Seam Sealing

The NX-x50 Owners Manual says
Hammock storage, care, sealing
...Do not seal your rain fly unless you find a reason to do so. Seams can
lose integrity from being jerked or pulled over time. If you find a spot that
needs sealing, use Sil-Net by Mcnett, or another product that is formulated
for sil-nylon fabrics.

Is there any reason to seam seal a new XL or Vertex tarp? Thanks

Don't want you to feel ignored. <smile>

The only top-side leakage on any of my Clark rain-fly / tarps was from hardware attachment points within the ridgeline seam. Those are no longer used by Clark.

I have found water in some but not all of the 3/4" Clark lower edge tarp hems after nights of rain. The hem is actually swollen with water collected at the low point. I squeeze the water out between fingers before wrapping up the tarp. Would I treat the hem with sealant? No, but if someone did, she'd need to allow a place for the water to leave, as well. Some canvas workers use nylon thread, claiming it expands slightly when wet, reducing leakage.

Same here. The only place my tarp ever leaked was where the seams all came together and hardware was attached to a black nylon loop. It left quite a puddle. Large enough to wonder how this wasn't an issue before.
I took care of it myself and hasn't leaked since.