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Big D CM, CM Kit Update

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CaptCBoard	Big D CM, CM Kit Update	Lead	[-]
Posts: 1190 (03/03/08 00:04:22) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Tags : None This news covers the same parts used in the Big D and the CM Kit, because the CM Kit is simply made of parts from the Big D. So-- I know this doesn't look like much, especially since its not quite done, but this is the new CM master with the replacement Pod Bay door bezels actually, finally in place. Getting these to fit properly was unexpectedly complicated. The problem was very simple-- seat these resin castings so they were completely even with the existing surface. The difficulty was that if they were even just a little bit off (toward the outside), then sanding them would make them look uneven. Sanding them to look even would have presented more problems-- too much here, sand the whole thing again and hope to get it right --but to do it so all 3 looked identical... No. There was too much possibility that something would look 'off', so I had to take the time and align things very carefully. That is now finished and only doing a gentle sanding of the red spot putty remains. I need to address some things inside the master, but that's all simple-- just plugging things that might make molding/casting problematic. I'll cover that very soon. I'm sorry I don't have more to report, but once this thing is in rubber, the kit is ready for casting! One other item-- The spare parts storage area is an octagonal passage, made up of these panels. Here, you can see a casting of the one that will be used in the Little D sitting on the master for the one made for the Big D. A mockup of this passage can be seen in this photo-- In this image, it is simply a printed piece of paper, cut out, folded and placed in position behind the doorway. The final piece, for both Big D and Little D, will be molded and painted. Scottt CaptCBoard@AOL.com Last Edited By: CaptCBoard 03/03/08 00:31:04. Edited 1 time.
CaptCBoard		#1	[-]
Posts: 1213 (04/17/08 23:29:50) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Much progress on this project-- What you see here is the end result of a BUNCH of fixing... I thought the Pod Bay door bezels were going to be the only challenge to getting this thing into rubber. I didn't document any of the tiny fixes that kept popping up, mainly because I kept thinking I'd done the last of them. But, as soon as one got fixed, one or two others would show up. None of them were hard to fix, but given how I handled this thing (very gently) I was just amazed at what was lifting, cracking, bulging-- sheesh!! Anyway... In this photo the CM is finished, with the exception of plugging the door openings. It is mounted to a circular hunk of MDF, which will be waxed so the mold jacket won't stick to it. The white 'wall' you see, with the metal rods sticking through it, is called a venting fin. When a casting is made, this is where all the air goes out of the mold. The resin that winds up in this part of the mold will contain the last of the air. Since this fin is extraneous and gets cut off the part, the idea is that there won't be any bubbles left in the part. To make this mold, the CM master has to be attached to the base so it can't move. It also has to be mounted in such a way that it can be removed from the base once the exterior part of the mold and the hard jacket have been made. It has to be removed so the interior part of the mold can be made. Here you can see how well the door bezel has been joined to the surface of the master. Once the bezels were mounted, they had to be faired in on the inside because they are thicker than the wall of the master. To do this, I simply poured small amounts of resin around each. To make this work, the master had to be positioned so each bezel was dead 'down', allowing gravity to pool the resin evenly in place. Care had to be taken so that there wasn't too much resin as it would just overflow and dribble down the face of the bezel. That would just about ruin it and it would have to be replaced-- again! Now the plugs are in place. The one on the left is the Pod Bay Door that will be molded in place, the one that never opened in the film. The other two are styrene disks that have registration domes on the outside. These two will be removed once the first half of the mold has been poured so that when the second, interior, half is poured, the two halves of the mold will come into contact through the openings. This is the mounting ring and base. When the whole thing is put together, the mounting ring will be screwed to the base from the underside. Here you can see how the mounting ring is attached to the master. Each of the 3 brass rods go through the ring and seat into the venting fin. Their ends are flush with the surface of the venting fin. With the mounting ring attached to the master and then attached to the base by screws from the underside, the master will be held securely in place. But because everything that holds the master in place can be reached without removing the mold and jacket, then the ability to pour the second, inner half of the mold cleanly is assured. This is the final assembly, with the master mounted and the plugs in place. You can see the registration domes on the center plug. Once the molding process is started, there will be other things added to assure proper mold alignment. I'll point them out as we go along. The mold should be poured over the next 3 or 4 days, so you'll see the results of all this careful work very soon! Last Edited By: CaptCBoard 04/17/08 23:35:35. Edited 1 times.
CaptCBoard		#2	[-]
Posts: 1219 (04/29/08 23:14:38) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	The Saga continues... The CM master has been covered with plastic wrap and the clay layer is being applied. The clay is a 'stand in' for the rubber that will be poured once the jacket is finished. These are the ends of the registration rods. In use, they will be longer than this, but for this process, they need to be only long enough that the jacket includes an impression of where they go. When the jacket is finished, these impressions will be opened with a drill so the longer rods can stick out. The clay has been smoothed out so that it is almost a flawless surface. Gatorboard fins and a paper cup have been added. The fiberglass will be laid against this divider so a flange is built up. The clay shapes placed against the fins will become registration points in the flange. Once all this was finished, several coats of Krylon Crystal Clear were built up to provide a barrier between the clay and the fiberglass. Done right, the clay will not stick to the fiberglass. Otherwise, cleaning the clay out of the hardened fiberglass can be a real problem! We now fast-forward beyond the time my battery died... Here both sides of the jacket have been laid up. Holes have been drilled through the flange so the halves of the jacket can be bolted together, to hold the mold securely. At this point the jacket has not been opened. It still needs to be trimmed around the base and holes drilled so that the jacket can be reassembled in correct relationship with the master inside. Here the jacket has been opened and the clay removed. In this shot, one half of the jacket has been placed in position so you can see the gap where the clay was, the gap that is about to filled with rubber. Another shot of this shows how the jacket has been drilled to let the air out as the rubber is poured. A bunch of 1/16" holes cover the surface from top to bottom, side to side, so no air is trapped when the rubber builds up. You can also see wooden dowels acting as stand-ins for the bolts that will secure the mold halves where they meet in the Pod Bay door openings. The plugs that block the door openings will be removed from the inside when the inner half of the mold is poured. Because the fiberglass is somewhat transparent, you can see the level of the rubber as it is poured. You can also see the spots of clay used to block off the vents as they begin to weep rubber. This part of the mold used up all the rubber I had on hand and I'm waiting for a new batch to arrive. I hope to get the rest of this thing done before the end of this week (before May 4). The inner part of this mold is much more difficult to do than this outer part-- which you will see!
mknorr		#3	[-]
Posts: 118 (04/30/08 04:02:57) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Awesome stuff Scott. I always find this sort of detail fascinating. Thank you so much for sharing.
robertfish	Re: CM Kit Update	#4	[-]
Posts: 117 (04/30/08 07:30:54) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Wow indeed; thank you, Scott. It's going to be interesting how I display this someday--I suppose I will want to add a skeletal spine with the Antenna kit, and some sort of engine compartment that shows early construction. And then get agreement from my wife to hang the entire model from the 16' ceiling in the Great Room... Now, that may be the most difficult aspect of this entire project! :-) Anyway, thanks---we're all getting psyched as things continue to take shape! -Robert
SAL9000		#5	[-]
Posts: 68 (04/30/08 09:33:03) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	I didn't know you could pour rubber in two goes. I thought it had to be all poured and cured in one, or maybe I'm thinking of concrete. Anyway, just love these updates. --Jim
AmodelMan		#6	[-]
Posts: 41 (04/30/08 11:18:14) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	I was thinking that too. That even if the rubber stuck to itself, it would be weak at that point, or there would be a residual seam in the casting. But then, I had thought the saran wrap would be a problem until I understood that the clay was simply a place holder for the rubber and had no other use. I initially thought the clay was there to make an impression of surface detail for later molding needs. Scott is the master, and we the unenlightened masses. This is why I enjoy details and insights like this so much! I gain endless fascination from pondering the possibilities, then formulate definitive ideas in the learning of it all. Thank you for sharing these Scott! -t
CaptCBoard		#7	[-]
Posts: 1220 (04/30/08 16:07:31) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	I never said the photo showed all the rubber that got poured. I took the photo at a time I was switching from an empty bucket to a full one, to continue the pour. I simply took a moment to shoot a photo to show you could see the level of the rubber. However, pouring new rubber against cured rubber has always resulted in a good bond, in my experience. It may be true that chemically there is no bond, but why else do people use a release when making the second half of a mold! Scott

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