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Diffrent seams to make tarp
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Timo Anttalainen

Locale: Finland, Espoo
Diffrent seams to make tarp on 01/07/2010 11:49:29 MST Print View

Couple questions to make tarp ridgeline. Felled seam (1), Its not fun to make 3 meters that. If i make same way i draw in pictures below (3)? I think its have same durability but it does not look so nice. It is so simple to make. Picture 2 is french seam.

Any ideas? I make tarp same style as 5 yards to ultralight. My machine is very old, 1950 or 1951. And i want to keep seams simple as possible.

ps. line 3. Forgot center picture, it's wrong.


Tim Marshall
(MarshLaw303) - MLife

Locale: Minnesota
Re: Diffrent seams to make tarp on 01/07/2010 12:23:16 MST Print View

i think the french seam is the easiest way to go for ridge lines. Just sew the flap down and it will look like a flat felled seam.


Timo Anttalainen

Locale: Finland, Espoo
? on 01/07/2010 14:23:58 MST Print View

Do you mean i sew 3 times?
Normal french seam is two times but if i fold it so there is 3 sewing for ridgeline.
So this my option 2. i sew only two times.

Do i miss something?


Jim W.
(jimqpublic) - MLife

Locale: So-Cal
Re: Diffrent seams to make tarp on 01/07/2010 15:19:06 MST Print View

I think your last message seam #2 is what Roger Caffin suggests for silnylon or other fabric that won't fray and you don't care how the inside looks (raw edge showing).

I haven't done that exact seam but it appears much easier than the classic flat felled seams. (My felled seam experience was sewing two double walled pyramid tents about 25 years ago.)

The important thing when sewing tent seams is to keep the fabric tight so the two stitching lines will share the load. It's good to roll the excess fabric up so you don't get lost. I found that masking tape worked well to keep the excess out rolled and out of the way. It's also good to have a helper watching to be sure that stray fabric doesn't sneak under the parts you're trying to sew.

And buy a good seam ripper.

Lance Marshall
(Lancem) - F - MLife

Locale: Oregon
Re: Diffrent seams to make tarp on 01/07/2010 15:32:38 MST Print View

Yes, 3 lines of stitches in the French seam as in drawing #1 in you last post. The first line of stitches help secure and hide the raw edges, the second and third lines of stiches share the shear load.

Drawing #2 in your last post also has two lines of stiches to share the shear load, so it should be as strong as #1 provided the raw edges don't fray into the stich line.

A flat felled seam isn't much more difficult than #2. Here are some pictures of a flat felled ridge seam.
Hope this helps,

Edited by Lancem on 01/07/2010 15:38:09 MST.

Tim Marshall
(MarshLaw303) - MLife

Locale: Minnesota
Re: ? on 01/07/2010 22:34:06 MST Print View

yeah, pic #1 is what i mean


Jan Rezac
(zkoumal) - MLife

Locale: Prague, CZ
RE: Diffrent seams to make tarp on 01/08/2010 07:48:05 MST Print View

Recently, I started to use the seam Roger Caffin suggests for tents. It doesn't have the neatest look, but it is stronger than all the seams you show here. It is so strong because the loaded line of sewing is padded by the extra layer at each side, and ripping through two layers is not as easy as through one (providing the thread is stronger than the fabrics).

strong seam for silnylon

Hendrik Morkel
(skullmonkey) - MLife

Locale: Finland
-_- on 01/08/2010 10:34:13 MST Print View

Timo, I made my 2,70 m Ridgeline with a felled seam, and its fine if you prepare it properly - use needles to put the silnylon together, roll excess fabric up and locate it with a clothes-peg, and off you go. Check the video I posted on how to make a felled seam in the thread in this forum if you want visual instructions.

I would prolly use Roger's seam the next time I would make a tarp (so after this one is finished =), it seams very easy and as its from Roger it certainly is bombproof (if made well!).

Derek Goffin

Locale: North of England
glued and sewed seams on 01/10/2010 06:55:01 MST Print View

I am working towards a cuben tarp tent. I plan on glueing the main seams with Aquaseal. Because of its poor peel strength the seams will be sewed with long stiches too.
If I was just glueing straight seams I would just overlay the 2 pieces by the glue allowance. Glue and press. If the sewing was needed I would add it afterwards. This does not work so well with a curved seam such as a catenary ridge. Nothing is flat while you are trying to glue and press.
I thought of sewing the same simple overlap seam by sewing one side, close to one edge, flapping back the large flap adding glue, pressing until set, then sewing the other line of stitching. The little bit without glue to the other side of the first stitching could be glued while seam sealing.
Another possiblity would be to first sew like Timo's first post in this thread line 1 picture 1 but with the left hand sewing margin very small and the right the full glue margin. (Sorry I am not good with these graphics) This would be easy even with a catenary as you are sewing flat. Now open out the fabrics and glue and press until set. Finally sew the other line of stitching.

Anyone who has sewed and glued cuben which way did you do it?

Edited by Derekoak on 01/12/2010 06:27:32 MST.

Steven Bergeron
(TheTurk) - F

Locale: SF Bay Area
Re: RE: Diffrent seams to make tarp on 01/11/2010 19:46:11 MST Print View

> Recently, I started to use the seam Roger Caffin suggests for tents.


Do you know where Roger recommended that seam for tents?

I've been researching various seams and would like to see what else Roger had to say (assuming there's more to read).



Chris Kurmann
( - F
Alternative seam for canvas on 03/05/2011 15:51:27 MST Print View

Hi all, I know this is slightly off topic as I'm sewing canvas and not nylon, but what are your thoughts on the following;Double tent seam

This idea should have the following attibutes
The edges are hidden so they can not unravel (like french or flat felled seam)
Two lines of sewing each share the same amount of force (unlike french seam or rogers seam)
Doable without use of pins or clamps and with simple folding (as opposed to felled seam)

I can't believe I'm the first with this idea so I'm wondering why no one else does this

Edited by on 03/06/2011 01:38:30 MST.

jerry adams
(retiredjerry) - MLife

Locale: Oregon and Washington
Flat felled seam on 03/05/2011 16:55:48 MST Print View

I don't see the advantage over a regular flat felled seam?

With a flat felled seam you have two rows of stitches carrying the load.

You don't have to pin - there's a ruler on the sewing machine so you can position the edges of the fabric on, say, the 1/2 inch mark, and you'll have the row of stitches precisely placed 1/2 inch from edge.

With canvas, you could have the top piece of fabric 1/2 inch, and the bottom 1/4 inch, fold over the top piece, sew the second row of stitches - then you'de only have to sew through 4 layers of fabric which would be easier in canvas.

But, I don't know, I'm just thinking

Chris Kurmann
( - F
Tests on 03/06/2011 01:52:44 MST Print View

Thanks for the thoughts Jerry,

I think this will simply have to be tested out.
I just did so with 4 small sheets. Two I put together with the seam Roger suggests and two with the glue method.
I haven't tried the felled seam yet.

From what I've noticed so far (And without actual tests in rain which I will do with bigger sheets);
My fumbling and inexpert hands find it a lot easier to simply glue, fold and sew then to hold the seam folded back on both sides and nicely streched to make Rogers seam.

I also see that when pulled apart with force both hold very long but Rogers seam quickly starts showing the sewing holes as the fabric is pulled apart by the thread. SO I think water will get in there.

I agree my idea gives a very thick seam. I will look at leaving out the middle band which is really only there to help fold and as a bit of extra strength. (Also I believe the cotton will swell when wet so the more the better around the seams)

One big advantage of Rogers seam is that the large sheets of canvas will all be on the right hand side of the sewing maschine where I would have to roll the two meters of fabric through the left side ;-). The felled seam has the same problem of course.

Another thing I afraid of is the glue. I hope it won't be food for fungi.

This is all for a tipi project by the way so if this is the wrong place for it please tell me.

I'll do some more practical tests and post again.

jerry adams
(retiredjerry) - MLife

Locale: Oregon and Washington
Re: Tests on 03/06/2011 07:50:06 MST Print View

Good you're trying different things, find out what works best for you, report back your findings