Using CA to harden fins

[Cougar93]

How many of you do this?

Lately, I've been using Fill 'n Finish to both harden and seal the fins for a more durable fin, and better paint finish. Has worked pretty well.

But, I'm wondering about CA.

For those of you that do it, do you do just one side at a time? My experience with that is that you will be warping. It would seem difficult to do both sides at once. CA sticks to wax paper... right?

 

[JRThro]

Originally posted by Cougar93
How many of you do this?

Lately, I've been using Fill 'n Finish to both harden and seal the fins for a more durable fin, and better paint finish. Has worked pretty well.

But, I'm wondering about CA.

For those of you that do it, do you do just one side at a time? My experience with that is that you will be warping. It would seem difficult to do both sides at once. CA sticks to wax paper... right?

I've used thin CA, one side of the fin at a time, with no warping.

 

[CAS2047]

I've recently built two "The Launchpad" kits and used thin CA to harden eight fins on each rocket. I did one side at a time and had no warping on any of the fins.

I use wax paper to set the fins on to dry, wet side up, but from time to time some CA does come in contact with the wax paper. My experience has been that CA does not stick to it. Although I've never actually put the wet side down....

 

[eizzle]

How do you guys spread out the CA on the fin?

 

[Delta-IV]

With CA, theres not much you can do but to allow it to spread as it flows out...I sometimes have the fin at an angle and allow it to run down...make sure you have a paper plate or something to protect from the drips....

 

[jj94]

I was also wondering how people spread CA on fins. I was guessing that some use a small piece of sheet metal or wood, as a squeegee.

 

[Stymye]

a piece of cardstock or an old plastic card. I just squirt the fin and spread it out. than a little sanding and filler.

 

[tonypv]

I've been useing brush on CA.
Works for me.

 

[dbarrym]

I do this on most of my LPR stuff. I use a cheapo plastic sandwich baggie and a finger; apply the CA, spread it around with the finger in a baggie (make sure the baggie/finger joint is smooth with no wrinkles) and let cure. I use a fresh corner and/or side per fin (i.e. 1 baggie does both sides of 2 fins). Works great.

 

[Cougar93]

Actually, if you go to Home Depot, Crazy Glue makes brush on for about $3.00. I did all my Richter Recker fins on one side last night. Worked really well, but there was some warping. No biggy, just stacked about 10 pounds of books on them... this has solved the problem in the past. But, the Crazy Glue in the bottle is great stuff. It goes on purple so you can see it better... but dries clear!

 

[powderburner]

Originally posted by eizzle
How do you guys spread out the CA on the fin?

Q-tips (or the dollar store equivalent)

Use 'em

Toss 'em

 

[Jirimar]

newb question

what's CA?

i have never strenghtened fins, but i'd like to start

 

[powderburner]

CyanoAcrylate something or other

Some of these guys buy the fancy CA that comes in larger bottles, generally available at hobby shops and some of the better-stocked craft stores. Better quality product, better quality containers, less fumes, probably slightly more expensive.

I buy the cheapo stuff at the dollar store, the kind that comes in three or four little foil tubes bubble-packed on a card, for a buck. The tubes leak if you handle them wrong, the cards may be old (and the CA inside already cured rock-hard), and the stuff makes an awful stink. Use in a well ventilated space, don't breathe those fumes.

 

[kenobi65]

Originally posted by powderburner
CyanoAcrylate something or other

a.k.a. Super Glue, Crazy Glue, etc.

It's available in different viscosities; it's the thin version that's used here.

 

[powderburner]

Originally posted by kenobi65
It's available in different viscosities; it's the thin version that's used here.

kenobi65 is *very* right on this one (I forgot all about CA gels), you want the thin runny stuff to get the best penetration into the fins and airframe materials.

Another thought: you can use CA on balsa NCs to toughen up the surface and to seal the wood grain. Makes subsequent finishing steps much easier. Especially makes the NC shoulder much much stronger and less prone to damage or wear-n-tear.

Another 'another' thought: you want to run a few drops of CA around the inside of the front of your BT (I am talking about cardboard BT for low-power rockets). Do this during construction, before painting. You may have to do a little sanding to clean up the edge, and to smooth the inside surfaces. But this added step will greatly improve the durability of your BT where the NC shoulder slides in and out.

 

[powderburner]

Originally posted by Jirimar
i have never strenghtened fins, but i'd like to start

See also: all the old TRF posts about laminating balsa fins with paper (try the 'Search' button in the TRF header)

 

[Jirimar]

thanks a bunch for the info

 

[eizzle]

I have fins that have to be glued together. Will it hurt anything to do it after the wood glue is dry (for 24 hrs, I mean) or would I be better off just using the paper cover method?

 

[Stymye]

with the brush on stuff ..how does it keep from crusting up the brush?


I thought it was referred to as ...cya ..not ca

 

[BARX2]

I push a pin into the root edge of the balsa fin then use the pin (the kind with a round plastic head) as a handle to move the fin around. I drip CA onto the balsa while working on a sheet of wax paper. I have found that after wetting the fin with the CA if I then gently wipe the fin on a clean section of wax paper it will remove drips and smooth out the CA very nicely.

 

[BAR_Daddy]

I do this. I use an index card or a piece cut from a folder to spread it. YOU HAVE TO BE QUICK THOUGH!

 

[Rocketeer]

I only use CA on very thin / flimsy fin stock. I usually coat fins with wood glue followed by Elmers wood filler after the glue is dry. Since both are water based, the wood filler seems to adhere to the wood glue well, and the fins are stiffer.

Yes, wood glue will warp the fins if you just set them down to dry, but I place them between two sheets of wax paper and set a heavy flat board on top while they dry.
They always come out perfectly flat.

 

[tonypv]

Originally posted by stymye
with the brush on stuff ..how does it keep from crusting up the brush?


I use a tack cloth to "clean" the fin before I use brush on CA, keeps the brush from getting "crusted up".
I use Loctite brush on CA, it can be found at Walmart and Lowes.

 

[Cougar93]

The Crazy Glue brush on stuff does not harden the brush. I'm really amazed and pleased with this stuff.

 

[gonogo]

I am trying to use this brush on crazy glue stuff tonight. I seems to work well so far. On two fins I have used about half a bottle. I have so far covered both sides of two. They are 3.25"X2.25"X2.5".

 

[jcsalem]

It sounds like most of you are putting the CA on the fins before attaching them to the rocket. Is that right? Are you then using CA to attach them to the rocket? Do they still attach well?

Jim

 

[Pem Tech]

How do you guys spread out the CA on the fin?

Thin CA pretty much spreads out on it's own, even though you can use your finger to spread it over larger areas, if you move quickly enough.


The only problem I have ever had are "drips" forming on the underside of balsa nose cones and such if too much CA is squished out at once. Oh course, I am always in a hurry......

 

[gonogo]

Im brushing it on after the fillets are done. The two fins I did are done and they are a little stiffer but not what I was hoping for. Tonight I will try just pooring superglue on and spreading it out, maybe that will soak in better.

 

[bigone5500]

You can probably let the CA wick into the balsa on its own by holding the tip directly on the fin and giving a slight squeeze. You will be able to see the glue soaking into the balsa too so this way you know where you have applied it already.

I'm not sure and haven't tried this but an idea I had is to wick the CA into the edge of the fin and let cure, then soak the rest of the fin with it. I'm thinking that the hardened edges will help prevent unwanted warping...any ideas guys?

 

[wyldbill]

I've used Minwax Wood Hardener with great success as well. It leaves the balsa very hard, but more easily sandable than CA. I'll usally apply it after I mount the fin, and usually just around the edges to a depth of 1/4"->1/2". It's a bit easier to deal with than CA as well.

FWIW,
-bill