Xarconian Cruiser with CA-papered fins and airbrush finish

Hi folks,

It's been a while since I posted about any of my builds. There were relatively few builds in 2014 (other things in life taking precedence), and I didn't have the energy to post much about the few builds I did.

Meanwhile I've replied to a few threads about papering fins with CA and using airbrushes recently, so I thought I could document some of my current practices here in this thread, more easily to refer people to them.

The build is actually done, though the finishing won't start until tomorrow. I had planned to filler-prime it today, then remembered the launch lug wasn't on yet...

For those of you not familiar with the Xarconian Cruiser, she is this one from ESTES:



I had worked my way through a Semroc Marauder and an Estes EPM-010 in recent months, and wanted to work on something needing a little more build craft than those, but not quite so much as the Fliskits USS Grissom that's in my pile. My focus turned to the cruiser, which Estes labels as skill level 5. Frankly, I would call this a 3 or 4, not a 5. The only real challenge is actually following the directions, which I managed to goof a few times.

While building it, I warmed to the design (didn't like it much at first), but the stock paint job doesn't do it justice. I'll be shooting for something akin to a Vorlon organometallic skin, I think.

This won't be a step by step build thread, but will be a highlights reel of sorts. It starts with the typical parts spread. There's a fair amount of parts...



After removing the fin parts from the sheet, and sanding them appropriately, I used Elmer's yellow carpenter's glue sparingly on the joint edges. I used an aluminum angle piece as a straight edge for alignment, and let them dry on a sheet of glass I use for such things.

One challenge with the kit is that the largest sections of the two wing fins were warped noticeably. I had tried moistening both sides and sitting them under heavy weights over night, which didn't flatten them. I decided just to press on. I figured a little warp probably wouldn't be too much trouble, and the chances of me cutting the complex shapes just right from flat stock was low.

When I choose to paper fins, I do so to reduce the amount of work involved in sanding grainy balsa smooth with multiple filler coats. I also do it to increase the strength of the wood... CA-papered balsa is very strong.

I start by using some Formula 77 Spray Adhesive onto computer paper (legal sized, in this case, to accommodate the long fins). Just a light spray of the glue onto the paper, to give it a little tack.

I lay the fin on the paper, avoiding papering within a mm or two of the root edge.



Using a sharp hobby knife, I trim around the edges of the fin. Note, I don't round or bevel the fins before doing this. That will come later.



Above you can see the result once both sides have the paper tacked on.

Next, very important: I use my carpenter's glue on the root edge and the exposed mm or two of wood near the root, and let it dry. This will be the first layer of glue in the double-glue joints that eventually bind the fin to the body tube. I don't have a picture of this step, but you really want the wood glue to soak into the balsa before you impregnate the balsa with CA. Otherwise, the wood glue bond will be much weaker.

More to come, tomorrow...

Excellent! I always enjoy your builds, you are among the finer craftsman in this corner of the innerweb.

I'm interested to see how the airbrushed finish holds up after a few launches. I've always been able to get better finishes through airbrushing vs rattle-cans on plastic models, but it seems like the airbrushed finish would get scuffed very easily on something that actually flies. I have airbrushed a pair of boost-gliders this past year but haven't got the opportunity to launch them yet.

I will be watching this thread. I recently finished building one of these too, but I didn't paper the fins. I agree - it is not a skill level 5.

Thanks for the compliments and the interest. It's always nice to see the time spent documenting a project is of interest to others, and potentially helps someone else out. Most of what I know about building came from this forum, and I like to give back when I can. Karma, you know...

OK, today we take up where we left off. The wing fins and the top fin are papered, and carpenters' glue has been used on the root edges, plus the mating points where the wing pods will attach (and where the top fin will connect to the small T piece).

The next step was to impregnate the fins with CA. I use thin CA from hobby lobby.



The thing to do before starting the project is to check how much glue you have on hand... I was running low but thought I had enough, so I went for it.

NOTE: Use proper personal protective measures when using CA. Control the ventilation, protect your eyes, etc..

I laid the wing/fin parts onto some wax paper (which resists binding to the glue), and dribbled CA on, starting in the "center" of the widest part and using a Q-tip, spread the CA out, keeping it nice and wet. The glue soaks through the paper and into the wood nicely, and the small amount of Formula 77 adhesive used for tack doesn't inhibit the passage of the glue. Adhesive label paper can be used, but I find the glue soaks through my tacky paper better. I stop adding CA when the paper is completely saturated and you can see the wood is stopping to absorb the glue due to saturation.

These fins are I think 3/32" balsa (I didn't measure, just a gut check) or perhaps 1/8". Thicker fins absorb more CA.

Anyway, I got all of the first sides of the fins done, and set the pieces aside for a while to cure. It actually was about 2 hours before I had time to get back to it, by which time everything was set up hard. The pieces did not much stick to the wax paper in areas where the glue had dripped over the sides.

I flipped them over and started in on the second side of the pieces, only to run out of CA as I was finishing up the first fin. D'oh! And it was Sunday, so Hobby Lobby was closed. Moving to the next fin, I tried a small area with "medium" thickness CA of which I had plenty, and it looked like it might work, but clearly not as much soaking into the wood. I stopped that and found a tube of el cheapo dollar store CA (last tube in a pack of 3), which was quite thin. I used it to complete the last two fins.

After all was set up, I put each fin on a hard surface and dry sanded with 220 grit 3M wet/dry sandpaper. Smoothing out the surface doesn't take much effort. For all that cured CA is fairly hard, it sands pretty well, and the impregnated paper doesn't give fuzzies. It took maybe five minutes per fin to get the flat surfaces nice and polished smooth, giving a final sanding at 320 grit to all of them.

I then used a variety of sandpaper-glued-to-sticks and sanding sponges to give the fins rounded over semi-bevels. The paper and the wood, impregnated with CA, can be treated as a single material surface with little risk of delamination of the paper. They turned out nice, except for that first fin where I ran out of CA on the second side. In one area, there hadn't been enough glue to properly bond the paper down. A section of it came up, so I trimmed it back to the point where it was well adhered.



I then generously dabbed some carpenter's wood filler onto the area:



When it had dried, I sanded it flush with the surface, and used a little medium CA to fill it in:



After a light sanding, the surface blends right into the papered area of the fin. This won't be visible in the paint job.

Keep in mind this is just a highlights reel... I haven't showed quite all the detail. There were a few more steps to complete building bottom fin and the top part of the top fin. I don't have pictures and I just followed the instructions.

Next step was getting the fins on. The kit comes with a marking template that you wrap around the main body tube. I followed the instructions, using an angle aluminum piece to extend the marks.



I applied a layer of carpenter's glue to the areas where the fins/wings would be binding eventually, and let that layer dry. Remember, I'll be double gluing the fins on, so there needs to be a dry glue layer on both the body tube and the fins.

One note: I no longer sand the areas of the body tube where the glue will go in order to scuff the glassine layer. I used to do it, in pursuit of a stronger bond between the fin and the kraft paper tube. But a year or so ago I did some experiments on scrap, and found that while bonds with sanded body tubes are just a bit stronger, and theoretically better able to resist a hard landing, the breakage is a bit cleaner if you don't scuff the glassine, making it easier to neatly glue the fin back on neatly. Basically, if the glue is going to break, I want it to rip the paper layer cleanly. Also, glassine is just another type of paper, made of cellulose, so while it is water and glue resistant, glue does soak in a bit. It's not impermeable plastic or anything. Bottom line, you get a fine bond between fins and body tube without removing the glassine, and I have reasons I will detail below for not wanting the glassine messed up.

While the first layer of glue was drying I prepared for the attachment. I copied the full size template onto cardstock. Then I used an extra centering adaptor and a spent 24 mm casing with a dab of glue on the bottom to make this:



The centering ring isn't actually glued down... I didn't want to waste it. The body tube fits nicely onto this, and stands perfectly straight up.

I took each fin/wing, lightly sanded the root edge to remove any contaminating CA that would interfere with the double glue joint, put a layer of carpenter's glue on, and stuck the fin onto the appropriate spot, carefully aligning the fin with the lines on either side of the joint. I sighted down to make sure the fin was sticking out at the right angle.



After all the fins were on and glue dry, I gave a small fillet of carpenter's glue to ensure there were no gaps in the glue joint:

Some thoughts on this model:

Estes could've sold more if they had marketed it with a nicer paint job. Now, it's overstock being sold for cheap, undercutting the LHS and other vendors. So I bought one! 8 bucks can't go wrong! Bought another one!

I am doing a few simple kits to hone my technique before building my XC. I am thinking of a Vorlon paint scheme.

Note that CA adds weight. It has no water content and does not "dry" per se. So, 2 oz of CA adds 2 oz of weight.

I'm still a fan multiple coats of sanding sealer and sandable primers, but am looking forward to trying to paper over the fins to see what all the yahoo is about. I was also thinking about thin fiberglass and epoxy, but that is probably even heavier...

I'm following your build with interest!

I agree with MarkusXL that a more engaging paint job would have garnered more sales of this model.

And indeed, using CA does add weight. I kept careful records as I built this model:

1. The three main wings & fins, balsa plus a small amount of wood glue to hold the pieces together, had a combined weight of 14.4 grams
2. Adding tacky paper brought the combined weight up to 17.7 grams (3.3 grams of tacky paper)
3. The wood glue I added to root and other mating surfaces brought it to 18.1 grams (0.4 grams of wood glue, dried weight)
4. Saturating with CA, then letting cure, brought the lot up to 22.0 grams (so, 3.9 grams of CA were used)
5. Sanding down, prior to rounding the edges of the fins, brought the weight down to 21.0 grams, so a total of 2.9 grams of CA persist in these fins on the model.

The entire papering procedure, not counting the wood glue on mating surfaces which would have happened anyway, added 6.2 grams of weight to the model.

The model as it stands ready for a primer coat weighs 111 grams (this includes a Kevlar cord, but not the parachute or swivel that will eventually be installed).

So, the CA-papering added about 5% to the total weight of the model. However, if I hadn't used this method of smoothing the grain, I would have used some other method. Whether it is traditional butyrate dope, or a bunch of coats of filler primer, or a rub with CWF then sand then primer (which will soak in), I would have been adding weight one way or another.

My observation is that CA papering adds a bit more weight than other methods (I've measured this in comparable builds, it adds about twice as much as saturation with filler primer and sanding), but for any but competition flying models, the difference is negligible. And it adds an awesome hardness to the fins, greatly improving their ability to withstand dings. So, where practical, CA papering is my method of choice. I'm not saying it is better than white glue papering, but I get consistently good results this way, whereas I've botched every attempt at using water based glues for papering. I've seen the builds others here have shown using white glue papering, and they can be beautiful. But for me, CA is the way to go.

OK, what's next?

The next step involved cutting sections out of the two smaller diameter body tubes included in the kit.

A template was provided; a couple of them in fact, to make the section cut-out and the angled part for the front. There was nothing particularly challenging about doing it. I used my angle aluminum to guide the blade. Many light passes with a fresh blade and the tubes were ready. I CA-treated the ends, so that I could sand them smooth without fuzzies.



From the leftover scrap sections, you are supposed to make four identically-sized pieces that will be used in the wing pods. Even with my Incra rule to do good measurements, I failed to measure twice/cut once. Oops.



One of the cuts was misplaced, so I had one short piece and one long piece.

Fortunately, even the smallest piece was larger than it needed to be:



I glued pairs together per the instructions, then set the large sections onto the main rocket with some wood glue:

The curved cut-outs in the wing pods are made using a template. Despite slow, careful work, my cuts left much to be desired.



The sad fact is that I'm not much good with my hands. So what's the solution? You guessed it! CA glue!

I stiffened the hand-curved edges of the cardboard with CA, then loaded up an appropriately sized drum sander on my drill press. I've only used the press a few times in the year or two I've had it, but when I've needed it, it has been a lifesaver. A quick buzzing of the edges with the drum sander and my pods were looking much better:



You'll notice something funky went on with the pod on the right. Uhh.. I outsmarted myself and didn't bother to use BOTH templates Estes provided. I just use one, twice. Of course, the pods have handedness and so I punched the connection hole in the wrong spot on the second one. I fixed it by cutting the hole into the right place, and relocating the strip of tube, with a glued-paper backing. Sanded down with a little CWF, nobody will be the wiser, except for the TRF readership.

I test fit them (measure twice!) and found all was now well.



Which brings me to a design preference I've got with the kit designer. I really hated those trapezoidal balsa inserts... the fact that they show through the pod ends really bugged me. So, after gluing them into place, I decided to do something about it. Here they are setting up after the gluing:



Note, the pods aren't glued to the wings; the only glue used at this step is to glue the balsa inserts into the pods. By putting them on the wings (dry fit), you make sure the positioning of the balsa in the pods is exactly correct for proper fit later. This is very important.

Anyway, after the pods/inserts were fully dry, I buzzed them down on my drum sander:



Now the balsa insert is curved to match the pods, which suits my aesthetics much better.

Nice build thread Marc,
I just finished one of these and had a first flight last weekend.
I to papered the fins, only I use watered down wood glue then pressed them between two boards with clamps to straighten them out. Those pods were/are a PITA.
Anyway with everything in the rocket, except a motor, and only primer, I ended up at 120g that's 15g over what Estes says. I used a C-6-3 in her and it wasn't enough to get her high enough, she deployed the chute just above the ground. Nothing broke (surprisingly) on her just a little mud on her.
I think two things with this flight went wrong .
1. that 15g over weight,
2. those pods causing drag,

I in the mind of papering over the ends of the pods to let the air go around them instead of through them.

brewster_rockit said:

I'm interested to see how the airbrushed finish holds up after a few launches. I've always been able to get better finishes through airbrushing vs rattle-cans on plastic models, but it seems like the airbrushed finish would get scuffed very easily on something that actually flies. I have airbrushed a pair of boost-gliders this past year but haven't got the opportunity to launch them yet.

Click to expand...

I've flown airbrushed rockets quite a bit with no particular extra damage due to the acrylic paint being relatively soft. In fact, the paint is less likely to chip or flake off during tube or fin flexing, since it dries flexible.

That said, airbrush paints are prone to being scratched, so you do have to be careful. I usually clearcoat them with a couple coats of Valspar clear lacquer, or alternatively just hit them with a coat of Future or whatever they are calling it now. Either way they tend to last just fine compared to the rockets I have painted with Lacquers or enamels.

JJSR said:

Nice build thread Marc,
I just finished one of these and had a first flight last weekend.
I to papered the fins, only I use watered down wood glue then pressed them between two boards with clamps to straighten them out. Those pods were/are a PITA.
Anyway with everything in the rocket, except a motor, and only primer, I ended up at 120g that's 15g over what Estes says. I used a C-6-3 in her and it wasn't enough to get her high enough, she deployed the chute just above the ground. Nothing broke (surprisingly) on her just a little mud on her.
I think two things with this flight went wrong .
1. that 15g over weight,
2. those pods causing drag,

I in the mind of papering over the ends of the pods to let the air go around them instead of through them.

Click to expand...

I've been concerned about weight as well. I'm wishing I put a 24mm mount in this beast. As it is, I can still use something like a single use D10 or D21 in it... I launch from the top of a hill, usually, so unless it goes straight up and down, I've got an extra 40 feet or so of descent altitude to work with, so I can give it a shot on a C6-3 with a bit more confidence that I'll have time to get the laundry out...

I glued the pods on with carpenters' glue, with tape to hold them in place until things set up.



From there it was Titebond Molding and Trim Glue (No Run, No Drip formula) for fillets, lots of sandpaper on details, and cleaning up the mold lines on the nose cone.

The cone was not actually in terrible shape. The cockpit area smoothed out with just some 320 grit paper, and the rest of it responded to sandpaper with a bit of putty on the seam lines. Here are some pictures of the completed build ready for priming:







I would be outside spraying Rustoleum Auto Filler Primer on it right now, except there are some snow flurries going on...

I'm only going to prime this thing lightly, because the wings / fins are perfectly paintable as is. I'll hit the tube seams with concentrated bursts to fill them in, then sand them down.

Got filler primer on her last night before the snowstorm. Discussion and pictures coming soon.

That looks amazing! I have one sitting in my basement, but I'm afraid to start on it...lol...Can't wait to see your finished! But yeah - weather is DEFINITELY not cooperating right now...

This week proved very difficult in terms of getting time to do anything, much less write up anything!

On Monday I returned to work, and the weather had turned frigid. However, right before the snowstorm, the winds outside were not bad, and there was no moisture in the 12F air to speak of.

I warmed the Rustoleum Automotive Filler Primer in some hot (~110F) water during dinner, then shook it vigorously for about two minutes. I've found this to be effective in preventing what I call "cottage cheese syndrome" when I spray the primer from cold can. This primer is essentially lacquer based and can be sprayed cold but I've found it handles much more nicely warm. Cold air is no problem at all. I sprayed this rocket outside in the light of an exterior garage light. A neighbor passed by, hurriedly, walking their nearly frozen small dog. They looked at me like I was crazy. But they waved politely. I waved back, thinking they must be the crazy ones, out in this cold just to pick up poop their beast lays on the frozen ground.

I sprayed on a light coat over the entire rocket then heavier coats on the body tubes with some attention to the spirals. But it was cold, and I was wearing only a light jacket (my "painting fleece" which is an old jacket that I don't care if it gets overspray on it). Here is the result, after two days degassing in the garage then a couple days in my basement:



Mostly pretty smooth but there will be some filler work to do, here and there.





With no sanding yet, the spirals are still visible:



Also around the top fin detail:



I have several methods I can use to fill these things. The spirals, if I just sanded down the body tubes, would still show in spots. Another coat of primer spurted along the spirals, then dried and sanded would cure it. But, there are other ways to do minor filling of residual spirals, that don't take as long to dry before moving to the next steps. And I need to fill in other things that are too big for filler primer anyway. I hope to work on this tomorrow, and I'll document here the surface prep.

Note, most of the primer you see will be removed....

I just bought one of these during the Estes sale. It'll be interesting to see how it flies with the added weight. I am working on a build using papered fins and was considering it for this build but may not to conserve some weight. I'm also considering a silver paint scheme.

This build is coming right along. The first primer coat always brings out a few surprises but overall it looks very good.

Some needle files really come in handy during part of the process.

Paul said:

I just bought one of these during the Estes sale. It'll be interesting to see how it flies with the added weight. I am working on a build using papered fins and was considering it for this build but may not to conserve some weight. I'm also considering a silver paint scheme.

Click to expand...

Anybody consider just upsizing to a D engine upfront on these? Mars Lander and ExoSkell are a couple that come to mind that probably should have been D s to start with

BABAR said:

Anybody consider just upsizing to a D engine upfront on these? Mars Lander and ExoSkell are a couple that come to mind that probably should have been D s to start with

Click to expand...

I strongly recommend anyone doing a build to prep for a D mount. I'm wishing I had, because I would have lots more choices in engines.

Also, As bradycros says, a variety of filing/sanding/shaping tools will be necessary for this job. I'm hoping to spend some good time with it this afternoon!

Marc

Marc_G said:

I strongly recommend anyone doing a build to prep for a D mount. I'm wishing I had, because I would have lots more choices in engines.

Click to expand...

You still can install a 24 mm motor mount.

A rotary tool (Dremel) with a flex shaft and grinding bits would remove the unwanted motor mount in no time.

Make or order the desired 24 mm motor mount and shove it in.

Nice thread, Marc. I agree about the ugly color on the face card. A fellow club member painted his bright orange on the top side, white on the bottom side, and it looked great! Is that an interceptor tail cone? I didn't realize this design used that, probably the black stock color. This tail cone needs something to make it stand out.

bradycros said:

You still can install a 24 mm motor mount.

A rotary tool (Dremel) with a flex shaft and grinding bits would remove the unwanted motor mount in no time.

Make or order the desired 24 mm motor mount and shove it in.

Click to expand...

Considered doing this, but rather than risk botching this bird I would just make a second one with a 24 mm mount, if it comes to that. I'll finish this one stock (except for the Kevlar cord instead of teabag/elastic) and see how she flies.

Marc

Marc_G said:

Considered doing this, but rather than risk botching this bird I would just make a second one with a 24 mm mount, if it comes to that. I'll finish this one stock (except for the Kevlar cord instead of teabag/elastic) and see how she flies.

Marc

Click to expand...

I guess another option is the Aerotech 18 mm D s. Pricey, but when you consider the sweat equity in your rockets, might be worth it: https://www.apogeerockets.com/Rocket_Motors/AeroTech_Motors/18mm_Motors_Single_Use

Great work, Marc, as always.

BABAR said:

I guess another option is the Aerotech 18 mm D s. Pricey, but when you consider the sweat equity in your rockets, might be worth it: https://www.apogeerockets.com/Rocket_Motors/AeroTech_Motors/18mm_Motors_Single_Use

Great work, Marc, as always.

Click to expand...

Yeah, I have a bunch of those. I might have mentioned them above... I forget. The D10 is a favorite of mine. When I put one in at the LPR club I often fly with, the predictable response is "What the HELL was that?" Then again there is the D21, which has occasionally resulted in fins left behind...

Progress update: I finished filling and just cleaned out the spraygun after putting on a primer sealer coat. Took pics but haven't brought them onto the computer yet. Will try to document tomorrow.

What I need to do tonight is decide on my color scheme... I've got a couple competing ideas.

Marc

OK, I had less time today for my painting than I expected, but I got the white coat on, then stopped there.

Let's catch up with some pictures.

My task yesterday was to fill spirals and other areas where things needed some smoothing.

I have lots of things I can use to do this. Here are a few options:



Frequently I'll use the Bondo/3M spot and glazing putty. But that's a strictly "out in the garage thing" due to the stinky fumes. So I set that aside. The Tamiya putty is something I have only used a few times (I used gray putty to smooth the mold line on the cone). IT's pretty stinky too but not bad enough for me to avoid using it sparingly inside. However, I've never actually tested it on top of filler primer.

So I decided today to use some CWF and a bit of spackle. Either one can fill just fine. In my current situation, I want to use something very soft on the spirals so I can easily sand most of it away without doing a job on the adjacent primer coat, so I decided to use the spackle for that. For places where I don't mind being a bit more aggressive, I went with the CWF.

Note: I haven't sanded the filler primer yet. I've found I get better results if I spray the filler primer and let dry, do my fill, then sand the piece smooth. Because of my haste during spraying of the filler, it was a much lighter coat than usual, and so things like the spirals were less filled than usual. In some pics you may even see pencil/pen lines showing through. No big deal though. I'll get the spirals filled and with the paint job nobody will see residual gaps.

Here are some pre-fill pictures:

Some lines showing through, with spiral very visible.



Here's the pod, taped for filler:



Same location, with CWF applied. Note, I didn't dilute the CWF... just rubbed it on. Most will get sanded away...



Another location for CWF:

One challenge when filling spirals is that you get excess material on, that needs to be removed. You can sand it down, as long as you are careful not to cut into the tube in adjacent areas. But it's better to get most of the material off before it dries. Here's a handy homebrew device that helps:



Using it to remove excess works like a charm. I simply took a gift card (used up!) and sanded it with my handy drum sander, with two different drums to give different sized arcs. Here is the bird after I had scraped off some spackle:



The area I had scraped has a LOT less material to be sanded away, as you can see.

Yadda yadda yadda. Things dried, I sanded, and here's the Cruiser:



I tried hard not to sand all the way through the filler primer, and if I did, not to break the glassine layer of the tubes. I'm fairly paranoid about this because when using WATER-BASED PAINTS (shouting for emphasis), they will swell the tube material if they soak into the kraft paper. The glassine is somewhat resistant to this, but if you scuff it, your paint job may swell your tubes. So don't do that. This is not a hazard with organic solvent paints. I botched a few jobs before I figured this out. The auto filler primer DOES NOT (again, emphasis) seal the tubes. It's porous. Water goes right through it. You can still damp-sand the filler primer if you are disposed to do that, just make sure not to mess up the glassine or you are going to regret it.