I need battens. I have access to miles of the round stock that most wave sails use but without tapers. Any tips for setting up a fixture to grind, sand or router them? I could wing it but I need enough of them that I want a system.

I have used a power-planer and an angle-grinder.

Using the planer was difficult as the batten has to thinned to about 2mm at the thinnest point, making clamping tough. I wasn't prepared to make a jig for the planer, as I didn't like putting my fingers too close to the cutting edge.

I have had good results with an angle-grinder and a flap-disk and with a grinding-disk. Just place the rod onto something flat - this is enough to hold the rod steady enough. Be aware of thickness - long full-length passes, not short grinds.

I'd go a bench beltsander. But like fins, its just not fun.

I have both 240 volt and cordless grinders . The 240 volt is a 5 inch and being 240 volt it runs at quite high revolutions. I use it for heavy work like boat trailers and other metals and jobs where I want to remove a lot of material and finish is not so important. I rarely use the 240 volt grinder on wood or fibreglass as it is too harsh. Even with 240 grit flap disc it is still easy to slip and take a chunk out.
For finer work I find my cordless 115 mm very handy. It runs at much lower revs and has a lot less grunt so I have a lot more control. You could use either for battens just take it easy if you go 240 volt.
A flexible pad with sanding discs or a flap disc would be ok. Not to course on the grit though. 120 to 240 should be ok.

Soft foam pad with fine paper. Flap wheels are too stiff

Belt sander with a narrow belt. 2 steel shims that are the angle that you need . Just need to support the batten while sanding the 2nd side. Using the narrow belt means that your not sanding the shims

Sander/polisher with 120 grit disc.
Forget the other options, this works best. I have done a lot of battens. Suit up, wear a mask and do it outside.
Clamp batten at one end using a clamp and a bit of wood over. Nowadays I don't use a clamp, I hold the rod in one hand and the sander in the other. Key is to get a nice little flat, then flip it over and the flat keeps it all stable when facing down....but almost definitely you will want to use 2 hands on the sander when learning to do it, so clamp
Practice a bit and use calipers.
www.bunnings.com.au/ozito-180mm-sander-polisher_p6290564?srsltid=AfmBOoruIjtNEfWkY-karAbr9S3Kwp-WXoojihwYMA9rWOtzSDlYtIYx

Lots of ways to grind down fibreglass, but most are bad ways. Harsh fast and aggressive tools rip the strands and cause small invisible cracks between the laminates. Most rod buttons are continuous rovings drawn through a mandrel as they are wetted out and then heat set in a form. There is seldom a cross weave, or a weft, to help lock the fibres together. Ripping them out just breaks down the strength, almost impossible to see but if you wipe with a guide coat you will immediately see them. What you nee to do is make some kind of jig system so your results are repeatable. As others have said, sanding over plaining grinding or sawing, and working with the grain as opposed to across or against it. We use those little 90 degree die grinders (AKA whizzers) with rowlock disks for most fibreglass grinding, it's tedious, but local and therefore dust can be controlled. not too harsh, not too fast not too aggressive.

There will be an army of them in use at the sail GP UK teams basecamp after that T bone the other day.

www.boschtools.com/us/en/cordless-die-grinders-35698-ocs-c/

Long taper - use long tool or it will never be flat

that's why I said bench belt sander so you've got half a meter of flat belt
and it sands longitudinal so prevents the tearing that Peter raises above
plus u can get it to throw the dust in a very repeatable direction where u then place your vacuum cleaner.

Thanks for all the ideas, everyone!
I made a fixture that is adjustable for different taper lengths.
The bed that the batten rests on can rotate to support the second cut after one side has been tapered.
The aluminum channels are tied together and pivot.
I used an existing batten to set up the angles and predrill the screw hole locations.
I put a few layers of blue tape on the guides to protect them and to see where I was cutting, I had to change the tape a couple times per side tapered.
I did the grinding outside with a 7" pad on polisher/sander.
Worked Bitchin!

SO it occurred to me are you putting flat tapering 'cheeks' on the battens or full round taper and keeping them in the round all the way to the end? If keeping in the round you are spinning the battens as you sand?

SO it occurred to me are you putting flat tapering 'cheeks' on the battens or full round taper and keeping them in the round all the way to the end? If keeping in the round you are spinning the battens as you sand?

Two flat planes, the standard wave batten taper.

In that case your jig is a work of art and perfect for the job. Do you put heat shrink over the batton, helps massively in the event of breakage no fiberglass shards through the sail pocket.

Also enables you to pull the whole batten out with out leaving the end inside the sleeve.

Select to expand quote

peterowensbabs said..
In that case your jig is a work of art and perfect for the job. Do you put heat shrink over the batton, helps massively in the event of breakage no fiberglass shards through the sail pocket.

Thanks Mate!
Next time I'll buy the heat shrink tube. By the time I finished the tapering I was out of patience and ready to get my sail back on the water. I did take a second and cover the tapers with a couple length wise strips of electrical tape.