# Best flame retardant for muslin



## DaveSHS (Jan 19, 2013)

Hi everyone,

I recently started a job teaching theater at a high school, and my predecessor left a large box of muslin. I want to use it to construct some flats for our next show, but I can't find any documentation stating if the muslin was fireproofed or not. I'm planning on spraying on some fireproofing solution after they are painted just to be safe, and I wanted to see if anyone has a recommendation for a particularly fireproofing product. Thanks for the help.

David


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## MPowers (Jan 19, 2013)

DaveSHS said:


> ......... box of muslin........ construct some flats.......can't find ... if the muslin was fireproofed or not. I'm planning on spraying on some fireproofing solution after they are painted just to be safe, .......anyone has a recommendation for a particularly fireproofing product.......



David, First - KUDOS TO YOU for not only being safety conscious, but also for being proactive in dealing with this issue. Many of the schools in which I do safety inspections, have no idea if the scenic units and materials they have are treated or that they even need to be. 

A couple of things about flame treating. I don't mean to be pedantic but there is no such thing as "Flame Proof". Fabrics and scenic materials can be flame RESISTANT, but not flame PROOF. 

Now, you can check yourself to see if the fabric was treated at the factory. Cut a strip from one edge about 2" wide and 8"-10" long. Hold one end in a pair of pliers or vice grips or similar and allow the swatch to hang down vertically. Use a match or a lighter and hold it under the lower end until the fabric catches fire. If it flares up and continues burning when the flame source is removed, it definitely was not treated. If it only chars or the flame dies out as soon as you take the flame source away, it probably was treated. And yes I said probably, you still do not have any documentation. So you probably do want to treat the fabric.

Spraying the scenery (or soft goods such as drapes) after it is built and painted is is the least effective way to treat your scenery. In addition you run the risk of altering the look of the paint job and there is usually a big mess from the spraying as a good portion of the product will simply run off the paint's finish coat especially if the paint is acrylic or latex. It is best to treat wood and muslin before or during construction. Rosco has a wide range of products for treating scenic materials 
Rosco Flamex - rosco.com
For Cotton muslin, before construction or painting, Roscoflamex NF - Natural Fiber Flame Retardant, is your best bet, It works best if the fabric is vat dipped. You can also brush it on after covering your flat but before you paint. For this method you would also want to consider using Roscoflamex WD - Raw Wood Penetrating Flame Retardant, on the bare wood portions of the unit. 

Another way you might try is the paint additive, Roscoflamex PA - Paint Additive Flame Retardant. This is a chemical you add to the paint, usually the base coat or prime coat. If you use the PA product, be aware that to be completely compliant, you will need to paint the back side of your scenery as well as the under sides of platforms. 

When you look at the Rosco web site, you will notice in the task bar at the top "Where To Buy" that will guide you to Rosco dealers near you.

There are other products available and in Ca. you might find several other brands. All are similar and produce the desired results. I just happen to be very familiar with the Rosco products, having used them for many years and now, as a Rosco Dealer. 

Hope this helps.


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## DaveSHS (Jan 20, 2013)

Thanks for the suggestions. The roscoflamex nf looks like a good fit and the lighting shop I go through is a dealer. I read on the rose brand site that some flame retardants can lose their effectiveness if paint is applied afterward, but when I checked out the flamex it seemed to imply that you would treat the fabric before applying paint, so it looks like I should go the way you recommended. To make sure I've got the procedure right, it looks like I should cover the flat with the muslin, paint on the flamex and let it dry, paint on the sizing and let it dry (I use a wood glue/water mixture), and then paint it. I saw that dipping the muslin was the most effective way to apply the flamex, but I'm concerned about distorting the shape of the fabric and adding wrinkles as it dries. Should I be? Thanks again.


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## MPowers (Jan 20, 2013)

DaveSHS said:


> Thanks for the suggestions. ........ To make sure I've got the procedure right, ......cover the flat ....paint on the flamex ...dry, paint on the sizing and let it dry ......and then paint it. I saw that dipping the muslin was the most effective way to apply the flamex, but I'm concerned about distorting the shape of the fabric and adding wrinkles as it dries. Should I be? ....


The procedure as you outlined is correct. If you are making hollywood flats with the muslin over a luan backing, make sure to thoroughly wet the fabric, if you are making soft cover flats, brush the muslin from both sides to insure full penetration. Don't forget to flame treat the wood frames of your flats (as well as platforms). If you decide to go the paint additive route you can use the same product for all the scenery. The dipping method works best for fabric and goods that are to remain in a "soft" form such as curtains, or draping. Cotton muslin will shrink or draw-up appreciably when it becomes wet for the very first time. This is why you leave a bit of slack or sag in a soft cover flat. The first size/prime coat will shrink and draw the fabric tight. Stretching the fabric too tight before the size/prime stage, on a large flat, can result in a frame being pulled out of square or warped.


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