Well… in that case… let's hope she keeps on living!
Got the front entry wall done today along with two other unrelated projects. After getting all that blocking in place I put the front wall stair landing ledges in place. With that I'm ready to create the two side wails, the inner partition wall and all the bracing that supports the elevator shaft. The I'll finish the stair case.
I will have to build a 1" high foundation under the entry hall and the loading dock. I'm going to fab it out of styrene since as concrete it will be a pretty smooth surface.
Here's the stair ledges in place. I spent a lot of time to make sure they were are the same height and level.
re: those other two projects… they're both very different and both on commission. The first is the 1/72 scale Cleveland Tractor Co. (Cletrac) high-speed tractor used to move aircraft at airfields in WW2. A member of the Military Modelers Club of Louisville asked if I could create one on my 3D printer. I said, if I can draw it, I can probably make it. It took a while to gather the images and then draw one on SketchUp. You have to draw in full scale in SU.
I broke it into a group of parts and scaled everything 0.013 and exported the pieces as STL files to my slicer. After printing and building most of a couple of trials, I was having a lot of trouble with the right tracks. They were a mess and making a mess of the printer. Couldn't quite figure out what was going on. Splitting the parts this way meant that all of them could be printed directly on the platen with no added supports that needed to be removed. For example: if I printed the body with the engine with the hood on, I would have had supports inside the engine compartment to enable the hood to print properly. Those supports would have been a pain to remove without damaging the model.
It's clear in this image that the right tracks just didn't print well. I had to attempt to clean them up, but was unsatisfied with the results. I wasn't getting paid to do this, I might have let it ride.
I went back into the drawing to see if anything was wrong. At first glance everything seemed okay, and then I saw it. The bottom of the road wheel boogie frames WAS NOT A CLOSED SHAPE. I thought the bottom surface was reversed (not normal-facing) and I had SU set up that non-normal faces are a bright red. I tried reversing the surface and then found that there was NO SURFACE THERE. I was actually seeing the inside of the shape and those surfaces should be red. Repair proved difficult and it was easier just to re-draw the shape. I then realized that I was using too small of a scaling factor. If a shape is not a closed solid, it can't form and may actually hemorrhage resin out to other areas.
1/72 scale factor is 0.0138. I was scaling to 0.013. I upped it to 0.014 and got shapes that were almost 10% bigger. At this small scale that made quite a difference in both appearance AND ease of printing.
I redid all the parts and printed them today. I had 100% perfect prints. The arrow is pointing to the 0.013 scales track. Notice how nice the definition is on all the details.
This is the rest of the model's parts. I'm going too make two of them, but have enough for three if needed. Instead of attempting to print the headlights separately (I tried and it was ridiculous) I drew them on a stalk and with cut them off to apply them to the model. The other thing that printed better at the slightly larger scale was the real of the chassis which fell apart a the smaller scale.
I'll have these assembled tomorrow.
For the second project I'm restoring the base to a cast resin chess piece. The chess set was bought in Tehran, Iran by a woman (married to an Iranian) who lives in Cleveland, but has two sisters living in Louisville. On a whim, she stopped into Scale Reproductions, Inc (America's best hobby shop IMHO) and asked the proprietor, Brian Bunger, if he knew anyone that could replace the missing base. He immediately told her about me. The set, because of where it was purchased is irreplaceable.
I believe I showed this picture earlier, but forgive me. Being resin, the figures are fixable. The base is missing.
The chess set was on a table and some workman were doing drywall work. They threw a drop cloth over the set and when pulling it off, broke the character and then threw the base out with the drop cloth.
I decided to make a silicone mold of the good one and reproduce the base. I don't want to make the entire figure because it would tax my skills to attempt to match the figures coloration. I do feel I can replicate the coloration of the base. Therefore, I didn't attempt to mold the entire figure, but limit the mold making to the base. The broken figure's feet are not complete, so I'm going to make the joint at the bottom of the pants and make new shoes. The base will be pinned to the figure. In fact, I see traces of a metal reinforcement in the sole of the foot.
I used Legos to make the mold box for the bottom, but in hindsight should have just used clay. The box was quite leaky. Luckily, the cured silicone is easy to clean up. The sprue filler tubes are created with left over sprue from my many plastic kits.
I will have to plug the opening where the legs got through the clay or I could attempt to fill the mold from there. You should feed from the bottom and vent the top so the resin forces the air out in front of it. Bubbles are the achilles heel of resin casting.
I filled the upper cope yesterday. The silicone I'm using is a Chinese product that wasn't too expensive. I typically use Smooth On and had some on the shelf that kicked. The mold material is two-part (A and B) in equal volume proportions. One of the two, has a short shelf-life and was a solid glob of rubber. I'm not getting much to do this job and didn't want the material costs to exceed the job. As it is, I'm barely breaking even, but I like doing these restorations since they're and interesting challenge. This product cures in 6 hours. It has low viscosity and has long pot-life so it out-gasses by itself. Some silicones, especially the higher strength varieties need to be vacuum de-gassed to remove bubbles.
I pulled all the Lego stuff of and turned the mold over. This time I built the walls entirely out of clay and had no leakage. This is a special clay that contains no impurities that can affect the silicone's curing.
You have to apply mold-release so the silicone doesn't glue itself to itself or to the model. The silicone did not damage the model. Tomorrow, I'll split the mold and attempt to make the first replacement part. Good thing doing it this way. If I screw it up, I'll just mold another… and another… until I get it right. There is some engraved printing on the base that will be picked up by the mold-making process.
So in today's session I was working in three-generations of crafting: wooden sticks, silicone mold-making and 3D Resin printing.