Diffrent seams to make tarp

You could sew the seam, maybe with a little extra width of fabric, then set up the tent and paint some silicone:mineral spirits at the seam from the side so the width of fabric is glued to the main fabric so it takes some of the load.

Or even just do a regular flat felled seam and paint mineral spirits:silicone on top and bottom and that might strengthen it.  (that is, seal seams with silicone:mineral spirits)

Thanks for the feed back.  I hadn’t seen Hilleberg’s tech section before.

Jerry – Interesting idea w/ leaving the edges long and bonding them as part of the seam sealing process.  My one concern with this is that every how-to I’ve seen on bonding patches includes compressing the layers while they cure.  That would be a challenge on a full ridge line.  But I suppose it’s possible w/ a couple 2×4’s, drywall screws and foam weather stripping for padding.  Might be more than I’m up for on this project.

Mario – A thought for your hem experiments.  Make a normal single rolled him (2 folds, creating 3 layers), but make the hem deeper than usual – say 1″ finished, consuming 1.5″ – 2″ of material.  Then fold that in half under the back side of the tarp.  This gives you your padding and creates 5 or 6 layers.

And on that note, I just realized my dollar seam (thanks for naming it) is actually 2 rolled hems, back to back.

Thanks for the suggestion Rene,  Although that would solve the problem of “padding the stitch” it would leave me with more layers of fabric than needed on the perimeter of my project.  The problem can also be solved by using glued reinforcement patches and being a bit more mindful of in which side of the project the reinforcement patch goes.

This quick drawing shows how the reinforcement patch can be used to “pad” the stitches of the hem line.  I know most people like to have their reinforcement patches on the inside of their project to minimize their exposure to the elements but perhaps this may not be the best when working with materials with lower tear strength.  (i.e silpoly PU 4000).

Ah.  You said “double rolled hem” so I thought you meant 5 or 6 layers.

Yeah, patch on the inside, roll to the outside.

Wowo Hilleberg’s method looks amazing… and cooling jets to reduce needle temperature to reduce seam hole! Intense.