Foam info - probably more than you want to know!

[rpeterman2]

A response to the foam question:

 

Let’s consider three elements when purchasing foam: physical construction (firmness and density), relationship between foam thickness and bell sizes/ techniques, and coverings for the foam pads.

 

Foam is defined in two ways: firmness and density.

           IFD or ILD (Indentation Load Deflection) is the foam firmness. This is measured by the force in “x” pounds required to compress a foam sample. The most common compression ration used is 25% of a 4” thick sample.  For example, on foam designated 28180, it would take 28 pounds of pressure to compress the foam from 4” to 3”, or 25% of the total thickness.  The higher the number, the more pressure it can take, and therefore the harder the foam feels.  For bells, some choirs use foam as soft as “12” and some like “30”.  Personally, I think the firmness should correlate with the size of the bell and how quickly it compresses the foam (thinking about marts!). If you have 5+ octaves of castings ranging from a half pound to 10+ pounds per individual bell, a variety of firmness would respond more consistently throughout the set. Upholsters would use an ILD of 25-35 lbs for bedding and an ILD of 40-55 lbs for sitting use. Bell ringers could use an ILD of 12 – 30.

          Density is how much the foam weighs per cubic foot (pcf).  The equation is: density= weight divided by length x width x height.  In a 28180 foam sample, the 180 is actually a reading of 1.8 pcf. Density does not tell you how firm or soft the foam will be. It is closely tied to foam performance and the higher the foam density, the better it is for seat cushions (and you should have at least a 180 for seat cushions)… and durability for bells!  The higher the density, the more durable the foam, and the more costly. Foam is a petroleum product.  When I purchased foam from a supplier, I explored a range from as soft as 12110 through 16120, 22150 and as hard as 30180.

          Manufacturers will also offer each of the above in different grade-levels – depending on manufacturer, the best can last 10+ years, depending on usage, with lesser grades lasting 6-8 years and 3-5 years.  Foam will need to be replaced depending on the number of bell choirs rehearsing week, and the rate of disintegration.

         

The second consideration is personal – what gives the “best” sound or damping and is least traumatic to the table techniques used?  Foam thickness is critical to the size bells using table techniques.  Most agree that 4” foam is best overall. Is there significant difference for the foam in ensemble ringing versus solo ringing? Will handbell manufacturers put the time and money into research on the firmness and densities of foam on the market to recommend which best matches the different bell sizes and techniques? This may not be as cost-effective as many foam manufacturers zealously guard their formulas and new products are always coming out.  However, this could be an area for further research as the instrument continues to evolve in its design and use.

 

Finally, consider the covers used to protect the foam both from handling and light.  Foam will deteriorate at a faster rate when exposed to light. The fabric selected will have a direct effect on the sound produced by table techniques and damping – in addition to the residual sound when a bell is placed on the table after ringing and before damping.  If you are shopping for foam locally, take the fabric with you that you are planning to cover the foam.  Many discussions on fabric have occurred on Handbell-L (internet handbell forum) and are archived for your perusal.  Corduroy seems to be a favorite. “Nakid” foam is preferred by some solo ringers since the foam can be placed on the table without having seams between foam pieces – and then covered with a long cloth.

 

Bottom line – “test drive” the products and covers to get the best possible response / sound and support for the investment you have in the instrument!

 

Here is a explanation from a foam manufacturer:

 

° Foam Types/Names We have different foam types to select from in order to meet the consumer's needs.  Our foam can be utilized in most applications but choosing the right foam will depend greatly on how you are going to use it.  Some people think foam is all the same but this is not true.  Most customers use foam in our A, B and C grade categories.  We also have other specialty foam available.  We carry polyurethane foam, memory foam and polypropylene foam.  You may request a sample of our foam by calling our customer service at 800-358-9490 and specifying the types of foam you are interested in and we will be happy to mail you a free sample.  Please note any request for larger sized samples than what we have available will be charged a nominal fee.  ° Foam Density and ILD Foam density is how much the foam weighs per cubic foot.  For example, foam that has a density of 1.8 lbs. simply means that a 12" long X 12" wide X 12" thick piece will tip the scales at 1.8 lbs.  Density is often confused and related to the firmness or softness of the foam.  However, density does not pertain to how firm or soft the foam will be.  The ILD or Indention Load Deflection will tell you how firm or soft the foam is.  For example, a piece of foam that is 15" square and 4" thick is placed under a 15" plate and compressed from 4" thick down to 3" thick.  A measurement is taken of how much weight is required to compress the foam down.  So if it takes 40 lbs. to accomplish this then the foam has an ILD of 40 lbs.  In general, we recommend an ILD of 25 - 35 lbs. for bedding use and an ILD of 40 - 55 lbs. for sitting use.  ° A-Firm Grade Foam Our A-Firm Grade Foam is the highest resilient and highest density polyurethane foam we carry.  It has a density of 2.0 lbs. and an ILD of 50 - 55 lbs.  In normal use this grade of foam will last for over 10 years but it depends on the use and weight being supported.  This foam is our best seller and can be used in any application.  We recommend the A-Firm Grade Foam for cushions to sit on such as sofa/chair cushions, boat cushions, RV cushions and for those who prefer a very, very firm mattress.  Our A-Firm Grade Foam is light gray in color.   ° A-Medium Grade Foam Our A-Medium Grade foam has a density of 1.8 lbs. and an ILD of 28 - 30 lbs.  This grade of foam will usually last 6 - 8 years but it depends on the use and weight being supported.  This foam can also be used in any application but we recommend it for sleeping or laying on.  Our A-Medium Grade Foam works great as a mattress since it is softer than our A-Firm Grade Foam.   ° B Grade Foam Our B Grade Foam has a medium resiliency and density.  It has a density of 1.25 lbs. and an ILD of 30 - 35 lbs.  Generally, B Grade Foam will last 3 - 5 years but it depends upon the use and weight being supported.  Our B Grade Foam works great in any application like as both our A Grade Foam but with a shorter life span.  We recommend this type of foam in applications that are not used on a regular or daily basis.  ° C Grade Foam Our C Grade Foam has a low resiliency and density.  It has a density of 0.9 lbs and an ILD of 28 - 32 lbs.  In most cases our C Grade Foam will only last a few months depending on the use and weight being supported.  We recommend this grade of foam for temporary use such as camping, guest beds or packaging.  ° Memory Foam What is Memory Foam and why is it so special?  Memory Foam is a specially formulated polyurethane foam.  Most consumers think this type of foam is new on the market but it is not.  Memory Foam or otherwise called Visco-Elastic Foam, Impact Foam or Slow Recovery Foam was developed by NASA for their space program back in the 1970's.  In the beginning, Memory Foam was just to expense and hard to find for the average consumer but since that time the availability and wide spread use has made it easier to find and more affordable.  Memory Foam has the unique ability to change firmness with the changes in temperature.  Mostly the warmer the temperature, the softer the foam will become.  This unique characteristic is what sets this foam apart from all other foams.  It allows relief in those pressure point areas such as shoulder blades, hips, calves or any area that protrudes from your body as you lay down.  Localized pressure points can restrict blood flow and may cause soreness or tender spots from the undue pressure being applied.  Memory Foam solves this problem unlike innerspring mattresses.  Innerspring mattresses can not eliminate localized pressure points.  The Memory Foam will mold and contour your body to eliminate localized pressure points giving you more comfort and relaxation.  The heat from your body is transferred to the foam thus warming it to a softer foam.  This is the key to relieving pressure points.  When making your purchase of Memory Foam please remember these tips:  Most people think more is better but this is not so with Memory Foam.  Our research shows that if you are applying Memory Foam on top of an existing mattress, it is best not to go over 3" thick and the existing mattress should be firm.  If the existing mattress is soft, the Memory Foam will only worsen your problem.  Some people have a misconception about the name "Memory Foam" and think the foam has memory of what was laying on it.  This is simply not true.  Memory Foam does not have a memory and it will return to its original state and shape after the person or object laying on it is removed.  It does have a slow recovery time so please give it several minutes to return to its original shape.  We recommend using this foam over an existing mattress, to sleep or lay on and it can also be used for sitting on.  Our Memory Foam works wonders for people who are bed ridden because it does not create bed sores.  We offer orthopedic Memory Foam mattresses and Memory Foam Overlays to meet your bedding needs.  You can also purchase custom cut pieces.  When ordering our Memory Foam it may be referenced to as VE-10 Grade Foam.  ° Closed Cell Foam Closed Cell Foam is another name for Polypropylene foam.  This foam has high densities and water can not penetrate it.  We carry a variety and assortment of thickness, widths and colors.  Our Closed Cell Foam is sold by pre-cut sheet sizes or by the linear foot off a roll.  Most of our closed cell foam inventory are closeouts and overruns so we are able to offer it at or below wholesale prices to the public.  Closed Cell Foam does not compress easily like polyurethane foam.  This type of foam can be used in boating applications (it will float), padding applications or any other use.  ° Foam Color Most of our polyurethane foams are white in color except our A-Firm Grade Foam is light gray in color.  Our Regular Sound Proofing Foam is a charcoal gray color and our Deluxe Sound Proofing Foam is light gray.  Our Closed Cell Foam colors vary.  Please keep in mind that foam goes through a natural process of changing color.  Even though our white foam starts out snow white, in time it will begin to turn a yellow-beige color.  This changing color will not affect the foam in any way other than the appearance.  Sunlight accelerates this process.  In some cases, sunlight can change a white piece of foam to a yellow-beige color in less than 30 minutes.  Artificial light will change the color also but not as quickly as natural sunlight.  Again, this will not affect the performance of the foam.  The gray foam goes through the same changes but the color change may not be as noticeable.   ° Using Glue on Foam If necessary you can use glue on foam.  We use and recommend a heavy duty spray adhesive to bond the foam.  We sell this type of glue on our website.  The glue does not damage the foam in any way.  It will give a very strong bond and in most cases if you try to pull the foam apart, it will tear beside the glue seam.  When gluing foam, you must spray an even mist over the entire surface of foam you are wanting to bond and for double strength we recommend spraying the glue on the foam and the surface you are gluing it to such as another piece of foam, sheetrock, wood, etc.  Occasionally, we may have to glue the foam together because our foam buns may not be large enough to accommodate a large size.  Also odd shaped foam pieces may have to be glued.  When done correctly, you may never know a glue seam is in the foam.  If you have any questions about your order and glue seams please call us at 800-358-9490.  You may request no glue seams but in some cases it may be unavoidable in order to obtain the proper size and dimensions.

 

 

[mic...@thegoldendance.com]

Charm wrote:

> Let’s consider three elements when purchasing foam: physical
> construction (firmness and density), relationship between foam
> thickness and bell sizes/ techniques, and coverings for the foam
> pads.

<snip>

Wow. That really was fascinating and informative. Who knew foam was so
complicated? :-)

That said (and I was sincere - I'm a science geek, so that stuff
fascinates me), Sonos and I use foam that we get from Joann Fabrics.
That green 3" thick stuff that comes in sheets. We cut it to size & it
works great. I have no idea what its official density/softness rating
is.

Sonos goes through foam fairly quickly, though, because we vacuum pack
our foam for travel. That breaks the cell structure down faster than if
we didn't do that, so we don't want to spend a lot of money replacing
foam when it's not going to last that long, anyway.

THAT said, I don't vacuum pack my own foam & it has lasted several
years. I do have it covered in muslin to protect it from dirt when I
take it to local gigs, etc.

3" foam is enough for marting if you mart correctly. Don't slam the
bell into the table, but rather put your weight on your back foot &
PLACE the bell on the table. You'd be surprised how little energy/effort
it takes to make the bell sound.

-Michèle <== blatant ad: has a DVD that explains marting and bunches of
other stuff
http://www.HandbellMusic.com