Mark writes:  would have though sewing is no more time consuming to glueing, especially if Arne easy methods are used.

It's not that easy to sew, I found. My first sail had a couple of tyvek panels, just as an experiement. It is extremely light and soft, and it is not a woven fabric. A more experienced person might be able to get things adjusted right, but I was a beginner and found it troublesome, compared with polyester cloth. I would be interested in Eric's response to that. I thought of using glue, at the time - even the double sided tape - but I never did, so I can't comment on that.

I thought it was very interesting material, possibly with potential, but I don't think I will be using it again. Also, I swapped the tyvec panels out after a few months, so I can't comment on durability, but I suspect it will not be very durable. Again, I await Eric's comments with interest.

(You have to be really careful with the hot knife on that stuff too. It melts and disppears in an instant the moment you put a hot knife near it).

A couple of thoughts.

Here in UK, Tyvek type material is now always used under roof slates / tiles.  There are other brands less expensive. 
i would have though sewing is no more time consuming to glueing, especially if Arne easy methods are used. And it saves the cost of glue.

Anonymous wrote:

Bonjour

I've expérienced Tyvex on Mingming for a junkwing. It supported up to 25kts.

I've start to sew it and finaly I glued it.

You have the details of the experiementation on a French web site with photos. 

Tyvek experiment for a sail

It's in French but you may translate it and it should be understandable.

I used 105g/m2 tyvex in 100 cm width. 

I glued the seams with a 3M 927 glue fim of 25mm wide. 

For the battens, rather than fiting some batten pockets, it may be faster to screw the tyvex betwenn two half battens, one on each side of the sail. The two half battens would also  reinforced the glued joint betwenn two pannels.

Eric

Bonjour Eric,

Thanks for the link. Le français is actually my first language (hello from Québec!)

Your description of your experiment is excellent. Very helpful and encouraging. A glue zone 25mm x 100mm failing at 50kg tension in sheer should be more than enough for an experimental sail. Do you have other posts describing the construction and testing of your sail? The weight of the Tyvek you used seems closer to (and even above) the weight of Tyvek Commercial house wrap. 

My main worry with Typar VS Tyvek is that Typar, though much stronger, appears to have a slightly fuzzy side that might not take gluing or taping very well. Samples will tell. 

Dear fellow junkies,

As I mentioned in the General Forum thread regarding the conversion of a Colvin Gazelle ( https://junkrigassociation.org/general_forum/13279770 ), I am thinking of making a test sail out of housing wrap material. I am fully open to being discouraged from trying this. I will start with a discussion of the available material, then will explain the construction technique I am envisioning, and then will end with the pros and cons as I see them.

My boat (Le Patriote, Colvin Gazelle, currently a gaff ketch) is located in North America. In our most common construction method, stick-framing, we use a house wrap product that goes underneath the final exterior cladding, to act as a water barrier both during and after construction. Since this house wrap effectively plays the role of exterior cladding during the months of construction, it has a certain UV resistance rating. There are two major name-brand products that I am considering: Tyvek and Typar. Both are random-lay fibre, laminated plastic products. Both have their edges sealed with specialized tape.

Both Tyvek and Typar have regular residential versions, as well as commercial versions, which are heavier, stronger, and have a longer UV resistance rating due to the longer building times for commercial buildings. These are the versions I am considering. The price difference with the weaker residential versions is insignificant. Here's a table of physical characteristics, alongside Dacron sail fabric:

Typar commercial claims a UV resistance period of 12 months, while Tyvek Commercial claims 9 months. I suspect this may only apply when used as intended, that is, with the proper outside surface facing outward. The side meant to be against the building may not be as resistant. Nevertheless, these figures are encouraging. They should not fall apart within a few months of use, especially if kept covered when not sailing.

Given these figures, I am leaning towards Typar Commercial, but I will get samples of each to test and feel. It's also cheaper. Critically, I will also test the strength of the tape bonds.

Pros:
- Testing junk sails very cheaply before settling on a design. Typar Commercial is around 30 cents per square foot in rolls 10 feet wide by 100 long, one of which which should be enough for my sails.
- Battens and running rigging not cheap, but can be reused in subsequent iterations
- Fast construction IF a tape-only method works
- Should be strong enough and last long enough

Cons:
- Looks awful. One side has printed branding.
- The effort and cost of building the sail are somewhat wasted as I can't keep it long-term even if it works very well
- Untested at sea, as far as I know. Could fail during voyage.

I am aiming for a significant saving of time as well as money. Time being the more important of the two. If I have to sew these sails then it's definitely not worth it (for me). I may as well spend more for real sail materials, cross my fingers, and hope the first sail design works well enough.

The building method I have in mind is, roughly, to have no seams running through the individual panels of the sails. The construction of seams would be entirely with the specialized housewrap tape. Possibly backed up by a to-be-determined adhesive where the fabric is laid against itself. The sail would be built with pocket for aluminium battens. All panel edges would also be built as pockets for a boltrope running around the periphery of the aluminium battens, fastened at each batten. I think that in this way, sail fabrication time could be reduced to a weekend.

The expected duty for this suit of sails is a coastal voyage of approximately 300nm, followed by sporadic local sailing on the Saint Lawrence River to continue testing. If they perform well, and last, I may just keep them until they fall apart, as a proof of concept.

Thoughts?