thickness for Balsa rails ?

I am in the process of ordering Balsa wood to do rail glue ups like firewire… Can anyone tell me best thicknesses to order? I want to make the job as  simple as possible without having to break to many peices during bending… I will just be force bending because I don’t have a steam box …Please help me Swaylockers!

cold bend balsa for rails with zap a gap success

has hovered at under !/4’’ in my tests of two boards

I have not exceeded maybe 16 1/2’’ nose finished dimension

perhaps why nose blocks are an honest option consideration.

I dont know fire wire but based on my hollow balsa  bent wood 

trials and tribulationsthats my humble take…

defering in advance to differing opinions

about fire wire techniques.

the xothermic heat of the zapa gap is enough

to temper thewood to  bend a 1/4’’ at a time .

starting with the nose

and using the length of balsa to

lever the bend. hope you get my drift

as many are confused .

… your couzin from dyslexia,


no clamp just tape.

Hey yep I have had good results with just taping the lengths on with masking tape one at a time, bit slow but about 8mm thickness whatever that is in imperial:)  I dont know but looks like Firewire use a very minimal ammount of balsa for their rails and then cover it with top skin or paint.

I used 3 lengths of balsa per rail for the one below which is just a pu stringerless blank, Tailblocks and nose cones make it easier to finish ends but I reckon next time going to try without on the nose and just layer the balsa. Going down to 6mm would increase bendability and would make a 18mm rail band to shape. Tip ; if your doing it without skin shape the board almost completely especially roll the rails down as near as possible then just shape the balsa with a hand plane to match outer curve of rail contour if that makes sense…

I think Bert used to do 1/2"-3/4" of 1/4" bands

the original firewire’s started at 3/4"-1" and cut that in half in year 2

1/4" is kind of hard to bend 3/16" little easier.

Paul (silly) used to cut thicker but shorter blocks to glue up

Ben (benny1) used 1" balsa scrim

MikeSwabs used many thinner strips

What I did was the thick block glue up with lots of scarf joints and then later it was to take the rocker guide you use to cut the foam blank from your block or to profile your raw cut and use that to template out a bunch of 1/8"-3/16" boards with scarf joints to create one big rail panel for each side 1/8"-3/16" thick and then glue these up to the rail one at a time using 5 minute epoxy and lots and lots of masking tape. You can insert cork or HD foam in between each balsa panel to gain thickness with out making it 100% wood.

The full wood rail look nice but suck water when dinged

these days  i just do a thin perimeter of 1/8"-3/16" wood to hold the rocker followed by 1" of solid corcel or last a foam HD foam on the outside of that like Gary Young and Josh Dowling does.

Greg made it even simpler with his timberflex construction skipping the perimeter rail altogethor.

to bend 1/4" you need strapping tape to hold it in place

Petey, before you order Balsa, let me know what you want. I bought a shed of balsa from a guy who used to make model airplanes. Longest peices are 4’ and widest are 4". I gotta check with my brother Oneula who has a lot of it stored away. Mostly the 1/8" and thinner stuff. I took the thicker stuff like 1/4" and 1/2" and use it to make thick stringer slices.

I would use 1/4" max depending on how much curve you have. 1/8" is the best. Maybe we can do a trade if you still have foam.

I’ve had to use a heat gun to bend 1/4" around rounder curves. Another option is to combine Balsa and cork.

Just send me a PM.

My last balsa railed board I used 3 pieces of 3/16".  I used solid pieces, scribed and fitted for the tight curves-


taped on-


being shaped- 


scribed and fitted-


I’ve done several with three layers of 5mm in the longest pieces that would fit the curves, and vaccumed on.  

Jeff that tail section is where I used a heat gun and bent 1/4" balsa to make it fit the curve. Broke several pieces learning how far I could push it. I like to do the same where I glue a layer of wood then work it down to size then draw the shape onto the next layer and cut it out before I glue it on. Once I have a layer on the foam, I use carpenter’s wood glue till I have the thickness I want. I think the way we do it now with a single band of wood followed by about 1" of XPS is the fastest and easiest to shape.I had a whole lot of 18" long balsa, so I used that for several boards. I pieced together enough for one side then glue it on, flip the board and do the other side. With 5 minute epoxy, you can do 2 layers on each side. The second gluing would be wood glue and I’d try to get as many pieces of wood as I could in that second glue up because I would let that one sit overnight. I found that it’s so much easier to shape the rail with the wood glue instead of epoxy. If you cut the rails as close to what you need before you glue it on, you’ll waste less and it will clamp down better. I just use lots of tape to do that. Don’t bother using the bag.

I’ve also found that You don’t need wood rails or stringers. I just wrap glass around on both sides so there’s 4 layers going around the rail. If I have 2 bottom and 3 top then there’s 5 layers of glass around the rail. Unlike others, I’ll stagger the glass so that the layer closest to the foam goes the furthest then the next layer wraps less. That helps when I sand it down. Making a small bevel in the foam helps to add more glass too. I’m riding 3 boards with no stringers right now.

i have always used 1/8. usually 3 layers for rails. then add solid nose/tail sections and trim back

Thanks for the comments all . So very cool that so many fellow boardbuilders  came forward to give their input on this topic. This gives my heart the warmest feeling of Aloha I could ever imagine. Im living in Bali indonesia now and have a great source of balsa . I recently travelled to Majalenka(about a 6 hour  drive from Bandung which is located in central Java) . I first asked local villagers if they had any Balsa available . Based on previous investigation I had asked many indonesians the name of Balsa in the Indonesian iternational language, bahasa Indonesia what the name of Kayu(wood) Balsa is . Just about all of them said Balsa. So  I was in Sundanese territory and was about to give up on my search after getting so many " I dont know what this type of wood is" answers.  Finally I gave it one more chance. I got on google and downloaded pictures of balsa. I showed my girlfriends father and  he still was not sure what balsa was. After almost giving up the search I was sitting around the house bored as heck (there is barely anything to do up in my girlfriends village other than eat and maybe a game of soccer) . I decided to take matter in my own hands, grabbed my girlfriend , borrowed her fathers motorbike and went on a BALSA MISSION!. After a few minute of driving I spotted several small species of balsa near to her home. As I went further into the highlands I started seeing perfect specimens of the balsa tree growing so straight and some as wide as two feet!  I was frothing literally! I took a peice of a dead balsa tree home to the village. It was so white, so light like a feather . I had realized It was all over the place expecially the higher I went ( already her village was so high in the mountains it was actually cold there!  Later I had discussed with my girlfriends father about this wood. He says the name is “Tisuk” and  it really never getsharvested because the locals don’s see any use for it  , deemed to light and fragile for house building purposes. Hahaha I thought to myself… So months after deliberation about how i could get it from the villagers I finally got a connection to harvest the trees and cut it into blocks or three centemeter strips.  To bad unless made into a surfboard this Balsa will probably never be able to reach America in its raw state…

well here is some of the balsa i got from Java . I paid 20$ for all of this …pictured are 2 meter , three meter and 2 1/2 meter lengths

awesome work , very inspiring!


well dont exactly know what zap a gap is but I  figure there are many ways to bend it , microwave oven , heat gun , steam box etc… keep up the great work Ambrose thanks

Very nice work Nocean . Super meticulous some of the best i have seen Thansk for comments… Aloha keep the stoke!

Hi Petey,

Great story!

Are you still there on Java?

How far are you from the saltwater waves?

You can also wet the wood, and bend it around an empty oil vat, let it dry...

bb30 does this. ultra tight curves!!!


my rails are premade like hess out of multi laminations on adjustable jigs. then the rocker of the blank is glued in when you attach the rail. that way i can shape bottom contours and freebag on the bottom skin then bag the deck on the the rocker table. i haven used balsa for a long time. i deem it unsuitable for rails. i would use yellow pine over balsa but currently using paulownia. woods like cedar oregon cypress yellow pine or paulownia are far more suitable even in combos with cork or as huie has shown eva foam. i prefer to use a planer for compsands as  i have more control over the shape as i dont want to make a production model as such

15 to 25 mm to answer the question

zap a gap is super glue 

Zap-A-Gap CA+

Click image to enlarge

Fills gaps. Works well on harder woods such as Bass and Spruce, even works on oily surfaces! Some uses besides hobbies and crafts include; jewelry manufacturing and repair, taxidermy, pool cue tips, darts, archery, knife making, mold and pattern making, furniture refinishing and antique repair, and for fishing, fly line splicing and fly tying. Wood turners and manufactures of custom wood products appreciate the ability of ZAP-A-GAP CA+ to help save their projects by filling in and bonding cracks that often occur in expensive hard woods. Allows 7 to 10 seconds for positioning. Cures in 24 hours. Accelerate the cure with Zip Kicker. Available in different size bottles.

that what they say,

ihave bee using it for a couple years

seven to ten seconds...!

can tool in 60 seconds

if you let balsa set for maybe two minutes you can turn on the mini grinder and shape a tailblock.

balsa rc plane modelers are on this stuff bigtime.


weird tried ordering some of that zapagap and they won’t ship it to hawaii


I got it

see P.M.