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I'm working on a project that I'm hoping won't go up in flames... literally! It's a table top (made out of wood) for a fire pit. I planned on protecting the bottom with this High Heat Ultra Spray Paint, but I'm not sure what kind of finish to use for the top. Normally I would use Thompson's Water Seal for outdoor furniture, but I believe that finish isn't fire resistant. Is there a finish out there that would protect this project from catching fire when placed over a smoldering pile of ash?

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    I believe the best solution would be to ensure the fire is completely out (including smoldering ashes) before placing any flammable object over the top of it. – FreeMan Jun 6 '16 at 19:21
  • That paint is not going to keep the wood from reaching combustion temperature and going...Poof! Also, the moisture in the wood will heat up and delaminate the paint. – Ashlar Jun 6 '16 at 20:05
  • Additionally, the paint will likely give off some nasty chemicals when it burns, and will also probably catch fire before the wood, increasing the likelihood of the wood catching. – FreeMan Jun 7 '16 at 21:01
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Use Cumaru hardwood (aka Brazilian Teak or Golden Teak). My internet searching seems to indicate that this wood has a Class A fire rating and is as resistant as concrete to fire.

This link includes a number of results from test data backing this up.

The type of testing that these hardwood decking and siding species were tested for is commonly referred to as ASTM E84-10 "Standard Method of Test for Surface Burning Characteristics of Building Materials". This fire testing standard was established by ASTM International (formerly known as American Society of Testing and Materials). A Class A fire rating using the ASTM test method is the equivalent of a Class A fire rating from the following test methods and agencies:

  • ANSI/NFPA No 255 from the American National Standards Institute/National Fire Protection Association
  • IBC 8.1 from the International Building Code
  • UL 723 from Underwriters Laboratories
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  • That might just work! Where would I find this Brazilian Teak sold by the board? I've done some searching, but I'm only finding tongue and grove flooring for sale. – Nate Jun 7 '16 at 11:56
  • Contact your local lumber mills/yards. – Steven Jun 7 '16 at 13:37
  • Or worst case, buy the tongue and grove and rip them down. – Steven Jun 7 '16 at 13:38
  • You'd only have to rip the tongue from one side and the grove from the other side of the top. You can use the T&G in the interior of your lid. Just don't glue the whole thing up tight - since it will be outdoors, it will be subject to a lot of temperature and humidity swings and will need a lot of room to expand and contract. – FreeMan Jun 7 '16 at 21:03
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In short wood is not the right material for this, I think you should re-think the requirements... coming to the inevitable conclusion that metal is very likely the way to go. Every fire-pit cover I can recall seeing was made from plate steel.

But if I'm reading the following right you already have problems you'll need to address!

a firepit made out of wood.

There's a reason barbecues and so forth are made from metal, brick or concrete, just sayin' ;-)

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  • Sorry, I should have clarified in the question, this is a table top for a fire pit. So when it's not being used as a fire pit it can be converted into a small table. – Nate Jun 7 '16 at 11:15
  • @Nate, simplest solution if you're going ahead is to douse the ashes with water. Not kidding. Assuming you can find cumaru or something similar and the cost is acceptable it's not a 100% solution since fire-resistant and scorch-resistant are not the same thing. Best thing to do if you need to convert the area from fire-pit mode to sit-around mode would be to damp the embers down. – Graphus Jun 8 '16 at 7:00
  • "Wood is not the right material". This, exactly. Although the water trick might still just work, of course "wood + water" is almost as bad as "wood + fire". I would personally be using a 3cm granite slab. – Damon Jun 8 '16 at 8:29
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Even if you coated it with a thin sheet of steel - which you'll never get to burn with a wood fire - a wooden lid would char badly.

You need to keep the temperature of the wood low with a decent layer of insulating material if it's going to go over the top of glowing coals. You might be able to achieve this with a steel sheet against the wood, then an air gap, then another steel sheet, but long term I doubt it.

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