Estes Corvette Class Build Questions

[Wrightme43]

Hello, this is my first intermediate class rocket build. I am a accomplished woodworker, but have been out of rockets since I was very young. I have built alpha's, vikings, sxt, generic e2x, a amazon, and a baby bertha.
I recently learned about apogee have been reading and reading, found this forum, and bluesrocks.

So long story short, I of course could not resist the aspire, and read about how to build to attempt to break the sound barrier. Then of course I read about mid power and high power builds on here and other places.

For this corvette class, I grain filled the balsa with diluted timbermate real wood filler, sanded to smooth, cut out squared edges and glued each three piece compound fin together with titebond 3 and a drop of thick super glue. They are between wax paper under very heavy books curing now.

I want to take them to work in the morning and photocopy them, cut out the paper copies and glue them over the balsa like a veneer or lamination to provide strength and smoothness.

Is this a terrible idea? Is there anything I should know or be prepared for? Any advice?

I planned to do the lamination, and I have a vacuum veneering press if needed, but I dont think it will be needed. I planned on slighty oversized paper wrap after thin super glue on the edge and end grain.

I also filled the spirals on the tube with thinned timbermate.

Motor mount is built.

I ordered a nylon parachute from apogee as well.

I am trying to use this rocket to learn building techniques for the aspire.

Thank you for any advice you can offer.

Steve

 

[Wrightme43]

 

[Wrightme43]

The reason for the lamination idea is I do not like butt joints especially with the wood grain going multiple directions. It seems like it would be a very weak assembly prone to breakage and loss.

 

[Wrightme43]

 

[cls]

The reason for the lamination idea is I do not like butt joints especially with the wood grain going multiple directions. It seems like it would be a very weak assembly prone to breakage and loss.

those joints are surprisingly strong enough. remember, properly done glue (Titiebond) is stronger than the balsa and cardboard material.

but, paper laminate works well, too, lots of folks do that. so if you want, go ahead!

btw nice job on the airframe tube spirals.

 

[Bill S]

I have one of the Corvettes. Good flier, have over 35 flights on it.

One thing I would strongly suggest concerns the fin tip "lasers". Do NOT mount them as the instructions say, with part of it extending out the back of the fin. They will break off eventually. Mount them so the rear of the dowel is not sticking out the back.

The decals were very fragile on mine, so I'd suggest giving them a coat of Krylon UV-resistant acrylic clear coat before cutting out.

I don't think its unreasonable to paper the fins, though its up to you.

 

[Wrightme43]

Weeelllllll, I already glued them in according to the instructions. Lol. I was thinking they looked like easily broken very delicate details.

Maybe I can fab up a lightweight pod like a F-104 starfighter wingtip pod?

I have a wood lathe, and make pens.

 

[Wrightme43]

Sounds good on the clear coat. Thats a good idea.

 

[Wrightme43]

Or I could just trim the back end off and round over that end of the pod with filler and sanding so it only sticks out forward.

 

[Bill S]

Or I could just trim the back end off and round over that end of the pod with filler and sanding so it only sticks out forward.

I think that would be a good idea.

 

[neil_w]

The reason for the lamination idea is I do not like butt joints especially with the wood grain going multiple directions. It seems like it would be a very weak assembly prone to breakage and loss.

Papering is fine and adds considerable strength. However, the strength issue you're concerned about in this case is not actually a problem:

1. The different grain directions are designed specifically to maximize strength. If the fins were a single piece with the grain going parallel to the leading edge of the main fin, the front and rear extensions would be very fragile and likely to break before you could ever get them on the rocket.
2. The complete root edge will be securely (I hope ) glued to the body tube. In essence, this is like three separate fins each glued to the body, that also happen to be glued to each other. The butt joints between the wood pieces will not see much of a load at all.

Now, if the pieces were not being glued to the root, then it's more of a legit concern.

That said, I paper *all* my fins (using label paper) because I like the combination of added strength and easy finish of the raw balsa.

A few other comments:
1) If you choose to paper the fins, be sure to sand them flat first. The glue bumps in the butt joints will show through the paper.
2) In the future you might try squeegeeing off more of the excess spiral filler when applying; you left yourself a lot of sanding to do there.

Good luck and keep posting pics.

 

[Back_at_it]

Looks like you are well on your way to a very nice build. The Corvette class is a fun rocket to build and fly and is the perfect size low power rocket in my opinion. For papering the fins, I was never a fan as I absolutely hate the wrinkles that you get from using wood glue and normal paper. Yes there are tons of people on here that do it just fine and I have been successful a few times myself but it's still a PITA!!!

Recently I tried using card stock and now I love it and have used it on several builds recently. I'd highly recommend that you go with card stock over paper as it is thicker and won't wrinkle up. I'd also recommend using some slow cure epoxy to attach the card stock to the fins. The epoxy will makes the fins stronger all by itself but more importantly you won't get wrinkles and you don't need to worry about warping.

 

[neil_w]

Looks like you are well on your way to a very nice build. The Corvette class is a fun rocket to build and fly and is the perfect size low power rocket in my opinion. For papering the fins, I was never a fan as I absolutely hate the wrinkles that you get from using wood glue and normal paper.

No wrinkles or warping or drying time when using label paper!

Also not as much strength, but maximum strength is not usually the goal, at least for me.

 

[Wrightme43]

Thank you all, and I really appreciate the advice of experienced people.

What is label paper?

Card stock is easy, I have the photo copies so I can go either way (trace onto card stock or use my paper and epoxy)

Thank you all again!

 

[Back_at_it]

No wrinkles or warping or drying time when using label paper!

Also not as much strength, but maximum strength is not usually the goal, at least for me.

I haven't had the best of luck with label paper. After a few flights it begins to peel off and leaving the rocket it the heat for any length of time has caused mine to get gooey and peel. Only did three rockets with them and I have had to remove it from two of them. The third still looks good but it only has two flights.

 

[neil_w]

I haven't had the best of luck with label paper. After a few flights it begins to peel off and leaving the rocket it the heat for any length of time has caused mine to get gooey and peel. Only did three rockets with them and I have had to remove it from two of them. The third still looks good but it only has two flights.

I have yet to have this happen with a single label-papered fin. I do not typically fly in high heat though (nothing above low 90's I would say).

Two keys that have worked for me:
1) Sand fin surface smooth (I use 400 grit) and then remove all dust before applying paper. Brush off loose dust with a paintbrush, and then use blue tape across entire fin surface to pull off any that remains.
2) Seal all edges well with your choice of glue (I used to use TBII but have since switched to thin CA; both work fine). The edges should *never* peel up.

 

[MALBAR 70]

If you are using label paper, make sure to use a tack cloth to clean any sanding dust off the surface of the fins. I also seal the edges with thin CA. More often than not I will coat the whole surface of the label papered fin after it's been attached to the rocket.
I haven't had an issue with peeling or lifting since I started wiping the dust off and sealing it with CA.

 

[kuririn]

Question: Why bother with sealing and filling the wood if it's going to be papered over?

 

[Wrightme43]

I filled and sanded before I assembled the fins. I did not decide that it would be a good idea to paper them till I looked at how they were glued together. Then I decided to paper them. Now I am considering using card stock. We do use high quality paper at work though and it seems ok.

I will test the idea on the scrap balsawood before going to the fins.

On the extra filler, it is Timbermate from Australia. My understanding is it is made by cutting up chunks of the species of wood required for the color, freeze drying, pulverizing into a powder, then mixed with a water based binder.
It sands like butter. Removable with plain water, but stays forever under sealer.

It is my go to for grain filling in wood working projects. No plastics, nothing crazy just easy to use.

It also can be gathered up as dust, poured back into the tub, and just used again. This was maple, but they make tons of wood types.

 

[kuririn]

I like Timber Mate also.
Use it straight from the container like putty for gap filling.
Thin with water for filling spirals and wood.
No solvents, easy water cleanup.
Funky smell out of the bottle though.
Haven't done a cost analysis of Timber Mate vs. CWF yet.

 

[Wrightme43]

Yes sir, the cost doesn't matter to me since it is the best in class for woodworking. This was bought in 2019, hard as a rock, soaked in water a bit, and used. It supposedly lasts forever. I just really like it.

 

[BABAR]

Looks like you are well on your way to a very nice build. The Corvette class is a fun rocket to build and fly and is the perfect size low power rocket in my opinion. For papering the fins, I was never a fan as I absolutely hate the wrinkles that you get from using wood glue and normal paper. Yes there are tons of people on here that do it just fine and I have been successful a few times myself but it's still a PITA!!!

Recently I tried using card stock and now I love it and have used it on several builds recently. I'd highly recommend that you go with card stock over paper as it is thicker and won't wrinkle up. I'd also recommend using some slow cure epoxy to attach the card stock to the fins. The epoxy will makes the fins stronger all by itself but more importantly you won't get wrinkles and you don't need to worry about warping.

Remember gloves and good ventilation when using epoxy!

Lots of opinions. I believe most posters on the forum suggest that for LOW power, epoxy is overkill (weighs more and costs more than wood or white glue.). There are at least two exceptions.

Gluing plastic or other non-paper and non-wood products, whatever you are gluing them to.

Motor mounts.
If you dry fit your motor mount a few times so you are really “ready” to smoothly and promptly insert it to the right depth in one easy motion, you can use yellow glue or white glue. Yellow glue however is infamous for “grabbing” the mount if you are slow or realize you pushed it in too far. White glue gives more working time and similar bond strength to yellow, it does take longer to dry but for motor mounts this usually isn’t an issue.

Lots of posters like epoxy for this because of the longer working time, so if you expect to need to “fiddle” with it, it is a good choice.

If weight, cost, smell, and gloves are not an issue, epoxy can be used for just about anything.

 

[Wrightme43]

Yes sir, thank you!
I always appreciate good advice.

 

[Wrightme43]

Well, I went with two part expoxy 30 minute work time epoxy that I use for wood work since I have it on hand. Mixed by weight on a powder reloading scale, and painted on the fins. Inside the roarocket vacuum press now.
It is what I learned veneering on, and isn't used much bow that I have a big poly bag and electric vacuum pump.

I will have to make a set of fins from 1/4 ply wood and veneer them with maple burl or something cool. I have been working in my mind about how to veneer a tube and make what looks like a solid wood work rocket.

If you are considering a lowcost vacuum press, I have used this one about 20 times and is good as new.

Roarocket is a skateboard company.

 

[techrat]

Papering the fins is a fairly common practice. It will (mostly) elinimate the wood grain and any seams (hopefully) where you butt-glued the different pieces together to make the final form of the fin. I added cardstock "fillets" to my citation patriot, but that's because I modded it for 24mm motors, so it flies on much punchier composites than it was originally engineered for.

 

[Wrightme43]

I have one of the Corvettes. Good flier, have over 35 flights on it.

One thing I would strongly suggest concerns the fin tip "lasers". Do NOT mount them as the instructions say, with part of it extending out the back of the fin. They will break off eventually. Mount them so the rear of the dowel is not sticking out the back.

The decals were very fragile on mine, so I'd suggest giving them a coat of Krylon UV-resistant acrylic clear coat before cutting out.

I don't think its unreasonable to paper the fins, though its up to you.

Bill I have 2 of the 12" apogee nylon chutes and 2 of the 15".

The corvette comes with a 12" plastic, but is only going up 600-650 on a c6-5. Do you think a 15" chute would help protect it, or should I just use the 12"?

 

[Sandy H.]

Well, I went with two part expoxy 30 minute work time epoxy that I use for wood work since I have it on hand. Mixed by weight on a powder reloading scale, and painted on the fins. Inside the roarocket vacuum press now.
It is what I learned veneering on, and isn't used much bow that I have a big poly bag and electric vacuum pump.

I will have to make a set of fins from 1/4 ply wood and veneer them with maple burl or something cool. I have been working in my mind about how to veneer a tube and make what looks like a solid wood work rocket.

If you are considering a lowcost vacuum press, I have used this one about 20 times and is good as new.

Roarocket is a skateboard company. View attachment 595721

Cool info on the Roarockit system. I'll look into it for future work, but I also have a regular vacuum bagging setup, so likely would just use that. Still could be good to recommend to a friend in the future or similar.

You obviously know woodworking and veneering, so my suggestion for an 'all wood' appearing rocket would be to basically soften the veneer a ton, probably use backed veneer just to minimize the chance of catastrophic failure when wrapping. I'd assume you'd want to overlap 1/8-1/4" and glue and tape the joint, then put it in a vacuum bag and pull a bit of vacuum, hoping it was enough, but not a full vacuum, as the tube would crush (unless using fiberglass tube, then you'd be perfect at full vacuum like your regular projects). After it sets, plane/sand the excess at the joint and hope that the split line is small enough to be tolerable. If not, use the glue/shavings method to hide it as much as practical and make sure to add your launch lugs/rail buttons right on the line, so when its on the pad, nobody would see the sin either way!!!

As you are a woodworker, be sure to check out the post a picture threads and the 'what I did instead of rocketry today' threads. People love pictures and we all have multiple hobbies. . .

Look forward to seeing the results!

Sandy.

 

[Wrightme43]

Hey Sandy, have you ever heard of super soft veneer softener? It will let you roll burl veneer around a pencil.

I was thinking a small rocket, turning a round form that fits perfectly inside a tube set up for thru the wall fin attachment. But there are so many ways to mess up and glue the form and rocket together.


I have some left over curly maple with 3m pressure sensitive adhesive but it requires heavy rubbing pressure to bond, and it is heavy.


I will figure it out, or someone will.

 

[Sandy H.]

Hey Sandy, have you ever heard of super soft veneer softener? It will let you roll burl veneer around a pencil.

I was thinking a small rocket, turning a round form that fits perfectly inside a tube set up for thru the wall fin attachment. But there are so many ways to mess up and glue the form and rocket together.


I have some left over curly maple with 3m pressure sensitive adhesive but it requires heavy rubbing pressure to bond, and it is heavy.


I will figure it out, or someone will.

I don't remember the specific brand of softener I've used, but it was crazy how flexible the veneer became. I mostly worked with raw veneer instead of paper backed, and it was amazing. I'm not that good at it, so haven't done anything to be proud of in a long time.

You might want to check out some of Lakeroadsters posts, as he does a lot of turning in his projects as well. You might get some inspiration.

I was also a pen turner. Just say *was* because its been a few years since I've done any due to work COVID etc. Ironically, I mentioned pen turning to my wife earlier today. The specific conversation was related to feather casting, as I seemed to recall there were federal rules about using feathers and you could get in trouble for making a feather pen blanks and/or selling pens made from them. I don't remember the details, but I thought was a rule of some sort. The reason she and I were discussing is that she decided she wanted chickens and so we compromised and now she has chickens. One of them has really beautiful feathers and they molt, so I have access to really beautiful chicken feathers and wondered if I should break out the casting rig again and make some chicken feather blanks. I'm way too busy until October to even think of adding another project, but I did ask her to start collecting smaller and interesting feathers when she cleans the coop, just in case.

OK, pretty sure I TRF'd this thread enough (i.e. 100% of threads that aren't actively managed go off course), so I'm glad to get back to the topic of strengthening the fins. Feel free to PM if you want to talk more or even start another thread about pen turning or similar. When I did some experiments with my veneer press and strengthening balsa using really thin fiberglass, I made press platens with marble tile and rubber floor mats. I used mylar on top for release agent and pretty much put the sandwich like this:

tile
foam pad
mylar
fiberglass
balsa
fiberglass
mylar
foam pad
tile


I put the whole sandwich in the vacuum bag (after epoxy, obviously) and pulled it down. It made a very strong laminate, but when I went to cut it (i.e. I did sheets, not cut fins) it would tear the balsa and make an ugly, but still strong fin. I would not recommend that, but there's something in the idea that isn't a complete failure. I think the marble tile and foam are good, but either thinner mylar and cut to shape fins might be pretty close. I prefer the platen method instead of just direct bagging to keep the epoxy smooth. Not sure if there are better ways, but that's what I've tried.

By the way, what kind of glue are you going to use. . . just kidding. . . another TRF running joke.

Sandy.

 

[Sandy H.]

[deleted: double post somehow. It looked like 5 posts at first. . . yikes!]