3D printed rudder

Lattely i’ve been playing with my 3D printer.
To me it seems that creating small and precise profiles for our boats is difficult, unless one has a mould.
So this si a sample rudder for our national class boats:

It was printed in two hlafs like this:

from pla plastic, glued together with super glue:

the shaft is 3mm brass tube, otherwise i use aluminum with a 2mm carbon rod in the middle.
Poliester putty, sticks well to the plastic

and finally spray paint

5 layers of it to smooth out the layers completely.
I was in a hurry with this one, so pre season testing can begin, for future rudders car paint will be used.

In my case build time was reduced greatly. No waiting for epoxy to cure, no sanding the wood core…and the shape is surely as defined by the airfoil chosen. It took the printer 7 hours to print it. 2 hours of work were needed to glue it and finish the surface.

The stiffness is alright, it is not as strong as glasfibre rudders, but at the speeds our boats create it won’t bend or twist.

Weight is 35g, not light, but when building three different boats a year and testing many different foils it certanly saves a lot of time. :slight_smile:


What a great idea . will start one today on my Makerbot printer.
to stiffen it up some add a slot for a piece of small carbon tube inside. should help a lot.

I’ve looked at 3d printers and due to my not so bright mind I’ve been a bit overwhelmed by the skill/brainpower required to use them. Is there information sch as “3d Printers for Dummies” available anywhere? Or am I just too long in the tooth - and I should let some young bright spark get on with it?


RGSAILOR, how is the makerbot, are u satisfied? any tricks?, I use ultimaker2

A carbon tube would help but there is no need for it really.

TF, there are some tricks used with 3d printers, once you learn them, the procedure is always the same. Designing your own parts thats where the bright spark comes into play, but even if you don’t intend to draw your own parts there are plenty of
pre-designed ones on the net(thingiverse.com, grabcad.com, shapeways… etc etc…
Many tutorials and tips about 3d printing can be found on youtube, 3ders.com, wikipedia and forums.

The printer is a big investment at first, but in the long run it’s well worth it.

Thanks for that spade,

I’ll check those sites out and see what I can learn.

I appreciate your finding the time to give me this info


The Makerbot is OK. I think they all have some issues in one way or another. my biggest problem is inside holes tend to be small. easy work around to add a bit to the size.

^ get to work…

Hey Marc
It’s called “professional development” I am working !
I take great pride in taking on any “crazy” idea’s the designers and "higher up’s " have here at work.
Good ideas come from many places. You just have to look for them. :slight_smile:
And when you need a rudder Call Spade, shipping from Slowenia should not be bad…

professional development. thats what you are calling now… if smells like BS and Looks like BS… :slight_smile:

hey, if lake anne is still hard, want to go to WSM on sunday?

Like my daddy always said, if you can’t dazzle them with brilliance baffle them with BS.


Your rudder looks good. I recently printed one for a footy, and it came out quite well, albeit it much smaller. I’m curious if you were worried about PLA decomposing over time, and also wondering about your “polyester putty” Is this just bondo?



Thanks Nathan.
Yes PLA is biodegradable, but not water soluble.(i didn’t belive that but after two weeks of soaking on the radiator in the bathroom nothing happened :))
I guess we will see if something starts to “eat” the rudder, hopefully it has at least some protection from the paint.

But this is a prototype. I can make a new one over night, meaning that I can test a new rudder every other day!!, then settle for the best one and make a mould, that’s what i am doing at the moment.

Not sure what you mean with bondo?
It is car filler, it has two components(red-hardener and white-mass)

Hopefully that answered your qiuestions, cheers.


I think Bondo is just a US version of your polyester filler. Two parts, smells quite strong of styrene, and when the red hardener is added to the grey base it comes out slightly pink.
It’s good to know that PLA does not dissolve or break down in water. This is actually quite important as It’s specific gravity is .2 less than ABS meaning it’s lighter!
My first rudder printed in ABS, has hollow voids in the thicker sections and as a result (without filler) the printed weight with shaft (1.8mm carbon) was 4.4g. Which is heavier than a balsa one, but still not too bad.

As an added thought. Why go to the effort to pull a mold off the ruder you are finally happy with. Why not just print the mold? It would save you a few steps.


Yes that’s the same smelly stuff we use all across the globe :slight_smile:
Off course i could not match carbon-balsa sandwich weight with the 3d printed rudder either, but the required stiffnes was reached anyway.
The reason i didn’t print the mould for this rudder is that i plan on making many such rudders, because part supply for our 750mm national class is poor.
A 3d printed mould does not last 10 or more moulding cycles because two component paint does not stick to pla good enough :confused:
Gelcoat is even worse.
But i am designing a canting keel mould which i will print.

Hi Spade
I really like your printed rudders. I am thinking that 3D printing may also be a good method of producing the form to make a Footy fin mould.
Please could you let me know what software/drawing package you are using to create the shape for printing. Is it easy to use? Does it come packaged with the printer?
Do you think you will be able sail at the Gold Cup in England or the International Cup in Germany this year?
Hope to see you again some time this season

Hi Phil, nice to hear from you again.
I use solidworks, in my opinion the best 3d cad software outthere.
It is user friendly, efficient and can do almost anything. It does have some bugs but overall it is way above autodesk, catia or rhino.

For printing i use a .STL file.

Actually two 32mm chord Naca0012 were printed last week, and they came out good.
I guess the whole footy can be printed no problem with my machine.
There are plenty images of 3D printed parts on my blog, to give you a feel for what the “prints” look like.

I am not sure about attending the cups yet. But i will definately try to be there!

Looks good… have you tried it yet?