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Painting with CA

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TheRadiator

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Hey guys, needed a bit of advice. I'm working on a Launch Pad MIM-23A Hawk. The boattail is made of paper, and the directions ask you to paint the boattail with CA. I tried this once before on a TLP SAAB 372. The finish looked pretty bad afterward. Lots of dried clumps of CA were on the paper because it dried fairly quickly. After a ton of primer and sandpaper I came out with something passable. What methods do some of you guys use when painting with CA? I'm trying to make this one look a bit better than the SAAB. ;)
 

Rocketmaniac

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Originally posted by TheRadiator
I'm working on a Launch Pad MIM-23A Hawk. The boattail is made of paper, and the directions ask you to paint the boattail with CA.
A while back when I built a Launch Pad Harm, I used 5 min epoxy instead of the CA for the nosecone........ (same idea, made of paper and coated with epoxy)......... The HARM was destoryed when I left it on the back porch with epoxy drying and the rocket got wet, but I still have the nosecone........
 

Stymye

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Nick were you using a thin cya?..it goes on like water
tho it can leave an uneven layer.
but a couple coats of primer usually takes care of it
 

astronboy

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I use the super thin CA. I liberally soak the paper letting it soak in. I then spread it evenly using an old credit card, or a similar scrap od plastic. Yes. dried CA soaked paper or cardboard comes out fuzzy and needs to be sanded (I use 320 then 400) , but it is light and strong.
 

rbeckey

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Radiator,
The thin CA you get at WalMart is not the same as the super thin CA sold in hobby shops. The WalMart stuff has thickeners in it, the hobby shop stuff has very little or none. It is like water. The stuff I use is distributed by BSI, but every hobby shop that has some has their own name on it.
 

TheRadiator

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Yep, I was using thin CA. I think it was made by Handibond. A good bit of it dried before I was able to spread and even out the CA layer. Sounds like either I didn't use enough CA or I didn't use enough primer, probably both. Here's a picture of the boattail in question by the way.
 

jetra2

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Originally posted by TheRadiator
Ooops I cropped too much
Now that's no way to up your post count! ;) :) J/K :D

I have used thin CyA to seal fins with relatively good success. It takes a little sanding and filling afterwards, but it works pretty good, and adds a lot strength. It's also a LOT lighter than epoxy and fiberglass, but it, for one, makes the fin a little more brittle and for two, it doesn't add as much strength.

Jason
 

astronboy

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I agree jetra. I use CA for strengthening centering rings, and soaking into body tube ends to prevent 'ESTES Dent' , but it has limited use on fins. I use it just on the corners of some fins, if I think that they may get landing damage.

For overall fin strengthening, I use the 'Peter Alway glue method' by coating the fins with one or two coats of yellow glue, spreading it, and pushing it into the pores with an old credit card. This allows a very thin layer to form on the top of the fin, and also seals the fin for painting. This method does add weight however, so I usually only use it on booster fins, and very weak fin shapes.
 

TheRadiator

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Well, it's not like I have the killer post numbers you guys have! :D I tried using thin CA to seal fins on my SAAB 372 as well, and the darn thing warped something terrible! I tried to correct it, but the one fin I started on still has some of the warp left. I was spooked to try it on the other side, because I thought the CA would ruin the fin. (Bear in mind this was before I found all the different vendors on the internet). I guess the hypothetical question is, if I had put CA on the other side of the fin, would that have corrected the warp? If so, I'm gonna cut another fin!
 

Rocketman35

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Warping is caused by the "shrinkage" of one side of a peice of material compaired to the other side OR by "expansion" of one side compaired to the other. In this case the CA on the fin shrinks contracting that side of the fin. With nothing on the other side of the fin to counteract this process. Now, if you put ca on the otherside it may, or may not correct the warping. It will (should) make it better but not perfect (if you did it right away, dont wait till it dries)
Im not the best teacher, so others may be able to say it better but i think you get the picture.

Chuck
 

rbeckey

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I don't do one side of a fin at a time with any liquid or adhesive. When I use sanding sealer or wood hardener I do both sides and lean it against something to dry evenly. I don't get any warpage this way.
 

Silverleaf

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I just got done doing the Quest Tomahawk, and while I did not have to paint over the card stock with CA, I did wind up replacing the Boattail with a Styrene one that I hand cut and shaped. After glueing the paper centering ring to the innner side of the BT, and attaching the CR to the MM with Wood glue and it dried, I CAed the fins to the Tail.

When I painted it, it was super smooth and had no blemishes whatsoever.

In the future, I will do all kits that need a rolled boattail/shroud with this process simply because of the strength and finished look.
 

TheRadiator

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I think I remember it warping before I had even gotten to the other side, hence why I stopped short. Well, when the weather clears up here, I may try that on my TLP Type 30.
 

astronboy

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Radiator:

I agree, it is important to coat both sides of a fin at one time in order that any shrinkage or expansion is even.

Are these fins glued on the rocket? If not, that could be part of the problem. I would not suggest using CA, Glue, epoxy, sanding sealer, Elmers FNF, or anything else on fins that are not already glued onto the rocket.

Having the root edge anchored on the BT helps prevent warpage .
 

wwattles

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Easy way to prevent warping:

Sandwich it between 2 sheets of glass. If you are still worried about it warping, put something heavy on top of the glass to keep it pressed against the fin. You can also help prevent it from sticking to the glass by very very lightly coating the glass with a non-stick cooking spray.

I've used this for several sets of fins, and haven't had a crack, break, dent, or scratch yet. My 2 cents.

WW
 

TheRadiator

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Astronboy,

No I think I was painting the fins before I glued it on. All of my other TLP kits have been built (except the Hawk I'm doing now). I'd like to try painting CA on my Type 30 since the fin design is rather simple and easy to duplicate. If that works well, then the Grail, Dragonfly, and the Hawk are getting this treatment as well! Hey, I'm outta TLP kits to build.... time to buy some more before they're all gone.
 

Micromeister

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Just to add a little fuel to the fire,
I've been CA soaking shoulders and boat-tails for a very long time. personally I like to soak cardstock and fibreboard wth med Zip CA I use a folded paper towel as a "Mop" to flow the material around the entire shoulder/ cone / boat tail / watever and let is sit, rotating the piece every so often to prevent runs.
What many of you guys may not know, Dryed Ca has about the same sanding density as styrene, if you sand your ca soaked transitions with 320 grit you can get them as smooth as a babys butt. Including removing any sign of the joint seam. I fly many Scale models in the micro-maxx to be 60 size bodies with CA soaked Nike style 3 and 4 piece fins. Unsupported by anything outher then the CA soaked cardstock parts, makes for some super strong, very light weight fins and shrouds. I normally fabricate and attached the Fins to the model and then CA soak the Fin shroud and connecting points, then Sand and finish. Heres a composite of my BT-80 bodied SS-N2 Styx anti-ship missile that had a light cardstock about 6" long boat-tail the has the fins CA and epoxied directly to the CA soaked shourd, along with many of the detials. Works just fine. This model has won two different regionals and a couple open meets in it's day. still flys well on a D12
Hope this helps a little.

PS Radiator I really think its the medium CA that make CA painting work. It gives enough time to coat the entire piece and smooth out most of the thick spots.
 

PunkRocketScience

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Hey Radiator-

I've been using thick/gap filling CA for coating fins and tubes for quite a while, since I build a TLP Perseus. I know that the spreader that I use (my finger...) is NOT the recommended implement, but usually I find it hanging around conveniently when I need to use something for spreading...

Usually it takes two coats to get a really smooth finish out of this, I sand the first one down with 150 grit and the second with 220-400.
 

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