program in one project.

BUILD - Horizon Models 1:72 Mercury-Atlas (#2002)
Mankind has always dreamed of space travel, to explore the moon and visit the distant planets. From 1962 this dream began to turn into reality, as the first Americans orbited the Earth using the Mercury-Atlas. Flying solo, they would pilot the Mercury capsule, which sat on top of the mighty Convair Atlas rocket, and experience extreme acceleration during the rapid ascent into space. Travelling at over 27,500 kilometres per hour, they would orbit the earth every 90 minutes. Upon re-entry, the ablative shield on the outside of their capsule would save them from temperatures of over 1,000 degrees Celsius. Once in Earth's atmosphere, a large parachute would slow them and their capsule to a safe speed, allowing a splash down in the ocean. The successful Mercury program paved the way for more ambitious manned spaceflight programs, which eventually saw man walk on the moon. [source: www.horizon-models.com]

I started my build with the Atlas launch vehicle, ie the Atlas missile body and engines. These early rockets were fairly basic single stage machines and the models are therefore equally straightforward to assemble as they consist pretty much of two halves. After doing some test fitting I felt that the Atlas body would benefit from some internal support to make it more rigid and I just happened to have been doing some gap filling around the house with self-expanding foam. 
It seemed that this might be a good option to fill the body of the Atlas once I had glued the two halves together. I simply used masking tape to block off the bottom and filled the body from the top. As you can see from the photo this stuff expands a lot and as it dried it poured out the top of the rocket and even out through the small locating pin holes I had pre-drilled on the sides of the rocket. It's very sticky when wet so make sure you protect the outside of the rocket body with tape as much as possible.
Once the filler foam had dried it was easily trimmed using a knife blade, with the end result being exactly what I hoped for. The lightweight filler had pretty much eliminated any flex in the body tube and would make subsequent sanding and scribing work much easier.
As I began the seam work along the length of the rocket I wondered if the panel line detail was not a bit over scale for a 1/72 Atlas body. As best I can tell the real body was made from welded bands of stainless steel so any seams between the bands would be very minor.

To deal with the existing panel lines I decided to fill them and sand smooth as a starting point. I used Super Glue (CA) much like I had done on previous builds where I had a similar need to fill gaps or deep panel lines that would require rescribing later on. I have found that Super Glue works well in this role as a filler but can be a little unreliable when it comes to the scribing. The scribing blade can sometimes get caught in pockets where the glue has not cured consistently and this leads to badly formed panel lines (a pet hate of mine). Luckily this problem tends to happen very infrequently but I was still concerned with this model given just how much glue I was using and how many panel lines would need to be re-scribed.
With the main body of the rocket dealt with for the time being, I turned now to the lower section of the Atlas. Kennedy Space Center has a display area with an Atlas (and Redstone) which you can get very close to for photos. It very likely that the Atlas at KSC is different to the vehicles used in the actual Mercury launches but I figured that using a combination of 1960's period photos and these KSC walkarounds I would not be too far off.
Comparing the kit parts with the reference photos I noted several areas that could benefit from some extra detailing and removal of over scale items such as those super heavy rivets. It's surprising how much difference it can make to a model by doing basic things like thinning down over scale parts.
To thin down curved parts I like to wrap the wet n dry paper around a section of wooden dowel. The curved surface ensures that the plastic part is consistently abraded and helps to minimise any high and low points. Once the part had been thinned to look more like the real item (which is clearly just sheet metal) I used some 30x30 thou Evergreen to fill in the ribs which run under the cover plate. These don't need to be perfect length wise as only the very top will even be seen.
One other difference I noticed between the model parts and the reference photos was that the kit had recessed panel lines on the bottom skirt section whilst on the real vehicle there were rows of raised rivet heads. I had an idea as to how I could represent these on the model and so the first step was to fill the existing panel lines. For this, I used Tamiya Basic Putty, rather than Super Glue, as I knew I would not need to re-scribe over this area. Some raised ribbing and cover plate detail was added from 20 thou card and I was then ready for a coat of Tamiya Fine Grey Primer to test my work.

To make life easier to reproduce lines of raised (positive) rivet heads several companies (HGW, Archer and Micro Mark) make these available in decal form. I have a couple of sheets of the Micro-Mark rivets for some time and have used them on very small projects. I saw an opportunity to try them out properly on the lower skirt of the Atlas and so I applied several coats of Gloss Clear over the primer to ensure the decals adhered properly. They are printed on a continuous carrier film so have to be cut out in strips and applied like any other decal. They performed pretty much as you would expect but I was disappointed with the thickness of the carrier film which is quite noticeable in the close-up shots. HGW uses a different approach by making the rivets like transfers which results in no carrier film. I'll have to try these out next time. Other small details were added from card and brass to match the photos I had on hand.
Next up was the Mercury capsule. Horizon has engineered the capsule sprues very cleverly to enable you to be able to make any of the variants of the manned and unmanned capsules. For the Atlas build I pretty much used the plastic parts as provided, later on when I built Freedom 7 I needed to use many of the provided PE parts to convert the capsule back to the porthole version used on Shephard's historic mission.
The fit of the capsule segments is excellent. I would suggest you build the centre core first, then attach it to the heat shield base and leave to dry. Next, attach the skin of the capsule around the outside using thin liquid glue to secure the parts once you have everything aligned properly.
When displayed in a launch configuration, the capsule has a framework tower fitted to the top. This tower contains 3 emergency rockets which are designed to fire and 'eject' the capsule from the rocket body in the case of an emergency. This safety tower is very visible on the finished model because a) it sits on the very top and b) its painted bright red !! Be sure to take your time to clean up the parts of the tower and test fit them to ensure the alignment is square before applying glue.
Once assembled the tower is quite sturdy, the nozzles for the rockets around the top have a very small mating surface and I had mine come away a couple of times before finally getting sick of it and pinning them with brass. As I mentioned above its important that you ensure the tower is square because it will be very noticeable once fitted to the capsule and rocket if it is crooked.

I had some difficulty sliding the tower base over the top of the capsule and so needed to sand down the capsule a small amount to obtain a proper fit. Go slowly here otherwise, you could loose all the nice ribbing on the capsule cap. Horizon provides PE parts for the wiring harness but I just can't live with flat PE being used for round cables like this. Instead, I used some 0.2mm copper wire to make up the cabling.
If you are modelling the capsule off the rocket then Horizon provides the retrorocket pack which is attached to the heatshield via metal straps.
As I was attaching my capsule to the Atlas booster I technically did not need to assemble the retro pack and straps but I was curious as to how it fitted and so spent 5 mins making it up for a photo. It actually looks very convincing with the use of PE for the straps. Everything fitted spot on, another testament to Horizons engineering skills. To allow the Mercury capsule to fit atop the Atlas missile NASA had to design an adapter which is shown here next to the capsule.
The capsule adapter has a few detail parts that need to be added. The LOX (Liquid Oxygen) vent has a cover which Horizon provide in PE. This needs to be bent to the correct shape and then glued to the adapter in the correct location. Like always in this hobby, measure twice and glue once.
I took the time to remove a square section of the adapter ribbing which sits under the LOX vent and cover. This was simple enough to do with a sharp blade and looks way better than just gluing the circular vent on top of the ribs.
The last thing I took the time to attend to was reshaping the three capsule attachment points on the top of the adapter ring. These were hand shaped from Evergreen strip and you can see the difference in this before and after photo.
At this point the work on the capsule, its tower and the Atlas adapter ring was complete. These parts were now ready for painting.
The Atlas D had three engines and Horizon provides each of the engine bells in two halves. This, of course, means we get some seams which are a bit tricky due to the raised ribbing on the surface of the bells. To help me get in between the raised bands and sand the seam I made a small modification to one of Flexi File abrasive bands. I trimmed the width of the flexible abrasive band down so that it fitted nicely between the raised ribs and it did a pretty good job of sanding smooth the Tamiya liquid primer which I had applied two coats by brush over the length of the seam. This was the first time I had used the Tamiya Liquid primer and it behaves much like Mr Surfacer.
The main umbilical conduit which runs along the surface of the booster to the spacecraft is provided by Horizon as two parts, A10 and B8. When I test fitted these parts they did not quite meet in the middle which resulted in a small but very noticeable gap of about 1.5mm. To address this I dry fitted the two lengths to the booster body and then inserted some plastic card to fill the gap. This was glued (carefully) to fill the gap and why dry it was sanded to shape. Take careful note of the instructions on where to locate the Rate Gyro (part A3) on the umbilical.

It was now time to start the painting process and I tackled the main booster body first. I wanted to try and achieve some variation in the bands of the body (just like the real thing) without making them look too different as this would be too distracting. Having decided to use Alclad ALC-115 Stainless Steel for the main body I knew that with this paint it was possible to alter its look by simply varying the undercoat. I selected several random bands on the body, masked each off in turn and randomly sprayed some Semi Gloss Black in each band. I did not want to make these band solid black as that would look too uniform on the finished model once the Stainless Steel was applied. It actually worked pretty well even though in the pictures of the finished parts you can't see that much variation, it is there, just not obvious in the photos.
The Atlas decal sheet has been printed by Microscale in the US. I personally find Microscale decals to be some of the best around as they are super thin, respond very consistently and predictably to setting/softening solutions and the colour opacity is excellent. Horizon provides options for each and every Atlas-Mercury launch.
With the parts painted I wanted to seal the Alclad Stainless Steel for general handling, masking and decaling. I have found that certain gloss clears do not lay down smoothly over NMF and so I did some testing of the clears I had at my disposal. Long story short the one that I found laid down almost perfectly over the metallic finish was the new Tamiya Laquer LP-9 Gloss Clear thinned with Tamiya's own Lacquer thinner. I sprayed a couple of very light coats to protect the sensitive Stainless Steel finish and was then ready to apply the decals. Perhaps the trickiest decal to apply was the one designed to be laid over the LOX Pressurisation Line that runs over the top of the vertical UNITED STATES markings. Horizon provides this special decal for both words (Decal 10 a& 12) and you need to carefully wrap the decal around the thin tube part. I used liberal amounts of Micro Sol (softening solution) and patience to get these decals to wrap properly. Fit the line to the model to ensure the decals align correctly to the ones applied to the body of the booster (Decals 9 & 11)
After working with the Alclads on the main booster body I turned my attention to the Mercury spacecraft. I wanted there to be some visible contrast between the Atlas adapter ring and the capsule so I used a couple of different shades of black. Tamiya has several in their line up which range from pure blacks to what I refer to as "licorice blacks" in the form of Rubber Black and NATO Black. For the capsule, I went with XF-86 Rubber Black with a couple of drops of XF-8 Flat Blue. The other parts were painted in Semi-Gloss Black and Pure Red from the newer Tamiya Lacquer range (for no other reason than I wanted to try them out).

The lower section of the Atlas booster has a lot of stencils that need to be applied. For the two types of equipment pods on the body sides, the extensive stencilling is provided in a single (large) decal. I initially thought about cutting this decal up into smaller sections but given how well the Microscale decals had settled down on the capsule and upper booster body I decided to roll the dice and apply it as provided. By flooding the larger pod surface with Micro Set and then methodically squeezing out any liquid and bubbles from under the decal once in place I was able to get it down without any issues. I applied Micro Sol to the decal once it had dried a little to soften it and then used a sharpened toothpick to coax the decal down into the panel lines.
The lower skirt of the Atlas is covered with many small stencils as well. Once again I took my time using the Microscale Set and Sol solutions to position and soften each decal. In this way, you can avoid silvering and other nasty problems in most cases.
I was getting close now to finishing the Atlas and wanted to see how it should be mounted in the display base. Horizon does provide a base for the Atlas which relies entirely on the strength of the centre engine nozzle bell. I wanted to mount my Atlas on a wooden base and so cut the insert section of their base off and pinned it to the wooden base. Unfortunately, this was not strong enough and the rocket teetered dangerously. I thought that if I could put a brass rod through the two outer engines it would be stable enough. Of course, I should have dealt with all this much earlier in the build but sometimes you just need to put your problem-solving that one. Luckily I had not yet glued the bottom skirt to the booster body so was able to use my Dremel to cut a hole in the top of the skirt and thus gain access to be able to glue some blocks of plastic on top of each of the outer engines. When dry I drilled a hole up through the nozzles and into the plastic blocks. This gave the brass rod a strong mount with the rocket and when attached to my wooden base solve the wobble problem.
The last step was to apply a light wash using MiG Ammo PLW which helped bring out some of the nice detail particularly evident on the Atlas lower section. The lower skirt was also sprayed with a flat coat of Tamiya XF-86 Flat Clear to further show the difference between it and the stainless steel body which was left untouched.
The completed Horizon Models 1:72 Atlas with Mercury capsule stands just a whisker over 400mm (15.7 inches) when fully assembled. I had originally planned to try out some metal foil for the booster body but am actually glad I went with Alclad instead. I have another of these kits in the stash and next time when I build the ICBM version I may have a crack at using foil.
In the next instalment, I will cover my build of the Horizon Models 1:72 Redstone booster and Mercury capsule as I model the very first US manned flight by Alan Shepard in Freedom 7.
A gallery of the finished model

Gary Wickham

You can find out more and find a store closer to you at the Horizon Models Website