Best Flame Retardant for XPS Rigid Foam Insulation Board

Joined
Dec 5, 2019
Location
5701 Delhi Pike Cincinnati OH
Hi All,

This spring I am hoping to work on a project with one of my classes where we design and build headstones for a future planned production of Edgar Lee Master's Spoon River Anthology. After some initial research, it seems like the best way to go about doing this is: use XPS rigid foram insulation board the create the headstones, use a dremel to router and carve out surface details, use a course drylok paint to give a rough texture/primed surface, and then paint weathering/aging.

I have used foam board before on small projects, but never anything so extensive. I want to make sure I get things right the first time, especially regarding flame retardants.

Foam: https://www.homedepot.com/p/Owens-C...oam-Board-Insulation-Sheathing-88WD/202085958
Drylok: https://www.homedepot.com/p/DRYLOK-1-gal-Gray-Masonry-Waterproofer-27613/100165469
Flamex: https://us.rosco.com/en/product/roscoflamex-pa

The question is: What would be the best flame retardant to apply to the foam? It seems like an additive to the drylok would probably work, but I've not been able to find any information. Any recommendations or leads would be greatly appreciated. Thanks!

Best,

Richard Buchanan
 

JohnD

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Van

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Yep, I would use VSSSD with Sand if you want that texture. Mix in some FR-1 or Rosco Flamex

Depending on how ornate you want to get with the carving of the headstones I've always found the following tools really helpful:
Surform, rounded and flat.
Wire wheel, Wire cone drill attachments.
Wire Brush, Harbor freight sells a great multi pack of steel and brass brushes that work great!
Heat gun.
Sawzall, for rough cutting.
Parring knives and bread knives.

Just one more thing, and maybe you know all this already, if you use any power tools, either battery of corded, be sure to wrap the vent holes in cheesecloth. Of course you'll want to make sure you don't over heat them but it beats having the commutators covered in melted polystyrene...
 

egilson1

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Rosebrand also has a new flame protection product called Fire Stop 701. it can be sprayed on after. Looks impressive.

 

kicknargel

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Aug 10, 2009
Location
Denver, CO
This has been covered in this:

and other threads.
 
Joined
Dec 5, 2019
Location
5701 Delhi Pike Cincinnati OH
Yep, I would use VSSSD with Sand if you want that texture. Mix in some FR-1 or Rosco Flamex

Depending on how ornate you want to get with the carving of the headstones I've always found the following tools really helpful:
Surform, rounded and flat.
Wire wheel, Wire cone drill attachments.
Wire Brush, Harbor freight sells a great multi pack of steel and brass brushes that work great!
Heat gun.
Sawzall, for rough cutting.
Parring knives and bread knives.

Just one more thing, and maybe you know all this already, if you use any power tools, either battery of corded, be sure to wrap the vent holes in cheesecloth. Of course you'll want to make sure you don't over heat them but it beats having the commutators covered in melted polystyrene...

Hi Van,

Thank for all the recommendations, but especially the cheesecloth over the vents on power tools. I have previously only used hand tools, which was messy enough. I will happily avoid getting melted foam particles in our tools. I appreciate it!
 
Joined
Dec 5, 2019
Location
5701 Delhi Pike Cincinnati OH
Rosebrand also has a new flame protection product called Fire Stop 701. it can be sprayed on after. Looks impressive.

Thanks for the recommendation, I am not familiar with this product. Something I could apply after the fact would be quite convenient. I will take a look.
 
Joined
Dec 5, 2019
Location
5701 Delhi Pike Cincinnati OH
This has been covered in this:

and other threads.
Thanks for the referral!
 

JohnD

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Fight Leukemia
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Location
north central OK
For those playing along at home, I have to say this new-fangled internet thing is awesome! Used to be was you had to go to the library and search all sorts of books to find things that google and bing can do so easily, like images of old tombstones.
 
Joined
Dec 5, 2019
Location
5701 Delhi Pike Cincinnati OH
For those playing along at home, I have to say this new-fangled internet thing is awesome! Used to be was you had to go to the library and search all sorts of books to find things that google and bing can do so easily, like images of old tombstones.
JohnD,

You are so right. Many of my students have no idea how good they have it. Whenever possible I do encourage them to do some searching for books in real-life library, sometimes serendipity presents things they would have otherwise missed. In this spirit, we are planning to take a field trip to a local historic cemetery called Spring Grove in Cincinnati, OH. It should provide some fascinating inspiration research for our projects. https://www.springgrove.org/
 

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