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Pat Sparks BOMARC Build


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2 hours ago, LSP_Kevin said:

More 3D printing! This time I'm having another go at printing the blast shield for the launch tower, and keeping the high probability of failure in mind, have basically conceived of them as test prints. I put supports under two examples using opposing orientations, and no tilt in the z-axis:




While I now feel comfortable with the basic mechanics of adding supports manually in Chitubox, I've got a long way to go before I can claim any sense of expertise, everything is just "best guess" right now.


That said, they both turned out better than I expected, and much better than the first one:




However, I'm sure the keen-eyed among you will have spotted some problems already. There's some layer delamination on both pieces (evident on the one on the right in the photo above), and the plate facing the floor on the left piece has anything but a straight length-wise edge:




It's fair to say that in these photos, they both look usable. Sadly, a side-on view reveals the wave-like distortions in the main blast shield on both pieces:




So while these are close, they're not close enough, and it's back to the drawing board. Pat sent me some screenshots of a suggested support layout for this piece, and ironically it's similar to what I used for the first one. What I did learn from this latest test print, however, is that as far as possible, it's best to avoid printing flat surfaces paralell to the build plate.


Until next time!



Yup, Flat when left flat kills in 3D resin printing....



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Thanks to a suggestion by Pat about how best to orient the blast shield for printing, I've finally been able to churn one out that's good enough to keep:








It's not absolutely flawless, but much better than the other 3 I've done so far, and certainly well within my own personal tolerances. Once I've cleaned up all the support scars, it'll do quite nicely. I'm hoping I can knock off the remaining launch tower parts in a single print, all going well.



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More progress today with the launch tower. As alluded to in my previous post, I decided to pack out the build plate with as many of the remaining parts as I could, and I managed to fit all but one on. And the resulting print, I'm happy to report, was about 98% successful!




All manual supports, and they probably took me the best part of 2 hours to lay out. I still have an over-reliance on 'heavy' supports, as I'm still not confident about where I can get away with lighter ones, so I tend to overdo the heavy ones. This means the supports are more difficult to remove, and it took me almost as long to remove them as it did to add them:




This little number was a particular challenge, being extremely delicate, and I was sure it wasn't going to survive the process intact:




But thankfully, it did. Just a lot of clean-up to do now. Once that's done, and I've figured out the proper assembly arrangement, I'll post a photo of the main assembly dry-fitted. It's quite imposing!


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Here we have the final piece of the BOMARC puzzle: the base clamp on the launch tower:



As you can see, the details around the bottom of the support arms didn't print properly, due to my not supporting them properly, so a reprint is under way. And that will, hopefully, be the last print run for this project!



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And we have a winner!




Just two tries for this one, which is a record for me with a part like this. And that concludes the 3D printing phase of this project.


Here's the clamp fitted over the tail unit:




I've also begun the painting process, starting with some Tamiya Fine White Primer out of the spray can:




The tail end hasn't been done, as that's where I was holding it! I probably won't use the rattle an on it again, though, as I had terrible trouble with paint runs and pooling. Back to the airbrush, I think.


And here's a quick dry-fit of the main components of the launch tower:




I still have to clean up all the parts prior to painting and final assembly. I also need to figure out what colour to paint it. I can really only find photos of it painted a mid to light grey, but they also all feature the grey version of the BOMARC colour scheme, whereas I intend to paint mine in the earlier black and white scheme shown in a previous post. Perhaps it doesn't matter much, and the grey will provide a nice contrast anyway.


Stay tuned for the next update!


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Your perseverence is really paying off Kev. She's looking epic. 

I'm sure Pat is thrilled to see his design become reality. 


Plenty of opportunity for what-if type schemes on something like this. 

Thunderbird 10 anyone?


Eager to see her all finished up. Well done mate. 

Edited by geedubelyer
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Thanks, Guy. Quite a long way to go yet, though! As well as the rest of the painting process - which is paradoxically both fiddly and epic - I also need to design and cut some paint masks for the bulk of the markings. There's several hours worth of clean up in the launch tower alone, and I've also realised - thanks to a nudge from Pat - that I'll need to make a base for this, as the piston in the bottom of the launch tower is supposed to swing into a cavity in the concrete block that it sits on.


That lot should keep me busy for a while!


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It's been a few days since I posted an update on this build, but I haven't been idle. Most of my time has been spent cleaning up the parts and laying down some primer, along with some test fitting and figuring out how all the launch tower pieces go together. I think I've got it all sussed out now, and to that end, I've assembled the rail umbilica, complete with articulating support arms:






The forward section of this thing is incredibly fragile, so I just hope it survives unbroken all the way to the end. For the next update, I hope to have a full test assembly of the launch tower and missile, before moving on to finish all the painting.


Any suggestions for the colour of the launch tower? I'm thinking plain ol' mid-grey, but will happily consider more knowledgeable suggestions.



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