Glassine Tubes

 The Thrifty Rocketeer blog continues...


You'll have to excuse me this week, as I slip into a rant.

You know what really annoys me?

Glassine coated body tubes.


You know the stuff... usually low power rockets that have a slick plastic coating over the tube, so that they can make the tube thinner and still have some rigidity left.

It may make for a slick, smooth surface to paint, but it is absolute hell when it comes to gluing fins and things onto the body tube....especially at a 90 degree angle.

Now, I know what you're thinking....  "That's not so bad.  You can rough it up with a bit of sand paper and break the surface."

Right.

Except, remember that the paper tube is so thin, it doesn't have a lot of body left to it, and any scratch or abrasion into the tube weakens it.


I find this not only annoying, but short-sighted of Estes to be producing these in traditionally popular kits.

I've run into this in the Commanche 3, and most recently the Goblin which I bought at Hobby Lobby.  I'm afraid that this may be the wave of the future.


And while I'm on the topic of the Goblin, there appears to be a reissue that contains a new blow plastic nosecone with the absolutely thinnest ring of plastic I have ever seen to secure your shock cord. 

I also noticed that there's something odd about the wood used for the fins.  Not only does it have a pronounced grain to it, but when sanding, it doesn't come off as dust, but as crumbs and longer threads of wood.  I don't think it's balsa but perhaps another type of wood that's been substituted.

Now, for the new entry into rocketry, the kids won't notice these changes at all.  If they've never seen a quality kit before, then this will be their first experience.

But I worry for the shock cord anchor that will snap off, the fins that will tend to snap off, and the finish of these faux-balsa fins that tend to flake off.

I don't recall the Goblin being this fragile when I built my first one years ago.

Do you?

Comments

  1. Chris MichielssenJuly 20, 2021 at 10:37 AM

    I agree, the tubes aren't as good as they once were, since Paramount took over Euclid tube manufacturing. A story was told about one Euclid employee who made the good tubes for the Estes account. He is no longer there.
    For years I simply glued fins onto the glassine surface without roughing up the tube. Now I lightly sand the root edge area with 400 grit before gluing on a fin.
    I hate the thin BT-20 and BT-50 tubes. One reason I had Paramount make some heavy walled BT-20H tubes for me. my BT-50 Odd'l kits all use heavier walled BT-50H tubing.
    One problem might be a higher percentage of recycled fibers in the Kraft paper mix. I'm guessing - I don't know that to be a fact.

    ReplyDelete
  2. Kirk G - The Thrifty RocketeerJuly 22, 2021 at 2:23 AM

    I have since learned that Estes introduced the Goblin in 1970, and just prior to a reissue, Semroc put out a clone or similar product. It was one of these superior quality parts that I got hold of for my first Goblin, and the current batch is just no comparison. The difference in the quality of Semroc products is just self-evident.

    ReplyDelete
  3. Randy Boadway eRocketsMarch 14, 2022 at 7:45 PM

    You guys are right about everything you say, at Semroc we try to use the tubes dimensions that Centuri use in their days. Plus we put a White Glassine layer on the outside of our tubes rather than just the clear that Estes sometimes uses. But, unfortunately, we are buying some Estes tubes as a stop gap between bad quality tubes.

    I know Estes started changing their old BT-50(24mm) tubes they use in their motor mounts, they are a thick walled BT-50 and they are superior to the BT-50 tubes of the past. I wish the same would happen with BT-5(13mm) and BT-20(18mm).

    At Semroc we can use ST-7 for the 18mm motor mounts, which are thicker, and ST-9 24mm motor mounts which are also thicker, Both of these ST tubes are slightly larger than the 18mm and 24mmn motors. They have always been that way in the Centuri kits. And it is that way in many of the Semroc kits.

    Thanks for the tube talk!

    ReplyDelete

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