Mast track failure!

[David Lindsey]

I have been working very diligently with my friend Mike Joclyn to get CAN 046 back into the water. Yesterday was the launch. Not the best conditions but the exercise did help to shake out issue that needed attention. 

On land removing sails the whole main dis-masted track and all.

Has a better means of attachment been devised? 

I note that its the Plexus glue that failed. Brittle glue remains on both the mast and the track. 

???????

David Lindsey

[swiftsolo1]

David never had complete failure before .. a foot or two at the top of the mast where the loads are highest … Can I  suggest new tubes of plexus kit should not be brittle .

Philip whats do you think  

Paul Osullivan

CEO, AMP RE Consulting. 

Paul.osu...@gmail.com

916 224 2374 

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[rha...@xmission.com]

Forte messed up on some of the early masts and used 5200 instead of
the specifications of using Plexus. I think there is a loaner gun
running around. Get a tube and mixing wand then clean the track and
mast well and re glue the track on using the Plexus. It has to be
Plexus or similar because you need something to make a chemical bond.

[Ron Watt]

Hello All,

I believe I have the loaner plexus gun and a mixing tube.

I used Plexus MA 425 to bond my mast track to the mast.

It looks like the plexus MA 425 has doubled in price over the last 10 years.

https://www.jamestowndistributors.com/userportal/show_product.do?pid=4885

David, if you need the loaner gun get intouch with me and we can work out a way of getting it to you.

Ron

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[David Lindsey]

Ron you’re very generous! Thanks. Actually I have access to a gun. Ian MacPhail has one. He also has some glue. He’s going to check on the freshness of the glue for me. Might have to order some. 

My question was has there been more success with other glues or some means of mechanical attachment? I gather not. 

I is really shocking to see how this track came off. Quite spectacular. It happened in a split second. All I heard was a zipper like sound from top to bottom. At first I didn’t know what happened. Then the main on the ground with the track attached. 

The remaining glue is extremely brittle. Almost ceramic like. 

Thanks for the quick reply guys. You’re the best! 

Mike Joclyn has been an absolute gem of a person. If it wasn’t for him the Red Violin would still be sitting in poor condition. 

David Lindsey

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[Robin Smith]

I have a gun too, but it is in victoria and I am in the okanagan....actually my son is coming up Tuesday, I may be able to swing some plexus, let me know if you are interested. I have tried many other two part glues and cannot recommend any of them . Plexus rules! Also, paint your mast and boom shiny white to minimize their surface temperature in the summer. 

Hey if you are down at SOSA send me a note. I am staying at Summerland resort.

Robin Smith

CAN048

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[David Lindsey]

Robin, that’s fantastic. I’m in West Kelowna. Boat lives at SOSA. We have Swifts there. Great location. 

I would take you up on that for Tuesday. If it’s not possible for what ever reason I can come get it from you in Victoria. I’m just waiting for a couple parts for my airplane. You’re only a pleasant 1:20 away. Air traffic should be a dream through Vancouver Terminal air these days. 

Let me check with Ian again regarding the freshness of his glue. 

Thanks so much. This is just great!

David Lindsey

PS. You’ll have to come up to Kelowna. Well have a beer at Kelowna Yacht Club. 

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[Robin Smith]

Ok I will get my son to pick up the goods.

Robin

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[Mark White]

I couldn’t find the old size tube of plexus in the US, so I changed over to the small tubes.

Mark

Sent from my iPad

On Aug 1, 2020, at 17:25, Robin Smith <robin0...@gmail.com> wrote:



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[Mark White]

Yep, Amazon 

Sent from my iPad

On Aug 1, 2020, at 17:37, Mark White <mwhit...@gmail.com> wrote:

I couldn’t find the old size tube of plexus in the US, so I changed over to the small tubes.

[Mark White]

Cartridge only.

Sent from my iPad

On Aug 1, 2020, at 17:41, Mark White <mwhit...@gmail.com> wrote:



<image0.png>

[Robin Smith]

Last time I tried, plexus could not be shipped across the border. I had it shipped to Bellingham, then brought it across under cover of darkness... or something like that..

Robin

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[William Scheumann]

David,
On USA20, the mast came with the track glued on with 5200. Forte was great. They took the mast back and re-attached the track with Plexus. I never had any issues with track separation as I used a pop rivet at both ends of the track to re-enforce the holding where the main stresses the track the most. This thread also contains great advise to paint the sexy carbon with glossy white. Best wishes regarding your repair and quick return to sailing.

Bill Scheumann

Sent from my iPad

> On Aug 1, 2020, at 1:20 PM, David Lindsey <swift....@gmail.com> wrote:
>

[Philip Ryan]

When I re-glued two sail tracks, I made the same observation - that the plexus was ceramic brittle. So I did a bunch of phone time with both Forte and Plexus, and the consensus was that the MA530 formulation was the correct one to use due to the massive elongation difference between the sail track and the mast under flexion loads. The Plexus guy said he was surprised that the bond held at all. Apparently the reason for the brittleness is UV breakdown of the Plexus. The exposure of only the edge of the joint allows a degradation process to happen which propagates through the joint - seems improbable to me, but I'm no chemist. The MA530 bond has held for a few years now with no problems.

The MA530 cures really fast, so you need a cool work space, at least two people, and really good planning and set up to make it work. 

For small sail track repairs, I use the small tubes that Mark refers to, and I bought them from McMaster Carr. I thought that one was MA425 (?). It seemed pretty brittle but it seemed to work.

At any rate, if the Plexus is more than a year old, and has not been stored in a refrigerator, do not use it. I never got a clear answer as to how old it can be if it is refrigerated.

I think I got my MA530 from Tony @  Forte as it was only available in large quantities at the time.

.

The Plexus guy referred to some new adhesives that were supposedly nearly market ready at the time. They referred to these glues as "low surface energy adhesives" and thought that they would probably work better in our application once they were available. They were supposed to be designed for bonding stubborn materials like polyethylene. I do not know what the outcome of that effort was.

Good luck! - Philip

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[Philip Ryan]

On my new mast, Mark made a carbon fitting at the masthead that supports the track against side loading. It seems to work!

Either the Plexus guy and/or Tony @ Forte indicated that the mast is bending by compressing the length of the sail track substantially, and calculated that we routinely over load the shear strength of the adhesive in the vertical direction, especially when we flatten the sail with the cunningham by bending the tip of the mast back. This suggests that a fitting which mechanically forces the track to compress (note Bill Sheuman's rivet @ each end of the track) would prevent the adhesive from "seeing" the whole shear load.

Having had bolts tear through the mast wall under load, I tend to think that a purpose built fitting similar to what Mark made would be preferable to a single rivet in the mast track. the goal would be to have the fitting "fail" cleanly before making a mess of the more expensive parts, i.e. the mast and the track. Currently we have the track peel off occasionally, and while that is very annoying, nothing is truly broken and the repair time and $'s is manageable if aggravating.

Note: If this business of compressing the track while bending the mast is the primary mode for overloading the adhesive, it suggests that painting the adhesive joint to protect from UV is good for preserving adhesive strength and flexibility, but painting the track itself (white) would keep the track cooler which would increase its resistance to compression. So perhaps one solution is to paint the mast white, but leave the track black so that at least it stays warmer when there is sun on it. This is consistent with my observation that most of the sail track bond failures I have had (mostly small ones and more than 10 of them) have happened while sailing in cold weather

One of the two guys that I was communicating with, suggested cutting the sail track into shorter sections to leave little spaces that the track could "compress into". I did not do this because intuitively, I could see no advantage between the two resulting negative characteristics: overloading the sheer strength over the whole length of the track, or multiplying the notch pont failure locations on the track. The track almost universally seems to  start peeling at an end or the corner of an end. Since sectioning the track would increase the number of  these notch failure starting points by at least four fold, I chose to leave it in one piece.

Philip

[Philip Ryan]

Tony @ Forte had some very strong recommendations regarding how to glue the track to the mast.

-  I tried to clean the plexus off the old sail track, and gave up and just bought a new sail track. cleaning the mast was straightforward.

- don't squeeze the joint. you want a little bit of joint thickness to provide the necessary compliance for the adhesive to express its flexibility/toughness. I was unable to control this variable in any way.

- prepare the work space fully. Preparations took me most of a day. The next day, gluing took about 1/2 hr and clean up took about two hours.

- you MUST have a helper unless you are a pro who does this everyday, or at least every week.

- assemble AT LEAST twice as much supporting materials and clean up supplies as you think you will need. This applies to solvent cleaners, rags, paper towels, mixer tips, trowels, shaping and cleanup sticks...

- mask off ALL things that you don't want adhesive on. This includes the sail track, the mast, all shrouds, halyards and mast fittings and any openings in the mast. A pro would not do this, the rest of us need to!

- use masking tape to make a hinge between the mast and the sail track. I did this with about 2 dozen tabs to get the track straight, and then filled in the gaps. Use good quality tape and sight it from the ends to get it straight. Test the operation of the hinge flipping the track into gluing position and re opening it. Support the mast in more middle points if necessary to make flipping the sail track easy.

- first, I ran a small bead of plexus on the track, and spread it out to fill the grooves in the sail track and give the methacrylate a little time to etch the plastic track

- then I ran the main bead of Plexus on the mast, and flipped the sail track onto it.

- then tape the sail track down just enough to mostly close the joint. put masking tape wraps around the mast. I left 2 -3 in gaps between the wraps. Do double layer wraps so the tape adhesive can hold on until the Plexus sets.

- the most frustrating part was trying to clean up the excess Plexus squeeze out before it cured too hard to remove. I did a quick joint shaping pass before taping the track down, but running out of time meant that I had to clean under all those tape wraps. Again, a pro is faster and I was too slow. So it was a pain.

Philip 

[Robin Smith]

I have had zero failures since dividing the track into four sections and painting it white. The gaps reduce the maximum compression in each section, there by reducing the maximum shear force transmitted through the glue.

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[Philip Ryan]

Nice to hear that somebody tried that and that it is working.

How big are the gaps between your track sections?

I assume you placed the sail track gaps in between battens to keep the battens from shock loading the track end notch points?

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[swiftsolo1]

Robin great work!! 

Any problem with the slug/ bolt rope  catching in the track gaps  as you hoist the mail sail ? 

Paul 

Paul Osullivan

CEO, AMP RE Consulting. 

Paul.osu...@gmail.com

916 224 2374 

To view this discussion on the web visit https://groups.google.com/d/msgid/swiftsolo/CACBnOVBbvai160OkVrqWfw9AbmiDFp31R7FLVFFCwiVq1qOqUg%40mail.gmail.com.

[Robin Smith]

My track gaps are at random spots, two locations were at sites where the track broke. The gaps are small, about 1/32", but I sanded them smooth and rounded on the inside in an effort to not snag the sail. The gaps widen as they distance out from the mast, to allow for more movement there. I have the bottom end of my track pinned with a rivet and the standard metal fitting, which has been good...but Phil is correct about pinning the ends making the problem worse. I would no recommend pinning both ends without adding compression gaps in the middle. Mast track issues are the only significant design weakness in these beautiful boats..so worthwhile focusing on.

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[David Lindsey]

Philip and Robin, thank you both for taking the time to respond to my mast track issue and questions. You have both provided really good insight and information. Stripping the glue from the mast was pretty straightforward. I have not stripped the track yet. It shouldn't be a problem (famous last words!).
I think you're both on the right track, no pun intended. I am tempted to actually measure the temperature of the mast including the internal temperature of the mast in full sunlight. On the other hand this just gives me a number and I don't know how this would help me beyond fulfilling my curiosity.

The removed glue does look "cooked" to me. This leads me to think that it is perhaps the combined effect of temperature, shear forces and Uv. No question the failure was through the glue vs the bound to either material. This gets me thinking...

Robin your solution may have addressed or at least reduced the shear forces by having the track in sections. The light coloured mast should definitely help reduce the temperature. But I have to wonder if these solutions only help extend the time period before there is failure? I guess we won't know for sometime.. 

I have to be honest. I am just not happy with this glue. I have another thought, it might sound a bit crazy but hear me out. I would like your opinion. 

Why not bond the track and mast together with platinum silicone? This of course depends on the track's ability to stick to silicone? I would have to test it. Does anybody have a scrap piece of track?

I once attended a lecture given by a chemical guy from Smooth-On. This is a smaller formulator that makes some specialty products. It's counter intuitive, but if you spray silicone on a surface before applying a paste silicone it will stick like you know what to a blanket. I know it will stick to the mast. 

Does anyone know what the tack is made of? I know it's not polyeth. 

Your thoughts gentlemen? 

David Lindsey

CAN 046

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[Philip Ryan]

When I was asking ten thousand questions of Tony @ Forte and the chemist @ Plexus, the clear consensus was that if there was an appropriate urethane adhesive, that would be the glue of choice. There was no such thing at the time (5 yrs ago). Urethane has the strength potential, but won't bond to the sail track well enough. So the next choice represents compromise - Methacrylate adhesive - which is why we are using Plexus. It bonds very well to both the acrylic track and the epoxy/carbon mast and IF you choose the right formulation it has adequate elongation, shear strength and toughness. I very strongly suggest doing everything in your power to find the MA530 formulation, as that is the only variety of Plexus which is flexible enough. The others are stronger, but they cannot tolerate the extreme elongation differences between the mast and the sail track. Yes - this means that almost all of the tracks were glued on with an inappropriate adhesive. Only the ones that Forte glued at the factory are right, and only after they learned that 3M-5200 didn't work.

If you decide to do something different, do your homework about adhesives and the length difference between the straight mast sail track length and the fully bent (compressed) length, and then spend a lot of phone time with the technical assistance department of the company who makes the adhesive you are considering. Don't forget to inform that scientist about the sideways shock loading, temperature range and UV exposure that the bond will need to tolerate, and make sure that they know that the bond will be created by an ameture craftsman in an uncontrolled environment. (I.e. it won't happen in lab conditions).

If I had to do it again tomorrow, I would use the MA530 Plexus.

Unless there are new silicone products that I haven't heard about, the only appropriate characteristic that they have is flexibility. Their strength and toughness are a small fraction of what is required in the mast to track joint.

Philip

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[David Lindsey]

Thanks Philip. Most interesting. You answered another question; the track is made of acrylic. 

Mike Joclyn reminded me via text tonight that we did his track 15 years ago and he hasn’t had any problems. He has sailed his boat extensively!

David Lindsey 

CAN 046 

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[Philip Ryan]

Yes - I think that's right.I think the track is acrylic or Lexan (a type of acrylic?), but I'm not sure that my memory is right.

The best way to make sure of the sail track material is to call Forte. They will have the answer.

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[Robin Smith]

Hi there, well the Smith team failed somewhat🤔 I have the gun and mixing tubes for the small plexus delivery system...and 530 plexus in the big double tube set. The big tunes are 75% full, about 1.5 years old, and shelf life of 6 months stamped on the front. So I suspect my offering is not very helpful, but let me know if you want any of it. I ca leave it under your boat...

Robin

CAN048

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[David Lindsey]

Robin, thank you so much. That would be great. It would be great to meet you. Ian is on his way here now. Plan to cook a steak for both Ian and Mike here on the Westside. No date set. Probably tomorrow night. Why don't you join us? My phone number is 778-214-1719. Four Swifties together!

David Lindsey

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[swiftsolo1]

Sounds fun guys .. wish I was there 

Paul Osullivan

CEO, AMP RE Consulting. 

Paul.osu...@gmail.com

916 224 2374 

To view this discussion on the web visit https://groups.google.com/d/msgid/swiftsolo/CAHyCSvOkGacYufvA1ZeiW_2wy6s42h4ALefdZgp3wcoLX7ZRMg%40mail.gmail.com.

[David Lindsey]

Hey Paul. Do you have Robins phone number?

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[swiftsolo1]

Try this 250 216 0665 ?

Good luck 

Paul Osullivan

CEO, AMP RE Consulting. 

Paul.osu...@gmail.com

916 224 2374 

To view this discussion on the web visit https://groups.google.com/d/msgid/swiftsolo/CAHyCSvMBzpgiGj2ZABRXebFOf66Gp3gAooz3yQYLEu8%2Bg6T6Vw%40mail.gmail.com.

[Philip Ryan]

I would trust out of date Plexus over any epoxy, unless the Plexus has been stored in a very temperature variable (hot) environment.

Steaks sound good!

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[David Lindsey]

My track is now glued on. Did it yesterday. About 24 hours ago. How long should it cure before bending the mast and loading it?

David Lindsey

CAN 046

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[William Scheumann]

David,

The technical data sheet for Plexus MA530 says it reaches 1000 psi after 160 minutes at 74F (23C).  Check itwplexus.com for more info.  They recommend painting or sealing to prevent oxidation, but you may want to wait a few days to allow full curing before doing so.  UV resistant epoxy or marine white 2-part polyurethane paint will do the job.

Bill Scheumann

Sent from my iPad

On Aug 9, 2020, at 2:33 PM, David Lindsey <swift....@gmail.com> wrote:



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[Robin Smith]

Hey David, can you leave any left over plexus gun parts on a swift boat cover? We are off to Nelson Monday morning.

Robin

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