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shawn Senior Member Joined: 30/03/2010 Location: New ZealandPosts: 210
Posted: 07:45am 19 May 2011
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Hi guys has anybody else put resin over there wooden blades?
finished carving and sanding mine, and was thinking about paint when my tin of vinalester resin stuck out of the shelf so i thought why not i mixed it up then added a little thinner and painted them with it, it soaked in and set!!
took a while around a week for them to be able to sand without sticking up the sandpaper but when i repeated this this time with the spreygun the finnish was great and you can see the lovely woodgrain and laminations.
Has anyone else used this as protection for the wood? will it last??
Shawn
mac46 Guru Joined: 07/02/2008 Location: United StatesPosts: 412
Posted: 09:50am 19 May 2011
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Shawn,
I have'nt used this resin personaly...on props, but I would think it will be just fine. You may want to use edge tape on the leading side. Recheck the balance ofcourse. Others may have a different openion.
.....Mac46I'm just a farmer
Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904
Posted: 01:30pm 19 May 2011
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Shawn, I have tried bright finish on various items on my sailboat, the harsh sun here down under has ruined the nice finish after one season every time. The resin will go milky and just flake off, very hard to repair to a nice finish hereafter.
Resin (epoxy pref.) might work well enough in the higher latitudes.
You could try spar varnish which is designed for outdoors, this needs about a dozen coats initially and regular top ups thereafter.
For long maintenance free periods you can't go past a good quality 2 pack paint for your wooden blades.Klaus
VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539
Posted: 02:22pm 19 May 2011
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Hi Shawn
I have used a few coats of silver fross aluminium paint to stop UV from attacking the wood, also found that epoxy resin is better as it is slightly flexible and doesn't get the hair line cracking as wood expands and contracts a few coats of enamel over the silver makes it look better.
All the best
BobFoolin Around
Rastus Guru Joined: 29/10/2010 Location: AustraliaPosts: 301
Posted: 03:14pm 19 May 2011
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Hi Shawn,
I used epoxy resin sealer on 20mm(3/4") plywood in 1987 and still have 1 sheet left.It has been weather exsposed in South Australia for the last 12 years and is still seviceable,although it now has surface grain cracks.On this test result I'd definately recommend it.I've been following your project with interest and notice you are getting better than average results from your primitive tooling.Keep up the good work.Cheers Rastussee Rastus graduate advise generously
shawn Senior Member Joined: 30/03/2010 Location: New ZealandPosts: 210
Posted: 06:56pm 19 May 2011
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Thanks guys this feedback is good! I guess I will paint them to protect from the sun, the resin is quite thick and strong which is good, gentle taps do not dent like they would otherwise.
frackers Newbie Joined: 06/11/2009 Location: New ZealandPosts: 23
Posted: 04:23am 07 Jun 2011
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Sounds like you are at the state I was with my first set of blades. I painted mine to keep the sun out but had to sand and use an etching primer to key to the resin and then undercoat and finally an oil based top coat.
For the rebuild I've gone for primer, undercoat and then topcoat - all oil based so they really stick to the wood.
Robin down under - or are you up over
Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1344
Posted: 05:18am 07 Jun 2011
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I just use 2 pack paint on my blades and they are still going well after a few years. The suspect blade started cracking so I epoxied the whole blade then thru another coat of 2 pack over and everything is fine with them.
Cheers Bryan
shawn Senior Member Joined: 30/03/2010 Location: New ZealandPosts: 210
Posted: 07:43am 07 Jun 2011
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Yes Robin I have bought some two pack primer for over the resin and then two pack for the top coat it has all added up though my small mill (3m dia) had just oil type primer and top coat and has given no trouble at all!
The new blades are laminated and 4m diameter also I think the resin has made them even stronger but at extra cost next time i will not bother
Rastus Guru Joined: 29/10/2010 Location: AustraliaPosts: 301
Posted: 02:29pm 07 Jun 2011
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Hi shawn,
Your blades look good,just seeing the timber finish is eye catching.I've been learning about laminates as well.Airo wooden props are laminated then 9 coates of resin before paint.If left unpainted a yellow resin is recomended for full exsposure,and its claimed to withstand leading edge damage better than anything else,although a purist would say that instead of 2 pack to stay with tradition is my guess? 2pack could be as good but have similar repair issues.Life's uncertainties have stopped me from starting to date,so you aren't travelling to bad.I will make a start as soon as I can and in the mean time there's more to learn and understand,Cheers Rastussee Rastus graduate advise generously
niall1 Senior Member Joined: 20/11/2008 Location: IrelandPosts: 331
Posted: 11:43pm 09 Jun 2011
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any chance of another few pics of those big laminate props Shawn ....especially when you,ve assembled them and give us an idea of their size ....
what type of wood did you use for the laminates ?...
theres something about wood blades thats hard to get away from ...
chainsaws...mmm ....a lot of fun there i,ll bet ....Edited by niall1 2011-06-11niall
Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904
Posted: 02:35pm 10 Jun 2011
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While I have not yet made wooden laminated blades for a windmill I made a few sailboat rudders in that fashion. I know, sailboat rudders don't rotate at high speed but they can be heavily loaded and need to be strong.
Looking at Shawn's pictures, there are a few things I would not have done...
Anyway, for laminating choose clear close grained wood, clear means *no* knots or cracks at all, close grained means around 10 growth rings per inch. Cut the wood from planks that are cross sawn - the grain goes across the thickness of the board. Diagonal grain is OK but then alternate your laminates so the grain runs alternating left/right as viewed from the end of the assembled blank.
Use a 2 part epoxy glue (with 'thickener', suitable for boat building) for laminating. Do not clamp too hard so all the glue squeezes out, epoxy is gap filling and a 1mm gap is OK as long as its completely filled with the thickened epoxy glue.
I would use an alternative laminate of American white ash and Douglas fir, there are of course many other suitable woods around. Criteria is they must be able to up take the glue (no oily or super dense woods) and not be too heavy.
If you are interested to make your own laminated windmill blades perhaps searching on laminated wooden rudder blades will hive you many hits on Google regarding the technique, the process is really the same.Klaus
shawn Senior Member Joined: 30/03/2010 Location: New ZealandPosts: 210
Posted: 05:17am 11 Jun 2011
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Hi nail yes lots of fun I do enjoy making blades and can do it quite fast now wood is by far the cheapest way to go no question! and will give years of great performance.
I will post more pics soon and i have a few shots of the mill head assembly to with my sliprings.
Thanks tinker your advice is good I guess I just thought I could improve a little on my last set they were full of knots in all the wrong places made out of cheap pine , funny thing is I built them up with very little care and no laminating they have withstood 140km gale gusts even when they were out of balance this adds huge stress to them but still fine and spinning away.
These blades have just been cut with a table saw then glued together with gorilla glue cheap old pine again and plenty of knots ooooh well we will see how they stand up soon enough
Just a quick edit the new blades do have a very good profile this with a well matched Alt is were all the power is made.Edited by shawn 2011-06-12
niall1 Senior Member Joined: 20/11/2008 Location: IrelandPosts: 331
Posted: 11:24pm 12 Jun 2011
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today when i was stopped at the toll bridge a small sail boat was being towed in the next line ...
its keel was HUGE ...must at been at least 7 feet long and thin.....seemed bigger than the boat itself ...
boat building techniques do seem to have a lot to share with wood props Tinker...if its a wood product and can survive in salt water under stress ...under a boat...
chances are it,ll do just fine in wind..... Edited by niall1 2011-06-14niall
Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.
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but they can be heavily loaded and need to be strong.
