Starship Avalon: build thread

Glued in the front transition:

Looks pretty good. I glued the shoulder first, then afterwards spread a very small fillet of TBII around the front to seal it down. In the picture you can see the remains of the previous glue that was on there; I'll try to sand some of that off. I also noticed I forgot to fill the spirals on the BT50; I had meant to do that before gluing the transition but oh well. I'll do the spirals and then at the same time I'll also use the CWF to smooth out the seams in and around the transition.

In the back, I cut the hook slot, applied some more CA to strengthen it around the cut, and did a dry fit:

Also good. This will get glued in with epoxy (since the paper is completely CA-covered) later, and then some CWF work there as well to smooth things out.

While I was in the neighborhood I noticed this:

Crap. I used epoxy for the rear centering ring, and apparently got it all over the damn place, including the one spot I most didn't want it. I guess I will be gluing the fins to the inner tube with epoxy; should still be able to use TBII for the exterior seams. Will also have to do just a bit of sanding on the fin tabs to make them seat properly now.

Finally, a bigger dry fit just to keep me motivated:


Not bad. I think once I get all this other stuff done the fins will go on comparatively quickly.

(snicker)....you and you damn epoxy! "OH NO, I can't use wood glue, it's not as strong" LMAO! One of these days you're gonna get sick and tired of goobers like that and realize, that it doesn't have to withstand being run over by a steam roller. :rofl:

I only use epoxy in two situations, which have nothing to do with strength:
1) where I have a tight centering ring and I don't want it to sieze
2) where I'm not attaching porous materials. This includes paper parts coated with CA. How else would you glue to a (for example) CA-soaked body tube?

I did it on my Magic Dart. The thread where you overlooked a particular section where I coated the inside of the tubes with CA. (# 21 ) There were no issues with glue to CA there. And as for tight centering rings, there's this stuff called sandpaper? Or if you are using plywood, that cool tool called a Dremel?

Magic Dart makes for a good re-read.

It does make for a good re-read, because that was (is) a gorgeous rocket. Although I saw plenty of mention of your CA-coating techniques, you never really focused on glue choices for attaching to CA-coated parts, not that I would have expected you to. Or maybe I missed it yet again.

If you say that TBII will adhere to CA-coated paper I'll take that under advisement, but it was certainly my impression that wood glue and CA would not be a good combination. For that reason I kept the CA away from the front and rear edges of the front transition, so I could use TBII to install it. For some reason I completely coated the rear transition, though. Maybe I'll try the TB on it anyway; it's not a structural component after all. Maybe I'll do some experiments here, always happy to have an excuse to do some of that.

BTW, seizing issues are more for paper-paper joints, like wound paper centering rings or, as I discovered, paper transition to BT. The plywood rings don't grab so quickly, and typically don't fit as tightly. I confess though I do appreciate the ability to freely adjust the position of mounts inserted with epoxy without having to hurry or worry.

I use TB 2 on everything. I have learned, that it's too too much for laminating balsa for turns on the lathe, so I use white glue instead. Wood glues are generally used on porous materials for obvious reasons, but TB 2 and the likes, are sticky, dry relatively hard, and not necessarily restricted to porous materials. It's glue! I would recommend experimenting also. YMMV. I do know about how plastics can be so difficult to hold glue, but I haven't run into many or any glues that don't stick well to other glues. Maybe someone else has better knowledge about glue to glue than I do, so maybe they'll weigh in and set the record straight. Honestly, I hadn't given any thought about glue to glue when I put the MDart together, but apparently it's not a problem. I can double check that motor mount now that it has 3 successful flights under it's belt. As for gluing CR's, my best foot forward was/is to pre-mark everything. Know where to stop pushing and always install with a gentle twisting. NEVER stop in the middle of the installation for any reason. Keep twisting and pushing till you reach your destination. And since I love to use those black fiber CR's, they tend to grip pretty fast. It's the one application that you have to do quickly if you want the best results.

neil_w said:

Not bad. I think once I get all this other stuff done the fins will go on comparatively quickly.

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Looking good. The tube sizes should have given me a hint, but I didn't realize how small this was going to be.

Somehow I always imagined it with ~38mm sized main body tube.

Nytrunner said:

Looking good. The tube sizes should have given me a hint, but I didn't realize how small this was going to be.

Somehow I always imagined it with ~38mm sized main body tube.

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Yeah, it seems a bit dainty now that I have the pieces in my hand. That is why I'm looking at it and wondering if it really needed a 24mm mount.

A larger version would definitely be worthwhile, assuming the whole thing proves to be a working design. Although then you'd need an even larger form to mold the helical pieces, or else a different strategy for that altogether.

neil_w said:

Yeah, it seems a bit dainty now that I have the pieces in my hand. That is why I'm looking at it and wondering if it really needed a 24mm mount. .

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Always easier to go DOWN a motor size after building than going up!

I can think of several Estes kits that a lot of people myself included WISH had 24mm engine mounts!

After filling all the spirals in the BT50 and smoothing out all the joints in and around the transitions with CWF, it was finally time to attach the rear fins. Sanded the tab on each fin until is settled flush into it's slot, then, used epoxy for the tab, and TBII for the parts contact the exterior BT. This pic shows the third and final fin clamped in place using my 3D-printed fin jig.


Then I put on some of the cleanest fillets I've done in a while, using my new bottle of TB Quick and Thick. I seem to have gotten the knack of the wide nozzle for applying fillets; some came out so clean I barely even need to run my finger over them (but I did anyway).

Next I need to attach the little extensions from each fin to the rear. These need to be carefully cut and sanded to fit each location. I first did an approximate cut of each piece, trying to make sure I made each one a bit too big so I could sand it to fit. I did pretty well; the pieces were pretty close to perfect before I even started sanding. Here's one after sanding being held in place by gravity for the moment:


Not bad, although I just could not get the curve to blend smoothly between the two. I'm hoping that some CWF or Bondo at the end will be able to improve that a bit. Well, I *know* it'll improve it, we'll just see how good I can get it. I did some similar stuff on the APRO Lander build and it seemed to come out OK, so I'm feeling OK about it at this point. (on the other hand, the rear transition looks like garbage in that picture. Should have shown the other side...)

Next up I need to paper those little guys (that should be joyous) and glue them in.

I really wish I had used heavy wall bt50, but since I didn't I needed to strengthen it up. And so I prepared a BBTM (Byrum Body Tube Mop):

That's a piece of foam screwed to the end of a dowel. And a couple of extra pieces of foam; I had no idea going in how long the first piece would last before it hardened up.

I debated the best way to do it, but ultimately I settled on drizzling thin CA into the end of the BT, and then using the mop to spread it around evenly. It seemed to work great, and I was able to get the CA all the way down the tube.

Still needs some sanding. Also I could confirm that the CA covered everything just from looking at the outside of the tube:

The dark stripes are where the CA shows through.

The only problem I encountered was that I couldn't really see the CA coming out of the bottle, so I ended up pouring in too much and it dropped all the way out the back. Luckily nothing was harmed (including me). I will be more careful next time. Also the rear transition got a partial soaking.

No biggie.

All in all a big success, the tube should be much stronger now.

Some Bondo also seems to have found its way onto the joints between the BT50 and the transitions. They're satisfactorily smooth now.

BBTM.....lamo! Way funny man. And hey, FWIW, I used a small medicine cup or plastic vessel of sorts to pour my CA into and dipped the mop. It pretty much saturates the mop, but once you get it in the tube, it's an even couple of strokes and you're done. No dribbles. I usually pour any left over CA back into the bottle since I only use the stuff for hard coating things anymore. NC's, shrouds and tubes and such. Doesn't seem to corrupt the CA any. Not by what I can tell.

And it appears you are moving along here bud. Way to go. Be on the lookout, I have a few coming up later today.

Gary Byrum said:

BBTM.....lamo! Way funny man. And hey, FWIW, I used a small medicine cup or plastic vessel of sorts to pour my CA into and dipped the mop. It pretty much saturates the mop, but once you get it in the tube, it's an even couple of strokes and you're done. No dribbles. I usually pour any left over CA back into the bottle since I only use the stuff for hard coating things anymore. NC's, shrouds and tubes and such. Doesn't seem to corrupt the CA any. Not by what I can tell.

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I may try that next time, using one of my epoxy mixing cups. The dribble strategy would actually have worked fine if I had been more aware of how much I was squirting in there.

And it appears you are moving along here bud. Way to go. Be on the lookout, I have a few coming up later today.

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Yes, actually coming close to the end of exterior construction. Unfortunately that means it's almost time to paint, and I absolutely dread painting this thing....

Time to finish the rear fins.

After papering the tiny extension pieces (seriously sometimes I doubt my own sanity) I glued them in uneventfully:


The seams between the two fin pieces and the curve between leading from one fin to the other were filled and shaped with some CWF; fillets were added and then we had this:


The eventual filler/primer coat should smooth out the rest. The rear fins are now complete:


Pretty good I'd say. The open-air motor mount would have been cool but this is still a pretty nice looking rear end (for a rocket, anyway).

neil_w said:

Time to finish the rear fins.

The seams between the two fin pieces and the curve between leading from one fin to the other were filled and shaped with some CWF; fillets were added and then we had this:

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If I had a nickel........
I know I have doctored nearly every single fin joint I ever made. It's always something that keeps em from fitting perfectly. That's why I invented filler putty. Glad you like the stuff.

Starting to ponder things like the build/paint sequence (ugh, gonna be miserable) and right now, the attachment of the helical pieces to the fins. I am a bit concerned over the strength of the joints, primarily on landing where the one or more of the helixes will probably be the first thing to hit the ground.

The joint is a butt joint; no slotting was or is possible.

Would sandwiching the joints with some 45 degree angled pieces of balsa, like shown in the following picture, help? I'm not sure if these would be better or worse than fillets. Or would basswood be better? The pieces would be a bit harder to fabricate in basswood, but I probably make it work.

The only alternative I can think of is just to fillet the heck out of it and hope for the best.

Dollhouse coping! It's already mostly the right shape, typically a bit harder than balsa, but not as heavy as a big fat fillet.

And yes, increasing your glue area / spreading out the impact should have a sizable strength increase at the cost of not much weight.

Dollhouse coping? No luck googling it...

Hobby Lobby stocks little strips of wood like what you're looking for. +1 on the use of it for strengthening your joints. Beats fabricating them. Although, you are putting bent wood on a flat strut. Might not be exactly 90*. Gets my vote though.

https://www.dollhouseminiatures.com/supplies/shapes.htm for reference to a number of different shapes and sizes.

I like the plain "cove" in 1/16, 3/32, 1/8, 5/32: at 3/16-1/4 you can probably switch over to something from the hardware store.

Apparently a better search term is "miniature cove moulding" , so today I learned something also.

dowels? in this case, more like short pieces of a toothpick. You could also put some pin holes in both parts where they will glue up, this makes little glue dowels, a little bit stronger than a butt joint. I like the molding strips too though, they increase the glue contact area.

But, aren't the helixes going to be attached to two struts, one in the front and one in the back? That shape will probably be fairly sturdy to take those twisting loads, even with the simple edge joint, since the helix shape is curved, it will already be supported in a way that avoids the twisting of the joints. Or did you change the design and I missed it?

Gary Byrum said:

Hobby Lobby stocks little strips of wood like what you're looking for. +1 on the use of it for strengthening your joints. Beats fabricating them. Although, you are putting bent wood on a flat strut. Might not be exactly 90*. Gets my vote though.

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It *should* be exactly 90 degrees if I position everything correctly, due to the geometry of the whole mess. I should see what HL has; last time I was there I looked for that sort of thing and didn't really see it, but maybe I didn't look in the right place.

GlenP said:

But, aren't the helixes going to be attached to two struts, one in the front and one in the back? That shape will probably be fairly sturdy to take those twisting loads, even with the simple edge joint, since the helix shape is curved, it will already be supported in a way that avoids the twisting of the joints. Or did you change the design and I missed it?

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No, nothing has changed, you have it right. It is possible I'm worrying over nothing. Each helical piece is about 7" long, 1" wide (at widest point). The rear fin attachment is 1.25" long, the front is 1".

dhbarr said:

https://www.dollhouseminiatures.com/supplies/shapes.htm for reference to a number of different shapes and sizes.
I like the plain "cove" in 1/16, 3/32, 1/8, 5/32: at 3/16-1/4 you can probably switch over to something from the hardware store.
Apparently a better search term is "miniature cove moulding" , so today I learned something also.

Click to expand...

Cool. I inquired and they said it's made from basswood, so it's fairly perfect for my application. But shipping costs would torpedo a purchase like this via mail. It's possible HL or another LHS might have something like this, if I want to search.

In the meantime I decided to do a little experiment. I glued a piece of scrap wood to my first fabricated helical piece (back when I was experimenting with *that*). Then I glued in some "molding" cut from 1/8" balsa, like so:



The end result is quite strong; I inadvertently snapped the fin in half while testing it. I didn't know if the relatively soft balsa would add much, but the whole assembly seems rock-solid. Can't judge how much better it is than just a good glue joint with fillets, though. Maybe I'll glue another piece to the other end that way and compare.

In any case, this seems like a viable option *if* I decide that any reinforcement is necessary. Weighs basically nothing and seems to add some strength. I made a bunch of these strips, took only a few minutes.

neil_w said:

I should see what HL has; last time I was there I looked for that sort of thing and didn't really see it, but maybe I didn't look in the right place.

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If you looked where the balsa sheets are stored, then you were there. Maybe you just didn't notice because you weren't looking for them. But that where they are.

I think triangular strips of balsa (maybe 1/8") should work just fine as a reinforcement of the joint. You shouldn't need anything fancy. If you're careful, you could even cut your own from scrap pieces of 1/8" balsa.

TangoJuliet said:

I think triangular strips of balsa (maybe 1/8") should work just fine as a reinforcement of the joint. You shouldn't need anything fancy. If you're careful, you could even cut your own from scrap pieces of 1/8" balsa.

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Indeed, that is exactly what I did above. Certainly *seemed* to add strength.

Mulberry Street is the HL brand in the dollhouse section, blue hang tag w/ 4x 24" sticks ~$4-5

Positioning of the front fins needs to be precise. In particular, the top edge, which will mount to the helixes, needs to be in the correct position relative to the rear of the rocket. By going through my OR model I figured out that it needs to be like this:


So I went and made a mark on each fin at the root edge, right where the vertical red line is in the picture. Here they all are, marked up:


You can see pretty clearly that the trailing edges are not exactly all in the same place; I find it nearly impossible to sand those long sharp points and have them come out exactly the same each time. That's why I can't use those points to position the fin; they'd all come out different.

Then I marked the spot on the BT 4 3/8" from the rear, for each fin:


I also decided, as you can see, to remove the glassine layer for these fins. Just wanted to try it, get a bit of extra strength. Turned out to be much easier than I expected, think I did it pretty cleanly.

Next the fins were mounted with the marks lined up, like so:


Still need fillets, will do them tomorrow.

Here is the fin can with all six fins:


Next I *had* to try this:


It's just being held by gravity here, but I wanted to verify that it matched up with the fins. It did, pretty well. Here's the underside:


You can see (kinda, sorta) that the fins match up pretty well with the mounting points on the helical piece. Not perfect, but pretty good. When it comes time to glue that all together, I'll need to be as careful as I can to get it all positioned correctly. It is a bit tricky to be sure.

Once the fillets are in, I might actually be ready for primer!

Excellent! :clap:

WOAH! Now you're on the move. Startin' to look like a freaking starship now! I seemed to notice something about your Bondo job. Looks like you are in the know about using alcohol after you apply it? They look rather smooth in that, I'm unsure if you sanded them already. I found out that dipping my finger in some denatured alcohol and rubbing the Bondo smooth, requires less sanding and you get rid of all those "chunkies" that form when you're applying it. Did you do that also?

That's coming out great.

What worked out for removing the glassine in a controlled manner? Knife scored outline and patience?