Starship Avalon: build thread

The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
You are far more dedicated to sounding down primer coats than I am.
Well, filler/primer must be sanded, like it or not. Of course, there is the option to not use filler/primer, but it really does work nicely. On some non-critical future build I'll probably try swapping it for regular primer, and see how it goes.

As a beginner BAR I used Chris Michielssen's prep techniques as a starting point, most of which were completely foreign to me. This includes, among other things, shooting the components with filler/primer before assembly. That works great and it is far easier to sand pieces of balsa before assembly *but* it starts to get unwieldy when there a lot of small parts to corral. So I switched, for now, to assembling first and then shooting filler/primer on the whole model (first tried, with good success, on the APRO Lander II). Exceptions still apply, such as the helical pieces and rings in this build; sanding after assembly would have been very difficult. Unfortunately, in this case, the nose assembly is exactly the sort of nooks and crannies festival that is hard to sand after assembly. But it also would have been impractical to prime those pieces before hand. In hindsight, I possibly could have built everything but the strakes, then primed and sanded, and then attached the strakes. That would have made sanding super easy.

Every build seems to have a different set of judgment calls to make in this area. I'm still not really locked into a technique that I can apply consistently.
 
I'm really liking this design!
I fill and prime before assembling because I could never get the nooks and crannies
filled and smooth on a finished model.

Before gluing things together, the primer is sanded down for a better glue bond.
Since I use Carpenter's Wood Filler to fill the fins it is water based. Wood glue will permeate that CWF filler.
Older style sanding sealer would seal the balsa and might not give the best bond.

"Every build seems to have a different set of judgment calls to make in this area."
Very true!
 
I'm really liking this design!
I fill and prime before assembling because I could never get the nooks and crannies
filled and smooth on a finished model.
Priming first definitely works great and makes it easier to sand, but assembling first makes it easier to prime. Also, since I have limited spraying opportunities, sometimes if I want to do *anything* other than sit around and wait it has to be assembly first, and I'll get around to priming when I can.

I seem to be heading towards a hybrid approach: assemble first anything that looks like it will be reasonably sandable afterwards. If I figure it correctly, this leaves me with a minimum viable set of parts to prime and sand separately. In this case, I almost surely made a error (albeit a small one) by priming after the strakes were attached, but the rest of the rocket should be pretty straightforward to sand since I left off the helixes and the rings for now.

I should note that although I care quite a bit about the quality of my finished product, I have learned that on these complex models I'm only willing to go so far before it becomes drudgery. So if I can do a *decent* job sanding the nooks and crannies I'm satisfied.

Anyway, onward.
 
I should note that although I care quite a bit about the quality of my finished product, I have learned that on these complex models I'm only willing to go so far before it becomes drudgery. So if I can do a *decent* job sanding the nooks and crannies I'm satisfied.

And unless you're Mr. Michielssen and trying to auction them for a price, then that's as good as it needs to be. :wink:
 
I prepped and primed a single piece of BT-80 for my two rings. Now I need to cut it into two properly-sized pieces. Here is my new setup:
ImageUploadedByRocketry Forum1490979353.437670.jpg

The fully prepped tube is slipped over a piece of coupler (which I purchased for exactly this use). I put a couple of pieces of blue masking tape on the couple to make a snug fit, so the BT80 wouldn't want to slide around too much.

On top, I wrapped a piece of 65# card stock that would serve as my cutting guide. I then did the cutting with my new best friend:
ImageUploadedByRocketry Forum1490979686.794966.jpg

I found the angle of the blade point to be much better for tube cutting than the old standby Xacto #11; also, due to the supports built into the handle, the blade has little flex and showed little tendency to wander. That's been my biggest problem during previous tube-cutting adventures: the flexible Xacto blade tends to have a mind of its own, and not follow the guide closely. No such problem here, for the most part.

I applied a bit of TBII to the cut edges to seal up the cardboard, gave them a quick pass with 400 grit sandpaper, and ended up with two pretty good rings, one .75" wide and one 1 1/16" wide.
ImageUploadedByRocketry Forum1490979360.870382.jpg

I haven't done any builds that require a lot of exotic tube cutting yet, but I feel like I'm ready now.

The story of these rings is just beginning, more updates to come once I actually do the stuff. :)
 
Last edited:
I'm a firm believer in "the right tool for the job", but I never considered the box cutter/utility knife to be a serious modeling knife/tool. I may have to rethink my viewpoint.
 
GUYS! There are many reasons to go with the kind of knife Neil is using. Xacto has it's place for sure, but a lot of precision cutting depends on what works best in your hand. Like Neil, the Xacto tends to wander in mine and getting a straight cut on fins is near impossible for me. That break-away knife is easier to guide for both cutting fins and tubes, as well as a great many other pieces and parts. For all those die hard Xacto fans I say, "Take The Next Planet. You'll have to pry this knife from my cold dead hands."
 
While working through the sanding of the primer, I had a painting window and decided to go ahead with painting the nose assembly. This will provide a test to see how well the overall technique works; if it proves too troublesome I can change my approach on the rest of the rocket. For now this is just a straightforward black base coat. I think I went a little heavy, but it should be OK (sorry for blurry pic).
ImageUploadedByRocketry Forum1491165890.874020.jpg
 
Last edited:
Well, filler/primer must be sanded, like it or not. Of course, there is the option to not use filler/primer, but it really does work nicely. On some non-critical future build I'll probably try swapping it for regular primer, and see how it goes.

No argument here, its got to be sanded to smooth things out. I just end up leaving waaay more of the latest coat on when I do it. Probably why I end up heavy at the end of the day :)

Edit: I didn't have as much airport downtime as I thought this weekend, so this is as far as I got. Hopefully I'll have a CP cranked out before your last coat of paint dries.
What are you planning to fly it on? D12?
Avalon1.PNG
 
Nifty CAD work! Sorry I seem to have missed your post you first posted it.

I'll probably try this one on a C11 first, and then move up to a D12 if all goes well.
 
I needed to check the size of the rings against the fins. I initially cut the rings to the width in the OR model; they were sized to be just about the full width of the fins at that point. However, that failed to take into account two things:
1) variability in fin shapes due to hand-cutting and sanding.
2) lost space at the edges due to rounding

And so, I found that while the front ring seemed OK, the rear ring needed to be about 1/8" smaller. So I got prepped it, made that cut, and... well let's just say it was *by far* the best BT cut I've ever done, even without using a proper cutting jig (for smaller BTs I use the yellow Estes tube cutting rings, but they don't go above BT60.) So today's small joy was accidentally figuring out how to do a really clean BT cut without a jig. In fact, I think I just got a much better cut than I do with the Estes jigs.

First I prepared the tube as before: slid it onto a piece of coupler (with an extra tape wrap, for snug fit), and then scotch taped it into place on the non-cut edge. I wrapped a piece of 65 lb card stock around it at the cut line, and then taped *that* into place. The card stock is my cutting guide. In my past cuts it worked OK, but the blade still drifted a bit; sometimes away from the card stock and sometimes into it. Not this time.

I extended the snap-off blade to the minimum, and held it pretty flat against the tube, with just enough tilt to ensure the that point of the blade was touching the tube. This picture was staged after I had finished cutting; card stock guide has been removed:
ImageUploadedByRocketry Forum1492451531.791052.jpg
Then I held the knife in position and rotated the whole tube assembly underneath it. The blade did not drift *at all*; I don't think I shaved a single molecule of card stock off the edge, and there was only one spot on the tube where the blade drifted just a tiny bit away from the card stock. And it turned really smoothly, never catching like it usually does.

The key, as far as I can tell, was the angle of the blade, much flatter to the tube than I have been holding it up until now. Such a small adjustment, such a huge difference!

Here's my finished product, along with the 1/8" ring I removed. The newly cut edge is on the right, you can (?) see how clean it is.
ImageUploadedByRocketry Forum1492451524.833010.jpg

I don't know what it says about me that I am still capable of feeling a great sense of accomplishment from cutting a body tube, but there it is.
 
Last edited:
I needed to check the size of the rings against the fins. I initially cut the rings to the width in the OR model; they were sized to be just about the full width of the fins at that point. However, that failed to take into account two things:
1) variability in fin shapes due to hand-cutting and sanding.
2) lost space at the edges due to rounding

And so, I found that while the front ring seemed OK, the rear ring needed to be about 1/8" smaller. So I got prepped it, made that cut, and... well let's just say it was *by far* the best BT cut I've ever done, even without using a proper cutting jig (for smaller BTs I use the yellow Estes tube cutting rings, but they don't go above BT60.) So today's small joy was accidentally figuring out how to do a really clean BT cut without a jig. In fact, I think I just got a much better cut than I do with the Estes jigs.

First I prepared the tube as before: slid it onto a piece of coupler (with an extra tape wrap, for snug fit), and then scotch taped it into place on the non-cut edge. I wrapped a piece of 65 lb card stock around it at the cut line, and then taped *that* into place. The card stock is my cutting guide. In my past cuts it worked OK, but the blade still drifted a bit; sometimes away from the card stock and sometimes into it. Not this time.

I extended the snap-off blade to the minimum, and held it pretty flat against the tube, with just enough tilt to ensure the that point of the blade was touching the tube. This picture was staged after I had finished cutting; card stock guide has been removed:
View attachment 317667
Then I held the knife in position and rotated the whole tube assembly underneath it. The blade did not drift *at all*; I don't think I shaved a single molecule of card stock off the edge, and there was only one spot on the tube where the blade drifted just a tiny bit away from the card stock. And it turned really smoothly, never catching like it usually does.

The key, as far as I can tell, was the angle of the blade, much flatter to the tube than I have been holding it up until now. Such a small adjustment, such a huge difference!

Here's my finished product, along with the 1/8" ring I removed. The newly cut edge is on the right, you can (?) see how clean it is.
View attachment 317668

I don't know what it says about me that I am still capable of feeling a great sense of accomplishment from cutting a body tube, but there it is.

And see? That's how us old farts (speaking of myself of course) finally started doing things right. That technique is exactly how I do it on large tubes. BT 70 & 80 don't work well on my homemade tube jig, so I have to embrace the big ones with a steady hand and a load of patience. Nice done Meester.
 
And see? That's how us old farts (speaking of myself of course) finally started doing things right.
Hey, I'm not actually that much younger than you (I don't think), though I have built far fewer rockets... :cheers:

Flush with success from my previous cut, I attempted to replicate it by trimming the smaller ring by about 1/16"... When I previously measured it it was borderline too big, but I was reluctant to make an extra cut for fear of messing it up. I applied identical technique and came out with another very good cut. Cool beans.
 
Hey, I'm not actually that much younger than you (I don't think), though I have built far fewer rockets... :cheers:

Flush with success from my previous cut, I attempted to replicate it by trimming the smaller ring by about 1/16"... When I previously measured it it was borderline too big, but I was reluctant to make an extra cut for fear of messing it up. I applied identical technique and came out with another very good cut. Cool beans.

YO....You be bad! Yank boy kno howta tho down on blade!
I'll be 62 this coming Saturday. I prolly got 10 years or so on you.
 
Impressive design! So are you going to paint it green and then mask to paint the black over it, or vice versa?

Black first, then two months (or so) of masking, then a coat of white then the fluorescent yellow-green. Then at some point I need to attach the rings.

I think I'm gonna go matte with the whole thing; still need to figure out which order to do the matte clear over the whole rocket vs. the yellow/green. I feel like the fluorescent paint needs protecting, but I'm reluctant to dull it too much with the clear coat. Still a while to go before I need to deal with that though, construction still not finished (argh!).
 
Black first, then two months (or so) of masking, then a coat of white then the fluorescent yellow-green. Then at some point I need to attach the rings.

I think I'm gonna go matte with the whole thing; still need to figure out which order to do the matte clear over the whole rocket vs. the yellow/green. I feel like the fluorescent paint needs protecting, but I'm reluctant to dull it too much with the clear coat. Still a while to go before I need to deal with that though, construction still not finished (argh!).

Definitely do some tests on scrap balsa and tube sections to see how the paint turns out that way. As you know usually the colors go on light to dark, and in this case it might be easier to mask over the green and spray the black instead of what you suggested.

I can't wait to see how you do it. Please document it well!!
 
Definitely do some tests on scrap balsa and tube sections to see how the paint turns out that way. As you know usually the colors go on light to dark, and in this case it might be easier to mask over the green and spray the black instead of what you suggested.

Good idea!
:)


It seemed to work well, other than the generally messiness of my hack and slash brush painting job. Also, I had a bit of white paint bleed under the masking tape, which is why I will be shooting a layer of clear over the mask before starting with the white on the actual model (fingers crossed). But the general strategy of painting the light over the black seems OK. Perhaps the fluorescent paint will end up slightly less bright than it would have otherwise, but it's still good.

Of course I will bloviate about the entire process in this thread, once I get to it.
 

Good idea!
:)


It seemed to work well, other than the generally messiness of my hack and slash brush painting job. Also, I had a bit of white paint bleed under the masking tape, which is why I will be shooting a layer of clear over the mask before starting with the white on the actual model (fingers crossed). But the general strategy of painting the light over the black seems OK. Perhaps the fluorescent paint will end up slightly less bright than it would have otherwise, but it's still good.

Of course I will bloviate about the entire process in this thread, once I get to it.

That's what I get for joining the thread late. Haha!
 
Finished sanding the primer. What fun.
ImageUploadedByRocketry Forum1492651635.010096.jpg

Next up: deal with the launch lug, and a bit of fun with the rings. Then the helixes go on!
 
Last edited:
I briefly debated the launch lug situation. 1 or 2? Where to put?

I ended up with one big on. The rear part of it will disappear underneath the front ring. If I had just put a short one in the same spot (close to CG) then it wouldn't have looked much different, maybe worse even. I also found that I could not reasonably put it against a fin root due to the long taper of the front of the fin and the forthcoming paint job. So I centered it between the front and rear fins. In hindsight, I might have placed it nearer in line to the rear fins, and therefore further from the front fins, to give myself more room to work later. Ultimately this could have gone a lot of different ways, but since I don't really care so much about the lugs I didn't sweat it.

Just figuring out how to draw a marker line for the lug had me scratching my head. I ended up using my fin jig:
ImageUploadedByRocketry Forum1492738679.059886.jpg
The aluminum angle (normally used for fin clamping) provided a decent enough guide for drawing the line. In the end, I did final alignment of the lug by eye anyway.

After the requisite Quick and Thick fillets, the lug is placed:
ImageUploadedByRocketry Forum1492738688.996799.jpg
 
Last edited:
Helix time!

Gluing them was straightforward. I checked the fit for each piece before gluing, to make sure it would sit flat on both front and rear fins. Some sanding was necessary on the front fin each time. Even when finished, it's not a perfect joint, so I'll be happy to have those little wedges glued in for extra strength (that'll come later). I was quite happy that at least the pieces sat on the fins pretty much on my pencil mars that I made way back at the beginning.

I actually made some little jigs to hold the pieces in position while gluing, but realized that I'd not be able to slide them off afterwards, due to the weird geometry of the whole assembly. Did I get them on straight? Who knows? They look good to the naked eye though.

But enough blather, here's what you came for:
attachment.php


Possibly my favorite part of the process was how the fin can fits into my rocket stand like a glove, even with the helixes attached.
ImageUploadedByRocketry Forum1492951148.033568.jpg
ImageUploadedByRocketry Forum1492951165.827397.jpg
 

Attachments

  • ImageUploadedByRocketry Forum1492950606.622455.jpg
    ImageUploadedByRocketry Forum1492950606.622455.jpg
    477.5 KB · Views: 237
Last edited:
Yup. Painting is going to be a real time consumer. You've prolly earned high marks on having one of the most interesting scratch builds around here. I love how this has progressed. Kudos Neil.
 
Yup. Painting is going to be a real time consumer. You've prolly earned high marks on having one of the most interesting scratch builds around here. I love how this has progressed. Kudos Neil.
The fins came out great! - really cool looking

Thank you gentlemen. I'm pretty happy to have gotten this far, although I do dread painting. I console myself with the notion that even if I screw up the paint job, it'll still be an interesting model.

If we ever get the laser cutter in at work, I'm going to try one of these beauties.
Better make it an upscale!!! But dontcha wanna know if it flies first? :)

Oh, and... laser cutter? Get out that hobby knife and get to it! Actually, *don't* get to it, wait and see how mine turns out and learn from my mistakes. The rings are still going to be a PITA.

Then again, waiting to see how mine turns out could be a long-term proposition. ;)
 
I added the little wood wedges to the joints between the helical pieces and the rear fins:
ImageUploadedByRocketry Forum1493583613.532811.jpg

The front joints seemed strong enough to live without them, despite not being perfectly flush. So I just filleted the front joints and that's that. I still wanted the ones on the rear because they'll be taking the brunt of landing forces.

Masking around those pieces is going to be a pain, as if masking this thing wasn't enough of a pain already.

But hey, she's basically ready for paint. First up: black base coat.
 
Last edited:
Back
Top