SCRAPPY-55 Build Thread

Discussion in 'Low Power Rocketry (LPR)' started by Woody's Workshop, Sep 29, 2018.

  1. Sep 29, 2018 #1

    Woody's Workshop

    Woody's Workshop

    Woody's Workshop

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    I'm using scrap pieces of balsa that were in shape of the fins. It must have come from waste from a larger kit.
    The Air Frame is BT-55 11-7/8" long which is salvaged from a scratch build that got ruined in the quick move out from the Fire back at the end of March.
    The 18mm Engine Mount is also a salvage part from another scratch build that also got ruined in the quick move out.
    The Launch Lug is a 1/8", 3" long previously mounted on Air Frame. Not the best location or length, but it is getting used and it will fly according to RocSim.
    I have previously papered the fins, marked and cut for the mounting tabs at 1/4" (from a scrap piece of cut off from my previous wood shop I saved, comes in handy) and 45 degree cut the front ends, and flat cut the aft ends as they will be flush with the bottom of the air frame.
    It's going to be a real challenge to work the fillets in the launch lug fillets, especially since that tube was previously done in TiteBond II, and is several years old.
    A fair amount of water soaking will have to be done to soften up the old glue so the new glue will bite in good. Also, when sanding the new glue if it doesn't bite in good, it won't feather. The new glue will roll up and pull off the air frame when sanding.
    Here is the design (Color is not accurate) and few of the first few pics.
    I'll do this one as I go and not wait until the end like the Quest Courier and Estes Alpha Butild Theards I'll be doing.
    Enjoy.
     

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  2. Sep 30, 2018 #2

    Woody's Workshop

    Woody's Workshop

    Woody's Workshop

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    This morning...er...afternoon I guess it is already...
    I took the Scrappy-55 out of the fin jig and checked the fin alignment.
    Looks good.
    I gave the first of 4 coats of TiteBond III to 1 side of 2 fins and covered the paper tabs.
    A couple of pieces of 2x4 held together with rubber bands makes a good stand for many things.
    I use smaller 1x3's on smaller rockets, and even 1x1.5 for the tiny ones.
     

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  3. Sep 30, 2018 #3

    Woody's Workshop

    Woody's Workshop

    Woody's Workshop

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    And...the second coat of TiteBond III is on those same sides of the 2 different fins.
    Couple hours of dry time, until the glue dry's enough to change color.
    Dry to the touch, yet can't be bruised and soft enough for the next coat to bite in real well.
     

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  4. Oct 1, 2018 #4

    Woody's Workshop

    Woody's Workshop

    Woody's Workshop

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    And the third coat is on.
    Bed time, so the last coat and starting the fillets in the morning before my Dr. Appointment.
    Have a good evening everyone.
     

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  5. Oct 1, 2018 #5

    samb

    samb

    samb

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    Thanks for posting this Woody. I’ve been curious about your “Titebond as filler/sealer” approach since you first mentioned it.
     
  6. Oct 1, 2018 #6

    Woody's Workshop

    Woody's Workshop

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    And...the forth coat of TiteBond III on one side of 2 fins AND the first fillets are in place.
    It will a bit longer for the fillets to set up, so maybe tonight I can get the second coat of fillets on.
     

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  7. Oct 2, 2018 #7

    Woody's Workshop

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    The glue hadn't set up enough by the time I went to bed last night.
    Here is the 2nd coat of TiteBond III for the fillets.
    After this coat sets up I'll give it one more coat and then smooth it out with a paddle to get the shape I want.
    Doing 2 filler coats first helps fill in the deepest area as the glue does shrinks when it drys.
     

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  8. Oct 3, 2018 #8

    Woody's Workshop

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    Had to wait until this morning to put the final coat on the fillets and paddle them out.
    I'll skip the rest of the fins being coating and the fillets. No use in duplicating here, what has already been showed.
    I'll pick up when the sanding starts.
     

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  9. Oct 10, 2018 #9

    Woody's Workshop

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    I have all the coats of TiteBond on now and fillets are done.
    I'll let the glue set up a few days before I sand.
    I'll get some pics up as soon as I get to town and pick up more batteries for the camera.
     
  10. Oct 10, 2018 #10

    samb

    samb

    samb

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    So Woody how did you learn this technique ? My first tutorials in model rocket construction were the beyond excellent Estes kit instructions from the late ‘60s and Mr Stine’s Handbook. I don’t recall either mentioning this use for glue.
     
  11. Oct 10, 2018 #11

    Woody's Workshop

    Woody's Workshop

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    It came about through a process of trying different things to get a better finish, while improving the strength of the components.
    I use to use wood filler, but that wasn't getting the job done on balsa.
    I had several fins break on landings, even after I started gluing them.
    So I improved on the papering fins technique as showed on Apogee's web site.
    I was an auto body tech for 17 years, so a good straight finish was important.
    And being a wood worker, I had a little better understanding of how glue works.
    I experimented with different things like thinning glue about 75% with water for the first few coats on balsa nose cones.
    It has worked out pretty good so far. I haven't had any damage to nose cones and it takes quite a wack to get a dent.
    I noticed after several flights the inside of the air frame would get scorched, so I started coating the inside of the air frame as well.
    It not only protected it from getting scorched, but on hard landings I got a considerable less amount of kinked air frames.
    So it's an added layer of strength.
    Yes, it adds weight. There is always a give and take.
     

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