Bending balsa with ammonia water?
 

Mornin' All,

I am building a Slow Poke kit and have reached the point where I need to wrap 1/16" balsa sheets over the curved nose formers. The instructions say to "liberally spray the outer surfaces with an ammonia/water mixture to make the sheets more pliable while bending." Unfortunately, they don't say what ratio of ammonia-to-water to mix up. They also don't say whether to wait for the mixture to soak into the balsa or to start bending right away. What do y'all suggest?

The bends are parallel to the sheet's grain.

Thanks for your help,

Harvey

RE: Bending balsa with ammonia water?
 

Harvey, you can just use plain water. Adding a little ammonia helps, but don't use more that 1 part to 4 or 5 parts water.

Spray or wipe it on and wait a few minutes before bending

RE: Bending balsa with ammonia water?
 

What Minnflyer said.

I will usually run a sponge soaked in warm water over the balsa. Keep running the sponge and testing the wood until you can get it to EASILY bend over the curve you are trying to achieve. But don't force the bend because you can snap the wood.

Ken

RE: Bending balsa with ammonia water?
 

I've used good old Windex(with ammonia formula) sprayed on sheeting to get it to bend to a curve. Hasn't caused any problems so far. As above, let it soak in for five minutes or so before bending. I usually saturate the wood pretty thoroughly.

RE: Bending balsa with ammonia water?
 

Thanks Gentlemen, that's the info I needed.

By the way, Ken, while you're here, I've heard that you're a Slow Poke fan. Got any words of wisdom? I'm building the 3ch, .15-.25 version. It'll be electrified. So far, I know to build the tail light.

Thanks,

Harvey
Houston, TX

RE: Bending balsa with ammonia water?
 

Harvey,
Yep, I'm a little bit of a Slow Poke fan!!! :D:D You've already covered the biggest tip, keep the tail lite. Other than than, follow the instructions and you won't have any issues at all.

Let me know if I can help with anything else.

Ken

RE: Bending balsa with ammonia water?
 

Just to add one more thing on the sheeting issue. It's my understanding that the water works for two reasons: It softens the wood to make it bend easier, but it also causes the wood to expand. Because you only spray the convex side of the sheeting, that side will expand while the other side doesn't, causing the sheeting to curve. I've always found that concept pretty neat.

RE: Bending balsa with ammonia water?
 

Ken,

In regards to building the Slow Poke's tail light, I built the fuselage exactly per the plans and haven't added anything extra. Do I need to take it a step farther and remove some wood?

Also, since I'll be installing a 35-30-1450 Rimfire, is there anything I need to know? I'll be maintaining the 2 deg right offset per the nitro motor instructions and I'll stuff the battery pack as far forward as possible. Any advice?

And before you wrinkle your nose at my electric Poke plans, rest assured that my next Slow Poke (a Sport 40) will be Saito powered. (Both already purchased and waiting patiently on the shelf! :D)

Harvey

RE: Bending balsa with ammonia water?
 

Scott,

What does the ammonia do?

Harvey

RE: Bending balsa with ammonia water?
 

Harvey,
You don't want to take anything off. When I say build lite that just means to be careful to not use too much glue and don't put on too much covering. The best advice I can give is to build it and then see where the balance comes out. If it's heavy move the battery pack forward and see what you need to add from there.

Ken

RE: Bending balsa with ammonia water?
 

Okay. It's just that I read on another RCU post that there is more wood in the Slow Poke's tail than is really necessary. While I haven't exactly skimped on the glue (I'm using good ol Titebond) I haven't gone hog wild either.

Thanks for the help,

Harvey

RE: Bending balsa with ammonia water?
 

Ammonia helps make the balsa more plyable (bend easier) some say it can permanently weaken the wood.
I use warm water and just wipe it on with a rag and only when needed. 1/16" sheet balsa bends pretty easy. here is a project I am working on. The wing sheeting is 1/16" the fuselage is thicker at 3/32" and I had no problem installing the sheeting dry to spite the sharp curves on the nose of the fuselage and the landing gear fairings.

RE: Bending balsa with ammonia water?
 

I THINK the amonia breaks down the moleular bonding in the wood a little more than water, water just opens the grain. Not enough to cause serious harm. Wet or soak the wood and form it over the area to be covered. Use tape or bubber bands or even weights to hold it in place while drying. Let dry completely before attempting to glue. Letting it dry in place lets the wood form a "memory" of the desired contours. Makes gluing easier later.

RE: Bending balsa with ammonia water?
 

Bruce that is exactly what it does. We used that in the finish construction business on ornate trim.

RE: Bending balsa with ammonia water?
 

Missileman, Bruce & Goirish, thanks for your inputs. This thread is becoming much more informative than I expected!

Goirish, did you find that the ammonia weakened the wood any?

Harvey

RE: Bending balsa with ammonia water?
 

Harvey-

I've always used windex, and never found that it weakened the wood in any significant way. When I have crashed planes, it's never been because ammonia-weakened sheeting gave way! :D

RE: Bending balsa with ammonia water?
 

Ammonia also evaporates faster than water so the peice dries alittle faster. I usually find that over night is OK but 24 hours is best and makes sure it holds its shape. As far as holding in place till it dries, I found rubber bands to be best cause tape doesnt work if moisture is there. As far as swelling the wood, it does but when it dries it goes almost back to original size.

RE: Bending balsa with ammonia water?
 

No--Just don't be in a hurry to glue--Do what Bruce said. If you are going around or building a cowl use rubber bands, tape anything to hold the shape until it drys. Also don't be in a hurry to bend it. Give the moisture time to do it's job.

RE: Bending balsa with ammonia water?
 

Pics are of my SlowPoke .40 . The sheets were edge glued with Elmers and then sprayed with water and wrapped around the fuse to fit, cut and glued in place with CA+.

RE: Bending balsa with ammonia water?
 

NICE!!!

RE: Bending balsa with ammonia water?
 

[And before you wrinkle your nose at my electric Poke plans, rest assured that my next Slow Poke (a Sport 40) will be Saito powered. (Both already purchased and waiting patiently on the shelf! :D)

Harvey
[/quote]


Some guys have all the Luck lol.

Bob

RE: Bending balsa with ammonia water?
 

TX goirish

dignlivn , I bet that a elec. Slowpoke will be cool . Go for it. Oh yea, pics please .

RE: Bending balsa with ammonia water?
 

Hey Guys,

I used your suggestions last night and while my sheeting doesn't look near as perfect as Insanemoondoggie's in post #19, I am happy with the results. Many thanks to all who helped!

Harvey

RE: Bending balsa with ammonia water?
 

Maybe, but I bet your garage is cleaner.:D

RE: Bending balsa with ammonia water?
 

Don't bet on it! [:o]

Harvey