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Forum Index : Windmills : Wood blades-Weatherproofing

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Throgdor
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Joined: 26/01/2012
Location: United States
Posts: 22
Posted: 12:48pm 24 Mar 2012
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What are some weatherproofing options for wood (pine / spruce) windmill blades?

I've read of folks using oil based paint, and I think I saw mention somewhere of Linseed oil.

What have you used and what do you recommend?
 
Tinker

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Joined: 07/11/2007
Location: Australia
Posts: 1904
Posted: 01:50pm 24 Mar 2012
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It would depend on where you live climate wise.
If you are in the higher latitudes you might get away with a clear finish (the wood grain shows) but if you are in the tropics a good 2 pack paint job is hard to beat.
Klaus
 
Throgdor
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Joined: 26/01/2012
Location: United States
Posts: 22
Posted: 01:56pm 24 Mar 2012
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  Tinker said   It would depend on where you live climate wise.
If you are in the higher latitudes you might get away with a clear finish (the wood grain shows) but if you are in the tropics a good 2 pack paint job is hard to beat.


I'm in what I guess would be sub tropics. Very humid in South Mississippi USA.
What is a 2 pack paint job?
 
Don B

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Joined: 27/09/2008
Location: Australia
Posts: 190
Posted: 07:19am 25 Mar 2012
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A clear finish might look nice, but it is softer and much more subject to attack by UV radiation, and will never last as long. A 2 pack paint will probably be polyurethane or maybe epoxy based, and will not begin to harden until the 2 components are mixed. Use white, as this colour is the most resistant to UV degradation.

If you do use a 2 pack paint, follow the paint manufacturer's directions carefully, including their recommended fillers, primers, and undercoats, to ensure that every coat is compatible with what is underneath it. Mixing paint systems is always risky.

You should also try to obtain some of the tape used on helicopter rotors to protect the leading edge of the blades from erosion if you want to get the absolute longest lasting job.

Regards
Don B
 
Throgdor
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Joined: 26/01/2012
Location: United States
Posts: 22
Posted: 12:12pm 25 Mar 2012
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  Don B said   A clear finish might look nice, but it is softer and much more subject to attack by UV radiation, and will never last as long. A 2 pack paint will probably be polyurethane or maybe epoxy based, and will not begin to harden until the 2 components are mixed. Use white, as this colour is the most resistant to UV degradation.

If you do use a 2 pack paint, follow the paint manufacturer's directions carefully, including their recommended fillers, primers, and undercoats, to ensure that every coat is compatible with what is underneath it. Mixing paint systems is always risky.

You should also try to obtain some of the tape used on helicopter rotors to protect the leading edge of the blades from erosion if you want to get the absolute longest lasting job.

Regards


Thanks Don! That cleared up what a 2 pack paint is for me. I am still in the trial stages on making good uniform blades that are fairly consistent, but closing in on my first set. Still loads of trial and error before I have a set I want to pour a bunch of money into to preserve.

I had figured on white paint and a couple coats of simple oil base paint for the first set or 2. But now I know what to get when it is time.

(I have even thought about using fiberglass resin.)

TEdited by Throgdor 2012-03-26
 
Tinker

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Posts: 1904
Posted: 01:55pm 25 Mar 2012
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  Throgdor said  
(I have even thought about using fiberglass resin.)

T


Please don't use 'fiberglass' resin on wood - it won't last. By 'fiberglass' I mean a polyester type resin that is mixed with just a few drops of catalyst.

Use epoxy resin instead but do include a white filler in the final coat or use white paint on the epoxy encapsulated & sanded wood smooth surface.
Epoxy has a mixing ratio depending on brand and can be anything from 2:1 to 5 or 6:1. The first is the resin, the second the hardener. The correct mix is shown on the container. Usually measured by volume but some types can also be measured by weight.

If you have never used epoxy before - its a 2 pack - please read up on it as its critical to get it right. The 'Gougeon Brothers website has heaps of info about epoxy.
Klaus
 
Throgdor
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Posted: 04:02pm 25 Mar 2012
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I did a search on "Gougeon Brothers" and came up with some info. Thank you.

(I had assumed that fiberglass would work as I know fiberglass is used in boat's marine construction. Still not sure why it would not last, but I'll take your word for it.)
 
Tinker

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Posted: 01:53pm 26 Mar 2012
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  Throgdor said  

(I had assumed that fiberglass would work as I know fiberglass is used in boat's marine construction. Still not sure why it would not last, but I'll take your word for it.)


What's commonly referred to as 'fiberglass' (at least here in Australia) is a layup of glass cloth & chopped strand glass mat encapsulated in polyester resin or vinyl ester resin etc. and an outer layer of gelcoat. That mix works very well for 'fiberglass' boat construction.
However, this type of resin does not adhere very well to wood. You might have heard of older wooden boats that were given a new life with a 'fiberglass' coat which subsequently de-laminated.

On the other hand, Epoxy resin makes a wonderful wood glue and is excellent for wood encapsulation but it must be protected from UV exposure.

Klaus
 
VK4AYQ
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Joined: 02/12/2009
Location: Australia
Posts: 2539
Posted: 12:45am 27 Mar 2012
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Hi All

When I used wooden blades I used a two pack epoxy resin called everdure as a base coat, it is a thin resin designed to soak well into the wood structure and is anti fungal as well, It is a Epicraft product and I see it is still supplied by Chandlers. several coats then a compatible epi craft white boat paint and it will last for 5 years or more, on refinishing a good sanding and several more coats last the best of anything I tried.

All the best

Bob
Foolin Around
 
Gizmo

Admin Group

Joined: 05/06/2004
Location: Australia
Posts: 5078
Posted: 12:51am 27 Mar 2012
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Yeah I agree, you need something thats going to soak a few mm into the wood. I had a set of timber blades that were painted in enamel, tough, but as soon as you get a tiny hole on the leading edge, water gets in and under the paint, and its downhill from there.

Same with fibreglass, its OK until there is a hole or crack in the glass/epoxy layer.

Glenn
The best time to plant a tree was twenty years ago, the second best time is right now.
JAQ
 
bvan1941
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Joined: 06/05/2010
Location: United States
Posts: 24
Posted: 07:16pm 29 Mar 2012
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Guy,
they make a "penetrating epoxy" that does what you all are trying to do with other schemes. "Smith Industries" sells this and it is the porosity of water. It bonds very well as epoxy is a "glue" the rest is not a glue and therefore dosen't bond well. Most people with vintage boats use this to repair rot, prevents water intrusion and strengthen the wood. Be advised you get what you pay for and nothing that one really needs is cheap! Be aware you have to balance your rotor after all this is complete.
Good luck,
Bill
Bill
 
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