Build Thread: Office Supply Rocket

[jqavins]

Yes, I do plan to try it. See the post before yours.

OK, the improvements I have in mind go like this:

• Solder it closed. While I was putting the two airframe halves together one end of the wire between the loops caught on the coupler and made life difficult, which would not happen if it were all soldered closed.
• The paper clips seem to be stainless, which means soldering it up would be difficult at best. But I can use iron wire like this or similar. Of course, I don't want it rusting, so I'd tin the whole length.
• The process would go like this:

1. Tin a bunch of wire, enough for all the lugs I plan to make in a sitting.
2. Cut the tinned wire to the length needed per design.
3. Form the flat dumbbell shape and solder it closed.
4. Fold the ends over.

The two for this rocket took well under an hour to make, so I figure that with a better, no paper clips required method I should be able to turn out four or five pairs in an hour once I get some practice.

 

[mbeels]

Yeah, or "music wire" from hobby shops can be soldered well. They are very springy, so that may be a good thing. For strength, I sometimes do a few wraps of thin copper wire to bear the load, and the solder just keeps things in place.

 

[kuririn]

Joe, for your Office Depot theme, a quick search of the OD website didn't turn up non stainless wire. However, it did turn up epoxy: https://www.officedepot.com/catalog/search.do?Ntt=epoxy
So how about cut and shaped stainless paper clips glued with epoxy?
(Put a couple of tails on it, glue flush to the inside tube).
Or simplify and use CA and straws: https://www.officedepot.com/catalog/search.do?Ntt=straws
Yes, OD has CA: https://www.officedepot.com/catalog/search.do?Ntt=super+glue
Cheers.

 

[jqavins]

One, thanks, but really the metal work is finished and the whole rocket is well into the home stretch.

Two, the theme isn't really Office Depot, but rather it's things I can find at the office, mostly my own actual workplace and just three items that are commonly seen in most at at least many offices. I debated whether or not superglue should be on that list, but decided against it. So if Office Depot carries shampoo that doesn't mean shampoo would be in bounds.

Office Depot in particular only came into it because when I snagged some cardboard from the recycling bin it happened to be an Office Depot box, which I decided I should not cover with any paper "decal" as I'd been considering.

 

[jqavins]

The design calls for 5 g of nose weight. Last night I weighed out paper clips and got 5 g on the nose with four of them I cut the four up into short pieces, dropped them into the nose held upside down, covered them weigh glue, and stirred (not shook). The glue will probably add about another gram or two, so I've got a smidge more nose weight than RS says I need, which is probably for the good. White glue won't adhere to the metal, but since the bits are actually encapsulated I'm pretty sure they won't go anywhere. This morning the big puddle of glue still wasn't dry; I stirred it again and left it to dry more. Once that dries I'll glue in the bulkhead.

 

[jqavins]

Another thing: I forgot to mention this morning that I found a way to fill that ugly tube joint. Filler isn't an office supply, so I made my own.

I sanded and sanded the extra tube that I'd cut for couplers, and collected the dust. Once I had enough, I mixed it with white glue to a poopy consistency. (Yeah, that's right, I said it. The color fits that description too. It has no smell.) The ends of the tubes were so bad that I started by cutting a v-groove. I smeared and pressed in the filler, scraped it flatish with a card, and left it to dry overnight. It went on well - maybe a little too thick - and I had enough to start on the spiral grooves. I didn't have enough to finish the spiral grooves, and there's probably been shrinkage in the tube joint, so I'll be sanding and sanding to make more. I'll mix it a little thinner next time.

Pictures tomorrow if I can remember.

 

[jqavins]

After sanding off the home made filler, I see that it really didn't do the spiral grooves any good. It did, though, greatly improve the tube joint so that now its quality is up to "bad". More aggressive sanding followed by another application might bring it all the way up to "poor". This is all because the prior use of the tubes left their ends in really rough shape.

I tried to dry fit the motor mount last night thinking I might go ahead and glue it in with the second launch lug, but found it too hard to get past the messed up end of the tube. Internal sanding (or knife trimming) will be necessary. I did manage to push one ring past the mess and it is a good fit once past.

The glue puddle in the tip of the nose, as of this morning, is very nearly dry. It doesn't flow at all but feels a very little bit tacky. That's after 36 hours or so. And there's been enough shrinkage to expose some of the metal, which means I may need to do it again. This time I'll go in multiple smaller layers to shorten drying time.

By this time tomorrow I should have the fins on and maybe the motor mount installed.

 

[mbeels]

Did you get any photos?

After fins and motor mount, that must be the home stretch, what else is left?

 

[jqavins]

There didn't seem to be anything photo-worthy recently.

All parts fabrication is complete; what's left is only assembly.

• Airframe Tube (Optional)
  • Aggressively sand down the ugly body tube joint
  • Make more dust and mix up the poopy filler
  • Fill the ugly body tube joint
  • Final sand the filler
• Fins:
  • Go to the library to cut the jigs for the fin alignment; that'll be this evening
  • Glue on the fins
• Shock Cord:
  • Determine how I'll attach the body end of the cord. That'll probably be to the motor mount
  • Attach to the motor mount if that's the answer. That'll probably involve adding some length to that end.
  • Or, do whatever else I decide on, e.g. Estes style folded paper anchor
• Motor Mount:
  • Clean up the aft tube end to facilitate motor mount insertion
  • Cut slits for the second launch lug, positioned where the forward centering ring goes, and insert the lug.
  • Glue in the motor mount, after running the shock cord/streamer subassembly through the tube if it's attached
• Nose Cone:
  • Ensure the nose weight is adequately secured. Add glue to further cover the metal bits if it seems necessary
  • Glue in the shoulder bulkhead.
  • Attach the shock cord to the loop under the bulkhead.

The groups can done, to a degree, in any order. So yes, I would call it the home stretch. If I were doing a paint job I would not call it that, as there would be a long way to go with that.

EDIT: I left out a step:

• Cut out and apply the paper "decals"

 

[BABAR]

After sanding off the home made filler, I see that it really didn't do the spiral grooves any good. It did, though, greatly improve the tube joint so that now its quality is up to "bad". More aggressive sanding followed by another application might bring it all the way up to "poor". This is all because the prior use of the tubes left their ends in really rough shape.

I tried to dry fit the motor mount last night thinking I might go ahead and glue it in with the second launch lug, but found it too hard to get past the messed up end of the tube. Internal sanding (or knife trimming) will be necessary. I did manage to push one ring past the mess and it is a good fit once past.

The glue puddle in the tip of the nose, as of this morning, is very nearly dry. It doesn't flow at all but feels a very little bit tacky. That's after 36 hours or so. And there's been enough shrinkage to expose some of the metal, which means I may need to do it again. This time I'll go in multiple smaller layers to shorten drying time.

By this time tomorrow I should have the fins on and maybe the motor mount installed.

Gorilla urethane glue might work better, although if you are a purist and only use white glue at work, it violates your theme.

 

[jqavins]

Even white glue is one of the exceptions to the "scrounged at my own office" rule. I don't know if anyone here has any, but I considered it a sufficiently typical office thing to allow myself to use my own. (Actually, to go buy my own.) The other two exceptions are rubber bands, which I know darn well people have around here but the first couple of people I asked didn't, and printed paper, 'cause the color printer here is out of order so I made the prints elsewhere.

So, yeah, I'm being a purist. Everything that leaves the pad except the engine will either be from my own office or something very commonly found in offices. I don't think polyurethane glue qualifies.

 

[jqavins]

As planned, I cut the jig last night, but we got home late and I ran out of steam without getting much of anything more done. I did check the glue in the nose cone and it was finally fully dry. I poked at some of the metal bits poking out the top with a knife point and they seemed solidly held; then I noticed that one had fallen out before I even started poking. (sigh) So I jammed it into one of the gaps and poured more glue, not such a deep puddle this time. Then I went to bed.

The jigs look good. I still haven't decided whether I'm going to install the fins or motor mount first. The motor mount will be easier if I have a plain, finless tube to handle, but the TTW launch lug might get in the way of the jig. I'll have to do some dry fitting to determine the best assembly order.

 

[jqavins]

Progress. Last night I tested the installation sequence and found I could get the motor mount inserted and the fins in the jig at the same time, so I did just that. Without attaching the shock cord to the motor mount. D'OH! So I'll use a different method, probably the Estes trifold.

Glue all dried this morning, and it looks like a rocket!

Before work I applied the first pair of fin fillets and glued in the nose cone bulkhead.

I'm counting ahead the gluing sequence with drying time.

1. Friday Morning: first fillets and bulkhead (done).
2. Friday evening: second set of fillets and shock cord trifold.
3. Saturday morning: third set of fillets; leave home for long weekend.
4. Monday evening: last set of fillets.
5. Tuesday morning: apply aft motor mount fillet.
6. Tuesday evening: apply "decals".
7. Tuesday evening: rocket is complete.

 

[neil_w]

Looks good. I think a trifold mount would be perfectly suited for this kind of rocket.

 

[Andrew_ASC]

Now you know you gotta launch it AT WORK.... Hahahahaha

 

[jqavins]

Well, yeah. I could have brought it to work this morning, done the first fillets when I got here and the second one's at lunch time. But I didn't, and as is it'll be done Tuesday anyhow, so no more chance for that to help. Oh well (again).

 

[mbeels]

It looks like the filler really worked quite well. I can only see a slightly darker area. I also think that the trifold method will work fine, especially since it is streamer recovery.

 

[jqavins]

Well, after work Friday I promptly got the second pair of fillets on, and they were indeed dry by bed time, so I got on the third. While the second was drying I applied the "This End Up" decal. Before doing the third I got the trifold in, and after laying it I did the "Office Supplies" decal.

Before going away for the weekend I applied the last pair of fillets, so when we get home Monday the rocket will be done. I'll post "glamor shots" (heh heh) on Tuesday.

Except...

It'll be a little while before I get to launch it, and there are a couple of improvents I'm considering. First, the white glue fillets are coming out really small, so I'm thinking of adding a second layer to build them up.

And, applying the paper decals went so well that I'm thinking I should have used paper rather than tape to close off the fin edges. I could remove the tape and do that. On the other hand, the tape is another visible office supply item for the theme, so I'm on the fence. Opinions?

 

[neil_w]

Tape!

 

[mbeels]

I think I like the tape, it shows the corrugations of the cardboard, and is in line with your theme for this rocket.

 

[JCRL]

This is looking great! Question: do you typically put this many fillets on your fins, or is it because you are using white glue?

 

[jqavins]

This many?

Oh, I understand. Four "sets" is just one fillet per side per fin, eight filets in total.

See how it's propped up in post #78 so the the body tube is pretty close to level? In that position I can lay a line of glue along the two root edges that are up and if it runs it just runs down into the root-tube junction, and forms a nice fillet. Thatss one set or pair. Once it's dry, or at least not runny, I turn it to another position and do another pair of lines. After four such pairs every fin has a fillet on each side. So when I refer to the first, second, third, and fourth sets of fillets that's what I'm talking about.

Because it's white glue the fillets practically disappeared when they dried. Or maybe it's because the fins are so thick that, with the center line of the root against the body tube there was still a lot to fill. In either case it doesn't look like there's anything there, so I'm leaning toward doing all eight again, a second layer. Still, though, not more than two layers at each junction.

 

[JCRL]

I understand; I thought that you were putting four layers of glue on each side of the fin.

 

[jqavins]

I did a second layer of fillets on one quadrant, and it does seem to have helped. I'll do the others, but didn't wait for that to take the pictures below.

 

[BABAR]

Looks great. May be a bit heavy to recover on streamers. Do trash bags count as office supplies? They make great chutes.

 

[jqavins]

I considered using an urban tumbleweed but decided it doesn't qualify. The same thing that makes the rocket heavy, those thick walled tubes, is also really tough. And those fins seem pretty tough too. That's also why I went with three streamers and some space on the cord between them. Some fin corner dings on landing are likely, but I'll just have to put up with that.

Or I could remove the tape, toughen the corners by wetting them with glue, then retape. I'll see after the first flights (hopefully Sept. 14 with RadRocks) if I want to do that before the second launch date (Sept. 15 with MARS, my home club).

 

[neil_w]

Oh man I will be pleased to witness the maiden launch of this thing. Seriously hope that day works out.

 

[Nytrunner]

This End Up sticker is hilarious.

Sure hope your coworkers get a kick out of it

 

[jqavins]

Oh man I will be pleased to witness the maiden launch of this thing. Seriously hope that day works out.

Well, if not, you could make the trip to Geneseo the next day.

 

[mbeels]

I also like the "This End Up" decal.

I wasn't sure from the photo of the engine mount, is there a thrust ring in addition to the motor hook?