Best sail repair kit and helpful hints required

[UNCIVILIZED]

Originally Posted by barnakiel

For a small damage, I make a two sided insignia patch. This can be applied on a sail set, as long as it is dry.

For a big damage, I use 3M 5200FC, then patch with insignia over-patches. This takes some hours to set (24, if you can afford this much). Stronger than original once dry.

Both methods work on dacron and laminates. Spectra sails seem the most difficult to glue on, but these are the most difficult to damage too!

b.

There are definitely some cautions to be observed if/when gluing laminated sails, & to a smaller degree, certain Dacron ones. Many of which are found in this excellent thread on sail repair, & one of my posts in it. Which is why I dug up the link. http://www.cruisersforum.com/forums/...ml#post2186899

Were I to take the time to do a 5200/cloth patch, I would use standard sail cloth instead. Since it's stronger, & also you won't be gluing to a surface which already has a much weaker adhesive (& contaminant) on it. Since even 5200 has issues with bonding to unclean surfaces. Sometimes only reaching the bond strength of toothpaste on them.

Also, there are some sail & cloth types which adhesives won't stick to, or shouldn't be used on. Some of which is also covered in that thread. With some of the thread's key bits reprinted below. However, not the ones on Contact Cement, & it's pro's & con's, which are in it as well.


Here's some of the highlights & out takes from that other thread. And there are more comments in it that are akin to mine, which also sync up with the below info:

EDIT: One of the other catches about some fabrics, hybrids especially, is that like knitted fiberglass cloth, their strengths are/can be very directional. So a repair to them needs to both account for the load path/fiber orientation, & also be done properly so that the repair has the correct strength to match what's around it. So that neither a hard spot, nor weak spot is created.
All of which is very sail, & cloth specific. Probably more of a racing thing too, but I don't know who else will be reading this & what folks have for sails. And the above even applies to some woven Dacron sails.

Also, if you read my posts above, I mention some of the issues with adhesives. Though there are also others. As for instance, some prep solvents used prior to applying the glue are incompatible with certain fabrics & films. To include the possibility of melting things. And I'm not a chemist, nor up to date on materials science, so...
Too, there are some adhesives which need to be treated with the same cautions as the prep solvents. Plus they can be pretty nasty for the user to handle as well.

Me thinks that some glues tend to be sailmaker only type items, or are only used when the sail's being made. The science & magic of which are out of my depth by quite a bit. But some upper echelon racers & sail makers would know, & perhaps be able to aid you in putting together a First Aid kit for higher tech sails.

There are other "fabrics" which have similar repair issues to Spectra cloth, in that they're either so slippery as to be tough to glue to. Or they're so strong that a lot of glues bonding abilities can't match their strength. And there's the reverse of that, where the protective layers bonded over the load carrying "fabrics" are much weaker than the "fabric" itself, which makes fixing the sail problematic again. If it's even possible.

[barnakiel]

Originally Posted by UNCIVILIZED

Were I to take the time to do a 5200/cloth patch, I would use standard sail cloth instead. Since it's stronger, & also you won't be gluing to a surface which already has a much weaker adhesive (& contaminant) on it. Since even 5200 has issues with bonding to unclean surfaces. Sometimes only reaching the bond strength of toothpaste on them.

5200 sticks very well to dacron, also wet. Sure thing, you do not want the sail to be oily or anything. It is not very common to have contaminants on a sail though. I wipe with acetone, anyways (this drives some of the moisture out too).

Make some test with old sails next time you have some 5200FC left over. You will get a shocker.

5200 does not stick too well to mylar though. Glue to the taffeta side instead (assuming this is not a mylar/mylar sail).

The mylar one can be fixed with insignia. In a load area I would use stickyback kevlar though.

b.

[foufou]

And do not forget dental floss as emergency thread

[barnakiel]

Originally Posted by foufou

And do not forget dental floss as emergency thread

Impressive!

Very cool idea!

b.

[UNCIVILIZED]

Originally Posted by barnakiel

5200 sticks very well to dacron, also wet. Sure thing, you do not want the sail to be oily or anything. It is not very common to have contaminants on a sail though. I wipe with acetone, anyways (this drives some of the moisture out too).

Make some test with old sails next time you have some 5200FC left over. You will get a shocker.

5200 does not stick too well to mylar though. Glue to the taffeta side instead (assuming this is not a mylar/mylar sail).

The mylar one can be fixed with insignia. In a load area I would use stickyback kevlar though.

b.

I always try & get a clean, dry surface to stick things to. Though when at sea this is sometimes tough to do. But one get's creative at times, needs be. Assuming that the Mrs. is willing to offer up her hair dryer
And yes, I'll try out some 5200 on some fabrics which are both wet & dry. Though load testing them will be "fun": In terms of replicating the loads applied both by winches, & those of periods of flogging, soaking, & other destructive stresses that sails see. Thoughts on this?


In the linked thread http://www.cruisersforum.com/forums/...ml#post2186899 I mention cautions & problems in bonding to Mylar, Taffetas, & some other films & materials, for several critical reasons:

One being that many of these films have only a fraction of the tensile strength of the sail's actual load carrying cloths & fibers. Let alone actually being able to replicate the original strength of the sails themselves via this method. As in some laminated sails, the load carrying fibers are rediculously strong. Like say, Carbon, Kevlar, or Vectran.
Though at the same time, some of these sails are incredibly fragile. Both the load bearing fibers, & the films they're glued to
And also, some such sails can be too slippery to glue to. Such as in Spectra's case. At least without more specialized adhesives for the most part. And lots of prep steps. With some sail gluing even needing "post-curing" techniques too.

Another issue is that many sails are load path designed. Both string sails, & even within the weave of standard sail cloths. So that it's tough to patch them without creating hard spots or weak spots. Which is true in some Dacron sails, even non-laminated ones. And you can run into issues of bond strengths vs. fabric/yarn tensile strengths again.
For example, look at how radial clew patches & their webbing reinforcements are applied. So that there's a spreading out of the loads in a non-concentrated fashion where each layer of reinforcing fabric or webbing, is added & teminates. It's a patten with alternating lengths & depths of these materials being added. Kind of in a star or radial, zig-zag layout.

Plus, some of the films in laminated sails can be too slippery to bond to/bond to with proper strength. That, or the films or fabrics may be weakened by some solvents in the adhesive itself, & in some of the prep solvents for the adhesives. The chemistry of much of this being beyond my education at present.

Also, there are a few other issues on top of these Thanks to the myriad of fabrics out there. With some materials, & sail construction types rendering many high priced sails disposable once damaged
Which is where having overbuilt laminated sails helps, as does an experienced sailmaker. Hopefully one backed up by a large volume of constructional data.

But most of the above is laminated sail specific. Hence the suggestion to the OP to do some searching for & reading of sail repair threads. And to focus on some of the basics of sewing & hand work, oriented more towards standard types of crusing sails.

That said, for more information on sail design, & construction. Including some info on higher-tech sails, plus other nautical sewing projects, there's Dan Neri's book The Complete Guide to Sail Care & Repair
Along with quite a few others. Including Brian Hancock's Maximum Sail Power: The Complete Guide to Sails, Sail Technology and Performance
Which can be downloaded free as a PDF, in addition to the standard format.

[barnakiel]

Originally Posted by UNCIVILIZED

One being that many of these films have only a fraction of the tensile strength of the sail's actual load carrying cloths & fibers.

!1+

Absolutely!

It is one thing to fix a light film sail with just a hole (puncture) in it. A completely different pair of scissors if the load carrying fibers get cut.

The good news is those light film sails are not the everyday of a cruising sailor.

There is a special commercial grade hot glue used to stick together film sails built in mylar panels. Not a method that could be used onboard (I think). (?)

I believe there is also a row of zigzag or triple step, aside from the glue.

b.

[UNCIVILIZED]

The problem with Mylar isn't limited to super light, or racing sails. As it, or one of it's "cousins" get used in some laminated sails as a structural film underneath of a layer of Taffeta. Usually on both sides of the sail. And in some cruising & racing sails there's only Taffeta on one side of the sail, which obviouly makes things wear much more quickly. Given that there's nothing to protect that thin film layer from the usual abrasions & UV which a sail is subjected to. This was what I was partially referring to with my fragility comment, above.

In additon to this, there are plenty of racing type sails which have zero Taffeta. With the obvious resulting issues.

So, if you're of the mindset of commonly gluing sails. Then you may try & fix these sail types solely with glue, not knowing any better. Most folks won't do this, but... I'm not sure that Contact Cement will hold up for this And nowadays it's not uncommon to buy a boat which has several of these as part of her inventory. Or to pick up a used one, seeing it's low price tag, but not knowing it's weaknesses.