Shear Insanity: a build thread

[neil_w]

Unmasking time! The rocket's gonna live in the shed a while longer while it still stinks, but after 36 hours the tape was ready to come off. Recall that I shot a coat of white before applying the black this time.

Overall, from a distance, it looks nice.


Let's zoom in.

That mask line is perfect. Of course, that's also a really simple mask, just a single wrap of tape. This close-up picture also shows the lousy finish of the black paint. That's a little disappointing but I can live with it; it looks pretty decent from a few feet a way. Also, the surface finish defects are not as bad as I've gotten on black rockets in the past. I think in hindsight I needed to wet-sand the white smoother before applying the black, or I'm suffering the consequences of having skipped the filler/primer step. Dunno. I hate painting.

The fin masks are not nearly so perfect, e.g.:

An extra shot of base color is simply not enough to compensate for mask joints that leave gaps. So add masking to the set of finishing skills that I need to improve on. Fortunately, the touch-ups should be easy, and it should all look fine when finished. In fact, doing touch-ups is so easy that in many cases I really don't care if I have a bit of leakage in spots like that. It takes less time to touch-up than to spend excessive time trying to get the masks perfect.

While the weather was perfect, I worked on my decal sheet. I noticed that the last sheet I printed didn't really have the deep blacks that I was expecting. These are the first decals I've printed on this (relatively) new printer and I'm still learning its ins and outs. So I printed another sheet, this time making sure to set the quality to "highest" (I think I left it at "normal" last time), and it is a little better. I did notice some defects in the print that appeared near one edge (thankfully, only there):

Very annoying, but I'm not going to print a third sheet. First time I've ever had a printer do this, no idea why. Hopefully not indicative of the print quality I'm going to get from this printer in the future.

 

[lakeroadster]

Looks really good Neil. I've found that for good results I need to run my fingernail along every tape joint, within minutes of spraying the paint, or the tape will lift.

It seems in our hobby we're always kind of walking the tape tight rope of too sticky (pulls base coat off), or not sticky enough (leads to paint bleed).

 

[jqavins]

I did notice some defects in the print that appeared near one edge (thankfully, only there):
View attachment 521957

That's almost as interestingly puzzling as it is annoying. Observations etc.:

• The defects seem to be evenly spaced. Which means... something, I'm sure.
• They are perpendicular to the short edge, which also has to mean something.
• Ink jet or laser?
  • If typical of inkjets, the defect lines are perpendicular to the print head motion, so it would have to be missing pixels at very consistent spots on pass after pass.
  • If laser, I don't know, but it still has to be significant.
• At first I wondered if it might somehow be caused by a mismatch between the image and printer resolutions. A different number of dots for the same size object may require interpolation which, if handled badly, could cause gaps. But then I noticed that the defects on the right extend grey lines into the white, where there's nothing to interpolate. And they don't run the full length of the paper (just the full width).

Try cleaning it. I know, you said it's a relatively new printer, but most of maintenance of any mechanism is cleaning, and it can't hurt. Like when your computer is misbehaving you reboot, when your printer is misbehaving you clean it.

Since you're not planning to print the decals again, it may be worth experimenting with paper.

 

[neil_w]

• Ink jet or laser?
  • If typical of inkjets, the defect lines are perpendicular to the print head motion, so it would have to be missing pixels at very consistent spots on pass after pass.

Excellent observation, which I overlooked. In that case, it seems to point to one of two things:
1) Mechanical damage to the sheet (either before or after printing) somewhere in the printer paper feed mechanism
2) A defective piece of decal paper.

I lean towards #1, even though I don't have a clear idea how it could happen, or why. It's something I'll need to keep an eye on.

 

[neil_w]

Touch-ups were uneventful. I didn't do my most careful job but this rocket is doing fine as a 1-2 foot paint job.

I have run into one problem. When I paint, I put little dowel pieces in the lugs to prevent paint from getting in there. I try to make them just tight enough to stay put, but not so tight that they are hard to move.

Well, the dowel in the rear lug came out easily, but the front one is really stuck. You can see in this picture that maybe I moved it a millimeter backwards (pushing from the front). I am not sure exactly what to do here. I'll try to keep pushing, but at some point when I see the body tube flexing I have to ease off. I am open to suggestions here; this is never happened to me before.

One last-ditch approach I'm thinking of is drilling a hole through the center of the lug, which could easy up the pressure. The problem is getting an angle to get the drill in there. There's almost not chance I could get it in straight, but I haven't yet figured out what sort of angle I could achieve. I'd have to be incredibly careful not to drill through the wall of the lug.

I wonder if I could make any headway with hand-holding and rotating the drill bit. It's just a piece of dowel, nothing extremely tough.

Who's got a good idea?


By the way, the white specks all over are just dust, they'll wipe off before I apply Future.

Also, at the left edge of the picture you can see a couple of the touched-up front finlets.

 

[lakeroadster]

Pretty much any lubricant (WD-40 or whatever) applied to the dowel will make the dowel swell, making the fit tighter. Not good.

Put the rocket in your freezer overnight. Take it out in the morning, hit the launch lug with a hair drier, then push out the dowel.

 

[jqavins]

That's a good idea, and simpler than mine. If it doesn't work, consider this.

Go the the hardware store and get a #4 wood screw. Drill a pilot hole (#38 or 39 drill, 2.5 to 2.6 mm, or thereabouts) and it only has to be about three threads deep. You can probably do that by hand spinning the bit, but going very slowly with the bit in a chuck is probably better; if you've got a hand drill, use that. Then put the screw in, and pull the dowel out.

* To start a hole on an angled face like that, start out normal to the face until the wood is just dimpled then rotate the drill down while still spinning it. If you don't have clearance to get all the way down, don't sweat it, as you're not going really deep anyway, so being a little off axis isn't important.


(Does it seem like I've done this before? Well, not for launch lugs...)

Henceforth, rub the dowels generously with a crayon or candle before inserting them.

 

[neil_w]

Regrettably, any solution involving use of a fridge or freezer is unavailable to me (don't ask why, it just is). Putting a screw into it is an interesting idea. My fear is that the force of pulling on the thing is going to cause damage.

Also, now that I think about it... wouldn't putting a screw into it (even slightly) tend to slightly expand the dowel and tighten in the lug?

I guess my first step is going to be experimenting with the drill and see what I can do with it. If I had a way to chuck a drill bit into my little electric screwdriver it would be perfect, but I haven't worked that out yet.

 

[jqavins]

Also, now that I think about it... wouldn't putting a screw into it (even slightly) tend to slightly expand the dowel and tighten in the lug?

That's why the pilot hole is important.

I guess my first step is going to be experimenting with the drill and see what I can do with it. If I had a way to chuck a drill bit into my little electric screwdriver it would be perfect, but I haven't worked that out yet.

Small drill chucks for 1/4" hex drivers such as this one are available from many sources.

And so are hex drive bits, like these.

 

[neil_w]

That's why the pilot hole is important.
Small drill chucks for 1/4" hex drivers such as this one are available from many sources.

And so are hex drive bits, like these.

I have a hex drive bit that's probably a bit big for this application... maybe I'll go pick up a small one (or set).

 

[BABAR]

Any chance you can find a loooong drill bit the right diameter size that might reach this from front or back parallel to body tube?

Alternative might be a coat hanger wire cut at an angle so the forward edge has a “bite” to it. Needs to be VERY straight.

Might want to run it on slow screw drive speed for control, as it may need to go through a rear lug.

 

[neil_w]

I think I can get a good enough angle with my electric screwdriver and the hex shank drill bits I picked up at lunch. Will report back here as soon as I have a chance to try.

Drilling all the way from an end of the rock seems doubtful… don’t think I have a long enough extender, but I’ll check.

 

[BABAR]

The enemy of good being better, best bet may be cut it off and replace it.

 

[neil_w]

The enemy of good being better, best bet may be cut it off and replace it.

Good heavens, not before I even attempt to fix it.

 

[jqavins]

But it's a good thing to keep in mind. Since cutting the lug off is a worst case last resort, and really not so bad in the big picture, you can take solace in the fact that there's only so bad this can get.

 

[neil_w]

My father, whom I love dearly, has a tendency to start brainstorming crazy and often ugly hack solutions to problems that arise when doing some sort of house chores. When he gets going I try to cut him off and emphasize: first focus on fixing it correctly, and only if that fails then start dreaming up crazy schemes. So my focus here is on plan A: simply remove the dowel, without damaging anything.

I loaded up the smallest bit from my just-purchased set of hex-shank drill bits into my electric screwdriver, and took a look. The angle seemed reasonable going from the front. I didn't think I needed to go all the way through the dowel.

Unfortunately, I could not get as good an angle going from the back, which otherwise might have been a bit easier with the square end, rather than the slant.

I started drilling, and the bit did not particularly want to stay put in the center of the dowel. Eventually I was able to get it started, not centered but with enough clearance from the edge that I felt safe. I drilled about 3/8" into the dowel and then withdrew. At that point I noticed that the dowel had moved another couple of millimeters. I didn't know if it was from the vibration of the drilling or if it had actually loosened a bit, but I decided to see if I could now push it out. I eventually figured out to hold onto the lug itself (rather than the rocket) while pushing on it, to avoid strain on the body. It was very slow going but I made steady visible progress and eventually got it out, apparently without harming anything.

The lug will need a bit of touch up paint but that's to be expected anyway. Ready for decals, hopefully next week (this week is crazy).

By the way: an electric screwdriver is not a very good drill due to its low RPMs, but in this case it was well-suited to the job.

 

[bobbyg23]

What printer do you have?

 

[neil_w]

What printer do you have?

HP OfficeJet Pro 9015e

 

[Bluegrass Rocket]

For future reference, why not use a launch rod as a long extension touching the embedded dowel and lightly tapping the rod. My 2 cents.

 

[neil_w]

For future reference, why not use a launch rod as a long extension touching the embedded dowel and lightly tapping the rod. My 2 cents.

I have temporarily, um, "mislaid" my launch rod.

 

[lakeroadster]

Regrettably, any solution involving use of a fridge or freezer is unavailable to me (don't ask why, it just is).

 

[jqavins]

For future reference, why not use a launch rod as a long extension touching the embedded dowel and lightly tapping the rod. My 2 cents.

Rod whip. It'd probably buckle half way between the hammer and the dowel, absorbing all the energy.

In addition to application of non-mobile lubricant prior to dowel insertion, it might also be a worthwhile precaution to refrain from angling the front face of the dowel to match the lug. If the dowel is as long as the root of the lug, angling the end really doesn't make any difference as far as I can see; am I missing something? Not doing so would make subsequent contingency actions easier.

Anyway, all's well that ends well, this time.


Apropos of nothing, I heard one of the Beatles say that when the Stones released "Aftermath", they wanted to call their next album "After Geography".

 

[neil_w]

Well tonight was very frustrating.

First, on a happier note, I did my various touch-ups, including the exposed bits of launch lug so they look completely black. That came out good. While doing that, I had a closer look at the black paint and it really did *not* come out good.

But whatever, I am no stranger to bad paint finish.

I decided it was time to start the decals. The first thing I noticed was that the print quality on the decal really was not good, on top of the fact that it wasn't solid black. I still don't know why this is, or what I need to do differently with this printer to get the quality I'm used to. But I decided to press on and see how it looked on the rocket.

First up, the roll pattern wrap. In the process of testing to see if the decal was starting to come loose, loads of black bits rubbed away.

That picture shows well the terrible quality of the black areas (pebbly appearance) as well as all the little bits that flaked away. I have had this happen before, and I do not know why. I had three coats of clear (Krylon UV-resistant) on there, what more am I supposed to do? Perhaps I should try one of the clears that is more specifically intended for this sort of thing. Not that that would solve the terrible print quality, though.

Fortunately, as always, I had a spare on the decal sheet, so I decided to be much more gentle with it. I seemed to make it past the soaking without ruining it, but while applying it (wraps are a *pain*) some bits of black flaked off, and it looked awful (the speckles as well as the not-blackness of it) so off it went, and frankly the whole decal sheet is headed for the trash.

I do not know what the problem is here, but it is *mighty* frustrating. I think I'm going to print this sheet on the laser at work and just live with the crappy color quality, unless I can think of something different to do with this printer to make it work better. Printing on standard copy paper is fine, something about the ink on this decal paper that is not responding well.

And so, for now, the decals are still not done, or even started for that matter.

 

[jqavins]

I bet there's some decal printing forum, or a user group for that printer where you could ask for help.

 

[BABAR]

Bad batch of decal material?

 

[neil_w]

Bad batch of decal material?

I really don't know. I've used paper from this batch successfully in the past, although I did have some issues. I certainly never had the print quality problem I had here before, seems more likely be related to the new printer.

 

[neil_w]

Laser-printed a new decal sheet. Found some print quality adjustments that I hadn't tried before, gradients might look a little better than I've managed in the past. Same finish problem I've had with laser in the past, so once again it'll take some aggressive application of Future to reduce the effect. Will try applying at next opportunity.

 

[KenECoyote]

Awesome design and build Neil! Years ago I considered a design that resembles a lightning bolt (the cartoon version) and this reminds me of it, but saner .
I'm a bit late to the "lug-tastrophe", but I would've suggested using an. X-acto knife to carve a slot and then use a screwdriver to twist it free.

 

[neil_w]

So here are my laser and inkjet decal prints, compared (please ignore the dust specs)

As you can see, the laser print is a deeper black than the somewhat mottled inkjet print. In the past the situation was exactly reversed.

And here is the roll pattern wrap applied to the rocket. Dealing with the un-clearcoated laser decal is *so* much easier for a large decal like this. I might well switch over to laser decals completely, because I'm just sick of the drama with the inkjet stuff (unless someone can point me to a true solution).

You can see that the laser black still does not look nearly as dark as the black paint (the white doesn't match that well either, for that matter). This will get better after many coats of Future are applied to gloss up the decal and match the paint better, but it'll never be perfect. Nothing I can do about the white.

By the way, roll pattern decals are a huge pain, in case anyone wasn't already aware of that. Wetting down the body tube beforehand so the decal can slide around a bit for final positioning is essential.

 

[jqavins]

Not today, obviously, but if you switch over completely to laser, you might look for black and white paints that match the decals better, rather than accepting that the decals don't match the paint. On the white side it looks like that would be an improvement. On the black side not so much.