Polyurethane ok? Sealant advice, please.

[dansemacabre]

I picked up some pine boards for my lighting canopy. I think I really got some nice ones. Anyways, is it safe to use a polyurethane coating on the boards? I don't want anything that's not going to be good around the hot MH bulbs, and I don't want anything to leech its way into my tank water (so I did not buy treated lumber). Anyways, I was wondering if the polyurethane would be good, and if not, could anyone recommend something? I figure it needs it as it's going to be directly over water. Thanks!

 

[fishfreek]

Sure its ok. I have even polyed stuff in the same room as a tank (open windows and a good breeze of course). For the MH bulbs you should try to have a standoff between them and the wood. This is just for the heat issue. Hot bulb and reflector in direct contact with the wood could cause issues but an inch or so of airspace between them will provide some room for air to circulate around it.

 

[dansemacabre]

What you recommend I use to create the gap? Obviously I can't use wood pieces... what's the route I should go? And thank for the info.

 

[fishfreek]

Metal spacers. They are like hollow metal cylinders that you can run your screw thru to affix the reflector to the wood. This puts the reflector on little legs standing up off the wood.

 

[dansemacabre]

Thanks!

 

[RandyStacyE]

Not just any polyurethane will do the trick. Most are junk. They do NOT permanently bond, lack in flexibility, UV resistance, require several coats, and contain solvents. If you want this tank to last, you should do some research on the coating you will use. It is the most important aspect of the tank. What good would it be if it can’t hold water.

The best way to waterproof a wood, concrete, steel, or fiberglass tank is to use "Sani-Tred products" at www.sanitred.com
They have an absolute life time warranty and NO SILICONE or epoxy. Their products are a type of polyurethane that is reef safe. As long as the structure will hold the water, Sani-Tred products will keep it in the tank. These products have been used on multi million gal wood tanks so they can easily be used to seal a tank for us. Sani-Tred coatings are tougher and more flexible than wood.

 

[tkos]

Whatever you use should be marine rated. Many hardware stores have a marine section and you know that will be fine to use. But also watch out as many of these products contain copper that is used to kill of marine creatures (yikes!!) like barnicles. Or else they may contain a substance called BTA or benzatriazole which is used to keep the product from hardening in the can and for many creatures it is poisonous.

 

[RandyStacyE]

The Sani-Tred coatings cure by drawing moisture from the air and contain no chemicals that keep it from curing. Contains absolutely no copper. I have found that whatever you can buy from a hardware store is a high priced low quality coating. They offer NOTHING as far as a guarantee. They are what is called a "temporary maintenance product". You can buy a "marine paint" but have you ever heard of people re-painting a boat. ALL THE TIME. Marine paints "chalk" and break down with age.
Sani-Tred products are not PAINT, never break down, crack, delaminate, or chalk.

 

[dansemacabre]

Ok...I'm not building a tank. I'm building a hood for the tank. The wood will in no way come into contact with the water (unless some condensation somehow forms and it drips, but the fans should prevent that). So, I'm assuming it is safe to use a standard polyurethane product to seal the wood for the hood (rhymage) just to keep it from rotting over the years. comments?

 

[r95rdstr]

Look into spar-urethane. It's an exterior urethane that will expand and contract with changing conditions like temperature and humidity. Polyurethane will separate from the wood and peel off.

 

[tkos]

Well I guess the Sani-Tried product sales man wins!!
---------------------

Spars are great varnishes as r95rdstr says. Especially if you are looking at doing a hood.

I am just going to post some info on painting hood in DIY right now. A problem I found.

 

[RandyStacyE]

r95rdstr,

Not all polyeurethanes will peel off. I agree most coatings/paints are JUNK.

The products I listed here are permanent/lifetime guarenteed. Not furniture varnish.