Primaloft One – 1.8 per sq yard

[Roger Caffin]

Hi Ron

> I was curious about common perceptions of silk as a good bag liner fabric and why or why not…
> Is there a perception silk is 'functionally' stronger (won't snag on dagger toenails) for the weight than a small denier heat calendered ripstop nylon? or that is is better at moisture management or drying, etc?

My wife and I have been using silk liners for many years. I think it just feels a bit nicer on your skin at night, compared to synthetics. This is especially noticeable when you are a bit sweaty. However, the downside is that it certainly does not last as long as the synthetics.

> Are these 8mm type silks as tight or a tighter weave than a Momentum or a Pertex Quantum?
Certainly NOT. You would never use the stuff to hold down, for instance.

These days I have switched to making silk pyjamas out of the same 8 momme fabric, with hood and foot covering. The pyjamas give me a lot more room to wriggle around under a quilt.

> Seems that a the key factor for a bag liner would be an air permability low enough to prevent excess heat escape but just enough to allow vapor to move thorough it.
Not in my book. The SOLE reason for carrying the extra weight of a SB liner is to protect the SB from getting dirty form the sweat and dirt on my body. The liner stops some of the draft, but that is secondary.

It may be a personal thing. Get some 8 mm Habotai silk from ThaiSilks and try it for yourself.

cheers

[Bill Fornshell]

Hi Ron,

Those are real good questions.

If someone was selling gear the answers would take on a different point of view or importance. I make my own gear and do not sell anything. So some of the questions are sort of a "so what" from my point of view.

For me when I make something it is ALL ABOUT WEIGHT.

If something doesn't work as I hoped it would I just make an improved version for the next hike.

I have been using a 5mm silk (0.57 ounce per sq yard) to save the weight difference between something like Pertex Quantum or Momentum. Both of those are more or less 1.03 ounce a sq yard. I also still have some of the old "UK" Pertex Quantum at 0.89 ounce per sq yard. It is about weight and not because it might be better, it may not be better. Silk is also cheaper than the other two if that makes any difference. I want Pertex Quantum on the outside such as in my Bivy and or a very good WPB outer garments for rain protection. With this I protect the silk garments from getting wet or very wet and get the benefit of the outer garments ability to help dry out what is under it. It is a "system" approach.

I use my Pertex / Cuben Bivy (4 ounces) about 100% of the time to help keep the silk things dry. I am using a tarp for a shelter about all the time now. If I was in a tent I think I would still use the Bivy. I do not worry about condensation but better safe than sorry.

My body heat inside the Bivy will dry damp silk sort of fast. Silk also will dry quick if there is a little sun out or a light breeze. I have slept out under my tarp in some rain but with all the silk stuff inside my Bivy I have never had a time when things got wet. I am careful. I have use Down for a long time so I am very careful about keeping thing from getting to wet.

A possible down side to silk is that it is cheap in white but cost a bit in color. I buy the white and dye my own color.

Dagger Toenails:
I don't get into my silk bag liner or my silk sleeping bag without socks on. I have not had a problem but don't want to take a chance of snagging the silk. I also have to say that I don't get into any of my sleeping things without socks on. Most of that is to help keep it clean but also so I don't snag the liner if I happen to have a sharp toe nail.

Bag Liner:
Two reasons to use a bag liner: (my option) One is to help keep your sleeping bag clean and two as a VB liner. I have used a VB liner for 20 years plus. I didn't depend on a liner to add any extra warmth to my sleeping bag other than to kept my body moisture out of the Down insulation or in warmer weather to help keep the bag clean. I know that I lot of liner makers say the liner will add ?? extra warmth but (my option) don't count on it. If I need extra warmth I wear more cloths, add an insulated liner to the bag (I have an old Moonstone with a Down liner that will attach to the top inside of the bag) or take a better bag. The insulated liner is the way to go. I made an insulated really light tunic that turns into that insulated liner. My first VB liner (many years ago) was some kind of heavy stuff that would hold water. It worked great as a VB but was very heavy. My first home made liner was some WPB ripstop stuff and it also worked great and was a lot lighter. Along comes Cuben fiber and that liner weighs about nothing and also works great. Now I am into wearing VB pants and shirt (RBH Designs) inside my sleeping bag when it is cold or up to about 60 degrees. I need a lot less in a sleeping bag with the VB cloths. The use of VB things is not really understood by many and has been the subject of some hot debates.

Tight weave:
I can't or don't know how answer this question. The 8mm silk is really nice. That is what I used for years or until I went "light as possible". My silk hammock is made out of 8mm silk and it is so cool in warm weather. I can say that if I had to pick from 8mm silk, Momentum, or Pertex Quantum – all these weigh about the same per sq yard – and cost was not a factor – I would go with Pertex Quantum. Why – I have it and have used it enough to know how well I like it. Is there anything wrong with Momentum – NO. If I could not get Pertex Quantum and cost was not a factor I would take the Momentum. If however cost was a factor then I would try the 8mm silk first to see if it worked for what ever I was trying to use it for. I buy my silk wholesale and it is much cheaper than what I would guess the current wholesale price of the other two are. At retail the current price (Today) of dyed 8mm is $7.65 a yard for 45 inch wide silk. The white 8mm is $6.00 a yard for 54 inch wide silk.

http://www.thaisilks.com/index.php?cPath=1&osCsid=330f174d6c17d02ac5764d0ea2600a0d

Ron,
While I have been slowly typing away Roger has added a post to your question. To end mine I would also suggest you buy some 8mm silk and try it for what ever you have in mind.

Then please post your thoughts as to how it compairs to the other two fabrics.

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