Fixing the External Hull Details
The detail on the kit is really good so only a few corrections were needed here. My first adjustment involved properly fitting the DLM Impulse engine replacement part. In order to achieve the correct look the back impulse deck of the saucer was thinned (from the inside) to a thickness of 0.030 inches and the alignment strips for the original impulse part were filed away.
Kit parts Thinned Saucer and
DLM Impulse Engine
Now that's much closer to the correct look!
With the saucer impulse deck so much thinner the top of the DLM parts center boss must be sanded down bringing the trapezoid almost to its proper dimensions. I also found that when I matched the flange walls up to the deck I had to insert a spacer strip behind the boss to match it to the upper deck.
There is some right to left asymmetry to the DLM part. Looked at from the front as in the pictures above the left side bottom flange (outlines the actual engine area) is too widens towards the outside instead of narrowing like the right side. The left bottom flange is also .030 too thin where it joins the trapezoidal center boss. Once built up you can file down the left side flange to match the right side. The buildup and filing below have the flanges matched side to side.
Unfortunately as you can see in the above picture there is also some asymmetry in the slant of the impulse engine surfaces relative to the center boss. Once I had the flanges fixed, I aligned the part to the saucer so the side flanges matched to the saucer impulse deck. It became obvious that I needed to sand off all of the engraved detail and some of the surface to bring the plane of the boss into alignment facing directly to the rear as well as trimming a bit of the bottom boss. See the lines on the picture below.
Next, while the linear strip along the impulse deck is the proper width, the top of the trapezoid is about 0.020 short on each side. You will need to fill out the outline to match with putty.
As has been noted by Gunstar1 the radius of the edges on the linear strip of the impulse deck and the edges of the trapezoidal center boss should be corrected to a true quarter round as in the studio model picture above.
Finally a light box was glued to the rear of the part to provide for the LED lighting without disturbing the main bridge lighting.
Even after all of this the right to left asymetry of the impulse part still bugged me. So I pitched what I had and began modifying the DLM part per my accurizing page and mine and Gunstar1's discussions. By the time I was finished I no longer had a nice clear part, but I did have a "Master" Back to DLM. Don was kind enough to use his excelent casting skills to make me perfectly clear parts from my master. The new parts are shown below. Notice that among other things they do not have the lip at the top.
The Lower Saucer Dome
The lower bridge dome lacks the broad raised ring of the studio model and its four bosses are too square in shape. First carefully file the 4 bosses to a slightly more trapezoidal shape. Take about 0.015 in off each top dimension. Then scribe in the bits of ring ring scribing to fill the gaps between the kit ring ends and the new boss edges. I did this under a 20 power microscope.
A single curved piece needs to be carefully cut out and glued in place to correct ad this broad ring as it is a raised detail. Simply filling the scribed grooves will not produce the right effect. The curved band is cut from 0.010 in. sheet stock. The curved piece is actually the base of a cone. In order to make it the proper radius you need to know the height of the cone. First I measured the existing part. The diameter of the base of the dome is 1.300 in, radius 0.65 in. The band needs to cover the first two scribed rings on the dome and is measured to be 0.125 wide along the slant. Next I measured the diameter at the top of the intended ring, the 2nd scribed line up from the base, 1.135 in. Applying ratios: the true radius (hypotenuse of the right triangle)/ radius of the base = the ring width/ the difference in the two radiuses or .125/.0825= true radius/.65 -> The true radius is .984. So to make the band draw one circle on the plastic sheet with this radius and then draw a second inside it with a radius 0f .984-.125=.823. Once cut out this ring is carefully bent around and into shape. Rough cut it and then carefully cut /file in the cut outs for the 4 bosses one at a time until everything fits. The final step is matching the two ends so that they just touch when it is in place. Finally glue it into place
Original Kit Part Modified Part
The other correction was a bit more of a pain. The ends of the vertical walls of each projection lack the proper slant. I order to correct this I had to glue small triangular pieces onto each wall. In addition the roof of the front projection had to be extended by .040 to produce the proper surface relative to the grills.
Once the tips and deck pieces are added on the next step was to file them to the proper angles of 126 degrees fro the rear and side projections and 124 degrees for the front projection. I then added in the gentle curve that is seen at the end of each projection. Finally the curving walls between the projections are much to steep a slant. Fortunately there is enough material in the part to allow one to simply file them back to the proper slant. I found that by drawing an arc 0.055 inches inside of the existing arc of the top of the wall I got the proper angle. The results are below.
The final step is to add back in the rectangular details (using 0.020 stock) in the center of each curving sidewall. Remember to lightly sand them so they are thinner at the top than the bottom.
After a final smoothing of the added bottom ring the 4 truncated pyramids were sanded down and a new top surface added made from 0.010 stock so as to properly overlap the added bottom ring. The results are below.
The lower bridge dome part has one other problem. The alignment pins are just where the LED's should go. I wanted to remove them but also wanted to retain the ease of assembly. So, before cutting them off I drilled 4 new holes and then glued in new alignment pins. Once done the existing pins can be removed while still preserving the ease of assembly. This same technique also works well on the bridge dome.
In order to correct the width of the deck above the slot lights just below the start of the bridge dome I glued on a 0.020x0.060 strip and sanded this down at the sides to match the contour of the side walls. This allows that deck to be both the proper width and as well to correctly match the alignment of the slot light walls where they meet the deck.
Additionally for ease of assembly I added two alignment pins (and holes in the main saucer) so that things would go together nicely after removing the 3 pins that block the slot windows. In the picture only the first has been removed.
Learning from recent suggestions on the boards I modified the edge of the upper saucer saucer by adding a 0.030 in. shim to the molded in ridge that the saucer edge pieces align to. This nicely spaced things so that the edge pieces beautifully lined up with the upper saucer rim. At the same time, I used a saw and dremmel tool to cut away the rim in those sections directly behind the saucer edge windows. This will allow them to be lit via either general internal lighting or small light boxes.
Like a lot of people I wish the lower saucer also had alignment strips as it would be easier if the rims could be assembled to the lower saucer first and then the top added. To make assembly easier I taped all of the sections in place and then removed the top saucer. After painting on olive oil on the rim segment interiors I added small ridges of Apoxie Sculpt two to a segment. These will provide the alignment guides for final assembly.
In order to allow for the spotlight lighting from the inside the 3 middle alignment / structual attachment posts between the saucer halves must be removed. I was worried about what this might do to the strength of the saucer so I added 4 new posts that were out of the way of the spotlights. These can be seen below.