The kit used for the model is the Airfix 1-144th Scale Saturn V. Of the kits that are produced this is widely believed to be the most accurate representation of the real vehicle

To enhance the model a new ware detail set will be used, along with a set of The ultimate Saturn V decals which are produced by Rick Sternbach. Further detail will be added by using some 3d printed parts purchased from Shapeways

The New ware set contains photo etch & resin parts

Whilst i was partway through building the kit i came across another aftermarket, a highly detailed 3d printed SLA & CSM. This is a great addition to the kit

The first job was to build the base section of the first stage, and to build in a support system as the rocket is quite tall and eventually will be perched on four small tabs, so needs something to centre it on the base and to stop it tipping if knocked

The New ware kit comes with a photo etched heatshield and a set of resin engines. To use these parts the raised detail shown in the image below must be removed.   

I decided to make the engines fit into place with a dowels to locate them. To give the dowels somewhere to locate into, a dam was constructed on the back of the heatshield. Epoxy glue was then poured in and allowed to dry. This gave a nice block for the dowels to locate into, and with the added advantage of adding weight to the base of the model

The engines were drilled to accept the dowels, to make sure that the hole was central a drill jig was made from some tube, a washer and a scrap piece of plastic. They were drilled, then the excess resin cut away and a piece of 4mm tube used as a dowel

A trial fit of the engines

A sleeve of steel tube is used as the locator in the base of the first stage. it was temporarily placed and centred using a plastic rod, the hole in model was made oversized so it could float a little. A slot was cut into the base to allow access to the inside of the base.  Two sections of plastic tube were cut and placed over the steel locator, and then 5 minute epoxy glue poured into the gaps between the steel and plastic. The brass rod was engaged into the hole in the baseplate and the model slid over it and centred onto the grey hold down structures. The rocket now sits true and square on the base.

With the base of the first stage dealt with the next job was to make a start on the main section of the first stage. I decided to add an extra stiffener disc halfway up. This would serve two purposes, firstly to add and extra centre locator for the brass rod, secondly to stiffen it up to help when eliminating the seams. A couple of 1mm thick discs were cut, and then the best fitting one was glued in halway up the stage

Airfix have engineered the model so the it clips together, and can be separated at various places to reveal the "innards". The positioning of some of the tanks tops is a bit off, and there is also a total lack of internal detail. 

 I have purchased replacement 3d printed thrust structures & engines for the second and third stages, so have made the decision that the model will only be separable at these two points to reveal the extra detail.

The graphic below shows where I plan to have the model separable

The image on the left shows the top of the stage with the  twist locators on. As the model will be separable a bit further up these were removed and the interstage will be glued at this joint line. This area will be visible when the rocket is separated so additional internal details will be added. The image on the right shows the locators removed, only a small section was left, this simulates the internal stiffeners seen on the real rocket 

The seams on the first stage were sorted out. Sprue goo was applied and left to dry. The the joints were filled and sanded. A coat of primer will then reveal if any extra work is needed, but not looking too bad at first 

The next section up is called the interstage, it is basically a spacer between the two stages. In real life it is bolted to the top of the first stage and the cavity it created will accommodate anything that protrudes below the join line of the second stage. 

The first images shows the kit part as supplied. The image on the right shows the two halves joined together, the internal locator tabs were removed. All the external details also removed as they are going to be replaced with resin items from the New Ware detail kit.

The twist locator has been reduced in height by about a half. This was done to add a bit of "realism" when the model is separated as the stiffener at this point  would not be as big at this scale. 

It can also be seen that at the split lines where the model has the external corrugated stringer sections that the detail bulges out. This is due to the way that the moulds were made and are not present on the real rocket

A pic of the interstage placed on top of the first stage. This will eventually be glued in place, after detailing and painting

To help with adding detail, and making sure that the resin and photetch detail parts are put in the correct places some visual aids were made by printing off the New Ware instructions and sticking them onto some tube. 

Detail was added to the top of the first stage LOX tank. Davis Weeks excellent drawings were consulted to provide sizes and locations of the items to be added. As can be seen in the image on the right the only detail present on the tank top were the raised panel lines and a flange at the apex of the dome.

Detail added includes an extra flange at the apex, three raised discs to represent pressure switches. Two LOX vents, a GOX distribution line and a couple of electrical panels. The bass rods are just temporary locators for the LOX vents, they the small GOX line, and electrical boxes are not glued in place yet as they will be painted separately and fixed in place later. Still to be added are internal stiffening ribs, and some electrical junction boxes. Stiffening ribs are also in place

The interstage also had the radial stiffening ribs installed. David Weeks drawings indicate three internal radial ribs with no vertical stringers, this is confirmed with a screenshot of the interstage being jettisoned. The Apollo 4 Saturn had cameras installed to record this happening. This was in the days before digital images streamed directly back to the ground and the cameras recorded the images and were then ejected from the rocket and fell back into the ocean to be recovered at a later date It can also be seen that no flanges or ribs can be seen at either end of the interstage, this is because the separation plane does not always coincide with where the rocket was bolted together. The stages were separated with explosive charges which when detonated cut the sections apart.

Image to the right shows the first rib going in, the small oblong pieces are spacers that were used to make sure the ribs were evenly spaced

All the ribs installed, and the interstage stacked on to the first stage

A start was made on the second stage, namely removing unwanted external details.

Point 1

These teardrop shaped items appear on both sides of the stage. They do not exist ion the real rocket, urban myth has it that when the moulds were being drawn the designer saw what he thought was a part of the rockets outer skin, but in fact was lumps of frozen ice on the skin.

Point 2

The raised lines will stay, they represent the joint lines of the external insulation that was glued to the outside of the stage. This was to insulate the liquid hydrogen & liquid oxygen tanks to keep the liquids at the extremely cold temperatures they needed be to stay as a liquid and not boil off. This type of insulation was replaced by a spray on type of foam on later Saturn V's (Apollo 12 onwards)

Point 3

The liquid hydrogen transfer pipe fairings. In total there are five of these, four moulded in and one to be glued on in the kit. They are to be replaced by the more accurate, and better detailed resin part seen the the right

Point  4

The LOX vent fairing, as can be seen the kit version is wildly inaccurate.

Point 5

The section here is the interstage, and shows the ullage motors. After the first stage had done its job and had been discarded just prior to the interstage being separated these motors fired to give the stage an additional shove forwards to make sure that the liquid fuel and oxidiser was pushed to the bottom of the tanks. This would ensure that the motors received a good supply of liquids at start up. The purple centre line shows that Airfix moulded the ullage motors and the LH fairings in line with each other, in reality they were staggered

Note-the resin parts shown below are still attached to the pour plugs and require trimming before fitting

After a lot of grinding, filing and sanding most of the unwanted stuff is gone. I had to pour some epoxy glue into recesses from the inside to make up the outer skin in a couple of places  

As with the first stage there is absolutely zero internal detail, and the kit supplied thrust structure is very inaccurate.

As mentioned previously 3D printed parts have been obtained to replace the thrust structure and the J2 engines for this stage, and also for the third stage. 

Here is a shot of them for comparison

After consulting David Weeks drawings and it became apparent that Airfix had placed the domed tank top about 25mm too far down the stage. The original placement was between the two grooves. It was moved to the correct position, and the third stage was held in place for a fit check to make sure there was clearance. Fortunately moving it upwards meant that the locating tabs could be retained as they are now hidden behind it

The extra detail on the aft thrust structure came with one additional "problem" that i hadn't considered. This was that when installed you can see through the centre section and up into the empty internals. One solution i thought of was to get hold of a white Christmas tree bauble, cut it up and simulate the dome of the tank. Then I had a lightbulb moment, I have a Skylab version of the Saturn V, so i borrowed a domed tank top from it.

Here it is shown during a fit check to the left, and to the right during the installation of locating rings

Time to add some detail to the innards. A small jig was made up to mark the positions of the internal ribs of the coned section. Towards the top of the image (about where the end of the steel rule is) the support for the extra tank dome can be seen

Internal radial and longitudinal stiffeners added. The internals will have to be painted before the two halves are joined as the tank dome and the internal structure are two different colours and it will be near impossible to do this when assembled. this means that the seam line will be visible, and as it is pre-painted there will be no way to fill and sand it. The solution was to glue some stiffeners in along the joint line that protrude out a little. The amount and placement of these is not correct as per the real deal, but accuracy sometimes has to give way for practicality and aesthetics

The back end of the stage was modified by the removal of the two locating rings that were to position the thrust structure. This was done for the same reasons as the other end, it will allow the domed tank end and the thrust structure to be inserted after the two halves are glued together

Grey primer sprayed to the insides of the first and second stages, and tank domes.

Colours sprayed onto a test sheet of styrene to help decide what to use on the model. Colours were applied over different base coats. So far the most likely candidate are Mr Color  353 Zinc chromate over a grey base for the internal walls. The tank domes will be a grey base,, topped of with Mr Color C581 yellow orange that has a hint of black mixed in 

Whilst priming the parts i realised that i probably should have done the same with the first stage tank dome as the second stage and painted it before assembling the stage. Now it is in place it will need to be masked at some stage during the painting process. A paper template was cut and then measured. This was then used to draw up an outline using Solid edge CAD program, and in turn this was imported into the Cameo software to produce a mask  

The areas where the external detail has been removed will need reworking to try and reinstate the stringer detail . A section was chosen and attempts made to rescribe the surface using a modeller's chisel. The chisel i had was 0.4mm wide, and the stringers on the model are about 1mm wide. The picture below is a before and after showing a definate improvement. A wider 1.2mm chisel is on order, and hopefully that will make the repairs more consistent

With the colours decided it was time to get some paint applied

 Couple of shots of the second stage put together with the tank dome in place , still not glued yet 

 The first stage tank top painted, next up will be to mask it off and then paint the inner walls

 The paint was given a day or so to cure and then the second stage was closed up 

 As planned the rear end of the stage can now be assembled in sections with the tank dome slid in first, followed by the thrust structure

 Assembly of the third stage was started. The rear of this stage is another of the areas that will be visible if the model is opened, as it is another of the planned split lines. As with the second stage a plan was cooked up to be able to glue the stage internally, and then install the thrust structure at a later stage.

 In between all the other activities painting of other parts has been ongoing 

The tank dome on the first stage was masked and the internal walls painted