How to Balsa rail a radius

I was asked on another thread how to get the radius on the balsa rails.

I use 3/32"- 3/16" thick balsa sheets 4" x 36"

Choose balsa grained planks that are flexible and not stiff. It is easy to figure out.

Take boiling or heated water out of a water cooler.

Use 3 or less 36" planks and pour hot water on the center 12" on both sides of the wood.

! place plastic bags between the wood so they don’t stick together.

Carefully tape, center outward, the planks around a solid radius. I use a medicine ball and 30gallon drums.

Let dry, remove tape, 

Procedure time- 10 minutes, not including dry time

This method yeilds enough thickness from 1 1/8"- 2 1/4" of nose or tail radius. I typically use 1/2" to 3/4" thickness for boards.

When gluing rails to blank I vacuum bag. I have a routine that has evolved from time cosuming to easy. Either way, worth the effort.

Board pic below is 9/16" thick prior to shaping rail.

Pic order

  1. Goal

2/3, wood being bent.

 

 



very cool…thanks for the tips!

whats your opinion on balsa as a core for fins?

PS – I noticed your festool sander in the background… can you recommend a good brand of sandpaper?  I mostly use the OEM/festool stuff, which is expensive…but have bought some pretty crappy “fits festool” stuff off of ebay.  wondering if there is something else I haven’t found yet.

 

Keith, 

Look no further!! —> Indasa<—  

http://www.burrellcustomcarpentry.com/subpage93.html

Wouter

edit:

http://www.2sand.com/791/Indasa-Rhynogrip-6-inch-Festool-9-Hole-Velcro-Sanding-Discs-50/box.html

Oh, and it is also super easy to add holes to your ol Festool pad by drilling it –> i did it and it works. Don’t know yet where to buy 16 hole? Festool fitting sanding paper though.

Hi Keith,

 I have only used festool brand. It is expensive.  Thanks for the heads up on the Ebay stuff. I was going to try it but I was skeptical. For my makita and hand sanding I use the NORTON 3X stuff you can get at any major hardware store. It is a little more expensive but worth it for its durability. Has the feel of a soft cloth backing and not just 3M paper. 

I rarely do glass fins and recently gave all my balsa glass ons away. The ones I used in the 90’s were made by (forgot his name, one of Bill B’s diciples) a super talented fin maker and never had a problem with one. They are custom orders and not stocked in surf supply stores.  Makes wooden boards look awesome.  I have hade major brand bamboo fins break and chip easily though.

Since I have gotten into cork my sand paper and blue tape use is way down. The 4oz outer glass job is way easier to sand and finish. When I get the exposed cork deck wired it will be even less sand paper use for me.

It is kind of amazing the dynamic beneifits of cork in many aspects of manufacturing surfboards.

suppose to be a south swell on Thursday.   Hyped rumor or truth?

Brilliant, thx BB30.  Great work.

Tape off, ready for future use, store in box they came in to keep shaped.

 

Aloha Charlie, great tip. How small of a radius do you think you could go?

I always love the way the nose and tail blocks on that first board you did for me look with the colored paper between the layers of wood. I used it a week or 2 ago, and I still enjoy riding it.

I think we’ll see some waves this week. In the 80’s we always had a spring break south swell. Solid overhead at Shark Country. I used to love that swell, but it’s been off for several years. Maybe we’re getting back on track. It would be big enough to tow surf outside your house on the outer reef.

Hi Harry,

 I have never surfed Shark Country. I saw it breaking nice last summer and fall on walks with my daughter. The outside reef directly behind the house is too close with no one out perfect conditions to go anywhere else. The water out there is pristine clear too. got to hit it early when the wind is down.

Making a tight radius is all about the wood selection. The ones I show being made in this post could make a tight curve.

Pic below demonstrates when a break happens. But It still looks nice even with the crack on the outer piece. I just keep on telling myself it gives it a custom hand made look.

Aloha,

Charlie

I finally used the pre-shaped radius I made.

I used six, approximately 1 inch wide, , 3 feet long balsa strips.

I acheived a 5/8" build out on the rail and that will be plenty of wood to shape the rail nicely.

Did all six layers in one vacuum pull for 90 minutes.

below pic of sawn off excess on top and bottom.

 

It took about 20 minutes to cut and place epoxy between planks and tape to nose.

fast potlife epoxy and kept in vacuum bag for 90 minutes.

Below pics of top and bottom with the initial sanding.

 

 


I beveled the ends for the transition on the remaining rails to be placed.

I added a tail block and matched to the bare rail.

I will get added strength to my tail block if I attach the wood rails to the sides of the tail block.

The top pic is distorted by the angle of the photo.


The same game on the side rails with six layers all at one pop.

I try to make the first one or two layers closest to the bare rail close to the rocker shape and the last four you can be less percise because they will quickly get cut off closer to the shape prior to sanding.

The side rails took longer, 90 minutes to make and glue and 90 minutes in the bag.

 


Charlie is that texallium or carbon?

I don’t bag the rails because I don’t have the vacuum equipment at my house. Lots of tape for me. I’ve found that if I use epoxy for the first layer of wood to foam, then wood glue for the rest it’s easier to shape the rails with hand tools. I also try to cut them to width as much as possible to keep the waste down. Bernie and I bought a shed full of balsa from the widow of a model airplane builder a couple of years ago. I have these 1/4" sticks that can bend to match the curve of the rail and not cut the wider sheets, but it’s a bit more work, and they’re only 18" to 24" long. 

Bernie should give you some of the wiliwili we have for tail blocks. I has a real wild grain and looks great after you glass it. It’s not as flexible as Balsa, but it’s light. He has a lot of blocks at Dad’s house.

Thanks for sharing this bb30.  A real inspiration.  Can’t wait to see it finished.

Hi Harry,

 The deck is texallium I think.  Bernie gave me a nice size sample of this cloth about 5 years ago and I finally got around to using it. It was super stiff, like single layer cardboard stiff. I vacuumed bagged it to the deck and used peel ply and it came out really nice. There is also a huge piece of this siver cloth Bernie gave me in the same roll and I am not sure what it is. He will have to instruct me on what to do with it.

With the balsa rails. the balsa wood is least expensive at certain lengths and widths from my supplier. Since the corecork came into the picture I have a couple thousand 3 and 4 foot balsa planks available. It cost about 15 dollars of wood for a  long board to add an inch plus to your width by adding balsa rails. Back in the day I used the cedar 1" molding from home despot which is inexpensive and works well also.

I never used wiliwili but I would love to try some.

aloha,

Charlie


Hi Greg,

 I don’t know if it is just my imagination, but balsa rails seem so easy to shape. Way more forgiving than 1lb foam. Just need to glass the board and go ride it. 

Pic below, modified MdKee quad set up.

aloha,

Charlie

Hi Charlie, those are texallium from Fiberglass Hawaii. We ended up using the vac bag to laminate because the cloth wouldn’t hold the wrap around the rails. I think it’s just glass with something added not the same strength of carbon. Bernie’s board used to get real hot, so I think he painted it white. I might be wrong, but I know it used to get hot really fast. I have a 10’ roll of 60’ wide Carbon, but because of the heating and hassle of glassing in a vac bag, and Bernie has all the vac gear, I haven’t figured out when I’ll be using it.

I talked to him today, and he told me a little about the corecork you use. Too bad, he said he saw you earlier. I’m going to ask him to give you some wiliwili. I don’t know if it’s going to work as well for rails, it’s really stiff, but very light. I have a couple of good sized blocks that are so light, but I also have some that is not so light. I use it for nose and tail blocks, and I cut a lot into strips to make tops and bottoms. I think Bernie used up most of the 1/8" stuff, but we have a lot of 1/2" and 1/4" or 3/8" strips between 2" and 3" wide. I still have a few uncut branches and a few big blocks at my house. 

I really enjoyed that video you linked with Dave Daum shaping. I learned a lot. 

8’ x 22 1/4" x 2 3/4"


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