Filling tube spirals

Discussion in 'High Power Rocketry (HPR)' started by Steven88, Oct 21, 2019.

Help Support The Rocketry Forum by donating:

  1. Oct 21, 2019 #1

    Steven88

    Steven88

    Steven88

    Forum Supporter TRF Supporter

    Joined:
    Jan 19, 2019
    Messages:
    175
    Likes Received:
    18
    Gender:
    Male
    I need some input on filling tube spirals on Loc paper tubes. I have tried Dap plastic wood filler as well as Elmers wood filler and epoxy clay for this. I am wondering if it is worth the extra work. I tried it on a scrap piece of tubing with the Dap filler and epoxy clay and even after using an automotive grade primer, the results were still bumpy. It would have looked better almost to have left it alone. Perhaps I didn’t sand it off good enough (Should have sanded it to where only filler was left in the spiral itself) but if you get too carried away, it starts to remove the glassine from off the tube. Maybe that doesn’t matter if you primer it afterwards? I love the looks of a smooth rocket but I wonder if it’s worth the extra work on paper tubes? It would be if I could get the results I want but if it leaves it bumpy it’s just a waist of time. Any advice on what to do differently or do most of you not worry about the spirals?
     
  2. Oct 22, 2019 #2

    DavidMcCann

    DavidMcCann

    DavidMcCann

    Well-Known Member

    Joined:
    May 15, 2016
    Messages:
    2,587
    Likes Received:
    155
    bondo spot putty and tons of sandpaper.


    or 14 layers of primer filler.....and basically sand it all back off.
     
  3. Oct 22, 2019 #3

    ewomack

    ewomack

    ewomack

    Forum Supporter TRF Supporter

    Joined:
    Jul 9, 2019
    Messages:
    208
    Likes Received:
    70
    I have also struggled with this. The Elmer's woodfiller seems to work great for smoothing fins, but I had mixed results with the tube spirals. I don't know if I inadvertently sanded too much of the dried filler off or what, but once I put on 2 coats, some of those aggravating spirals still showed. It was an improvement over my last few attempts, though. I also wonder just how much trouble it's all worth, especially since any rocket has a chance of getting launched into oblivion.
     
  4. Oct 22, 2019 #4

    Steven88

    Steven88

    Steven88

    Forum Supporter TRF Supporter

    Joined:
    Jan 19, 2019
    Messages:
    175
    Likes Received:
    18
    Gender:
    Male
    The rockets get scratched when they leave the rail anyway. I’m about to the point that if I’m building it for show and it’s just going to sit in my office to show off then it’s worth the effort of getting it smooth. If I’m building it to fly multiple times, then let the spirals be, but still
    its a little hard to just let the ugly things be
     
  5. Oct 22, 2019 #5

    richP

    richP

    richP

    Well-Known Member

    Joined:
    May 23, 2019
    Messages:
    110
    Likes Received:
    101
    Bondo Glazing and Spot putty, sand, and then a few good coats of filler primer. As said above; spray the primer, let it dry, sand most of it off, repeat until the spirals are gone. Should be between 3 and 5 coats. Whether you go thru the trouble depends is all you. I would say that if you spent the time to make very nice fillets, sealed the fins and plan on doing a really nice paint job, then fill the spirals. Overall, you are only adding a few extra hours of work to get the body perfectly smooth for painting.
     
  6. Oct 22, 2019 #6

    llickteig1

    llickteig1

    llickteig1

    KLOUDBusters Chief Logistician

    Joined:
    Jan 23, 2009
    Messages:
    1,570
    Likes Received:
    197
    Gender:
    Male
    Location:
    Wichita, KS
    Fly bigger motors. Can't see the spirals from further away.
     
    LOC, Chad, NAR29996 and 1 other person like this.
  7. Oct 22, 2019 #7

    wsume99

    wsume99

    wsume99

    Well-Known Member

    Joined:
    Feb 28, 2014
    Messages:
    108
    Likes Received:
    13
    This is my method as well except I can normally fill the spirals with 2 coats of primer. I'm going to try the epoxy clay method on my next cardboard rocket just to see if it's different. Apogee (I think) has a video where the clay is applied and then the excess is scraped off with a straight razor blade. I'm going to give that a shot.

    Also, here are a couple of my own observations...

    If you sand through the glassine layer the paint adheres really well and all the fuzziness will sand right off after you put a coat of primer on.

    For filling spirals I first apply the glazing and spot putty, sand it all off leaving just the spiral filled and then apply two heavyish coats of filler primer with just a few minutes between them. If you get a run or drip it doesn't really matter because if you are trying to fill spirals then you're sanding most of the primer off anyway. 220 grit paper takes off the filler primer really easily in my experience.
     
    Last edited: Oct 22, 2019
  8. Oct 22, 2019 #8

    Steven88

    Steven88

    Steven88

    Forum Supporter TRF Supporter

    Joined:
    Jan 19, 2019
    Messages:
    175
    Likes Received:
    18
    Gender:
    Male
    Great advice... Tks guys
     
  9. Oct 22, 2019 #9

    Steven88

    Steven88

    Steven88

    Forum Supporter TRF Supporter

    Joined:
    Jan 19, 2019
    Messages:
    175
    Likes Received:
    18
    Gender:
    Male
    Can’t see em flying by on a galloping horse!
     
  10. Oct 22, 2019 #10

    fyrechaser

    fyrechaser

    fyrechaser

    Builder of flying things TRF Supporter

    Joined:
    Apr 2, 2009
    Messages:
    759
    Likes Received:
    35
    Gender:
    Male
    Location:
    Blackwell, TX
    The type of primer matters as well. Using a high build primer will help quite a bit. I use KILZ oil based primer in a rattle can, and usually only takes a couple of coats. If you use KILZ, let it dry for at least 24hrs before you try to sand it and it will sand very easily. After I've sanded both coats almost all the way off I look closely for any low spots and then apply spot putty. (The red stuff you get at the auto parts store, comes in squeeze tube) I usually apply one more coat of primer after I'm satisfied the surface is smooth, and I sand that last coat mostly off. I use KILZ as well on large fiberglassed rockets to fill any of the weave that might show.
     
    LOC, g.pitts, Theory and 1 other person like this.
  11. Oct 22, 2019 #11

    Theory

    Theory

    Theory

    Well-Known Member

    Joined:
    Nov 30, 2018
    Messages:
    531
    Likes Received:
    283
    Gender:
    Male
    interesting, never thought of using KILZ. use the gallon pail around the house all the time, but the spray can has me thinkin

    thanks for the tip
     
    fyrechaser likes this.
  12. Oct 23, 2019 #12

    fyrechaser

    fyrechaser

    fyrechaser

    Builder of flying things TRF Supporter

    Joined:
    Apr 2, 2009
    Messages:
    759
    Likes Received:
    35
    Gender:
    Male
    Location:
    Blackwell, TX
    Wear a particulate mask as it makes a ton of dust while sanding.
     
  13. Oct 23, 2019 #13

    LOC

    LOC

    LOC

    Forum Supporter TRF Sponsor TRF Supporter

    Joined:
    Nov 23, 2016
    Messages:
    176
    Likes Received:
    66
    2 coats of a high build primer are all you need. https://www.u-pol.com/us/en/products/coatings/primers#.Xa-puuhKiUk
    Use thin CA glue to seal the tube ends then wet sand with 220 or 320 depending on sanding skill. 15-20 minutes of we sanding and you're good to go. If you didn't get primer on proper, you may need a 3rd coat. But wet sand with 400 on a 3rd coat and get yer paint on.
     
    g.pitts likes this.
  14. Oct 23, 2019 #14

    Chad

    Chad

    Chad

    Well-Known Member

    Joined:
    Jul 23, 2018
    Messages:
    209
    Likes Received:
    70
    Gender:
    Male
    Location:
    Dallas
    on thing to keep in mind, sanding using your hands will just sand out the spirals since your skin will press the sandpaper into the spiral grooves. Use something solid so you sand over the spirals and not into them.
     
    Homer_S, roc_boy, LOC and 4 others like this.
  15. Oct 23, 2019 #15

    AfterBurners

    AfterBurners

    AfterBurners

    Forum Supporter TRF Supporter

    Joined:
    May 8, 2012
    Messages:
    6,909
    Likes Received:
    129
    Gender:
    Male
    Location:
    Dallas Texas
    I usually use an old t-shirt or a Halloween mask to keep the particles out and from breathing them.
     
  16. Oct 23, 2019 #16

    georgegassaway

    georgegassaway

    georgegassaway

    Lifetime Supporter TRF Lifetime Supporter

    Joined:
    Jan 18, 2009
    Messages:
    4,479
    Likes Received:
    294
    Apply masking tape along both sides of the seam, about 1/32" from the edge on each side, so that the open gap can be primed/filled, but NOT a lot of the rest of the tube surface. Apply filler or primer or whatever, let dry thoroughly. Repeat until it is thick enough for the "valley" of primer to be ABOVE the rest of the tube surface. Peel away the tape. Do 1-2 coats of primer, THEN sand the spiral seam, which now is an "outie" that you are sanding down, to be flush with the rest of the tube surface.
     
  17. Oct 24, 2019 #17

    fyrechaser

    fyrechaser

    fyrechaser

    Builder of flying things TRF Supporter

    Joined:
    Apr 2, 2009
    Messages:
    759
    Likes Received:
    35
    Gender:
    Male
    Location:
    Blackwell, TX
    Chad, very good advise. I use a block to sand across the spirals.
     
  18. Oct 24, 2019 #18

    fyrechaser

    fyrechaser

    fyrechaser

    Builder of flying things TRF Supporter

    Joined:
    Apr 2, 2009
    Messages:
    759
    Likes Received:
    35
    Gender:
    Male
    Location:
    Blackwell, TX
    Opps, I quoted the wrong post, but I think AfterBurners post is relevant as well. Sorry folks.....
     
  19. Oct 24, 2019 #19

    Steven88

    Steven88

    Steven88

    Forum Supporter TRF Supporter

    Joined:
    Jan 19, 2019
    Messages:
    175
    Likes Received:
    18
    Gender:
    Male
    I was afraid that using a block of wood would tend to flatten the tube but as long as it’s kept moving around the tube and not in one spot for too long it should be ok
     
  20. Oct 24, 2019 #20

    tomsteve

    tomsteve

    tomsteve

    Well-Known Member

    Joined:
    Feb 24, 2014
    Messages:
    777
    Likes Received:
    109
    ihave some various diameter pieces of body tube 4-6" long that i cut into about 3rd. glue a grab block on the od then put some 3m sticky back sandpaper- 150 grit- inside. makes great sanding blocks.
     
    NikeMikey, dhbarr and Steven88 like this.
  21. Oct 24, 2019 #21

    dhbarr

    dhbarr

    dhbarr

    Amateur Professional

    Joined:
    Jan 30, 2016
    Messages:
    5,897
    Likes Received:
    699
    Yup this one -- I originally made my first one to help the kiddos with pinewood.
     
  22. Oct 24, 2019 #22

    Steven88

    Steven88

    Steven88

    Forum Supporter TRF Supporter

    Joined:
    Jan 19, 2019
    Messages:
    175
    Likes Received:
    18
    Gender:
    Male
    Love the tip!
     
  23. Oct 24, 2019 #23

    LOC

    LOC

    LOC

    Forum Supporter TRF Sponsor TRF Supporter

    Joined:
    Nov 23, 2016
    Messages:
    176
    Likes Received:
    66
    Yes, a foam block is a must. I use the Harbor freight jobs. 10 for like $5 and use for the rough stuff. Then when they wear, I wrap with the finer grit to recycle. I'll have to try this "tube" block idea(not like there isn't a crap-ton of cut-offs around here). I'm pre-coffee and struggling to make a visual. Have any photos? I have to spend the weekend in the paint booth so awesome time to try some other techniques!
     
  24. Oct 24, 2019 #24

    Bill S

    Bill S

    Bill S

    Well-Known Member

    Joined:
    Aug 6, 2019
    Messages:
    167
    Likes Received:
    21
    Gender:
    Male
    I use some N100 particulate masks that I picked up years ago. They work okay on spray paint/primer fumes; they help a bit but I can still smell the volatiles even if most of the particulates are stopped by the mask.
     
  25. Oct 24, 2019 #25

    neil_w

    neil_w

    neil_w

    When in doubt, add more rocket TRF Supporter

    Joined:
    Jul 14, 2015
    Messages:
    7,065
    Likes Received:
    1,198
    Location:
    Northern NJ
    I'll repeat my spiral method again.

    1) Smear thinned CWF over entire body tube. Smooth it out with your finger(s) to create a fairly even, *thin* layer.
    2) Sand. Don't worry about roughing up the glassine.
    3) Apply one good heavy coat of filler/primer.
    4) Sand.

    Done.

    If the body tube is on the larger side, and it's just too much area to completely cover with CWF, then just work around the spirals. But don't expend any effort to keep the CWF *confined* to the spirals.
     
  26. Oct 24, 2019 #26

    Steven88

    Steven88

    Steven88

    Forum Supporter TRF Supporter

    Joined:
    Jan 19, 2019
    Messages:
    175
    Likes Received:
    18
    Gender:
    Male
    Is CWF some kind of wood filler? I have Elmers and Dap wood fillers. Will they do the job as well or are you partial to CWF?
     
  27. Oct 24, 2019 #27

    neil_w

    neil_w

    neil_w

    When in doubt, add more rocket TRF Supporter

    Joined:
    Jul 14, 2015
    Messages:
    7,065
    Likes Received:
    1,198
    Location:
    Northern NJ
    CWF is Elmers Carpenter's Wood Filler (the regular kind). I don't know much about the DAP.
     
  28. Oct 24, 2019 #28

    Steven88

    Steven88

    Steven88

    Forum Supporter TRF Supporter

    Joined:
    Jan 19, 2019
    Messages:
    175
    Likes Received:
    18
    Gender:
    Male
    Ok great.
     
  29. Oct 24, 2019 #29

    Steven88

    Steven88

    Steven88

    Forum Supporter TRF Supporter

    Joined:
    Jan 19, 2019
    Messages:
    175
    Likes Received:
    18
    Gender:
    Male
    Do you have a particular brand/type of filler primer that you recommend?
     
  30. Oct 24, 2019 #30

    neil_w

    neil_w

    neil_w

    When in doubt, add more rocket TRF Supporter

    Joined:
    Jul 14, 2015
    Messages:
    7,065
    Likes Received:
    1,198
    Location:
    Northern NJ
    I use the Rustoleum, but have also used the Duplicolor. @hcmbanjo strongly recommends the Duplicolor for its easier sandability; I didn't notice a big difference.
     

Share This Page