Strengthening balsa with CA techniques

[Stymye]

I also like the Zap brand aka ; Extreme Power(I get it at hobby Lobby)it does seem to last longer,
mabey because they sell alot of it so it fairly fresh. just an assumption.
cya has the catylist mixed in before it's even bottled so it is curing from the first day, just at a very slow rate. This process is kicked up by moisture from the surrounding air.You can use a mist spray bottle to kick it .
the shelf life of cya is generally 1 yr. but that can be accelerated immensly by how it is used or stored.

Before the bottle is opened, it can be stored in the fridge and that will slow things down a bit.once opened I don't like to do that because when you get the bottle out it has to warm up to room temperature or the condensation inside the bottle will speed the curing process up big time once you open it

the main reason for using cya is for quick gluing ,,so waiting for it to warm up kinda defeats the purpose.

cya is one adhesive you don't want to "stockpile" or buy in big bottles.no more than you would stock up on bread

 

[frankenhead]

I was going to post a question on this but I see its being covered here.

I have a Launch Pad rocket with big long fins and would need alot of CA to stiffen them. Could I use something else ? Maybe thin out some epoxy and brush it on ?

I definitley need something . The grain runs long ways with the body. see pic

 

[JBeau]

The only ideas I have for stopping the FLEX ability if those fins are:

1) Remove them, recut them with grain in the right direction

2) Form a rigid steel collar and affix along the base of each fin - weight penalty

For just strengthening, I'd paper laminate those babies with strong self-adhesive paper.

 

[m85476585]

Laminating will help with stiffness too. I like to use plain paper and wood glue because it's cheaer than self-adhesive paper.

 

[dbarrym]

Did these fins come pre-cut with the grain running that way?? If so, that would be unacceptable...

I would not just stiffen them with epoxy or CA alone, they WILL break along the grain at some point (landing or handling). As mentioned, laminate them or cut off and replace with fins having the grain parallel to the leading edge.

A long, narrow fin shape like that would be a good candidate for a 2-piece fin, with the upper tapered section having the grain parallel to the LE and the bottom section with the grain perpendicular to the body tube.

 

[Stymye]

laminate with paper would be good and,it cuts down on finishing bigtime.

 

[m85476585]

Unless you press the fins under a hardback book with an embossed cover. Then you have to fill the fins where the letters made a slight indentation.

 

[frankenhead]

Originally posted by dbarrym
Did these fins come pre-cut with the grain running that way?? If so, that would be unacceptable...

I would not just stiffen them with epoxy or CA alone, they WILL break along the grain at some point (landing or handling). As mentioned, laminate them or cut off and replace with fins having the grain parallel to the leading edge.

A long, narrow fin shape like that would be a good candidate for a 2-piece fin, with the upper tapered section having the grain parallel to the LE and the bottom section with the grain perpendicular to the body tube.

pfffff , just read the directions again. it said make sure leading edge is runs with grain. and said make 4 fins ... i made 3. Im a dumbass I dont know what my brain was doing LOL.

Well , I`ll try the paper laminate trick and see how it goes. I`ll be sure to post a video when the fins rip off the rocket on launch.

The kit came with balsa sheets that were NOT pre cut. I had to cut em. Now you know why my name here is frankenhead LOL

 

[maxpower]

Someone said to use plain paper? Like notebook paper?

What is the technique for using paper?

Thanks

 

[m85476585]

Here's what I do: I take a sheet of plain white paper (what I put in my printer) and lay it on a sheet of wax paper. Then I smear a <u>thin</u> layer of Elmer's wood glue on one side of a fin. Next I set the fin, glue side down, on the paper.
I do the same thing to the top, so I have wax paper then plain paper then a fin (or two side-by side, depending on how many fit), then another sheet of paper, then more wax paper. I put the whole thing between 2 white laminated boards (like what cheap furniture is made of), then stack books on top. I let it dry for about 24 hours then trim the paper off.

 

[Micromeister]

Talking about CA brands and not knowning how long the stuff sat on the hobbyshop shelf, reminded me of another trick i've been using for several years now that seems to lessen the effect of air moisture contamination that ruins CA's. I now keep my open 8oz bottle of CA in a zip lock keeping it closed when not in use. Since starting this practice I haven't lost a single bottle of CA using it all. How many of us have found our CA bottles totally hard as a rock even if capped. Roll a Zip lock around the bottle and secure at the bottom with a rubber band then just open an peel the bagggie down the bottle a little while in use and reseal, expelling as much air as possible when finished.
I've used just about ever brand on the market, US Gold seemed to be about the best and most expensive, but I Love ZAP med CA. it's my CA of choice now.
I've even started buying bulk "refill" pint bottles and have worked out a way of refilling the 8oz bottles from the bulk bottles, seems to be working and as long as I keep the material as Air/moisture free as i can I haven't seen a reduction in the quality or speed of bonding. Just remember to keep those bottles closed to air born moisture and you'll not lose so much.

One more CA extender, keep your open CA bottles ABOVE your accelerator bottles. the accelerator fumes are heavier then air so will not contaminate the CA if they are spereated by a few inches and a little elevation. I try to keep the accelerator on one side of the table and CA the other sitting on a piece of 1/4" scrap wood. seems to be enough
Hope these little things help

 

[RimfireJim]

Originally posted by frankenhead
pfffff , just read the directions again. it said make sure leading edge is runs with grain. and said make 4 fins ... i made 3. Im a dumbass I dont know what my brain was doing LOL.

Well , I`ll try the paper laminate trick and see how it goes. I`ll be sure to post a video when the fins rip off the rocket on launch.

The kit came with balsa sheets that were NOT pre cut. I had to cut em. Now you know why my name here is frankenhead LOL

Man, if it was me, I'd just buy some new balsa and cut out some new fins correctly. Why go to all the work finishing it with them wrong when they are likely to break on landing? Fixing it then is going to be harder than fixing it now. OTOH, maybe the paper laminate will be enough to strengthen them as is.
-Jim

 

[Mad Rocketeer]

Originally posted by RimfireJim
Man, if it was me, I'd just buy some new balsa and cut out some new fins correctly. Why go to all the work finishing it with them wrong when they are likely to break on landing? Fixing it then is going to be harder than fixing it now. OTOH, maybe the paper laminate will be enough to strengthen them as is.
-Jim

Yeah. I'd cut 'em off, sand, make four new ones, attach 'em as specified, then paper 'em.

 

[frankenhead]

Originally posted by RimfireJim
Man, if it was me, I'd just buy some new balsa and cut out some new fins correctly. Why go to all the work finishing it with them wrong when they are likely to break on landing? Fixing it then is going to be harder than fixing it now. OTOH, maybe the paper laminate will be enough to strengthen them as is.
-Jim

Yeah , I might as well. its pretty cool rocket. i want it to last.
https://www.unclemikesrocketshack.com/TLP/Hawk.html

 

[Brian62]

ya. I jsut got that one from countdown hobbies. I got the small version. I think I will try the printer paper glue lamination in this one.

 

[frankenhead]

The wood glue and paper trick works kick a$$ ! Totally stiffened up the big fins. Adds a little weight but who cares ... just use bigger motor.

Pre cut printer paper to fit
put glue out on paperplate
applied with brush to fin
put paper on glue , be sure to work out air bubbles
put wax paper on boards
sandwiched fin and used clamps
left clamps on about 6 hrs
viola !

Glue still needs more time to completely dry. One thing is paint glue on 1 side of fin then put on paper. The carpenters glue soaks in and drys fast if you try to paint both sides (unless yer quick )


Kudos to Matt (m85476585) who posted the idea.

 

[flyingeagle]

I use a Q-Tip soaked with CA and paint it on like a paint brush, fast and evenly. I paper most of my fins unless they are to small like a rake on the rocket then I use CWF. The only time I use CA is after papering on the main fins. That will be on the leading edge, trailing edge and the out side edge, never on the root edge. I seal the edges after papering to adhere the paper edges. I also paint CA on the inside of the BT for the nose cone and the end edge of the engine mount. Don’t use to much or it will soak all the way to the outside of the BT. I did put three coats of CA on a balsa nose cone sanding in between each coat and it turned out like glass. I just roughed the nose cone to help adhere the primer and paint.
The only thing I’m not sure of is that I had some papered fins get fuzzy from the paper fibers lifting after priming. I sanded them gently with 400 grit carefully not to go through the paper and primed again and they did it again, Fuzzy! Now I’m not sure if I should paint CA over the paper and sand them smooth. Has anyone in here ever put CA over the papered fins? I don’t know if it will now cause the fins to become brittle?