97" x 21" box cushion

[ChrisR]

I need to make a 3" thick cushion for a bench that measures 97" x 21" .    What size would you cut the foam?  Advice very much appreciated.

[MinUph]

If your going to wrap this i'd cut the foam 97 1/2 x 22.

[otlass]

I would make the foam the exact same size, but when I sew the cover I would finish the band at 2 1/2"!

[kodydog]

That is a long cushion. I'd go 98" X 22"on the foam and finish with a 2-1/2" band. Don't over stuff it or you'll get a bow or cup. No mater how you cut it, after a while it's going to wrinkle. Make sure the customer knows this. Is there any way you could talk the customer into two cushions or adding buttons. Make sure to mark several reference points along the way so the top comes out at the same point as the bottom. Match your corners.

[sofadoc]

I love it when this type of question comes up. Everyone's answers are just a little bit different.

It varies for me, depending on the fabric, and firmness of the foam. In most cases, I would cut the foam 98 X 21. I can do any necessary compensation with batting.

[Darren Henry]

I'd go the same as Kody.

[gene]

What if the window sill, boxed window, whatever, is exactly 97" long? If you make the cushion exactly 97" long, it may be too tight to fit the space.

Compressing the boxing from 3" to 2 1/2" causes the foam to push out the sides just a little bit. The welt cord is a bit over the edge of the sides. Even without batting on the sides, a 97" boxed cushion may fit too tight.

With 97" between two side walls, I would shoot for a 96 1/2" finished size. The extra 1/2" is divided by both sides into 1/4" which easily is filled by the foam and welt cords.

I always ask where the cushion is going to lay.

I love it when this type of question comes up. Everyone's answers are just a little bit different.

Yep, and if it works for you, and your customer is happy, and they pay their bill, that's all that counts.

gene

[BlueFlamingo]

I'm not a PRO but I've done enough projects to think that Gene's response is "Spot ON"!!  You have to KNOW all about how the cushion is going to be used and where it's going to be used before you can give accurate dimensioning instructions it seems to me!!!  In my limited experience once I've determined what I want my final dimensions to be I cut my foam 1/2" larger all the way round (height, length and width) to ensure a nice snug fit.  It's always worked well for me. But again, I'm NOT a PRO!!!

[Virgs Sew n Sew]

With the work that I have done so far, I've always had the original foam to measure and then replicate.

Having said that, last week the President of our local Chamber of Commerce visited me with a job that she dropped off.  Name dropped because I really, really, really want this job to be absolutely perfect since she's job some clout.  I always want them to be perfect but I realize that if she's pleased, her word of mouth could send a lot of maybe larger jobs my way.

Anyway, the job sounds a lot like ChrisR's.  This is a long cushion on her boat.  She purchased foam and fabric.  Foam is 2" thick and she wanted the cushion to be 23-3/4" x 117".  I asked her if it would be okay to make two cushions (it seemed a no-brainer as she had purchased 2 lengths of foam to begin with) and she immediately agreed.  Whew!  So, I will have 2 cushions that finished should measure 2" x 23-3/4" x 58.5".  I am welting the cushions. 

Should I also cut the foam wider and longer?  Why is the foam cut larger than the finished product in some cases?  I have learned a lot just this week from some of the threads!  Nice to understand what I should do and not just "punt".

Thanks!

Virginia 

[MinUph]

Virginia,
  The reason you cut filling larger is so it will fill out the casing and put some pressure on the fabric. Generally speaking you cut the foam the size of the cover with the seam allowance. So if a cushion is finished 20 x 20 you cut the fabric and foam 21 x 21. In the case of long cushions this extra is a bit to much so I cut the long dimension down 1/2". No fill will keep long cushions from wrinkling with use and to much fill tend to buckle. This is all done with a dacron wrap.
  Also with boats or any vinyl application you need to allow for breathing. Fabric zippers, breathers, something to allow air to move out and in.

[Virgs Sew n Sew]

Thanks!

I am putting zippers in.  Ordered them a couple of days ago.

Virginia

[Virgs Sew n Sew]

Just got the first of my 24-3/4 by 59-1/2" cushions done.  Following your advice, I cut the foam 25-3/4 by 60" so of course, the cushion fits perfectly and it looks fabulous!  I should finish the second one either Friday or Saturday depending on how many interruptions I get.  These cushions are the ones for the President of GI's Chamber of Commerce so I've really been stressing over getting them to look just perfect.  This is one lady I want to be 1000% happy!

Thanks again for the advice everyone!

Virginia

[baileyuph]

There are a few more considerations than covered here, for example foam density  is an important driver in what size the foam should be.  Another factor is one should include considerations when the cushion is to be crowned.

The thickness of the foam plays a roll in determining its size,  if it was easy, as they say everyone would be doing it.  

A cushion is about a big part of engineering furniture upholstery as any part of the furniture.  Then, consider crown when usin marshall coil spring units instead of foam.

We are possibly only scratching the surface of cushion theory.

Another point foam density and cushion crown can play a part in handling the wrinkles in the longer but narrow cushions.  Cutting the cording mateial on a bias can also be part of the engineering for wrinkle control as well as foam density.

This is why answers are so different, the problems and solutions are so variable and handled differently.  It wasn't mentioned, but the fabric used for the cushion presents a factor that should be cranked into the equation of cushion engineering.  A thin fabric compared to a thick fabric and how to handle that should be cranked into decisions regarding cushion making.  Think about it, putting the same filler in a canvas weight cushion cover is not the same engineering consideration as when the cover is made of a much thinner fabric.

Lots to think about,

Doyle

[Virgs Sew n Sew]

Since you brought it up Doyle, I'm interested in a discussion pertaining length of cushion when you throw the variable of fabric type and thickness into the mix.  What is the difference between thin and thick fabric for starters?  Also what happens when you use vinyl instead of cloth?

The beauty of this message board is that every persons take on a question provides additional information and makes for a great "classroom".  Y'all are great teachers!

Virginia