Straightening Balsa

All the leading edge stock at the hobby shop is warped. Is there a way to make it straight and, have it stay that way?

Yes. Lay the piece of LE Stock on your workbench, flat side down, and pin/nail it down straight, starting at the middle and working your way toward the ends. When you are satisfied that it is perfectly straight, apply thin CA glue to the edges, gluing it to the workbench firmly. Cover with 2 layers of 6 oz fiberglass cloth and epoxy. When it's cured, it will be permanently straight. What's the next question?

Seriously...I would use 3 smaller pieces of square stock and glue up a laminated LE, or I would otherwise laminate or mold a LE from sheet. You will never straighten a piece of wood and have it stay for any length of time...or retain your sanity, for that matter. Redesign the structure for alternatives is the best advise I can give. Generally, using smaller pieces of stock, like a 1/4" square LE with sheeting, is a better alternative than a 3/4" chunk already shaped. There have been some threads on straightening profile fuselages from kits, so you might want to do a search for those. Mostly, it's pretty much a waste of time and money to start with a warped piece of wood.
Sammy

I agree, been there failed, order new wood.

I share in your grief for straight leading edges. The last order I placed for 40 pieces of 36" I received 11 that could be used for my kits! That's why I got a new supplier. This time I ordered 40 and got 40 straight ones. Almost a miracle!

Want to reveal the names of the first and second suppliers?

At least the second one

SIG! The 3/4 X 5/8 was outstanding. Also very light as in 6 pound. The other company is in southern california, and most builders know their products well. But I'm not going to bash them on the internet as they do have some good stuff.

If you soak balsa sheet in an ammonia solution, (don't know strength but you buy it in bottles for household uses I believe) it can be molded to just about any shape around a male mold. Seen complete turtle decks and compound curves done like this. The new shape becomes the natural shape of the wood. I guess it would work for L.E. stock, taking longer to get fully soaked and longer to dry out, but it does sound a lot of trouble to get a straight piece of wood. Much simpler to buy straight wood if poss. Regards Ian R.

I usually laminate spars, etc for this reason. On a piece of warped formed leading edge stock, I have split it down the middle, held it straight and glued it with fair to good results. It is the nature of wood that some pieces will be warped.

I had a "wild hair" to build a Giant Stunmaster profile from scratch. The only molded leading edge I had was warped. To cure, I took the razor saw and cut a bunch of kerfs in the warped setcion, which was about 10 inches long. I filled the kerfs with titebond and secured the leading edge to the work bench until it cured. Came out as close to perfect as it could get.
I then put the "cut" side on the bottom and built the plane. (took about 4 hrs. to build. ). Flys as good as one can, and you can't really tell where the cuts were made.
Bill Little <><

This has always been a problem, it may be worse nowadays.

One solution, perhaps not reasonable here, is to use laminated construction. For example, you can laminate two 1/4" wide x 1/8" strips to form a decent 1/4" square stock. The 1/8" material is pretty easy to come by, stripped from sheets. You have to control the straightness while you are laminating, of course.

If you are using 3/8" square LE stock, try laminating three 3/8" wide strips from 1/8" sheet stock.

Also, if you can substitute spruce spars, they are typically straighter stock. The weight penalty may not be as important as it initially seems.

[photo not recovered: 3e69bb3870f12ad5.jpg]

"There's no bigger task than protecting the homeland of our country." -George W. Bush, 8/23/02

LAST EDITED ON Jul-12-03 AT 12:35 PM (CDT)
 
I buy all my wood from Riley Wooten at Lonestar Balsa. Quick service & excellent wood. Generally cheaper than the LHS, even after shipping.

>I buy all my wood from Riley Wooten at Lonestar Balsa. Quick
>service & excellent wood. Generally cheaper than the LHS,
>even after shipping.
>
>/\/\/

Ditto...
Fast service too!: I have ordered it and had it get here nearly as quick as I could drive down to the LHS and pick thru their sorry stuff.
SOMETIMES you can straighten warped wood- soak it and pin/weight it down straight until dry. Often it will just bend back the way it started after it dries- NO guarantees here!
As much time/money/effort as models require these days, it pays in the long run to use ONLY the very best materials, etc. and reject all else substandard.

I use nothing but LONE STAR wood in all of my kits. However, they will not produce a 1"X1" leading edge. I've been trying to get them to do the L/E for 8 years now and it's no go for some reason. The last word I got is they don't want to spend the money to get the cutter heads for that size. So I have to go else where for it. Most of my profiles use this L/E. Changing over to sheeted L/E construction is not much of an option when you figure all the plans that have to be changed and rib templates remade, and there are many. And to straighten out 80% of the order is beyond reason when you consider the cost in time alone to do this. I don't get much profit as it is let alone hours of bending time to go with it.

Ron B.
F4Fguy

At the risk of sounding like Johnnie Cochran:
"If You Laminate It Must Stay Straight"!
Sorry about that.

Ron B.

>Ron B.
>F4Fguy
>
> At the risk of sounding like Johnnie Cochran:
> "If You Laminate It Must Stay Straight"!
> Sorry about that.
>
> Ron B.

That was Johnnie Cochran? It sounded more like Jesse Jackson. But anyway, I was thinking about this possible cure for warped LE stock: If you could stick it to a sacrificial plank, both straight and parallel (wouldn't have to be perfect), then you could run it through a table saw, splitting it in half. The 1/8" saw kerf could be filled with a third piece of balsa, cut from sheet stock. It still sounds like a huge PITB. Laminating seems like the best option, unless you want to mold the LE, put in ribs or foam core, and web the aft face with vertical grain 1/16" balsa, perhaps with a plywood doubler in the center.

Bent Balsa Rap

If you laminate,
Stay up late.
Get it right,
it must stay straight.
If it don't,
it aggrivate.
Laminate,
keep it straight.

I'm working on the "Warped Balsa Blues". Maybe I'll post it later. Steve

>Bent Balsa Rap
>
>If you laminate,
>Stay up late.
>Get it right,
>it must stay straight.
>If it don't,
>it aggrivate.
>Laminate,
>keep it straight.
>
>I'm working on the "Warped Balsa Blues". Maybe I'll post it
>later. Steve

Wow Steve, that's beautiful. I'll be that Snoopy Doogie Doo Doo guy is quaking in his Adidas.

LAST EDITED ON Jul-12-03 AT 07:52 PM (CDT)
 
Phffffttt, screekay, screekay, phfffttt! to you, too! Stoopdawg

PS: Who does I see about a Nike contract? Adidases is too small-ish for da Stoopdawg's paws.

The Warped Balsa Blues

Well, I woke up in da mornin',
after buildin' haf da night.
Went on down ta loco hobby sto'
Lookin' fo' some balsa,
jus' light an' straight I need.
But what I found...
jus' made me shake my head.
I gotta get some good wood,
so light and so straight.
If I don' git some good wood,
no point ta stay up late.
Oh, I gots da Blues,
da Warp-ed Balsa Blues.
Yeah, I got da Blues,
Da Warp-ed Balsa Blues.

<applause here>

Thankyah, thankyah vera much. Steve

I have taken to laminating all my LE, TE and Spars just because its so hard to get straight wood that will stay straight. I have soaked wood in hot watter and bent it stratigh then hung it vertically to dry with good success, but the one that isn't successful doesn't show up until the finish is on the model. I haven't had any of my laminatel edges warp, and you get a little added strength as well. Something I do with Free Flight spars and edges is to laminate .003 CF between the wood, mat would probably work too, these spars are straight and STRONG!