In terms of weight, how does Tyvek compare to silnylon? is it good for tarps?

It is heavier if I recall.

Tyvek HomeWrap is heavier than silnylon but it would probably work for a tarp. There are special sewing instructions for Tyvek. Some people use tape instead of sewing.

Any idea where can we find those sewing instructions, please?

Any idea where can we find those sewing instructions, please?

check out the tyvek article (part 2) on the home page. you'll find sewing info there.

Tyvek is hard to tear, but will get holes. They can be repaired with duct tape. Tyvek requires serious reinforcement at tie-outs (I use duct tape on both sides and gormets) and is a bit heavier than silnylon.

Tyvek is hard to tear, but will get holes. They can be repaired with duct tape. Tyvek requires serious reinforcement at tie-outs (I use duct tape on both sides and gormets) and is a bit heavier than silnylon.

and considerably bulkier

I thought it sewed very well and was sturdy. I am a builder and have tyvek all the time-so I make stuff out of it. I think it weighs 1.7 ounce/yard, but I may be incorrect.
http://i159.photobucket.com/albums/t123/hootyhoo_bucket/Bivy%20Sack%20Tyvek%20and%20Ripstop/DSCN0003.jpg

http://i159.photobucket.com/albums/t123/hootyhoo_bucket/Bivy%20Sack%20Tyvek%20and%20Ripstop/DSCN0005-1.jpg

http://i159.photobucket.com/albums/t123/hootyhoo_bucket/Bivy%20Sack%20Tyvek%20and%20Ripstop/DSCN0002-1.jpg

There are some other pics on photobucket--hootyhoo_bucket

I thought it sewed very well and was sturdy. I am a builder and have tyvek all the time-so I make stuff out of it. I think it weighs 1.7 ounce/yard, but I may be incorrect.

There are some other pics on photobucket--hootyhoo_bucket


Great looking project, hootyhoo! Here's the link (http://s159.photobucket.com/albums/t123/hootyhoo_bucket/) to the photobucket page you mentioned with the rest of the pics.

Thanks for sharing.