RichO Posted May 23, 2018 Share Posted May 23, 2018 It sort of looks like Shapeways missed the fourth version, "WTF". You'll get thing straightened out tho, and it will all look great. Link to comment Share on other sites More sharing options...
roma847 Posted May 27, 2018 Author Share Posted May 27, 2018 Thanks guys for watching. Link to comment Share on other sites More sharing options...
roma847 Posted May 28, 2018 Author Share Posted May 28, 2018 Hello everybody, in connection with the planned Flour-Technique for the production of the ET's Instafoam insulation I receiced a hint by David Hanners (papermodelers.com/forum), that this structure alone would not be sufficient, in order to faithfully reproduce the ET. He meant that I would necessarily have to consider the typical annular bands in the insulation too, wherewith he probably wanted to challenge me. Maybe some of you know David Hanner's contribution "Detailing the Space Shuttle" in Michael Mackowski's "Space in Miniature #3" book. When he built a Shuttle Stack (1/144) ages ago for this contribution, he coated bands of the ET with liquid cement to soften the plastic, then scuffed the surface with heavy-grit sandpaper, turning the ET during he sanded. He worked in sections, and finally he softened it up with medium sandpaper. Unfortunately I have only a black&white copy, on whose figures one cannot see the details of his stack clearly enough. Although I had an idea what he meant with the annular bands, I was not sure. But Michael Mackowski was so nice and had thankfully sent me some scans of David's original photos like these here. As one can see in the photos, he had roughened the ET in circumferential direction with sandpaper, which was a promising approach, but that's not the typical Instafoam structure. Independently, the crucial question for me is always how certain details looked at the STS-6. Source: retrospaceimages.com (STS-6) Source: NASA (STS-126) BTW, in my view, not this structure but the Intertank is the dominant structural feature of any External Tank, especially since this band/ring structure is not always very distinct. But at least he made me think, though it could surely become difficult to create such a regular as well as delicate structure. My idea for the ET front end is relatively simple and came up when I looked at my WSF-IT, especially at the sight of the fine ribs in the Thrust panel. There are 26 ribs in this panel, which is approx. 24 mm wide, corresponding to approx. 0,9 mm for one rib. Therefore, I imagine this ET front part as WSF 3D print with adjacent annular bands at a distance of about 0,9 mm. It would be ideal if these bands would become flatter towards the nose. Or one could choose a uniform height and sand off these bands softly to the nose. But I think that a good 3D designer can easily model such a front piece, which is why I have already asked Michael Key, if he could do this job. In this image I tried to count the bands from bottom to top, which is not that easy, and came to about 55. Source: retrospaceimages.com (STS-6) Depending on what this structure of the 3D front part looks like, one could also use the Flour-Technique to level out the gaps if necessary. For the ET rear part (185 mm), this approach would also be possible in principle, although I do not know what height Shapeways can print. But even a division into three parts would be conceivable without thinking about the costs. But I could also imagine a different solution without 3D printing, with a lot of small Evergreen strips plus Flour-Technique, or better not? This is really a tricky matter ... 1 Link to comment Share on other sites More sharing options...
Mustermark Posted May 28, 2018 Share Posted May 28, 2018 Another challenge for your Challenger. This looks like a very time-consuming task with Evergreen strips. It seems to me the depth of the undulation is very small. Could you put on one layer of flour-paint, remove narrow rings of the paint from the ‘valleys’ and then give another flour coating? Link to comment Share on other sites More sharing options...
Space Ranger Posted May 28, 2018 Share Posted May 28, 2018 If it were me, I'd be tempted to simulate those bands with various tints of paint, sprayed on "dry" (i.e., from a greater distance than normal so that the paint partially dries before reaching the surface of the model). This would yield a rougher-than-normal surface, which would simulate the texture of the sprayed-on insulation. Link to comment Share on other sites More sharing options...
RichO Posted May 28, 2018 Share Posted May 28, 2018 Consider the cost of the 3D printing. I like the texture of WSF, and craftsmanship, but the cost of these parts are very expensive. Remember that a good Scratcher could always find an alternate solution and material. Link to comment Share on other sites More sharing options...
roma847 Posted May 28, 2018 Author Share Posted May 28, 2018 Thanks Mark and Michael for your well-meant comments, but the overall "pebbled" or rough surface of the Istafoam structure I can create by using the Flour technique that my Raumcon friend (inselaner) invented, no problem. The tricky problem is the fine band or ring structure on the surface, which could be simulated possibly by WSF 3D printing, if one were to model a narrow and very flat wave-like ring structure by creating fine grooves (approx. 0,3 mm) in about 1 mm intervals, much like between the fine ribs in the Thrust Panels. Because of these minimal distances, a removal of narrow rings out of a first flour coating is impossible, especially since this layer is only wafer-thin, sorry Mark. I hope that the matter has become a bit clearer now. 3 Link to comment Share on other sites More sharing options...
roma847 Posted May 28, 2018 Author Share Posted May 28, 2018 6 hours ago, RichO said: Consider the cost of the 3D printing. I like the texture of WSF, and craftsmanship, but the cost of these parts are very expensive. Remember that a good Scratcher could always find an alternate solution and material. I fully agree with you, Rich, that's all right. As I said, I could also imagine a Scratch solution. For this one would have to glue "only" about 170 flat Evergreen strips, maybe 0,25 mm x 0,5 mm or 0,25 mm x 0,75 mm, each at a distance of about 0,5 mm around the ET, followed by a Flour technique coating, whereby this wave-shaped ring structure could arise. This one could check out in a test with a little less strips. Link to comment Share on other sites More sharing options...
RichO Posted May 29, 2018 Share Posted May 29, 2018 I have never seen this "flour technique" before. What a gorgeous finish and texture! Certainly something to consider. Link to comment Share on other sites More sharing options...
saturnapollo Posted May 29, 2018 Share Posted May 29, 2018 (edited) Could a steel comb used in some manner not produce parallel lines? Maybe direct onto whatever surface texture you end up using or painting it with an ever so slightly lighter undercoat and then using the comb to remove lines of the top coat. At this scale that might be all you would need. Or another option - to wind thick thread around it before the flour? Don't know how good or easy either idea would be in practice or to achieve. Keith Edited May 29, 2018 by saturnapollo Link to comment Share on other sites More sharing options...
roma847 Posted May 31, 2018 Author Share Posted May 31, 2018 On 5/29/2018 at 2:26 AM, RichO said: I have never seen this "flour technique" before. What a gorgeous finish and texture! Certainly something to consider. I fully agree with you, Rich. That was an ingenious idea of my friend, which immediately convinced and absolutely thrilled me, even though the typical Instafoam ring structure is missing ... Link to comment Share on other sites More sharing options...
roma847 Posted May 31, 2018 Author Share Posted May 31, 2018 On 5/29/2018 at 5:26 AM, saturnapollo said: Could a steel comb used in some manner not produce parallel lines? Maybe direct onto whatever surface texture you end up using or painting it with an ever so slightly lighter undercoat and then using the comb to remove lines of the top coat. At this scale that might be all you would need. Or another option - to wind thick thread around it before the flour? Don't know how good or easy either idea would be in practice or to achieve. Keith Thanks for your nice tips, regarding the steel comb, this is almost impossible to realize because the distances of the grooves of only approx. 1 mm are much too small. The same would apply to the thread, which would also only create a spiral. This is really a tricky matter ... Link to comment Share on other sites More sharing options...
Kallisti Posted May 31, 2018 Share Posted May 31, 2018 Wow amazing effect with the flour there, the final texture looks superb! Link to comment Share on other sites More sharing options...
Dave Posted May 31, 2018 Share Posted May 31, 2018 The flour technique is very impressive. Link to comment Share on other sites More sharing options...
roma847 Posted May 31, 2018 Author Share Posted May 31, 2018 Thanks Guys, yep, this technique is really awesome. Link to comment Share on other sites More sharing options...
roma847 Posted May 31, 2018 Author Share Posted May 31, 2018 Hi everybody, in the ARC Forum I got an interesting hint to Simon Atkinson, who used a lathe for simulating the grooves in his External tank. He is a professional modeler and illustrator since more than 40 years and here is his awesome Shuttle stack (1/72), which is currently (2016) in store at The London Science Museum. Source: satkinsoncreativearts.com A similar technique, e.g. by engraving the grooves, I have already imagined, but unfortunately I have no lathe, which would probably need a CNC control to get even intervals. But for that, 1/72 is of course much more workable, especially since the grooves should be at least 2 mm apart. This approach is marvelous, but if you take a closer look at its texture, the grooves for my taste are a bit too pronounced and smooth, because only perfect even grooves are created with the lathe, and thus seem almost a bit artificial. Nevertheless, I think that this structure could also be simulated for a 1/144 ET, if one can realize the corresponding spacings of approx. 1 mm by a clever 3D modeling of a narrow and very flat wave-like ring structure by creating fine grooves (approx. 0,3 mm) in about 1 mm intervals, much like between the fine ribs in the Thrust Panels. Regarding the Spray On Foam Insulation (SOFI) of the ETs one has to distinguish early and later missions, as for the Orbiter's TPS Tiles and Blankets. In the earlier missions like STS-6, this wave-like ring structure was more pronounced, while it is less or barely visible in later missions. Later at the SLWTs, the SOFI was also much more evenly applied and reworked. 2 Link to comment Share on other sites More sharing options...
saturnapollo Posted May 31, 2018 Share Posted May 31, 2018 (edited) Not sure you would actually notice the spiral effect with the thread. Re the steel comb idea, how about this; https://www.ebay.co.uk/i/132521713963?chn=ps&adgroupid=43920634520&rlsatarget=pla-359427365517&abcId=1063846&adtype=pla&merchantid=113746022&poi=&googleloc=1007326&device=c&campaignid=797602469&crdt=0 Still not sure how practical it would be though. Just an idea. I agree that, nice though the above model is, the grooves are too pronounced. Keith Edited May 31, 2018 by saturnapollo Link to comment Share on other sites More sharing options...
roma847 Posted May 31, 2018 Author Share Posted May 31, 2018 Thanks Keith, I know such Profile Gauges, but I can hardly imagine creating this groove structure therewith evenly across the entire circumference and over the entire length of the ET. Link to comment Share on other sites More sharing options...
roma847 Posted June 2, 2018 Author Share Posted June 2, 2018 Hi everybody, last but not least, in the NSF forum I have still found now a Hi-Res. photo of the during STS-6 used ET-108 on which one can recognize this structure very well on the long LH2 Tank, which confirms my previous imagination. Source: nasaspaceflight.com (woods170) As one can see on this, in the SOFI insulation foam there is in fact a uniformly rounded wave structure, which possibly was to be realized either as 3D print (WSF) or by means of my envisaged variant of Evergreen strip-rings + Flour technique. And that also explains now the alternating light-dark effect of the bands, which is not a color effect, but only created by the shadows of the "hills" in the "valleys". Link to comment Share on other sites More sharing options...
roma847 Posted June 2, 2018 Author Share Posted June 2, 2018 Dear friends, sadly we must take note that Donald H. Peterson, one of the crew members of STS-6, passed away a few days ago. Source: commons.wikimedia.org Seated are Paul J. Weitz (left), crew commander, and Karol J. Bobko, pilot. Standing are Donald H. Peterson (left) and Story Musgrave, both mission specalists. Source: flickr.com (NASA Kennedy) This sad news consternates me deeply, especially since Paul J. Weitz left recently too. Forever remembered, may they all rest in peace ... 1 2 1 Link to comment Share on other sites More sharing options...
Mass Posted June 3, 2018 Share Posted June 3, 2018 (edited) On 5/31/2018 at 5:00 PM, roma847 said: Thanks for your nice tips, regarding the steel comb, this is almost impossible to realize because the distances of the grooves of only approx. 1 mm are much too small. The same would apply to the thread, which would also only create a spiral. This is really a tricky matter ... I was going to say "You cold try a profile gauge. The teeth are very close and not too sharp, and you can (as it says) set the profile to fit the tank and that will avoid the spiral" but see that its been raised. Still, if you fond a long on e(and there are ones out there) ..... Edited June 3, 2018 by Mass My stupidity and rushing :( Link to comment Share on other sites More sharing options...
roma847 Posted June 6, 2018 Author Share Posted June 6, 2018 Thanks Mass, as said, I know such Profile Gauges, but I can hardly imagine creating this groove structure therewith evenly across the entire circumference and over the entire length of the ET. Link to comment Share on other sites More sharing options...
roma847 Posted June 6, 2018 Author Share Posted June 6, 2018 Hello everybody, after the tough struggle for the rings of the ET now back to the grooves of the last FUD-IT, whose ultrasonic cleaning in the Dental lab was still on the agenda. For that I had procured the recommended intensive cleaner TICKOPUR R 60, which we wanted to use based on the conditions recommended by BANDELIN. Soure: bandelin.com Since this cleaner i.a. Sodium hydroxide (5-15%), also called caustic soda, caution was bidden, which is why protective gloves were required. After the nice colleagues of the ChiliDent Lab were back on board after their short break, it was finally time and the Final Countdown was imminent. In the beginning of May in my #1457 I had presented the critical areas with the strongest wax nests and captured in pictures. In order to shorten the cleaning time, we have increased the concentration of the TICKOPUR to approx. 20 %. Through the rubber ring, the height of the glass insert in the ultrasonic bath could be adjusted so that it hung about 3 cm above the bottom of the tub, which is as important for optimal cleaning as filling the tub with the same solution, that the boss has personally mixed. Due to the size of the glass insert, the Intertank could be inserted lengthwise, which is also advantageous for the cleaning effect. After setting the thermostat to 70 °C, the appliance was switched on by the assistant, and the bath began to bubble. After every 30 minutes, the IT was turned a quarter turn further. Overall, the cleaning time was about three hours. After that, the tank looked white and completely clean, which one could already see at first glance. So finally the work was done, and with a tip into the kitty I thanked me once again and light-hearted said goodbye. And as one can see in this photo, the cleaning was really perfect, because there are no wax residues left, which is why no aftertreatment was required too. This is especially also illustrated by comparing the photos before and afterwards. And here once again a few pictures of both ITs in comparison, where the FUD-IT looks even more filigree than the WSF-IT. Nevertheless, I think that one can use both ITs, depending at whim and purse. 1 Link to comment Share on other sites More sharing options...
RichO Posted June 7, 2018 Share Posted June 7, 2018 Congratulations Manfred!! The new cleaning method worked out beautifully. I can't wait to see your insulation foam come to light with the freshly cleaned IT part. Link to comment Share on other sites More sharing options...
roma847 Posted June 7, 2018 Author Share Posted June 7, 2018 Thanks Rich for your nice congrats! Yep, the IT looks clean as a whistle, as the saying goes. If one knows how to do it, Ultrasonic cleaning is really easy, and now I have the know-how, and all of you too ... One either needs sa good equipment, or one has a good dentist with a helpful lab team. BTW, the IT already has its SOFI and is ready for priming and painting. 1 Link to comment Share on other sites More sharing options...
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