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3M Dual Lock—Q's & A's and Tests for Canoe Uses

Glenn MacGrady

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Stripperguy, I recall that you attach a movable solo bucket seat to composite floor rails using 3M Dual Lock. I'm thinking of using it for a movable wooden solo seat on wooden rails -- strips of it on the "slider" rails and a patch of it on each of the four corners of the seat rails. This would make the seat movable and removable (though not slidable) and would avoid kludgy slider clamps or brackets. Just plop it on the slider rail where you want it and move it, or remove it, when necessary. This solution would also be a way to kick out of a foot entrapment under a wooden bench seat.

Which of the three densities of the product did you use?

How many square inches of contact surface? Too much contact area might be hard to remove or rip the glue side off the rails.

Do you remove the seat to portage?

Do you remove the seat to cartop?

Has the adhesion of the mushroom side or glue side of the tape failed or begun to fail?

Thanks for any info and pictures you can provide.
 
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The video in that link is interesting. I had heard of 3M Dual Lock, but did not know that it used interlocking mushrooms instead of Velcro-ish hook & loop.

These parts of the product description are intriguing, and raise my curiosity.

Interlocking mushroom-shaped heads have five times the tensile strength of hook and loop products
Durable — open and close up to 1,000 times before losing 50% of original tensile strength
Easy to apply and maintain, easy to clean out dust or debris

I like the "easy to clean out dust or debris” aspect, which becomes an issue with hook & loop, and the “five times the tensile strength of hook and loop”.

I wonder how the “Durable — open and close up to 1,000 times before losing 50% of original tensile strength” compares to various Velcro’s, even the industrial strength stuff. I’m guessing (?) the Dual Lock is more durable than Velcro; the Velcro I have used in canoe outfitting, even paddle shaft keeper straps, has eventually lost a lot of grip.

1000 times for a seat connection would be acceptable. For something like a paddle shaft strap that thousand count might only get me a few years before losing 50% of the strength; although that initial strength may be more tenacious than I want to quickly release a spare paddle.

I’m tempted to get some of the black, outdoor stuff for an outfitting look see. I don’t much like Velcro in most outfitting applications, but there are times it seems the best/easiest choice.

About the Stripperguy questions, I’d guess leaving the seat Dual Locked in place while portaging works; one less loose thing to carry, and if it somehow fell out I think I’d notice. I’d be hesitant to leave anything not permanently installed in the canoe while cartopping.

I’ve had some things I thought permanently well affixed jiggle free on washboard roads, including one end of a strap yoke that was held by (my bad) poorly installed machine screws; the sudden, quite loud whappitywhappitywhappity of the webbing strap on the roof was WTF vehicular alarming.

Fortunately I carry spare machine screws, in the truck and in my canoe kit.
 
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I am intrigued as well. It is starting to make a lot of sense for sliding seat, partial spray decks, etc., but still, there is a lot of force generated against those components. I wonder about the lasting power of peel and stick adhesives used in some of the offerings.

I had not given it much serious thought, but the improvements in these "velcro" type materials makes it time to reconsider. I suppose the the only way to know if they will hold up is to try them out in real-world conditions. They sure have the possibility of being a convenient solution.
 

Glenn MacGrady

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Note that the product comes in either black or clear strips and that there is a low profile version, which I think I would prefer for my contemplated use. Amazon has a 10 foot trial roll of this product that can be used for prototyping and testing.

The low profile versions would logically seem to have less grip, but I wouldn't need much grip just for a movable bow-solo seat on this canoe:

tRB6Ce1.jpg

Nevertheless, Amazon also has 6' rolls of the regular profile version.

I see other virtues to being able to remove the bow-solo seat completely. It can give a longer space for stand-up poling positions. It can lighten the canoe when portaging. It can prevent sliding seat rattling when cartopping, And it can also deter theft when cartopping -- i.e., it's less likely that someone would steal a canoe with no seat.
 
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Stripperguy, I recall that you attach a movable solo bucket seat to composite floor rails using 3M Dual Lock. I'm thinking of using it for a movable wooden solo seat on wooden rails -- strips of it on the "slider" rails and a patch of it on each of the four corners of the seat rails. This would make the seat movable and removable (though not slidable) and would avoid kludgy slider clamps or brackets. Just plop it on the slider rail where you want it and move it, or remove it, when necessary. This solution would also be a way to kick out of a foot entrapment under a wooden bench seat.

Which of the three densities of the product did you use? Glenn, I will need to go back to one of my build threads to jog my memory...

How many square inches of contact surface? Too much contact area might be hard to remove or rip the glue side off the rails. I would say a total of 8 to 10 sq inches of active Dual Lock. On my seat platform, I have about 15 inches to allow varied seat placements.

Do you remove the seat to portage? No, it is neither in my way nor likely to fall off.

Do you remove the seat to cartop? Yes...however, I have once or twice forgotten to stash the seat in the car, and it was still firmly attached after the trip(s) home, sometimes a couple hundred miles.

Has the adhesion of the mushroom side or glue side of the tape failed or begun to fail? I did have the adhesive side fail on one patch (out of 4) of my Red Kite which has sat in my storage trailer for 2-1/2 years. That Dual Lock was initially applied in 2014. I attribute the failure to a poor cleaning job before application.

Thanks for any info and pictures you can provide.

The Dual Lock is surprisingly strong, I can lift my carbon copy Kite by the seat alone, which is a severe test, applying the load in pure tension like that.

As for pics, I apologize in advance, I don't have many that show the Dual Lock itself.

View attachment FhJf7SHHjgd3hlttMt_5C5ammFC7mCLyq_U8cXcoZsrLCy_v5Sol-pk_rAKOLb4GGJ72pTV_LJf476GFjy4K7AohX0v0H9qfzGzR

This pic shows my PFD strapped to the seat and pedestal, and my paddle tucked in from carrying a mile or so...

View attachment KToGR4s9xgLWvzd3z8FC0kRZNseHpF-_otvh0LYxWQ_7OFFPPmO7LKW6IoLvjvUop5KNSioh75HI5HhRKx6uF_7Yy-y6j8Zelnfy
 
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McMaster Carr has snap together fasteners mushroom shaped with acrylic adhesive "which bonds well to most materials and can be used outdoors." 25' by 1" costs $91.
 
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I've used the "super adhesive back" hook and loop from McMaster-Carr with the acrylic adhesive and can attest that it will peel the paint off a surface before the adhesive fails. It bonds to vinyl coated fabrics like dry bags etc and stays put in sub zero weather. McMaster-Carr has a lot of hook and loop type choices......

https://www.mcmaster.com/hook-and-loop


EDIT: the "snap together fasteners" on the McMaster-Carr web page above are mushroom shaped....


Best regards to all,


Lance
 
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I am very interested in Dual Lock, for a specific outfitting purpose; making DIY spray covers. I won’t use Velcro again, for wearing out/getting dirty/losing grip reasons, but Dual Lock looks more promising.

I’ll have to further investigate the application suitability of the (outdoor use) varieties that adhere to ABS substrates (3550, 3560 and 3570) and costs for 20 feet of Dual Lock.

If the Dual Lock will adhere to vinyl there may a simple no-sewing way to make spray decks in my preferred partial-cover style.

I’m thinking two pieces of heat sealable waterproof Packcloth, cut \_/ as open cockpit partial spray decks, with all four edges folded over and hem ironed heat sealable sides together. Maybe a 4 or 5 inch wide “hem” along the gunwale lines for edge durability

A paddle pocket could be as simple as a top piece of that material attached with Dual Lock, maybe for the shaft straps as well. Even the creation of drainage baffles at the open ends would be easy enough; I’ve DIYed that before with ½” foam pipe insulation (and once with a section of hula hoop as a raised cowling support).

No snap rivets, no loops and hooks, no drilling. No freaking sewing!

I’m interested enough to research which variety of Dual Lock would be best in that application, order some and experiment with some scraps of Royalex (thanks again Doug) and heat sealable Packcloth; install the Dual Lock to both materials, press together, peel apart, press, peel, press, peel repeatedly.

If Dual Lock proves to stick durably and dependably to the non-heat-sealable outside of the Packcloth, and is pliable enough to roll up (not stuff, heat sealable Packcloth doesn’t stuff very well) with the covers in storage that may be the easiest possible spray cover to DIY.

The MRC Independence is our only open canoe with no spray covers of any kind, and it is long overdue for some maintenance and spruce up. That canoe was a battered and busted freebie, and has needed a paint job since the day I first repaired and regunwaled it. Can of red EZPoxy would take care of that.

If anyone has used Dual Lock as a spray cover attachment, or knows more about the differences between those three outdoor-use Dual Lock varieties please do tell.
 
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Pete,

Are you still here?
I had time to look up an old build thread where I first used the 3M Dual Lock
Here is a link to the final page of that thread where the Dual Lock is presented.

https://adkforum.com/showthread.php?t=19626&page=9&highlight=kite

The particuler version I used holds up to 57 psi tensile and 32 lbs/in of width in shear, or so I boasted in that other thread.
That should be info enough for you to backtrack to find which specific Dual Lock I used.
 
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I am intrigued as well. It is starting to make a lot of sense for sliding seat, partial spray decks, etc., but still, there is a lot of force generated against those components.

I looked at the various types of Dual Lock and think* I have changed my mind on using it as spray cover attachments.

The least expensive Dual Lock I found is a “Trial Bag” version of low profile SJ4575, 1 inch x 10 feet for $25.

https://www.amazon.com/3M-0511119763...kle_mcd_asin_2

With Dual Lock, unlike Velcro hook & loop, both sides are identical, mushroom snapped together. So a 10 foot roll equals 5 feet of parts A & B when snapped together.

With (very short) partial covers, each 5 feet long, a full strip attachment would require 40 feet of Dual Lock. Even if that least expensive low-profile version worked, it would require $100 worth of fastener material. The possibly more useful versions of Dual Lock run up to $50 for 10 feet.

$200 for enough to make two 5’ long covers with the taller, beefier Dual Lock, attached full length on boat and fabric. YIKES!

The last DIY cover I made used $6 worth of stainless steel rivet snaps. I already have a modified pop rivet tool, anvil and flaring tools, so it’s back to drilling holes for tried and true snaps.

I wonder about the lasting power of peel and stick adhesives used in some of the offerings.

I had not given it much serious thought, but the improvements in these "velcro" type materials makes it time to reconsider. I suppose the the only way to know if they will hold up is to try them out in real-world conditions. They sure have the possibility of being a convenient solution.

Dave, I ordered a trial-bag 10’ roll of that Dual Lock; I have some other outfitting ideas for it, using smaller pieces. And I will experiment with attaching it to scrap Royalex and leftover heat sealable fabric and repeatedly pulling the Dual Locked fabric free.

Oh boy, another shop experiment!
 

Glenn MacGrady

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I ordered a trial-bag 10’ roll of that Dual Lock; I have some other outfitting ideas for it, using smaller pieces. And I will experiment with attaching it to scrap Royalex and leftover heat sealable fabric and repeatedly pulling the Dual Locked fabric free.

Mike, the trial version of the clear low profile I linked above is only $18.54, unless you want the more expensive black color for some reason.

https://www.amazon.com/3M-Dual-Lock...3471df5aafc&pd_rd_wg=ek7g3&pd_rd_i=B004V3RALO

I'll guess that the plastic strips are too inflexible to attach (or sew) to fabric.

I would be most interested in the tensile strength of four square inches on wood mated to wood, as that is the minimum contact area I would be using on a movable seat. That is, one square inch on the ends of the four bench seat rails mated to one square inch in four matching places on the slider rails. Perhaps you have a spare bench seat and some wood scraps for "rails" so that you could do the exact test. Would be most appreciated. And if the tensile strength is not enough, I'd be willing to order you a roll of the medium density high profile version to test compare with the low profile version.
 
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The 3m website says the Dual Lock Reclosable Fastener SJ4570 Low Profile is designed for indoor use and low to medium temperature performance. The Dual Lock Low Prole has one stem density of approximately 705 stems per square inch.

The standard profile Dual Lock Fasteners are available in three stem densities: DL 400 400 stems/ inch² (62 stems/ cm²) DL 250 250 stems/ inch² (39 stems/ cm²) DL 170 170 stems/ inch² (26 stems/ cm²)
I am thinking that the low profile has a super high stem density to compensate for the low profile.

I am also thinking it would not be the best choice for spray covers: Recommended Applications: Graphic panels, Display shelve, Light-weight access panels, Cushions, Components, Decorative acoustic panels
 
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I used dual lock when attaching Bell Rob Roy covers back in the day... about three per side - 6" of the clear with the adhesive foam on the back to adhere to the hull. I then sewed the non adhesive to the cover. McMaster Carr in the past was the 3 m dual lock. Going the whole length of a splash cover would be overkill in my opinion. I use snaps if there is a cockpit to insure the cover stays with the hull.
 
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So many variables in this, pondering a material I have never seen, let alone used.

Mike, the trial version of the clear low profile I linked above is only $18.54, unless you want the more expensive black color for some reason.

I think I’d prefer black for a couple reasons. I have black trim and black outfitting on most of our canoes, so the black would be matching, where I doubt the clear is invisible clear but perhaps more milky translucent.

Another reason is some “clear” outfitting things get fugly looking over time. Think clear float bag tubes or ect. This once upon a time clear Tygon tubing grab handle quickly became disgusting.

P1220469 by Mike McCrea, on Flickr

That probably wouldn’t happen with the Dual Lock firmly adhered to the canoe and no room for bacterial growth underneath, but probably isn’t good enough. At least with black I wouldn’t see the grunge. If I do opt to try Dual Lock it will be on a boat that is stored indoors, not out in the weather.


I would be most interested in the tensile strength of four square inches on wood mated to wood, as that is the minimum contact area I would be using on a movable seat. That is, one square inch on the ends of the four bench seat rails mated to one square inch in four matching places on the slider rails. Perhaps you have a spare bench seat and some wood scraps for "rails" so that you could do the exact test. Would be most appreciated. And if the tensile strength is not enough, I'd be willing to order you a roll of the medium density high profile version to test compare with the low profile version.

The first “experiment” will be to see how well and durable it sticks to Royalex and to heat sealable fabric. After that I am sure willing to try the one square inch bench seat rail experiment. I have plenty of old bench seats and varnished wood to approximate slider rails.

You know my scientific method is often flawed. If you will describe exactly how you would like to see that experiment performed I’m willing to give it a shot, I can spare eight square inches of Dual Lock in the name of science.

The 3m website says the Dual Lock Reclosable Fastener SJ4570 Low Profile is designed for indoor use and low to medium temperature performance.

Dave, the specs for the low profile 4575 I ordered specs “low surface energy acrylic adhesive bonds well to a variety of substrates including metals, powder-coated paints and a broad range of plastics”, “Features good temperature resistance of 158°F (70°C)” and “Best suited for outdoor or indoor use”

https://www.3m.com/3M/en_US/company-...3242262&rt=rud

I used dual lock when attaching Bell Rob Roy covers back in the day... about three per side - 6" of the clear with the adhesive foam on the back to adhere to the hull. I then sewed the non adhesive to the cover.
Going the whole length of a splash cover would be overkill in my opinion. I use snaps if there is a cockpit to insure the cover stays with the hull.

Dan, good to know that 6” pieces of Dual Lock work, that would make the cost much more reasonable. I had thought a full length strip of Dual Lock for a couple of reasons. In part for the (?) strength of the low profile version and in larger part because, with the Velcro’ed spray cover I made years ago, the ends of the Velcro were the first areas to start becoming detached from the hull, so using a full length strip would leave only two ends to more firmly adhere (I’m thinking a little bead of G/flex just around the edges of last couple inches of the Dual Lock at the ends).

My wife sewed the Velcro to the fabric perimeter of that cover, but our sewing machine is long kaput. If the 4575 stays durably adhered to heat sealable fabric in the experiments I may yet give it a try.

But, I’ve done snaps, I have the pop rivet gun modified for snaps, the other implements to set snaps and I have years of confidence in snaps. I used snaps spaced very 10 inches apart on the last cover and, for my rain, splash, spray and paddle drip partial cover purposes, that spacing has been plenty sturdy.

PA220002 by Mike McCrea, on Flickr
 
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3M TB4575 initial impressions.

TLDR: Low Profile Dual Lock was a fail. Still testing the adhesive backing.

For starters I am disappointed/concerned about the discrepancy in the on-line 3M description of the low profile 4575 versus the printed package description.

Both describe the 4575 as having “Low surface energy acrylic adhesive that sticks to metals, glass, many plastics” and etc. Both describe the 4575 as being “half the thickness of standard Dual Lock”.

But, the on-line 3M the 4575 as “Suited for indoor/outdoor use” while the package card lists only “Indoor”. More concerning, on-line Dual Lock claims “Durable — open and close up to 1,000 times before losing 50% of original tensile strength” while the package card lists “Closure Life 100”.

100 uses is inadequate for potential spray cover use, but I have (or had) other ideas for this stuff, even if it is inappropriate for outdoor use.

Physical inspection of the 4575. What I received in the “trial bag” is two 10 foot rolls. I’m liking that; a 20’ in a trial bag would be plenty for a spray cover.

The “half the thickness of standard Dual Lock” caliper measured at 1/16” thick, so the “standard thickness” Dual Lock should only be 1/8” thick and not obtrusive even in exposed outfitting. The low profile “mushroom” connections feel considerably smoother than I had anticipated, another plus.

The initial “connectivity” of the low profile 4575 concerning for something like spray cover use. Unlike Velcro it is necessary to press the two pieces together with considerable pressure, really pushing/squeezing them together to seat the all of the “mushrooms”.

The “peel apart” tenacity of the 4575 is the most disappointing surprise, it is far less tenacious than even non-industrial big-box Velcro, and inadequate for spray cover use even if used as a full length strip.

Bummer. As a spray cover attachment the low profile 4575 is a complete fail.

I can at least test the “low surface energy acrylic adhesive”. I adhered 6” lengths of 4575 to scrap pieces of Royalex and heat sealable Packcloth. And hard rollered it together with every mushroom fully engaged, not a likely field-practice technique.

I’ll let that adhesive set up for a day or so and test peel the Packcloth off the RX multiple (100?) times.

Given the lack of “mushroomed” stick with the low profile stuff, if it doesn’t stay stuck to both surfaces, especially the more suspect Packcloth, I am certain that the presumably more tenacious “standard” Dual Lock will pull free from one or the other surface.

If I does stay stuck, which I think it may considering the very weak mushroom stick of the 4575, I’ll wet the mated materials in a bucket of water and test the acrylic adhesion after a few thorough soakings, even trying to lift an edge with a blade or peel it apart with my fingernails.

I'll guess that the plastic strips are too inflexible to attach (or sew) to fabric.

I would be most interested in the tensile strength of four square inches on wood mated to wood, as that is the minimum contact area I would be using on a movable seat. That is, one square inch on the ends of the four bench seat rails mated to one square inch in four matching places on the slider rails. Perhaps you have a spare bench seat and some wood scraps for "rails" so that you could do the exact test.

Glenn, the low profile Dual Lock is relatively flexible, don’t know about the standard profile. Dan Cooke sewed it on a Rob Roy cover, but I expect Dan can sew anything. Me not so much

The tenacity of the low profile 4575 is all but useless for any outfitting application I can think of; I may eventually use it for some low-weight interior use, but the seat rail to slider rail experiment you requested is probably not worth trying with that stuff. If your desire is simply to have the seat not slide while seated it might work, but the low profile stuff sure isn’t holding a seat in place while portaging or cartopping.

If you like I can at least try that as an anti-slide experiment; full length strip of the low profile Dual Lock on faux slider rails, 1” tabs on the four ends of a wood seat frame, try to move the frame while seated.

I’d be happy to mail you, or anyone else, 6” strips of the low profile 4575 for inspection/testing. If the “grip” had been even marginally better I might have used it for a cover in conjunction with snaps, something like a snap every 12” with a 6” piece of Dual Lock spaced in between the snaps.

That’s a nope; the “grip” is so weak that I don’t foresee many uses, and 20 feet of it will last me a lifetime.

The Dual Lock is surprisingly strong, I can lift my carbon copy Kite by the seat alone, which is a severe test, applying the load in pure tension like that.

Given that testimonial the standard profile must be far superior, and I’m still tempted to give it a try. I’m starting to like the idea of a DIY spray cover using widely spaced snaps with (better) Dual Lock in between.

One final note about Dual Lock, and perhaps an occasional advantage over Velcro. Velcro is damn near like contact cement, it gets stuck instantly, sometimes off kilter. Dual Lock must be firmly snap-pressed together.
 
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The “peel apart” tenacity of the 4575 is the most disappointing surprise, it is far less tenacious than even non-industrial big-box Velcro, and inadequate for spray cover use even if used as a full length strip.

I had a small piece of dual lock I was messing with a few years back and I also remember being disappointed in how easily it came apart. But, if I remember correctly, it only came apart easily when peeled. Trying to separate it by shear or pulling two pieces straight away from each other was a different story. I have no idea what version I had.

Alan
 
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I had a small piece of dual lock I was messing with a few years back and I also remember being disappointed in how easily it came apart. But, if I remember correctly, it only came apart easily when peeled. Trying to separate it by shear or pulling two pieces straight away from each other was a different story.

Good point. I now have two different experiments with the low profile 4575 Dual Lock underway. Heat Sealable fabric to Royalex, and, for Glenn, a varnished wood seat with four 1” Dual Lock squares on the ends of the frame, and two 11” strips on a varnished piece of wood to approximate slider rails.

Even using the low profile 4575 the seat snapped into place with a resounding and reassuring click. Once the acrylic adhesive has had a day to set up, as I’ve read it needs, I’ll get to some further testing, trying to scooch the seat back and forth while seated, and doing a some weight bearing experiments in the fashion of this undertaking.

https://www.canoetripping.net/forums...ing-experiment

At least this time I only need to test a couple of things to weight bearing pull/peel/sheer failure. Hell, I may dirty up the 4575 with spider webs and leaf litter and see how easily it cleans up and sticks together afterwards.

I’m like a kid at Christmas, waiting for the acrylic adhesive to cure; I do love a good shop experiment.
 

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As for my experiment with one square inch on each of the four ends of a seat rails mating to a strip on the "sliding" seat rails, I'd want the tensile stick to be:

-- easy enough to pull off the seat to adjust while paddling without ripping the glue side off, although in reality I probably would put the movable seat in only two positions: all the way forward for a bow paddler and most of the way to the center to a position for a solo paddler. That would be four square inches of contact patches at any given position.

-- definitely needs to be strong enough to stay stuck during normal ups, downs and bounces of portages over rough terrain. I'd rarely want to remove the seat for a portage. A vigorous shake test would seem to be in order

-- doesn't have to withstand cartopping vibrations and aerodynamics, as I would always remove the seat for cartopping.

-- needs to retain stickability to survive at least a few hundred removals, which would all be more in the nature of "lift offs" or "pull offs" than "peel offs" if Alan's separation experience is valid.

I could increase the total stickiness, if necessary, by putting an end strut to connect the ends of seat rails and then put a strip of low profile DL along part or all of the two 10" seat struts. However, I'd be more inclined to increase total stickiness by staying with one sq. inch patches at the ends of the seat rails but changing to the high profile DL, which I assume is much stronger per square inch.
 
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Low Profile Dual Lock Experiments

Glenn’s (anti) sliding seat tests first.

As for my experiment with one square inch on each of the four ends of a seat rails mating to a strip on the "sliding" seat rails, I'd want the tensile stick to be:

-- easy enough to pull off the seat to adjust while paddling without ripping the glue side off, although in reality I probably would put the movable seat in only two positions: all the way forward for a bow paddler and most of the way to the center to a position for a solo paddler. That would be four square inches of contact patches at any given position.

Glenn, I am assuming by “pull off the seat to adjust while paddling” you don’t mean while still in the canoe; I think that maneuver would require some awkward off-seat moves. I tested for beaching the canoe and changing seat location.

I didn’t want the acrylic adhesive Dual Lock adhered to the few pieces of varnished brightwork I have left in shop stock, so I attached two 11” strips to a varnished DIY wood garbage can lid, with 1” squares on the bottom of a wood seat frame.

PA290001 by Mike McCrea, on Flickr

To approximate a canoe seat I screwed the trash can wood panel onto the top of my Workmate tabletop platform, snapped the Dual Locked seat frame atop (the Dual Lock does snap resoundingly in place with hard surface pressed against hard surface), and folded the workmate down to 14” high off the floor, to kinda sorta approximate a seat height/position.

PA300011 by Mike McCrea, on Flickr

Results:

It was impossible to make the seat slide while sitting on it. No way, no how was the seat sliding out of chosen position. That has been a downside of various sliding seats for me, so I’m already liking the Dual Lock concept in that regard.

-- definitely needs to be strong enough to stay stuck during normal ups, downs and bounces of portages over rough terrain. I'd rarely want to remove the seat for a portage. A vigorous shake test would seem to be in order

Testing the attachment tenacity of low profile Dual Locked seat:

Picking the seat straight up the Dual Locked seat held the weight of the Workmate, the clamped in place tabletop extension and the faux-rails trash can lid (37lbs total). Just barely though; if I gave it a downward shake holding just the seat I could get it to detach. With the Dual Lock holding just the seat weight in place I don’t think it is falling out in “normal ups, downs and bounces of portages over rough terrain” unless your seat is made of solid gold.

Removing the seat:

Holding the seat with just the side rails with wood trash can lid (3lb 8oz) suspended below I could not shake or bounce the seat free. But, if I grabbed just one rail end the seat came free with minimal effort. Grabbing both rails on one side took a bit more (unmeasured) effort. Peeling the seat off straight up, all four Dual Locked corners at once, took more effort than I was willing to contribute to this experiment.

-- needs to retain stickability to survive at least a few hundred removals, which would all be more in the nature of "lift offs" or "pull offs" than "peel offs" if Alan's separation experience is valid.

Very hard to measure. I took the seat on and off a few dozen times, from the same square inch of “rail” Dual Lock location, with no apparent loss of tenacity. The spray cover test may be more revealing in “closure life”.

I could increase the total stickiness, if necessary, by putting an end strut to connect the ends of seat rails and then put a strip of low profile DL along part or all of the two 10" seat struts. However, I'd be more inclined to increase total stickiness by staying with one sq. inch patches at the ends of the seat rails but changing to the high profile DL, which I assume is much stronger per square inch.

I don’t think a wider end frame addition is necessary, even with the 1” square of low profile 4575 on the ends of the frame the seat seems firmly locked in place for your stated desires.

Test #2, low profile Dual Lock as spray cover attachment.

I attached a 6” strip of 4575 to a piece of Royalex and a scrap of heat sealable fabric. To better approximate a spray cover placement I screwed a section of old wood gunwale above the heat sealable material/spray cover Dual Lock location.

PA300013 by Mike McCrea, on Flickr

Results:

It takes some pressure along the length of the 6” long Dual Lock to fully mushroom seat the spray cover material, it doesn’t snap into place as with the pushing down the hard wood-on-wood seat frame. Dan is right again, a full length strip of Dual Lock would not only be overkill, it would be a huge PITA to pressure push fully seated.

In that regard, snaps every 10 inches would be faster and easier. But. . . . .for a rain, splash, paddle drip cover using snaps every 10 or 12 inches, with 6” pieces of Dual Lock in between, may have merit.

The snaps, if connected first, would assure that the pieces of Dual Lock are properly aligned cover to hull, and the Dual Lock would help hold the areas between snaps tightly against the boat. And, if my aching thumb was tired of pressing snaps, I could probably use just the Dual Lock. I think an experimental snap & Dual Lock spray cover is in my future.

PA300016 by Mike McCrea, on Flickr

Peeling the 4575 Dual Locked spray cover material off the Royalex repeatedly (@ 50 times) did not seem to weaken the tenacity in any measureable way. To be abuse-certain I hard rollered the Dual Lock closed each time.

PA300018 by Mike McCrea, on Flickr

As Alan noted the Dual Lock, even roller seated, releases very easily if lifted/peeled from one edge. But, in tension, pulling the cover material vertically over the gunwale piece, even the low profile stuff is surprisingly strong, in fact all but impossible to pull free in that manner.

The acrylic adhesive seems plenty tenacious, on varnished wood surfaces and on the heat sealable fabric. Last test; I submerged the Royalex and heat sealable fabric in a basin of water to test the waterproofieness of the acrylic adhesive.

PA300019 by Mike McCrea, on Flickr

I got onto some boatwork in the shop and plumb forgot about that acrylic adhesive saturation test. For four hours. The 4575 Dual Lock is still well adhered to both the RX and heat sealable fabric, so I’d judge it passed that wetted test.

Tomorrow I will stick and peel that wetted Dual Lock on and off another 50 or 100 times, but I’m now at least convinced the 4575 is good for outdoor use.

One last note: I e-mailed 3M with questions about the Trial Bag TB4575 low profile Dual Lock package card discrepancies vs on-line information. 100 clousure life, or 1000? Indoor, or indoor/outdoor?

And, which Dual Lock they would recommend for spray cover attachments? Hoping to get an answer next week.

Having done those low profile experiments I’d really like to repeat the same tests using standard profile Dual Lock. I’m mostly curious if the standard profile is (hopefully) easier to press together. Or more difficult to seat all of the mushroom heads, which would be a nope for easy spray cover attachment

I’m pretty certain standard profile will be stronger, but I don’t know how much more strength is needed in those applications.

Who loves ya Glenn? Or who loves spending most of a day on shop experiments? Me on both counts.
 

Glenn MacGrady

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Most interesting. An informational birthday present. Danke. Merci. Gracias. Tapadh leat.

I've been assuming the regular profile is stronger and harder to attach and detach than the low profile, but maybe that's not necessarily true because the low profile has a larger mushroom density than the three regular profiles, as DaveO pointed out. The regular profile comes in three different densities that can be mixed and matched, but only four combinations are recommended. Here's a screen shot from the 3M site:

RSx4Gbj.jpg

To have a more complete 3M comparison test, Mike, I'd still be willing to buy and send you a roll of 250. I don't know if there are trial rolls of 170.

In addition, do you have a strain gauge to test pull force? In any event, I think you should also test the claims about easy clean-ability by mashing some dirt, mud, sand and insect guts into the mushrooms.
 
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