Fin skinning with 1/64" plywood

[James Duffy]

Here's a quick video showing how to skin fin cores with 1/64"-thick plywood that I just whipped up. I hope some of you may find it helpful, or at the very least a good waste of ten minutes.



James

 

[DigBaddy]

Great tip on which books to NOT use!!!!

 

[aviserated]

Very interesting. What products are you going to use to seal, prime and paint?

 

[James Duffy]

Very interesting. What products are you going to use to seal, prime and paint?

You're going to make me do another video, aren't you? <G>

I use diluted Elmer's Carpenter's Wood Filler on wood parts. After sanding that I like to prime with Rustoleum grey Automotive Primer, then sand again. Paints are more often Tamiya spray lacquers for large areas, with details airbrushed with Tamiya acrylics.

James

 

[neil_w]

I use diluted Elmer's Carpenter's Wood Filler on wood parts. After sanding that I like to prime with Rustoleum grey Automotive Primer, then sand again. Paints are more often Tamiya spray lacquers for large areas, with details airbrushed with Tamiya acrylics.

John Brohm recommended the Automotive primer to me in the past... I'm trying to understand how it's different from the regular primer. It's not high-build, is it?

 

[teepot]

I just used automotive primer for the fist time. It fills spirals. The 2x primer does not. I was quite surprised. It will need to be sanded though where the 2x doesn't.

 

[afadeev]

Here's a quick video showing how to skin fin cores with 1/64"-thick plywood that I just whipped up. I hope some of you may find it helpful, or at the very least a good waste of ten minutes.

Spreading TBII with a brush? Fancy!

(finger works for me ;-)

John Brohm recommended the Automotive primer to me in the past... I'm trying to understand how it's different from the regular primer. It's not high-build, is it?

Automotive primers are (frequently) enamel-based, so they dry super quick (3-5 minutes).
They also sand easily, and smoothly. Makes for very quick paint-sand-paint-sanding cycles.
They do tend to be pricier than HD/WM primers, and a bit stinkier during application. My wife can smell them from 2 floors away, so apply outside, or late at night after your SO is soundly asleep:
https://www.rshughes.com/p/Krylon-I...osol-Can-12-Oz-Net-Weight-90340/075577_90340/

 

[BABAR]

They do tend to be pricier than HD/WM primers, and a bit slinkier during application.
https://www.rshughes.com/p/Krylon-I...osol-Can-12-Oz-Net-Weight-90340/075577_90340/

I hate slinky primers, especially expensive ones.

 

[afadeev]

I hate slinky primers, especially expensive ones.

Thanks, you got me. An English major I am not (or was not? or would not have been, ever?)...

 

[BABAR]

Hey, I'm the guy that voice rec replaced "balsa" with "ball sack" and I missed it. It's all in fun.

 

[James Duffy]

Spreading TBII with a brush? Fancy!

(finger works for me ;-)

Ewww...

Save your fingers. Your loved ones will thank you: https://www.amazon.com/Pro-Grade-Ac.../ref=sr_1_1_sspa?dchild=1&keywords=acid+brush

James

 

[NOLA_BAR]

Yes, another video please on the paint! Especially on masking the camo like part.

 

[neil_w]

Technique videos are always welcome and appreciated, especially from master builders.

 

[afadeev]

Ewww...

Save your fingers. Your loved ones will thank you

James,
I am a man, but I can change, if I have to, I guess...

 

[DigBaddy]

I've seen this ply at our regional home improvement box store, Menards. A bit more than online, but no shipping. Was thinking that they would be perfect for fin skinning when I first noticed them. They have a lot of other basswood and balsa in the store too.
https://www.menards.com/main/doors-...17-c-12188.htm?tid=2085960573052481284&ipos=6

 

[James Duffy]

The edges of the skinned 1.8x upscaled Citation Patriot fins were rounded off on the belt sander, and test fitted against the slotted tube from the BDRM kit.



Should be a fun project!

James

 

[Ronz Rocketz]

After the sequels, it turns out that the story of Star Wars was not about the Skywalkers but about the Palpatines.

 

[Lord Rory Gin]

Here's a quick video showing how to skin fin cores with 1/64"-thick plywood that I just whipped up. I hope some of you may find it helpful, or at the very least a good waste of ten minutes.



James

I just realized that kids these days have no comprehension of what a gross is. i.e. 144 count. Tell them they can buy 1 gross of acid brushes and they will look at you sideways going "huh"?

 

[James Duffy]

After the sequels, it turns out that the story of Star Wars was not about the Skywalkers but about the Palpatines.

People are just going to have to watch the fin skin video to figure out what the hell you're talking about.

James

 

[icyclops]

OK, so I see this post is in Low power so I am going to make this comment. I do not understand why you would want to skin these fins with expensive ply when you could skin them with good quality card or Bristol stock. This would save so much time in preparing the wood ply fins for paint and be just as strong as ply for LP. I have done this many times with card stock and it is a little less weight depending on the stock you use....plus a smooth surface for primer/paint. And using your book weight technique there is really no more chance of warpage than using the ply.

Seems this is a more expensive way and in my opinion does not really add that much more strength based on the internal fin structure you show.
Nice video though.
Just my 2 cents....results may vary.

 

[James Duffy]

Seems this is a more expensive way and in my opinion does not really add that much more strength based on the internal fin structure you show.

Fair comments. In short, I don't care for papered fins. They always seem to suffer from hangar rash. Additionally, they really wouldn't work well with a hollowed fin core such as the ones used here. Finally, in this dojo final appearance is what matters.

I don't mind spending $12 (+ ~$3 postage) on a sheet of plywood for a project. Heck, that's about the price of the E20 motor that I'll use to fly the beast.

James

 

[Cape Byron]

Finally, in this dojo final appearance is what matters.

It shows in your attention to detail.

I don't mind spending $12 (+ ~$3 postage) on a sheet of plywood for a project. Heck, that's about the price of the E20 motor that I'll use to fly the beast.

Yeah, that's about half the price of a 3 pack of Estes 'C' motors in Oz ($28.99 AUD is rrp).

 

[icyclops]

So you must like to sand and use wood filler.....I do not as it takes too much time. Papering not only provides a smooth surface to accept primers and paint with little work. I do not know what you mean “hanger rash”.....when I paper fins with a card stock over hollow core fin structures it comes out smooth and strong. It works very good. All I have to do it seal the edges with a thin coat of white or wood glue....done. The trick is to use not too thin of stock, a little thicker is better. You are right, final appearance is all that matters and I get great looking smooth fins this way.

Paper card or Bristol board—$1.20 to $4.00 per 20 x 30 sheet....cheap

To each their own....enjoy.

 

[aviserated]

I really like your 1/64" plywood method. I am going to use it on my new builds. To me, building is just as fun as flying.

 

[Lord Rory Gin]

So you must like to sand and use wood filler.....I do not as it takes too much time. Papering not only provides a smooth surface to accept primers and paint with little work. I do not know what you mean “hanger rash”.....

To each their own....enjoy.

I did a little google search on the term - its aeronautical in history. It refers to the minor damages that occur to planes as they are moved on the ground and positioned in hangars; entirely 100% preventable contact with equipment, buildings and other planes. I presume the extension of thought goes to model rockets that have minor damage that is not attributable to actual flight. It may be something like errors in the build process, banging the rocket against a wall, rockets falling off a shelf or a pet finding a chew toy!

 

[James Duffy]

I presume the extension of thought goes to model rockets that have minor damage that is not attributable to actual flight. It may be something like errors in the build process, banging the rocket against a wall, rockets falling off a shelf or a pet finding a chew toy!

This is absolutely correct, I incorrectly assumed that "hangar rash" was a common term. (Hey, I'm a pilot, and we use this term with alarming frequency!)

In my experience the greatest threat to a model or high power rocket is transport to and from the launch site, and not the actual flight.

James

 

[dr wogz]

"Hanger Rash" & "Hanger Queen" are also common terms in the R/C plane world too..

Landings / recovery can be pretty hard on a model too.. especially when things aren't turned on, get tangled, disconnect, etc...

 

[icyclops]

This is absolutely correct, I incorrectly assumed that "hangar rash" was a common term. (Hey, I'm a pilot, and we use this term with alarming frequency!)

In my experience the greatest threat to a model or high power rocket is transport to and from the launch site, and not the actual flight.

James

James, how are you moving your roc’s. . Man, all my little bumps and chips have been done in flight or motor Cato....which has not been that many....and I just throw them all in a box or lay the bigger ones on the back seat....wow, didn’t know some were that fragile.
So I have not heard that term before....maybe invest in some bubble wrap. lol

My last “oh-no” was a chute tangle on a broadsword. Came down horizontal on the grass and did hit the fins....absolutely no damage to the fins....unbelievable...and they were papered over solid balsa...

Thank goodness it was grass....

Hanger Rash...Learn something new all the time. Thanks

 

[BABAR]

My equivalent to Hanger Rash is probably “Trunk Rash”.

being a Low Power rocketry guy (so is that L-0? Or is that Mid Power? Would Low Power be a Negative One?) on very hot or very cold days I will sometimes prep anywhere from 4 to 12 rockets at home, CAREFULLY put them in the trunk, and drive 7 minutes to my launch site (one advantage of flying L-<1!)

AFTER launching and recovering them, often it is colder or more frequently HOTTER than when I started, so after removing the motors (sticking them in a plastic bag and tying it up, otherwise stinks up the car) I am not as patient about putting them BACK in the trunk as I was LOADING them in the comfort of my garage. So they may get a bit tossed and tangled, especially when it is REALLY hot.

I can see pluses and minuses comparing balsa skinning to paper skinning. It’s nice to have options in the tool box.

 

[afadeev]

Fair comments. In short, I don't care for papered fins. They always seem to suffer from hangar rash. Additionally, they really wouldn't work well with a hollowed fin core such as the ones used here. Finally, in this dojo final appearance is what matters.

Personally, I am not a fan of papered fins over cavernous fin frames. Those tend to result in fragile fins that get damaged by sitting on a shelf.
However, I got into just such a mess with a recent TLP build (pics below). The frame is constructed out of flimsy balsa, and even 'painting' final product with epoxy still resulted in one fin cracking while being handled during painting.



The fins overall shape, however, is awesome. There is no way I would have been able to achieve a perfect diamond shape with custom trapezoid on top by any other means. I am now wondering if replacing paper outer skins with 1/64"-thick plywood would produce a more durable result.
Thus my two questions:
1). I don't suppose there is any readily accessible method for bending 1/64" plywood, is there?
2). Assuming "no" to the question above, what's the best compound for sealing the edges between plywood sheets?

I would expect to end up applying four (4) 2x2" 1/64" plywood sheets per fin, and ideally, the transitions between them should be invisible and perfectly smooth.

I don't mind spending $12 (+ ~$3 postage) on a sheet of plywood for a project. Heck, that's about the price of the E20 motor that I'll use to fly the beast.

The price is exceedingly reasonable.

TIA,
a