Alcubierre Build Thread

Discussion in 'Scratch Built' started by neil_w, Sep 27, 2018.

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  1. Apr 7, 2019 #361

    Rktman

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    Eric Noguchi

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    Spectacular! (I just had an eyegasm). That dark cloth background is a great touch too.
     
  2. Apr 8, 2019 #362

    Bruiser

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    This came out really great but it's no surprise to those of us that follow your builds :)

    I hope you are able to get videos of the first flight and the Iris T too!

    -Bob
     
  3. Apr 8, 2019 #363

    neil_w

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    Here's a little report not specifically related to Alcubierre, but relevant to this thread.

    I've been finishing up a Deuce's Wild using some of my leftover silver-painted decal paper. First, I had a 1/2" band wrapped around the BT60 body tube: that worked fine except for one of the ends wouldn't lay down. I ended up putting a dab of CA under there, and it was good.

    On the other hand, I had some pieces to put on the fins (flat!) and those were a complete failure. Here's the design:
    upload_2019-4-8_8-50-11.png

    I had three problems with the fin pieces. Apologies for no pictures, but in the heat of the moment I wasn't thinking about the camera (hadn't planned on documenting this since it seemed routine).

    Problem 1: The edges wouldn't lie down, period, but remained slightly curled up. Let's say the last..... I dunno, may 1/32" of each edge. Would. Not. Stay. Down. Trying to get CA under that edge without making a mess all over the fin seemed like a fool's errand, and I couldn't think of any other way to fasten the edges down.

    Resolution: These pieces were cut with a blade from the rear. Perhaps this imposed a slight bend upward at the edges that made itself known when the decal was wet and flexible. Not sure how to fix this because cutting the silver from the front makes for a messy edge. Maybe worth a try to trim all the pieces down just a bit (slightly smaller won't hurt) cutting from the top side. Maybe messy edges are better than no decals. I'll have to experiment. Not sure why this didn't bite me with Alcubierre, could be that they worked better being mostly scissor-cut, or that the edges are more likely to stay put when the decal is bending outside a curved surface.

    Problem 2: The decals would not conform to the paint dam between the red and white. I could see the edge through the decal, and it seemed likely that there was a bit of an air gap under there. With a normal decal some Micro-sol on top would have taken care of that, but that won't work on top of paint.

    Resolution: The painted decals are simply not as flexible, and won't conform to fine irregularities. That's not going to change. The fix is to eliminate the fin irregularities. If I want this to work I'll need to either smooth down the paint dams or else move the decals to the edge of the red/white boundary instead of straddling it.

    Problem 3: The silver decal was not completely opaque, as it turned out. You could easily see the boundary between the read and white underneath the decal.

    Resolution: This should not have been a surprise. In the future, a coat of primer before painting metallic decals should do the trick. I got lucky with Alcubierre because the decals were always on top of solid cranberry. For this rocket, if I can solve problem #1, I'm definitely going to have to move the decals off the red/white boundary, and just onto the white. Won't look as good, but better than nothing I think.


    Final note: I had the logo decal printed and clear-coated and ready to apply. And now for the life of me I cannot figure out where I put it. Not a happy camper right now. :mad:
     
  4. Apr 8, 2019 #364

    neil_w

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    If you listen very carefully, you can hear it...
    lug.JPG
     
  5. Apr 9, 2019 #365

    Rktman

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    Eric Noguchi

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    Since you mentioned Micro Sol I assume these are water slide decals. Would using a slightly larger silver vinyl decal over the 1st hide the paint dam and adhere better? I know you wanted to use up the water slide ones but since vinyl is thicker it would certainly hide any irregularities better.
     
  6. Apr 9, 2019 #366

    neil_w

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    Vinyl would undoubtedly adhere better, although I believe you'd still see the dam underneath. I don't have any silver vinyl, though (would vinyl take on paint? Dunno).

    I did a nice little experiment with the silver decal paper and came back with perplexing results. I tried some pieces cut with a knife from the front, cut with a knife from the rear, and cut with scissors. Here were the preliminary results, as viewed from the edge
    Silver decals-1.jpg

    If you click for the full-sized version, you'll see slightly lifted edges for the two sets of knife-cut pieces, while the scissors pieces are absolutely flat. Note that the lifting here is not nearly as bad as what I saw on the rocket, maybe because I have a smoother gloss surface here (it's the back side of a laminate flooring sample from HD). But qualitatively it's the same. Oddly, there doesn't seem to have been any advantage to cutting with the knife from the front or the back.

    After fully drying, all edges laid down completely, which surprised me. However, the after effects of the lifting were still visible in some places:
    Silver decals-2.jpg

    Again, click for larger.

    Overall, these looked far better than I expected them to. However, the scissor-cut pieces still performed noticeably better. *All* scissor-cut pieces went down perfectly flat immediately, whereas *all* knife-cut pieces show some sort of edge issues.

    I've cut some new silver pieces (with scissors, natch) in a modified design to butt up against the paint dam rather than overlay it. Will give it a try tonight.
     
  7. Apr 9, 2019 #367

    afadeev

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    Vinyl can definitely be painted, and all the paints I've tried so far adhere really well, and lay smooth (i.e.: no wrinkling).

    I've taken a short-cut with my second Sat-V build, and just wrapped un-filled spirals of the main 4" tube with white vinyl wrap. Looks better than expected: clean, uniform, and completely covers paper tube imperfections. It adhered really well after applying a light coat of gloss paint to the BT, to give vinyl something smooth and less-porous to grab onto. Also increases torsional rigidity of the airframe:

    satV-2nd tube.jpg

    YMMV,
    a
     
  8. Apr 9, 2019 #368

    neil_w

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    Hmm, I could try spraying some vinyl pieces to experiment... First I'll see if I have any luck with the newly-cut silver decal paper.
     
  9. Apr 9, 2019 #369

    Rktman

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    Eric Noguchi

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    Silver vinyl (and other metallic colors) are available in rolls in places like Hobby Lobby and craft stores. The most extensive collection seems to be for Cricut machines and I ended up just getting a more generic brand. Works great, really covers imperfections, and you can use soapy water to keep it from adhering while you maneuver it into position. Squeegy out the water and it locks down tight. Whichever route you go I hope it solves your problem.
     
  10. Apr 9, 2019 #370

    neil_w

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    I will consider that route in the future, especially since I now have occasional access to a Cricut so I could actually do some fancy shape cutting if needed. For this Deuce build though, everything is on-hand materials. That's one reason i went with that color scheme... all paint I have on-hand (and might finally have killed my beloved can of metallic blue).

    It is a good point, though... cut vinyl is a legit alternative to painted decals, and in many situations would be better. Where the painted decals really are essential is when you need a perfect match to an uncommon paint color. But there are a *lot* of vinyl colors available, and if you can stay within the cheap color zone (still a lot of options) you can get a roll for less than $5 with discount coupon. Yeah, I've been walking the Cricut aisle at Michael's a bit lately; after a recent reorg my local store now has rockets and Cricut in the same aisle...:) Stocked up on B6-4s and C6-5s with recent 50% off coupon.
     
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  11. Apr 9, 2019 #371

    Gary Byrum

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    Vinyl CAN be painted but you have to be careful not to over-do the 1st & 2nd applications. Go lightly because rattle can paint can and will ruin like crazing.
     
  12. Apr 10, 2019 #372

    BABAR

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    Sounds like a good alternative to filling spirals!
     
  13. Apr 10, 2019 #373

    neil_w

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    Silver decals applied. They initially went on flat, then edges started coming up, then I frantically tried a number of tricks to get them to lie down, then eventually just gave up and hoped that they'd do the same as what my test pieces did earlier. Which is to say, lie down nice as flat as they dried. And indeed they did!

    silver ok.JPG

    Weird behavior, don't get it, but good end result. :)
     
  14. Apr 20, 2019 #374

    BSNW

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    Neil......holy crap man!!!!! THAT is one beautiful ride! Well done. I wish I could see it launch. Hey...you going to NARAM this Summer? If so bring that beautiful rocket!!!
    Andrew
     
  15. Apr 20, 2019 #375

    BSNW

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  16. Apr 22, 2019 #376

    neil_w

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    Thanks for the kind words. Sadly, my ability to travel significantly to any rocket launch is virtually non-existent. For now, this bird will fly locally only.

    In other news, I just checked on my Deuce and now that they're *fully* dry, the edges have lifted again. For those keeping track, that means they went down initially, then lifted, then went back down as they dried, and then lifted again after finishing drying. Yeesh.

    Anyone have a good suggestion how to seal the edges back down? I'm probably going to end up trying to work a bit of CA under each edge with a pin. That will not be fun.

    Wish I could understand why this happened. I'm now even more relieved that I had none of these problems with Alcubierre. Why???
     
  17. Apr 22, 2019 #377

    Gary Byrum

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    Hey Neil....Have you ever modified one of those pipettes to distribute CA? They can be heated over an open flame just enough to make it stretch. Then you pull the ends apart to form a really tiny tube in the center. You can cut the sides apart and use the bulb end for applications. This is great for getting in those hard places. Of course, they're only good for a couple of uses. I bought a whole bag of em online for way cheaper than the hobby stores sells for.
     

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  18. Apr 22, 2019 #378

    neil_w

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    Haven't tried it, but you have me interested...
     
  19. Apr 22, 2019 #379

    Gary Byrum

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  20. Apr 22, 2019 #380

    BABAR

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    For flat areas place your decal
    Place wax paper over it
    Place a hotel key card over that
    Bind with something, clothes pins or tape or rubber band
    Allow to fully cure.

    For curves surface
    Cut a piece of spare body tube of same diameter and use this instead of key card

    Not sure if you can repeat the above with a clear coat. Likely the wax paper or parchment paper would mar the finish
     
  21. Apr 22, 2019 #381

    neil_w

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    Could work, although not easy to get even pressure applied across entire decal. Still wish I understood why it would be necessary; I *want* there to be some flaw in my technique that I can identify and fix, but I'm having a hard time with the "identify" part of it.
     
  22. Apr 22, 2019 #382

    BABAR

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    ?Maybe put layer toilet paper/Kleenex between the wax paper and the card?

    I am wondering if the decal is swelling up a bit, and the paint on the outside constricts the swelling, so the deep surface expands more than the superficial surface, leading to the curl.
     
  23. Apr 29, 2019 #383

    neil_w

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    Deuce of July update: I stupidly decided to apply a coat of Future (my usual clearcoat). Stupid for two reasons:
    1) The logo decal already lost some ink during application. I should have realized it would run like crazy under the Future. I put three decent coats of clear on that decal and it *still* wasn't sealed properly. I think I'm done with Inkjet decals; from now on it's laser only.

    2) The foam brush I used to apply the Future was catching on the points of the white vinyl stars, which seemed to have no particular interest in staying affixed. So after that Future coat dried, I attempted to CA down a few wayward points, which *kind of* worked. Today I applied another coat of Future just to the blue part with the stars, in the vain hope that it will seal them down.
     
  24. Apr 29, 2019 #384

    neil_w

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    Back to Alcubierre. I learned a useful tip today: adjust nose cone fit *before* painting. The Alcubierre plastic nose is a frustratingly tight fit in the body tube. I originally suspected just a quick bit of sanding would fix it, but how wrong I was. It is taking a *lot* of sanding, and I still don't have it to where I can blow it off from the back. I'll just have to keep going, slowly, until I get there. But I have definitely takin off some paint at the base of the nose cone, so now there is a fine ring of white at the very base just above the shoulder. Glad I got my beauty shots in already.

    But seriously, from now on I will be doing all this sanding right at the beginning of the build. I was stupid to put it off so long.

    Also did some shock cord work. All I need to do now is finish assembling the parachute (a 15" Odd'l chute with a spill hole; I will now have used all the Odd'l chutes thrown into my past JonRocket orders. Nylon chutes are nice but for not-too-large LPR I have had perfect success with the plastic chutes so far.)
     
  25. Apr 29, 2019 #385

    Gary Byrum

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    I tried that brush on method back when I first discovered the Future Bath. But now I use a spray bottle I bought at W'mart. Sprays on a lot more even and you never have to make contact with the rocket. Except for wicking the drips off of the bottom.
     
  26. Apr 29, 2019 #386

    neil_w

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    I don't think I have anywhere I could spray it. Maybe outdoors by the shed, then I'd have to rig up a way to hang the rocket. Hmm, doable.

    Usually I haven't had a problem with foam-brushing, but this time... oy.

    Do you dilute with Simple Green or spray it straight?
     
  27. Apr 29, 2019 #387

    Gary Byrum

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    3 parts Future, 1 part S Green. That formula worked very well for me.
     
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  28. May 15, 2019 at 7:33 PM #388

    neil_w

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    This is long overdue...
    alcubierre_facecard.png
     
  29. May 15, 2019 at 8:14 PM #389

    Nytrunner

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    That's a 4 I'd say
     
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  30. May 15, 2019 at 10:42 PM #390

    BABAR

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    4.5

    When does this candle get lit?
     

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