Time for a progress report on the SA-5 build. I started on the aft structure of the first stage. I needed to drill a hole for a brass rod that would attach the model to the display base. I marked an X on the top of the part and put the heat shield on the bottom of the base. I then went to my drill press and drilled a hole through the top down through the heat shield on the bottom. I then inserted a length of brass tube through the top and down into the hole in the heat shield. I only pushed it through until it was flush with the outside of the heat shield. Then I applied epoxy to the portion of the tube sticking out of the top. When that had cured I removed the heat shield and then applied epoxy to the tube from the bottom side. Then I put the heat shield back on. Once that had cured I had a rod that was positively attached to the aft structure and would not move while I added weight. With the head shield removed, I put some BB’s in and then poured in epoxy to secure them. With that I was ready to start adding details to the aft section.
I then glued the halves of the tank section together and then removed the molded in antennas. Next I added some details to the heat shield. I scribed lines into the heat shield to match the pattern of SA-5. I filled four holes for the inboard engines that will not be used. The inboards did not have the turbo pump exhausts around the engine bells like the outboards did. I also added four small bits of styrene rod to represent the water quench disconnects. I then added the flame shields for the outboards by bending some insulated copper wire bent to the correct shape.
I then went back to the aft structure. I filled the ribbing that was molded in. It is in the wrong place and does not cover enough of the base. I sanded that smooth and applied a light coat of primer to make sure I had them filled properly. I created a pattern to allow me to get the stringers spaced properly. There are fourteen stringers between each fin, with a blank area surrounding each fin. With the pattern secured to the part, I started gluing the .020 x .020 styrene strips in line with my pattern. I had to cut out a bit around where the inboard turbo pump exhaust goes. After adding all the stringers, I sanded a slight taper into the leading edge of them. With that complete I created 8 access doors from .005 styrene sheet and sanded rounded corners into each one. I then made two umbilical doors out of the same .005 sheet styrene. I then marked all round the aft structure for the placement the doors. I glued them on with my Tenax cement.
That’s it for now. Much more work on the first stage to go.
I felt a bit better about the damage to the paint job after calming down and looking it all over. The alligator skin was not all over the model. It appeared to be mostly in areas where I had laid down a heavier layer of clear coat. So now I feel a bit better about being able to remedy this situation.
I finally received my bottle of Tamiya Lacquer thinner that I had order last week. Others had advised that the lacquer thinner would be able to remove the crinkled finish so I ordered some. I got out some cotton buds and started removing the damaged finish. I started with the back end of the engine cover since it had some of the worst crinkling and it had an area with a smooth surface without much detail. I dipped a cotton bud in some of the lacquer thinner and started rubbing the surface. With very little effort the rough surface came off, but so did all the paint and primer. It took it down to the bare plastic.
The problem was that in the process of removing the paint it created clumps of paint that could get lodged in some of the fine details. If I used this process on the whole model, it would take a lot of clean up to get all the clumps out of the details. It got me to thinking about some alternatives. I had some 90% isopropyl alcohol. I used it to clean brushes after painting, and I wondered if it might work here. The main concern was whether it would do any good against the lacquer clear coat. I gave it a shot anyway. It worked! I was able to remove the alligator skin and keep much of the paint/primer in place. The new surface was smooth and looked like it would be able to be re-sprayed and still look good. In the photo above, you can see in the areas above and to the right of the bare plastic where I used the alcohol and was able to preserve the primer but also smooth the paint. It also didn’t create balls of paint that could gunk up the fine details.
After going over the whole model and removing the alligator skin, I let it dry for a couple of days to let the paint firm back up before re-spraying the white-gray base coat again.
It now looks good again and I’ll let the paint cure for a few days. This will give me a chance to get some Vallejo clear coat and matt coat. I’ll use those since they should be more compatible with the Vallejo paint that was used for the base coat. I’ll still test it on a test part first to be sure there isn’t some other problem that could crop up.
Well I don’t usually overlap builds, but I knew I was going to have to wait a bit before I could get back to the Millennium Falcon. I started my next project which is another kit from Martin’s Models from the UK. This one is a conversion set that modifies an Airfix 1/144 Saturn IB into a Saturn I Block II SA-5. It was the first Saturn I flight to have a live S-IV second stage. I love that rocket. It has those great classic lines.
Again the resin parts are quite rough and some are out of round, but it will be a great starting point and should build into a nice model.
I started by removing the pour plugs from the parts and doing any necessary trimming to the resin parts. Next I started removing the fins from the thrust structure of the kit part. This time I would not be removing the fairings from the base part since SA-5 had these. When I used the Airfix kit to make the SA-205 Apollo 7 Saturn IB a few years ago, I had to remove them. For SA-5 I did have to remove part of the top of the parts that made up the first stage fuel tanks since SA-5 had only a very small flat section. In the picture you can see how much had to be removed. The part on the right has the extra plastic cut off while the part on the left has not been modified yet. You can also see how much the plastic had yellowed over the years. I bought this kit when Airfix re-released it in the 1990’s.
You’ll notice that I had to fill a couple of divots that I made when I was removing the fins. I got a bit zealous with the Dremel and created an oopsi moment.
Next, I moved on to some of the resin parts. The tapered interstage needed to be sanded a bit on both ends to get a flat and square surface. Unfortunately the interstage is not quite round. I’ll have to do more work here to get a more rounded part. The nosecone was not pointed enough for the version that was on SA-5. I started tapering it a bit more. I’m almost there. I’m not sure how much more I can sand it though. I keep hitting air bubbles that prevent a sharper point. I’ll continue to try and refine it.
Sorry for the out of focus on the interstage pic above.