French Seams

[MinUph]

French Seams are not what we assume.
  There has been much discussion on French seams. I was always under the impression a top stitched seam was a french seam. Others call a baseball stitch (two seams) parallel to the main a french seam. I just did a headboard and the client wanted french seams on it. The designer sent me pictures for example. Neither top or baseball are truly french seams. A french seam is basically a small 1/2" or so flange. Look it up and there are YouTube videos showing them.
  I thought I would share this education with you guys and gals.

[Mojo]

Paul:

I used to sew french seams on certain jobs ( motorcycle seats, marine seats, etc. ). The procedure I used for french seam is the same as this video. The only difference is that I did not use tape but instead cut strips of the same fabric I was using for the cover material and then used that as my backing tape. Using the backing tape method provides much more strength to the seam itself. Here is the method I used:

https://www.youtube.com/watch?v=uFSn-EIgQoc

I have seen some get a french seam confused with a fell seam. This seam is sewing two ends together, opening it up and laying it flat and then sewing a top stitch on one side. We use this seam everyday in making awnings. We also call it a locked seam. This seam provides 90 % of the strength of the fabric itself.

https://www.youtube.com/watch?v=-jbtZgwAQpo

The problem with seams is the terminology and subsequent confusion. One of the biggest headaches I had when I first started in this trade was learning the terminology. I still get a curve ball thrown at me on this forum by someone using a term to describe something I have never heard of before. :)

Mojo

[gene]

I thought the French seam had the tongue sticking out???  :-)

Mojo, do you use any basting tape in your sewing? I've used it a few times on difficult fabrics and curves but I've found a few pins or staples from an office stapler work well. I also use it when I'm matching the print on fabrics.

gene

[Mojo]

We use it on all awnings to seal the stitch holes. It also is quicker then pins and needles or staples when sewing a 20 ft long piece of canvas.

We go through a boat load of basting tape.

Mojo

[gene]

Thank you for the reply. Sailrite uses a lot of bias tape in their videos and I was wondering if that is common or if they are just trying to sell it.

gene

[Mojo]

Gene:

I am not sure about using basting tape in other applications. I never used it before when doing other work but when I started doing awnings I started using it. I should clarify that we only use the tape on center seams. We do not use the tape on outside edge seams.

In regards to seams we use a fell seam on center seams for most awnings that require 2 panels. On some assemblies we use a simple overlap seam that is double stitched simply because the assemblies themselves wont tolerate a fell seam because of internal clearances inside the assembly. The assemblies seem to get less tolerant every year in regards to fabric replacements. The casement assemblies for example require a near perfect square in order for the lead rail to close tight. In other words the depth of the fabric has to be near perfect otherwise one end of the assembly will remain slightly ajar when the assembly is retracted. Not a good thing when that assembly is subject to 65 mph winds going down the road.

Depending on the assembly type we use either a perpendicular overlap seam or a parallel fell seam. 

Mojo

[Eric]

Mojo, you ever thought about, or looked into purchasing a welder to do seams?

[Mojo]

Yup. Mucho dollars for a good setup. About $ 5,000. We are going to do an analysis on this including costs as well as the strength.
We just went to a 10 year warranty on our vinyl and we would end up bankrupt if the strength of those seams are not as good as
a stitched seam.

We have 2 fabric/textile consultants we work with who have been inside shops and plants all over the world. They have seen it all and know what works and what doesn't. We will call them in and go over the welded seam venture before we go any further. It has to be a sure thing otherwise I wont roll the dice and risk our company. My biggest concern is wind and rain loads. RV awning applications are completely different then standard commercial and residential awning installations simply because the RV awnings are all mechanized and go down the road at 65 mph.

Mojo

[SteveA]

I guess gorilla glue won't work ?- don't mind me today ! 
On going bad opinions always dull :) I thought it was Friday
SA

[65Buick]

Mojo, don't the customers know to stow their awning going down the road at 65mph?

Kdding aside, I was curious about the welding as well.  I bought this car cover, and the seams are 100% triple welded. No thread.

As for the terminology of various seams, I found this to be a problem since people use different terms to mean the seam thing. Better to just ask what the customer wants by pointing to examples (when this is the case).

[kodydog]

The first time a designer asked for French Pleats on a toss pillow Rose and I looked at each other then looked at her and asked, what's that. Two pleats in each corner that face each other. It makes a pretty neat looking pillow but adds a little extra work.

[Mojo]

I did several large motorcycle seats using french seams. When you start doing curved contours using french seams it helps to take a valium
to keep from throwing the work through a window. I would also make sure no priests or nun's are in your shop. The language can get pretty colorful. I did one seat and by the time I was done I invented over a dozen brand new curse words.

Mojo

[MinUph]

The first time a designer asked for French Pleats on a toss pillow Rose and I looked at each other then looked at her and asked, what's that. Two pleats in each corner that face each other. It makes a pretty neat looking pillow but adds a little extra work.

I call these kiss pleats.

[gene]

I've heard them called faux corners.

[baileyuph]

Yup!  The definition of "french seam" has evolved.  It even isn't anything we have brought up - that is
accepting the French Definition of long ago.  They did it, named it, and time has changed their original
definition.

The french used it frequently and don't believe the way it has been used the last "60 years plus or minus"
it has been used and named as the French did.  Even in the auto work over time, the name tag
has evolved.

Guess what matters is how it is understood.

I have restored some cars, now over 75 years old that used the older French term for the application
back then but that "seam" definition hasn't been used in our country  (to my knowledge) since
like I said, probably almost a 100 years ago. 

Everything evolves!

Let it happen,

Doyle