The Path to Level 1: Acquisition, Build, Test, and Certification Attempt Thread

[smstachwick]

I ended up expediting the poring over the instructions to tonight. Now I feel like I have a good sense of how the thing goes together.

What was less clear is the positioning of the display lugs vs the 1/4” lugs or conformal rail guides provided, but I have no doubt this will become more clear once I cut out the templates. Don’t want to put the cart before the horse.

The instructions came with an extra page telling me to disregard specific instructions on installing the thrust ring and motor hook, and to install the retainer threads at a specific point in final assembly instead. I marked up my instructions to indicate which ones to ignore, just to save some time.

 

[Rex R]

When installing the fins, put a motor case into the mount otherwise the mount will distort/ flatten out. The fins require a good bit of effort to simply snap into place.

 

[smstachwick]

When installing the fins, put a motor case into the mount otherwise the mount will distort/ flatten out. The fins require a good bit of effort to simply snap into place.

I’ve got an AeroTech RMS 29 Hobbyline case available. Either that or a G80-13T that has gone at least 10 years without use.

 

[Rex R]

Figured you deserved a 'fair warning' and yes either of those should work nicely.

 

[terryg]

I did my L1 on an Aerotech Astrobee D many years ago. I replaced the antenna with small springs so that I could fly it without breaking them. A flight with an H128W and I was hooked for good.

 

[smstachwick]

I spent part of the morning and afternoon at my friend David’s place, and I put a good bit of progress into the build.

The motor mount, Labyrinth gas cooling system, and upper tube coupler are mostly or totally complete. The shock cords are tied on with bowline knots instead of the square knot specified in the instructions. The rail guides are glued on. The extra bits of the fins’ Fin-Lok tabs are snapped off, the fins are sanded, and they fit great.

Finishing work will likely start tomorrow, before further assembly. I’ll have to run out and get some filler for the spirals and perhaps some primer.

Pictures incoming later this evening, I’ve got a Dungeons and Dragons game coming up

 

[smstachwick]

The tiniest gap between the ends of the rail guides and the ends of the lug slots.

 

[smstachwick]

So, weird snag here. I bought some Plastic Wood, a brand new can, and the stuff seems pretty unwieldy. I can’t seem to get an unobtrusive layer to stick in the spiral grooves. I tried to get a very thin layer in the groove but didn’t get any to stick when I tried to smooth it down.

Do I just need more acetone solvent? Or am I going about the filler all wrong?

 

[John_461]

Are you using acetone to thin out the wood filler? Try using plain tap water to thin the filler out to a toothpaste-like consistency.

I've seen some builders on this site repurpose an old Elmer's school glue bottle to get the filler exactly where they want it and not where they don't.

 

[conneryc]

Good luck with your build and certification attempt. I also did my Level 1 back in 2000 with an Aerotech kit, but I went with the Strongarm. I used the baffle system, but as much as I modified the kit I don't think I followed the directions lol. The Astrobee D looks like a pretty good build.

 

[smstachwick]

Are you using acetone to thin out the wood filler? Try using plain tap water to thin the filler out to a toothpaste-like consistency.

I've seen some builders on this site repurpose an old Elmer's school glue bottle to get the filler exactly where they want it and not where they don't.

I have been using acetone and the consistency has gone from wet sand to peanut butter to chocolate shake to sputum, but it’s still volatile, difficult to apply and get to stick. I think you might be onto something with the idea of water and an applicator.

The nice thing is that I can scrape off the current application pretty easily.

 

[smstachwick]

Are you using acetone to thin out the wood filler? Try using plain tap water to thin the filler out to a toothpaste-like consistency.

I've seen some builders on this site repurpose an old Elmer's school glue bottle to get the filler exactly where they want it and not where they don't.

I tried your suggestion to use water this evening and got a better result. It was a bit like fingerpainting wood glue.



That’s more relief and less consistency than I wanted, and the spiral still pokes through in a few places, but it’s an improvement. Maybe some more water and acquiring a small glue bottle to repurpose will be the last piece of the puzzle.

Regardless of the result of my next spiral filling session, I intend to sand and inspect before scraping it off. I figure a little bit of progress and a lot of rework is better than no progress at all.

 

[smstachwick]

Here’s the result of using the glue bottle. I may actually need to do more sanding with this but at least it looks cleaner for now. I’m happy with that.

The downside is that because I habitually pick at things, it’s way too easy for me to pick at the ends of putty thread that are peeling up and make the whole thread completely unravel, so I’ll probably force myself to avert my eyes from it for the rest of the night and only go after it with sandpaper tomorrow.

 

[conneryc]

Just a suggestion....After putting down your bead like that, use a putty knife (piece of plastic, credit card, etc) and smooth out the bead. It will make is much easier to sand and get a better transition after it dries.

 

[smstachwick]

Just a suggestion....After putting down your bead like that, use a putty knife (piece of plastic, credit card, etc) and smooth out the bead. It will make is much easier to sand and get a better transition after it dries.

Oh finally! A good use for credit cards!

 

[loopy]

Yeah, I see the 29/40-120 case as a G motor. Anything less and I'm using the 24/40 or 24/60. Better performance, cheaper reloads, cheaper case if it gets lost.

I will say that if you plan on doing a lot of mid power flying, the 29/40-120 case is absolutely invaluable...Great selection of reloads that are reasonably priced, and a lot of bang for your buck.

 

[smstachwick]

Here is the final sanding result for the first filling of the spirals.



The lines from the glue bottle failed and detached completely. The sections where I did a real messy job of it fared better, although I’d still estimate that the percent covered is in single digits.

Tonight specifically, there were enough bare sections of the tube to the point where I was OK spot-sanding, but still with my technique of rotating the tube in the sandpaper, in the spiral motion, just rocking it back and forth. 320 grit, I don’t see much point in going really rough.

Still, I’m not discouraged by the result. I’ve got the recommended credit card smoothing technique to try, and I did manage to get some coverage.

I will likely attack it when I have further daylight hours available in the afternoon or evening, possibly as early as Thursday but more likely over the weekend. I’ll have to clean the dust off first

I’m also realizing that safe storage of this kit will be important, as the forward corner of one of the fins got very slightly bent while I was working on the sanding.

 

[smstachwick]

I did the tiniest bit of work this morning, squeezing putty along one turn of the spiral. As recommended, I broke out an old ID card that I’m not using and went to work. Scraping it turned out to be less than successful, but pressing/rolling the putty with the flat side of the card seemed to work fine.



I’ll probably return to sand that down tomorrow morning. If that goes well, it will be my technique throughout the build.

 

[thzero]

I use Platinum Patch external patch filler myself as it dries pretty quick. Or bondo glaze putty.

 

[smstachwick]

I did the tiniest bit of work this morning, squeezing putty along one turn of the spiral. As recommended, I broke out an old ID card that I’m not using and went to work. Scraping it turned out to be less than successful, but pressing/rolling the putty with the flat side of the card seemed to work fine.

View attachment 560758

I’ll probably return to sand that down tomorrow morning. If that goes well, it will be my technique throughout the build.

Well, that did NOT go well.

Most of it came off before ever getting down to the characteristic thin line I was looking for, most of what stayed on for that came off while I was sanding other segments.

I might head to The Home Depot and pick up some much finer grits. I used 320 today, I’m wondering if 400, 800, or even 1000 might be workable while still being gentle on the stuff I want to keep in there. I’ll probably do that in conjunction with thinning the plastic wood further.

Should those fail, I think my next options are to try a new filler material or put enough coats of primer on to fill them. Are AeroTech tubes typically suitable for this?

 

[mikec]

Should those fail, I think my next options are to try a new filler material or put enough coats of primer on to fill them. Are AeroTech tubes typically suitable for this?

AT tubes are no worse than any others and probably better than Estes.

https://www.nar.org/educational-resources/model-rocket-building-techniques/filling-seams-balsa/
You used the smelly plastic wood? Thinned Elmer's Fill and Finish (aka CWF) is what I've always used, it's likely a lot easier to sand. I always use 400 grit or even 800 for this. And I also don't worry much at all about filling spirals.

 

[smstachwick]

AT tubes are no worse than any others and probably better than Estes.

https://www.nar.org/educational-resources/model-rocket-building-techniques/filling-seams-balsa/
You used the smelly plastic wood? Thinned Elmer's Fill and Finish (aka CWF) is what I've always used, it's likely a lot easier to sand. I always use 400 grit or even 800 for this. And I also don't worry much at all about filling spirals.

How is the adhesion on that? Obviously the plastic wood hasn’t proved satisfactory in that regard.

 

[mikec]

How is the adhesion on that?

If you thin it a lot the adhesion is great, but then it goes all over and doesn't fill as well, so it's a tradeoff. And there are many other techniques, like masking the seams and shooting filler primer, some people like Bondo, some like Kilz, etc, etc.

I do a couple passes of CWF and accept the residual seam. But you can see the seams on all my rockets (except the fiberglass ones.)

 

[jmasterj]

I've used Bondo with success. Sometimes it's easier to primer first then fill spirals. It's always easiest to just leave them be, though!

 

[smstachwick]

I've used Bondo with success. Sometimes it's easier to primer first then fill spirals. It's always easiest to just leave them be, though!

I’m seeing that.

What I really need is something that will stick hard, take a shape, and be workable long enough for me to get it how I want it. Getting all three has been rough. Maybe something that’s more liquid initially like on the NAR site’s photos is the way to go.

If I didn’t already know that it shrinks during drying I’d say I want something like the Gorilla wood glue I use for other builds.

 

[mikec]

I'd advise thinned CWF, but be warned there are many types now and it's hard to find the stuff you want -- I last found it on amazon, Elmer's Products E848D12 Carpenter's Wood Filler, 1/2 Pint, 8 Fl Oz (interior, you don't want stainable, white, exterior, or anything but this.) And try 400 grit paper.

You want enough water to form a thick but runny paste.

 

[cwbullet]

Good luck, and thanks for sharing your thread. This kit is a good choice for a level 1. I skimmed the thread and did now see what glue you used to attach your ail guides. What glue?

 

[smstachwick]

Good luck, and thanks for sharing your thread. This kit is a good choice for a level 1. I skimmed the thread and did now see what glue you used to attach your ail guides. What glue?

Cyanoacrylate as instructed. The stuff I have comes with a brush on the cap so I can apply it very neatly.

 

[jmasterj]

Cyanoacrylate as instructed. The stuff I have comes with a brush on the cap so I can apply it very neatly.

The rail guides, motor retainers, and couplers were the only places I didn't use CA on my Aerotech kits. Those locations all got epoxy.

 

[conneryc]

Filling the spirals is similar to filling nail holes in a wall. You put filler into the hole in the wall and then you use your putty knife to scrape across it to remove all of the excess and leave a smooth surface. Filling the spirals works the same. Put a little filler along the spiral and then use your card or putty knife to scrape across the spiral, not along it. This will force the putty into the gap while removing the excess. Start at one end and do this all the way down to the opposite end. You'll be left with a filled spiral with only minimal sanding needed.

The other option is to just use high build sand-able primer like this (Rust-Oleum Flat Gray Spray Primer) to fill in the spirals plus cover the entire tube to get it ready for paint.