Estes Argent Build Thread! I HAVE NO IDEA WHAT I'M DOING

[ActingLikeAKid]

I figure that rather than dribbling my questions in here and there, I'll just start a build thread for this thing and if I hit a stumbling point, reply to the thread. After a half dozen or so LPR builds as a BAR, I thought "how hard could this be?"

So far ... actually, not bad. Just trying to make sure that I cross all my Ts and dot all my Is.

Here's where we are so far.

1. Inventory all parts. ....Well, yes. I did that. Since most people here are aware of what the contents of a rocket kit look like, I won't bore you with a picture of the parts laid out neatly on the table. Also I didn't feel like clearing it off.
2. Assemble Motor Mount. Done and done. I now realize that if you leave off the aft centering ring, you have a little room to put some epoxy in to do internal fillets. Oops. BUT I did take the time to triple check that the mount would fit in and the fins would fit in as glued. Tacked the rings on with a little Titebond, then when I was sure they were where I wanted, layered on a bead of epoxy. Probably overkill.
3. Filling the spirals! I tried out an idea I had here. I put some thinned CWF in a ziploc bag and cut off the corner. Then I squirted a thick bead of CWF along the spirals, then scraped off most of it with a putty knife. I took pictures...

(this is before I scraped. Scraping went REALLY well as soon as I learned to twist the tube and be careful not to stick my fingers in the CWF. )
I'll add some more of the sanded spirals. Someone (I thought?) suggested 200 grit to knock down the CWF but that seemed REALLY aggressive. I used it on the fin can and it took off the glassine too. Switched to 400 grit for the rest of the body tubes and that worked fine. Also I'm going to hit the fin can with some sanding sealer and go over it again with 400, just so that I have a smoother surface. The ziploc bag trick worked a treat!
4. Shock Cord attachment on the motor mount.
After WAY overthinking this, I settled on using a cable-clamp u-bolt to attach my kevlar string. I like K'tesh's 2-loop method, but I went back and forth for a while on how to attach it. Finally settled on the U-bolt. I'm going to glue in a layer of balsa just to give the bolt a little more to grab on to. I had some balsa from a previous project and cut a bit to fit. Up next: Drilling holes and bolting it in place. This should work well; I'll put the nuts on underneath and add a little epoxy on top. There should be very little force making the loop want to pull back toward the bottom of the rocket, and when the cord tugs, it will sink the nuts into the balsa. Not sure if this makes sense, it's late. Anyway. Pictures.

5. Fin Sanding! This took a while. Taped everything up (which ended up being kind of useless; I think it would have been more critical if I'd been power-sanding). I set a sheet of 100 grit on the table and just went to town. I liked the idea of sanding each side of all the fins, then swapping to the other side, that gave me even bevels. It was helpful for me to count strokes; if you're reasonably good at using even pressure, that will give you pretty good matching results (e.g. if it takes 60 strokes to get the angle you want on the first fin, do 50 on the second and then check to see where you are)


So that's what's done so far.

Up next:
6. Finish sand (200 -> 400) the fins and seal them
7. Install cord loop on motor mount, install kevlar on cord loop.
8. Install motor mount (I plan on using epoxy for this - I'm using it for pretty much everything on this build. It might be a little heavier, but I want something that can survive ....)
9. Install fins. Since I didn't leave off the aft CR, I can't do true internal fillets, so I'll just goop them up with epoxy & do the "double dip" method. Someone posted a homemade "fin guide" that was a sheet taped to a piece of styrofoam; going to copy that to check alignment.
10. Fillet fins.
11. Join body tubes and smooth joints
12. Prime; check finish; fill where I need to.
13. Paint.
14. Launch!!!

Since I'm going baffle-less on this, I think i'm going to pick up a nomex blanket for the chute. Cheap insurance and all that....
Trying to decide on a paint scheme for this. Someone on youtube did a super job with black and white, but I'm not sure I want to do that. I'm thinking a sort of titanium silver with black fins/transition/nosecone would look really slick, but I don't know if you can get a good-looking titanium rattle-can paint (without breaking the bank).

 

[Rex R]

years ago I built a yf12 (sr71 is a variation) and the instructions called for something like 1 drop of orange paint to 25 drops of silver paint to get natural Ti look...was a real pita converting that to a useful measurement/qty for the airbrush(big model 1/48 scale). I would just use an orange base and apply silver over it. check the fit of your fins in the fin slots and don't sand the tabs. Estes seems to think that nobody sands plywood fins before gluing them in place. see what apogee says for nomex sizing and order the next size larger(iirc a 9 x 9" should do the trick) buy a spare chute from Top Flight recovery(the stock chute is nice, but is not rip stop nylon).
Rex

 

[ThirstyBarbarian]

Looks good so far. For the shock cord attachment, I don't think you need the balsa piece added to the plywood. It probably won't hurt, but it's also probably not necessary. Also, I know you are just positioning it for the camera and have not installed it yet, but it looks like your picture shows the balsa piece and the u-bolt being positioned over the aft centering ring --- be sure to install it on the forward CR! (I'm sure you didn't need this reminder, but we've all had a moment that ended with "Doh!")

 

[ActingLikeAKid]

Looks good so far. For the shock cord attachment, I don't think you need the balsa piece added to the plywood. It probably won't hurt, but it's also probably not necessary. Also, I know you are just positioning it for the camera and have not installed it yet, but it looks like your picture shows the balsa piece and the u-bolt being positioned over the aft centering ring --- be sure to install it on the forward CR! (I'm sure you didn't need this reminder, but we've all had a moment that ended with "Doh!")

Heh, thanks! I was looking at the pictures and was thinking "wait, did I...is that backwards?" but it was late and I was tired and didn't feel like re-taking them. Good call, though. On a related note, I wasn't sure if I was going to sand the leading and trailing edges (as someone else did) or just the leading edges. After getting some really nice rounding on all the fins, I realized I'd rounded the trailing edges. So ...YES! I'm rounding both! These are the perils of working on rockets after everyone else has gone to bed ....
As for the balsa piece, my biggest concern was that the two holes would weaken the CR. But the more I think about it, the more I realize that if something is pulling on the cord hard enough to rip that through plywood, I probably have other issues. As you say, though, it shouldn't hurt. And it weighs almost nothing.....

 

[ActingLikeAKid]

years ago I built a yf12 (sr71 is a variation) and the instructions called for something like 1 drop of orange paint to 25 drops of silver paint to get natural Ti look...was a real pita converting that to a useful measurement/qty for the airbrush(big model 1/48 scale). I would just use an orange base and apply silver over it. check the fit of your fins in the fin slots and don't sand the tabs. Estes seems to think that nobody sands plywood fins before gluing them in place. see what apogee says for nomex sizing and order the next size larger(iirc a 9 x 9" should do the trick) buy a spare chute from Top Flight recovery(the stock chute is nice, but is not rip stop nylon).
Rex

Huh. Orange and silver; who'da thunk it. Thanks! And I'm going to have a very close look at the stock chute; I've seen more than a couple reports of failure on it....

 

[Buckeye]

I don't understand your thread title. Seems like you know exactly what you are doing, and the build is proceeding nicely. Shameless attention grabber? :eyeroll:

Consider a baffle. Wish I did.

For my Argent, I tried something new for me. Aerogloss Sanding Sealer. Old school modeling dope from the hobby shop. Much better than the Home Depot sealers and fillers I used in the past.

 

[ActingLikeAKid]

I don't understand your thread title. Seems like you know exactly what you are doing, and the build is proceeding nicely. Shameless attention grabber? :eyeroll:

OK, maybe a little attention-grabby . I've been on here for a couple of months, but still have this "I'm probably about to miss some super important step and kick myself later" feeling -....which is actually kinda accurate, because I'm kicking myself about putting on the aft CR. Ah well. Next time, someone will learn from my mistakes.

Consider a baffle. Wish I did.

OK, I considered it but decided it wasn't worth the effort. Why do you wish you did?

For my Argent, I tried something new for me. Aerogloss Sanding Sealer. Old school modeling dope from the hobby shop. Much better than the Home Depot sealers and fillers I used in the past.

I've heard good things too but haven't been able to find it locally; hate the long wait and shipping charges online. [There used to be a Hobbytown about 8 minutes from my house. Now it's relocated to about 30 minutes away] I used flat acrylic sealer from Walmart in my last build and it came out pretty well....

 

[Buckeye]

OK, maybe a little attention-grabby . I've been on here for a couple of months, but still have this "I'm probably about to miss some super important step and kick myself later" feeling -....which is actually kinda accurate, because I'm kicking myself about putting on the aft CR. Ah well. Next time, someone will learn from my mistakes.



OK, I considered it but decided it wasn't worth the effort. Why do you wish you did?



I've heard good things too but haven't been able to find it locally; hate the long wait and shipping charges online. [There used to be a Hobbytown about 8 minutes from my house. Now it's relocated to about 30 minutes away] I used flat acrylic sealer from Walmart in my last build and it came out pretty well....

The Argent is long and simple, with plenty of room to pressurize with a baffle. Reminds me of the Aerotech kits (Baraccuda) that work great with their "cooling mesh." I like baffles for ease of use, fast packing, and clean recovery gear. Now I have to scrounge up a Nomex blanket or use messy dog barf.

Yeah, I hear you on the demise of the local hobby shop. An RC plane shop or model train shop will probably have Aerogloss in their building supplies aisle. Not sure about Michael's, Jo-Ann, or Hobby Lobby (stores that pass for "hobby shop" these days )

 

[ActingLikeAKid]

I hear you ... I decided that since this was my first "big build", I'd minimize the things I hadn't done before, if that makes sense. And yeah, I have vague 35-year-old memories of going to the local hobby shop with racks and racks of Testors paint, shelves full of weird and wonderful stuff, and ... yes. Aerogloss. Closest we have now is Hobby Lobby, and I've looked but they don't seem to carry it. If this @$#@#! rain ever lets up, there's going to be a launch this weekend, there'll be a vendor there who might have it.

Cheers!

 

[ActingLikeAKid]

Update: Got the holes drilled in the top CR. Got the tiny u-bolt in after some sanding (I drilled the holes a little small because I didn't want the bolt to be loose). And.... the second set of nuts that I got for the u-bolt were the wrong thread pitch (You'll forgive me - you try choosing the right little packet of machine nuts at Lowe's when they're not on the right pegs and you're also trying to make sure the two four-year-olds with you aren't getting into anything dangerous....)

Back to Lowe's before I can get this done. Ugh.

Good news: The U-bolt looks great and I like how it fits. With a little Loctite and epoxy, it will be there forever.

 

[ActingLikeAKid]

OK, motor mount is done, kevlar is cut and I'm ready for the next step. The cable-clamp u-bolt came out great; I couldn't find my loctite, so I put a little epoxy on the nuts to hold them in place. I also marked it up, because the last thing I want to do is get it in and realize - with not a little horror - that the thing is in backwards. So with that done ... I'm leaning toward epoxy for gluing the MMT in. I know Titebond should work just as well, but with that hunk of steel in it, I've kind of abandoned the "keeping it light" direction....

 

[K'Tesh]

OK, motor mount is done, kevlar is cut and I'm ready for the next step. The cable-clamp u-bolt came out great; I couldn't find my loctite, so I put a little epoxy on the nuts to hold them in place. I also marked it up, because the last thing I want to do is get it in and realize - with not a little horror - that the thing is in backwards. So with that done ... I'm leaning toward epoxy for gluing the MMT in. I know Titebond should work just as well, but with that hunk of steel in it, I've kind of abandoned the "keeping it light" direction....
View attachment 278814View attachment 278815View attachment 278816View attachment 278817

Ok, you'll likely have some trouble threading the shock cord through that if it's installed... I'd suggest going ahead and installing the shock cord (then pulling it inside the motor tube to keep it out of the way and clean). You can use a fishing swivel to keep the two loops together.

Normally people angle their eye bolt or U bolt so that the eye is parallel to a radius, which makes it easier to fish their shock cords in place.

 

[cbrarick]

Another thing to think of is that that big, thick u bolt will take a big thick quicklink. That would never work with that rocket...don't worry, I did the same thing with my first MPR build.

Now I do something completely different. I put on the CRs in a temporary manner (tape), slide it into the body tube and mark where the fins will hit the mmt by running a sharpie down the fin slot (or just the sharpie point if the whole pen won't fit-they slide right out.) I also mark a ledger line across my aft cr to the mmt.

then I take it all apart and file 2 notches into my top cr for my kevlar to fit thru. Use enough kevlar to get a loop all the way from the mmt to the end of the booster. I put the ends thru and leave them long enough for it to extend 3/4 of the way to the aft cr
Then i make tape dams on the mmt so that I can contain the epoxy off my fin marks. The tails get glued down, after dry i stuff the kevlar into the mmt held in place with crumpled paper.
after you put in the mmt/cr in and do the fins at the same time

after everything drys use a stick to push the newspaper and kevlar forward - problem done.

 

[ActingLikeAKid]

Thanks all! So I don't think I need a quicklink - I ran a length of Kevlar twine in a U shape with a loop on each end, then tied my shock cord to the two loops. If there were some sort of catastrophic failure, as long as the Kevlar survived, I should be able to restring it by just tying a new bit to the end. Or something creative.... anyway, it's all in and tied up and looking good (pics to come!)

Next important question, and since I seem to be doing the complicated bits OK and falling down on the "well, that's simple, I should just do it" parts..... Is there anything important to think about/do when I join the tubes? My plan is (for both nose to BT, BT to transition piece, and big BT to fin can) to just smear epoxy over the bits that need to go together, smush them together, wipe off the excess with rubbing alcohol, wait til it's all dry, then cover the joint with CWF and sand til smooth.

Am I missing anything?

 

[rharshberger]

Thanks all! So I don't think I need a quicklink - I ran a length of Kevlar twine in a U shape with a loop on each end, then tied my shock cord to the two loops. If there were some sort of catastrophic failure, as long as the Kevlar survived, I should be able to restring it by just tying a new bit to the end. Or something creative.... anyway, it's all in and tied up and looking good (pics to come!)

Next important question, and since I seem to be doing the complicated bits OK and falling down on the "well, that's simple, I should just do it" parts..... Is there anything important to think about/do when I join the tubes? My plan is (for both nose to BT, BT to transition piece, and big BT to fin can) to just smear epoxy over the bits that need to go together, smush them together, wipe off the excess with rubbing alcohol, wait til it's all dry, then cover the joint with CWF and sand til smooth.

Am I missing anything?

Good ole' Elmers Glue-All will be just as strong as the epoxy and won't take as long to cure. Most people don't realize that on cardboard rockets the majority of adhesives are actually stronger than the cardboard, so failures are the cardboard not the glue. I don't recommend Yellow wood glues for couplers though, they tend to grab very quickly.

 

[ActingLikeAKid]

Good ole' Elmers Glue-All will be just as strong as the epoxy and won't take as long to cure. Most people don't realize that on cardboard rockets the majority of adhesives are actually stronger than the cardboard, so failures are the cardboard not the glue. I don't recommend Yellow wood glues for couplers though, they tend to grab very quickly.

....huh. Okay....Part of me is dubious, but then I started thinking about the (relatively) massive surface areas involved and how there isn't/shouldn't be stress that's trying to pull those joints apart -- there shouldn't be a force tugging on the end of my rocket (ahem); there ought to only be compression forces - everything gets pushed together on the way up, then each half gets pushed together by the ejection charge.....right?

I've seen people putting CA on their tube ends; would that be a necessary step here, or is that just for a tube end that will be exposed to the elements?

Thanks...!

 

[rharshberger]

....huh. Okay....Part of me is dubious, but then I started thinking about the (relatively) massive surface areas involved and how there isn't/shouldn't be stress that's trying to pull those joints apart -- there shouldn't be a force tugging on the end of my rocket (ahem); there ought to only be compression forces - everything gets pushed together on the way up, then each half gets pushed together by the ejection charge.....right?

I've seen people putting CA on their tube ends; would that be a necessary step here, or is that just for a tube end that will be exposed to the elements?

Thanks...!

Try gluing two pieces of cardboard together, wait 24hrs then pull apart, the glue will not be the failure point (white glue, yellow glue and epoxy) . As for the CA, many of us do it to harden the airframe area where the nosecone/separation point is, it makes it just a bit stiffer, and less susceptible to moisture shrinking and swelling.

 

[K'Tesh]

....huh. Okay....Part of me is dubious, but then I started thinking about the (relatively) massive surface areas involved and how there isn't/shouldn't be stress that's trying to pull those joints apart -- there shouldn't be a force tugging on the end of my rocket (ahem); there ought to only be compression forces - everything gets pushed together on the way up, then each half gets pushed together by the ejection charge.....right?

I've seen people putting CA on their tube ends; would that be a necessary step here, or is that just for a tube end that will be exposed to the elements?

Thanks...!

One thing to remember is that with TTW fins, they lock the motor mount in place, and since they have a bond along the edge of the fin tabs, they help transmit the forces of the motor through the rest of the airframe.

CA on the tube ends is to strengthen the body tube. It reduces the amount of damage that the ends can can happen not only in landing, but in routine day to day handling. It's completely optional, but I'd recommend it.

FWIW, I also use a small length of coupler to reinforce the bottom edge of my larger rockets that don't sit of their fins (unless it would interfere with staging), further strengthening them against hard landings or rough handling (read: stupid accidents).

 

[Rex R]

for a neater tube joint, only apply the glue(what ever you end up using) on the inside of the tubes not on the couplers. that way the excess glue gets turned into a filet inside the airframe.
Rex

 

[ActingLikeAKid]

FWIW, I also use a small length of coupler to reinforce the bottom edge of my larger rockets that don't sit of their fins (unless it would interfere with staging), further strengthening them against hard landings or rough handling (read: stupid accidents).

I'm a master of stupid accidents. Is it worth cutting off a bit of the coupler for this, or should I order one from Estes at my leisure and just slip a bit in?

 

[Rex R]

could you get away with slicing up to 1/2" off your coupler, since you're going to be gluing the tubes together, yes. if you think that you might want to do another rocket w/ Estes 2.5" tubing, then get a couple of couplers when or if you order some tubing.
Rex

 

[ActingLikeAKid]

Progress and pictures! After a fun launch morning with the kids (and my first ballistic re-entry, that was exciting and made me wonder if we should all be wearing hard hats) I have some more to share....

First, as recommended, I used plain old white glue for the coupler. This is what WAY TOO MUCH GLUE looks like...


...no idea what I was thinking. But when I put the coupler in and saw it all running down inside, I had the presence of mind to wrap a paper towel around a ruler and was able to mop up most of the mess.
Per K'Tesh's suggestion, I trimmed a half inch or so of coupler and used it to strengthen the aft end. And since there wasn't really a fillet of glue back there, I just gobbed a whole bunch of epoxy around the inside of the BT, put in the coupler ring, then smoothed everything down.



I like how it came out.

Another question, though: There's a loop on the nose cone and the top of the coupler. While I'm not worrying THAT much about weight, it seems silly to keep them on if they're not attached to anything. Is it worth the effort to trim them off, since the nose cone is going to be attached to the top half of the body?




As always, thank you for the input. Fins are sanded and the sealer is drying; going to glue those in fairly soon. Is there any reason NOT to use epoxy? That's the direction I'm leaning.....

 

[rharshberger]

Progress and pictures! After a fun launch morning with the kids (and my first ballistic re-entry, that was exciting and made me wonder if we should all be wearing hard hats) I have some more to share....

First, as recommended, I used plain old white glue for the coupler. This is what WAY TOO MUCH GLUE looks like...

View attachment 278927
...no idea what I was thinking. But when I put the coupler in and saw it all running down inside, I had the presence of mind to wrap a paper towel around a ruler and was able to mop up most of the mess.
Per K'Tesh's suggestion, I trimmed a half inch or so of coupler and used it to strengthen the aft end. And since there wasn't really a fillet of glue back there, I just gobbed a whole bunch of epoxy around the inside of the BT, put in the coupler ring, then smoothed everything down.

View attachment 278928View attachment 278929

I like how it came out.

Another question, though: There's a loop on the nose cone and the top of the coupler. While I'm not worrying THAT much about weight, it seems silly to keep them on if they're not attached to anything. Is it worth the effort to trim them off, since the nose cone is going to be attached to the top half of the body?


View attachment 278926

As always, thank you for the input. Fins are sanded and the sealer is drying; going to glue those in fairly soon. Is there any reason NOT to use epoxy? That's the direction I'm leaning.....

Go ahead and trim the loop or even part of the shoulder off, then you can use 2-56 nylon screws as pins to hold the NC on and it still be removable, just harden the holes in the airframe with CA.

 

[ActingLikeAKid]

Go ahead and trim the loop or even part of the shoulder off, then you can use 2-56 nylon screws as pins to hold the NC on and it still be removable, just harden the holes in the airframe with CA.

1. How many?
2. Why would I want a removable NC? (This is single-deploy, no altimeter or anything)

 

[rharshberger]

1. How many?
2. Why would I want a removable NC? (This is single-deploy, no altimeter or anything)

You may decide to put an altimeter or some other payload in it (just to see how high it goes or whatever), if the NC is friction fitted it can come open at altitude, pinned it will stay close and be easily removable. I would use two pins. I just like to create options for myself.

 

[ActingLikeAKid]

Huh. I have a smaller rocket that can do a payload section; I just keep the NC on with electrical tape (so far, the payloads have been just little Lego guys because the kids think that's great). Never bad to keep options open, just trying to decide if I want to wait on nylon bolts....Would you just glue nuts into the inside of the NC?

 

[rharshberger]

Huh. I have a smaller rocket that can do a payload section; I just keep the NC on with electrical tape (so far, the payloads have been just little Lego guys because the kids think that's great). Never bad to keep options open, just trying to decide if I want to wait on nylon bolts....Would you just glue nuts into the inside of the NC?

I would not bother with nuts, drill the hole slightly undersized through both the airframe and the nose cone at the same time, then thread a metal 2-56 screw in and it will tap the NC plastic for you. You could even use short metal screws, of course just a wrap of tape around the NC will hold it on just as well, but not as pretty. Usually you can get the 2-56 screws at about any hobby shop (metal ones anyways) that sells RC aircraft, also many local fastener sellers can get them or have them in stock. I just bought some at my local Tacoma Screw, and picked up a 1000 2-56 nylon screws for $8 on clearance from Fastenal for which I only had to wait a couple of days.

 

[ActingLikeAKid]

Hmmmm....Thanks. Considering now

 

[ActingLikeAKid]

I think I'm going to glue in the fins tonight. Anything special to be careful with?

 

[K'Tesh]

I'd say keep the loop on the NC. Let's say for sake of argument that the rocket gets lost to a tree for a couple of months. You get it back, but it's not worth saving as an Argent, and you've already bought/built another. You could still use this nosecone to create an upscale of the Estes Yellowjacket, or some other classic design. It won't be a true upscale (where all the shapes are 100%), but it'll still look sweet.