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Hey all. I'm building a raised planter bed as a gift with salvaged kiln-dried pine. I know that using poly wont last as it will flake and bubble in the UV light. Would a spar urethane do, or would the chemicals leach into the soil and possibly harm the plants? It's probably only going to be flowers in it, not veggies so i'm not worried about eating anything nasty. Any input would be appreciated, thanks.
 

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You might use a marine grade spar varnish on the exterior however I think I would use fiberglass resin on the interior. Neither would really leach chemicals into the soil but I don't think the spar varnish would hold up to the constant exposure to water on the inside.
 

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It's expensive but west system epoxy with a pigment anywhere UV wil hit it. It is the most " waterproof" finish. Ther is and soaks into the wood so not the peeling issues of any file finish. It paints on well and is inert(safe) once cured.
 

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I just got to wondering Steve if a fiberglass resin is the same thing as bondo or is it something different? Is there anything that i need to use with it (fiberglass cloth, hardener, etc.)?

MidlandBob, i gotta be honest, i have no idea what a west system epoxy is...:blink: Is it anything like a deck sealer/finish?
 

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Spar varnish is fine as long as it's not a poly or urethane spar varnish. Urethane is readily attacked by the UV in sunlight and it will quickly become yellow and opaque and then begin to crack and peel. If you want to use a spar varnish get something at a real marine supply store or marina. Nothing carried by any of the big boxes will work.

Another point, pine is not a good wood for an outdoor application particularly if it will be in contact with the ground. It's very susceptible to rotting from moisture unless it has been pressure treated.
 

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I just got to wondering Steve if a fiberglass resin is the same thing as bondo or is it something different? Is there anything that i need to use with it (fiberglass cloth, hardener, etc.)?

MidlandBob, i gotta be honest, i have no idea what a west system epoxy is...:blink: Is it anything like a deck sealer/finish?
Fiberglass resin is different than bondo. Visually it looks more like thick varnish. I can't say what the formula is for bondo but there is fiberglass resin in it with some kind of solids. It's kind of like mixing saw dust with glue for putty. The resin is the glue. The fiberglass cloth would add strength to it but if it were me I would just use the fiberglass resin like varnish without the cloth. Walmart sells bondo brand resin and the hardener is in the plastic cap that covers the top of the can. The plastic cap is also the mixing container. If you were making a boat where the fiberglass would need add structural strength I would recommend the cloth but not for the inside of a planter box. Beside its a real pain to insert cloth into the resin. You have to brush a coat of resin on and then put the cloth in it and work out air bubbles and then put another coat of resin over it before it sets up and the stuff sets up just as fast as bondo. Then in the process you end up getting it on your hands and it creates little strings you can't seem to get rid of. The cloth just makes the job twice as nasty as it would otherwise. Don't try to wash the brushes out. Buy some cheap disposable brushes and throw them away after each batch.
 

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I think that you and your in-laws would both be better off if you used the proper wood for this project. In the long run it will cost you less because of the reduced need for coatings. Your in-laws will be better off because they will have a planter that will last without periodic maintenance.

If you must continue with the pine then I recommend fiberglass resin. I have used that in boat repair work. BE SURE that all surfaces are totally covered. If you leave anything open it will rot.

George
 

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WEST SYSTEM??

http://www.westmarine.com/webapp/wc...chTermScope=3&Ns=Most+Popular|0&keyword=Epoxy

That link should get you to West Marine. They have the "gold standard" in wood epoxy originally for boats but have wide application in woodworking. You do find it in other stores particularly boating stores often called a chandlery.
West epoxy has Variable to long working time and good penetration into wood surface. It is the most "water resistant" finish there is. They have a few different things to mix with the epoxy to thicken it or make it even better as a gap filler. Collectively it's called WEST SYSTEM as there are many options depending on your needs. I have also purchased a competitors line called East System.
The resin usually used with fibreglass is cheaper polyester. Polyester does not bind as well to wood.
If you did want to coat wood for in ground use it would be best except for the price.
One of the plastic decking boards would be good though also more expensive than cedar or pressure treated.
 
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