Vinyl Stretch

[mpm32]

Ok, so vinyl stretches more in one direction than the other. 

How do you decide which way to put the stretch?

In a seat bottom do you put the stretch front to back?

What about the sides on a box cushion?  Does the stretch go top to bottom?

On a 54" roll of vinyl which way does the stretch run usually?  Across the roll or does the stretch run the length of the roll?

I'm trying to figure out the yardage for my boat project and I imagine I should take this into account when calculating the yardage I need to order.

[scottymc]

The stretch is across the roll, generally you cut front to back down the roll.Also piping should cut length ways so there is less stretch, this might also help the people having trouble with the wavy piping thing.

[mike802]

no need to calculate stretch into your order. I cant recall if it stretches up or across the role, it may differ with brand, most stretches on the bias.  I have worked with vinyl that seemed to stretch equally in all directions and others that defiantly stretch more in one direction. stretch is usually taken into account when applying the vinyl over something and you want a tight fit, or you are trying to stretch it over a curve.  The stretch is not usually a problem and most of the time, I don't pay much attention to it unless I need it for some reason, or it is giving me trouble.  Sometimes the stretch will give you wrinkles where you don't want them, usually in pleats, or tuck and roll, but it is usually minor and you just have to play around with what you have to find the best result.  Some vinyls have more stretch than others, usually the softer vinyls stretch more and some vinyl is made stretchy like All Sports.  If you are planing on cutting welting on the bias you may want to order extra material, but most of the time just cutting it out up the roll works fine.

[Darren Henry]

 8) Mike just saved me 20 minutes of typing  8)

:-* Thanks Dude.

[mpm32]

Thanks for the replies, that helps a lot!

[mike802]

No problem Darren, glad I could help ;D

[mpm32]

OK, you mentioned tuck and roll.

I am going to do some panels where I top stitch pleat lines, then fold along each pleat line and sew along the fold on the backside.

Like this;

http://www.jalopyjournal.com/forum/showthread.php?t=372599

Which way would I run the stretch in this case?

[scottymc]

I was always taught to cut up the roll from the front to the back of the seat. The way you describe doing those pleats sounds like alot of sewing, why not back stitch them on top of the foam.

[JuneC]

Scotty, if you did it that way, wouldn't they all lay to one side?

June

[MinUph]

  When I do roll and pleating I sew like Scotty said but up one direction then down the next. They lay nicely. Also I don't fold the foam. I lay it out on the foam and slice through the foam leaving the backing in tact then just fold over the vinyl or whatever I'm using into the slice and sew it down.
  Different strokes for different folks I guess. Just the way I learned.

[scottymc]

Scotty, if you did it that way, wouldn't they all lay to one side?

June

Yes, but it's hardly noticeable as you sew around 2mm from the folded edge. A more traditional looking way is to go the same way but leave out the foam and back sew the panel onto calico and slide the foam into the pleats later, it makes them deeper and rounder. I have never seen pleats done the way that was done in that link. It works but in a very round about way, the last row of stitching in the process is through 2 layers of vinyl , 2 of foam and 2 of whatever backing they were using.    

[scottymc]

Yeah Paul that's the way I do it for a standard job, forgot to mention slicing the foam.