Making DIY Dynel (Faux) Tape?

[Guest]

As far as I can tell there is no such thing as selvage edged Dynel tape. This thread on the Kayak Forums was instructive. And comical at times.

http://www.kayakforum.com/cgi-bin/Building/index.cgi/md/read/id/242109/sbj/shop-dynel-tape/

“Get out in knee deep water, pick up the boat and carry it ashore”. Sure, try that in a gear-loaded boat with the waves crashing against the landing. Let me know how it works out.

My scissor cutting action remains at kindergarten level, even with fray-resistant Dynel, and I’d like to try making Dynel strips with a cleaner edge.

Rudimentary Experiment A – If I want a 2” wide Dynel strip cut the fabric to a 4” width and fold an inch underneath on each side to form a doubled over, clean-edged 2” strip of Dynel.

The ? part; somehow adhere the linear foldovers in place before laying the fabric atop an epoxy basecoat, epoxy topcoating for full fabric saturation and then laying on/rolling down the release treated peel ply.

I think repeatedly using the hard roller over peel ply as the epoxy sets up would knock down the folded outer edge agreeably. It works on the selvage edge of sewn tapes and thick swelling materials.

The Experimental Plan A question is “What glue or adhesive to use to fold over and adhere the Dynel to itself”. Something that won’t interfere with epoxy resin, and will remain somewhat pliable in stem curve application.

Some thin coat of spray adhesive would be easiest to apply. What say the builder folk?

 

[Quinn]

The 3M spray tack that some composites stores sell would probably be your best bet.

Alternatively, I bet you could just sew a folded over piece of dynel together, and then trim the allowance real close. although I haven't ever tried this, so maybe it would be a complete disaster.

Quinn

 

[dogbrain]

Mike, You must be joking about fray resistant, right? The dynel I have would fall apart in your hands if you tried to sew or glue it to itself.

mark

 

[frozentripper]

Something that's worked with material that's hard to cut cleanly with scissors is placing the material flat on a piece of plywood, pressing down hard with a straightedge along the intended cut line and then cutting along the edge with a very sharp X-acto knife. The straightedge clamping down on the material so that it doesn't move around while being cut might help. Never actually tried cutting Dynel.

 

[dogbrain]

I have one of those fabric cutting mats and a rotary cutter, which does a great job of cutting almost any fabric, except for dynel. Actually, it cuts the dynel perfectly but when you go to pick it up from the mat, the cut edge of the fabric is partly embedded into the cutting board. This doesn't happen with any other fabric I've ever cut. The coarse simple weave of the dynel is then pulled apart when trying to extract it. I went back to just using really sharp scissors and being just a little dissatisfied with the results.

 

[Guest]

The 3M spray tack that some composites stores sell would probably be your best bet.

Alternatively, I bet you could just sew a folded over piece of dynel together, and then trim the allowance real close. although I haven't ever tried this, so maybe it would be a complete disaster.

Quinn, I am trying to avoid any sewing, I’d probably make a mess of it.

Which 3M spray tack or adhesive? I have 3M 77 and 90 in the shop. I don’t have Hi-Tack Composite 71, which is designed for use with epoxies, and don’t know if it will allow the folded Dynel to remain pliable enough to drape over a stem curve or vee after folding and spraying.

https://www.3m.com/3M/en_US/company-us/all-3m-products/~/?N=5002385+3290539321+3294857497&rt=rud

If I go the spray adhesive route I’ll try it experimentally first, on something other than a hull stem, just in case folding over for a clean edge proves sloppier than a single-ply cut edge, or if the result is horrible once epoxied in place.

Mike, You must be joking about fray resistant, right? The dynel I have would fall apart in your hands if you tried to sew or glue it to itself.

Mark, maybe there are different Dynel fabrics. All of the Dynel I have used, 5oz 600 denier Dynel from Jamestown Distributors and Sweet Composites, has seemed identical.

Cut with scissors, even on the bias or on a curve, it frays far less than my experiences in cutting S glass or E glass. I don’t know if that is the material itself, or the weave or even possibly the sizing. Not just in cutting the material, the edges hold together better when rolling or brushing on epoxy.

I have never tried a rotary cutter and if I ever do will avoid using it for Dynel.

 

[Alan Gage]

This thread on the Kayak Forums was instructive. And comical at times.

http://www.kayakforum.com/cgi-bin/Bu...op-dynel-tape/

“Get out in knee deep water, pick up the boat and carry it ashore”. Sure, try that in a gear-loaded boat with the waves crashing against the landing. Let me know how it works out.

Now Mike, I didn't take you for someone who would use a partial quote to pull something out of context. The next sentence (that you omitted) has direct application to canoe tripping and could be the answer we've all been searching for: If it is loaded with gear, use both hands.

I don't have any ideas about the dynel tape dilema. I just try to keep the cuts as clean as possible but I always end up with some loose strands that feel like rope once saturated with epoxy. I looked at the weave picture on Jamestown's website and it does look finer than the xynole I've been using from RAKA.

Alan

 

[Quinn]

I think the 3M 77 should work. If it were me I would spray the cloth, fold it over and then try to compress it a bunch to knock down the folds. Then I would spray tack the whole thing to the hull and wet it out. That being said, I've never done the fold it over part.

 

[Guest]

Now Mike, I didn't take you for someone who would use a partial quote to pull something out of context. The next sentence (that you omitted) has direct application to canoe tripping and could be the answer we've all been searching for: If it is loaded with gear, use both hands.

I was recalling that suggestion from memory and forgot the all-important use both hands part. The full suggestion, cut & pasted:

Best of all options... Don't drag the boat by the bow toggle. Get out in knee deep water and pick up the boat by the coaming and carry it out. If it is loaded with gear, use both hands.

That is one hella strong coming. And paddler.

 

[dogbrain]

I’ll have to check out the Jamestown dynel, mine is from raka. I’m actually doing stems on a buildnow. Here’s a picture of the coarseness of the weave.

It looks ok now but applying epoxy pulls on individual threads and makes the edges a little messier.

Mark

 

[Guest]

Wow, that is way different than the Dynel fabric I have used.

Not a close up, but here’s a couple of pieces of (poorly) cut Dynel between some peel ply.

PB040032 by Mike McCrea, on Flickr

 

[Alan Gage]

I’ll have to check out the Jamestown dynel, mine is from raka. I’m actually doing stems on a buildnow. Here’s a picture of the coarseness of the weave.

It looks ok now but applying epoxy pulls on individual threads and makes the edges a little messier.

Mark

This is the same as what I use. If I'm not mistaken it's actually xynole rather than dynel. I've read that they're essentially the same thing and also read that they're not the same. I don't know what to believe but it's been working well for me. But, as you say, threads start coming loose during wetout.

Alan

 

[dogbrain]

I think you’re right Alan, and I agree that it works very well for abrasion resistance. I probably have enough of the xynole for a dozen canoes, but I’ll likely order a yard of the real stuff in the future anyway just for ease of use.

Mark

 

[Guest]

I’ll have to check out the Jamestown dynel, mine is from raka. I’m actually doing stems on a buildnow. Here’s a picture of the coarseness of the weave.

It looks ok now but applying epoxy pulls on individual threads and makes the edges a little messier.

Seeing the photo I understand why Mark thought I must be joking about “fray resistance” with Dynel. Wetting out that open weave must be a pain along the edges, and trying to fold over and glue it together would be a nightmare.

I am curious about what applications are used or intended with that open/mesh weave Dynel (or Xynole) material. I use the more fabric-like anti-fray Dynel solely as skid plate material, as an outer layer just at the stems where the abrasion resistance is appreciated.

The Dynel does use a lot of resin compared to S-glass, or even E-glass, and “Swells up like an old sweatshirt” (quoting someone on Canoe Tripping years ago) if not compressed under peel ply (or vacuum bagged), and I can see how the Xynole would use less resin/not be as heavy, especially if larger pieces were used.

Is the open mesh Xynole used as an outer layer in skid plate applications, or as a substrate layer below S-glass or etc in select areas in the build schedule of a canoe?

If used as an external skid plate how is it for abrasion and impact resistance?

 

[dogbrain]

Mike, The xynole strands aren't in any way adhered to each other, so they just pull right out, or even fall out if you're not really carefull. I use it the same way you describe. Wet out the fabric, put peel ply over the top and let it partially cure. Then I go over it with some thickened epoxy until that solidifies. Then I take a chisel or a scraper to the edge and try to feather it into the hull. I use a little more thickened epoxy to get those edges feathered while I'm doing fill coats on the hull. The xynole is light years better than e or s glass for abrasion resistance. I had to re-apply a really thin short piece to the bow of my solo boat after 3 years of heavy tripping use. As far as impact resistance, I'd say the xynole is worse than glass. I've had a couple chunks come off of the bow above the water line. I don't use my wood boats the way I do a plastic boat, so I'm never really hitting too many rocks with much force. I'll be ordering the stuff you have and will use it next time. It sounds quite a bit better, and probably more abrasion resistant since the weave is more dense.

Mark

 

[Guest]

The xynole strands aren't in any way adhered to each other, so they just pull right out, or even fall out if you're not really carefull. I use it the same way you describe. Wet out the fabric, put peel ply over the top and let it partially cure. Then I go over it with some thickened epoxy until that solidifies. Then I take a chisel or a scraper to the edge and try to feather it into the hull. I use a little more thickened epoxy to get those edges feathered while I'm doing fill coats on the hull.

Parsing, that sounds like a lot of work/steps, and something fray prone. I detest stray hairs pulling free from fiberglass as I’m wetting out. Even with some babysitting push-back it gets messy, and at some point I need to realize that I’m doing more harm than good with those stray hairs.

The xynole is light years better than e or s glass for abrasion resistance. I had to re-apply a really thin short piece to the bow of my solo boat after 3 years of heavy tripping use. As far as impact resistance, I'd say the xynole is worse than glass. I've had a couple chunks come off of the bow above the water line.

The tighter weave Dynel fabric has proven incredible for abrasion resistance. In DIY impact tests better even as a single outer than E-glass or S-glass, and it proved to wet out more thoroughly with hand laid materials than thicker stuff.

I really like the idea of laying down a two-ply skid plate, an underlayer of something cut on the bias and a top layer of Dynel laid in the other orientation. Or maybe vice versa; the Dynel fabric hangs together pretty well even cut on the bias or into curves, so maybe that as a bias cut top.

I don't use my wood boats the way I do a plastic boat, so I'm never really hitting too many rocks with much force. I'll be ordering the stuff you have and will use it next time. It sounds quite a bit better, and probably more abrasion resistant since the weave is more dense.

I do try to miss visible rocks (eh, not always successfully), and rarely know I’m about to impact something just barely submerged ‘til I do. Or drop over a little ledge scraping the stern stem on my way down.

And there are the short strainer drag-portages on day trips, and grinding the bow onto some rocky shore in hopes I can get out in only thigh deep water and quickly pull the canoe above the waves before it slams ashore sideways. And other stem abuses that save my aging body at the expense of the more easily fixable hull.

Dynel skid plates, every boat.

Let us know what you think. With shipping, quantity ordered and etc I do not know if Jamestown or Sweet Composites (or others) are the best value.

Jamestown
https://www.jamestowndistributors.com/userportal/show_product.do?pid=4214

Sweet’s (this page, style 90285)
https://www.sweetcomposites.com/Polyester.html

(Beware the 28325 nylon peel ply above in that link; it is green pull peel ply and cautious epoxy set up timing is required so that peel ply pull comes off cleanly. That green-pull stuff sucks if you finish late at night or well lubricated. Even if I plan to topcoat on green epoxy I’d rather use the release treated stuff)

 

[recped]

Mike, have you ever looked at the Dynel "sleeve" that Sweet Composites has? When I bought my bulk lot of Dynel I also ordered a yard of the sleeve material. It's basically a tube sock of Dynel. I can't find the piece I bought and I don't remember the exact width but I'd guess it would yield a double layer about 2 inches wide when flattened.

 

[Guest]

Mike, have you ever looked at the Dynel "sleeve" that Sweet Composites has? When I bought my bulk lot of Dynel I also ordered a yard of the sleeve material. It's basically a tube sock of Dynel. I can't find the piece I bought and I don't remember the exact width but I'd guess it would yield a double layer about 2 inches wide when flattened.

I had seen it listed but never thought about it. Sweet’s product descriptions sometimes leave me confused:

Dynel sleeve is a knitted material used for covering paddle shafts. It comes in a standard weight and light weight. Dynel cord is used for reinforcing edges and tips on foam-core paddles. It is about 3/8" diameter with a hollow core so that it will flatten out when pressed. The cord and standard sleeve yield about 23 yd/lb. The light-weight sleeve yields about 45 yd/lb. All three products are the same price — be sure to specify which you want when you order. They can also be made up in colors at higher cost. Generally colors must be special ordered but some may be in stock. The sleeve is put up on variable-size rolls, typically between one and two lb. For the cord only, the 10-49 lb price applies to a full carton, with 12-15 lb in a typical carton, and the over-50-lb price applies to a full case, with four cartons making up a case.

(How is the light-weight sleeve heavier than the standard sleeve?)

A favor; if you can find that yard of sleeve please flatten it out and let me know the width. If it is 2 inches wide that might be ideal for clean edged skid plates on vee stems, where the wear is in a narrow, well defined strip, or even along the worn length of vee bottoms.

I don’t know if the standard or light weight cord would be better, might try a couple yards of each to see which works better with peel ply and roller compression.

To fully saturate the sleeve I might return to an old trick used with long lengths of glass tape; mix a pot of epoxy, loosely coil the tape (or sleeve), stick it in the epoxy pot, massage it around until fully saturated and then pull one end from the pot while laying it in place. The excess resin will squeegee off the fabric as it drags across the edge of the pot, and the remainder can be use to topcoat anywhere it looks thin.

Thanks, this may be the neat-edge solution I’ve been looking for.

How is the Canadian distribution of Dynel going?

 

[dogbrain]

Mike, the dynel you’re using sounds like it could be cut into much thinner strips than I dare to cut with the xynole. My experience is that I only need a strip about 3/4” wide or less if possible to protect the stems of a wood boat. I have a bunch of that green peel ply and yes, you have to remove it before things really set. I bought some treated stuff, but haven’t got into that yet.

Mark

 

[Guest]

Mike, the dynel you’re using sounds like it could be cut into much thinner strips than I dare to cut with the xynole. My experience is that I only need a strip about 3/4” wide or less if possible to protect the stems of a wood boat. I have a bunch of that green peel ply and yes, you have to remove it before things really set. I bought some treated stuff, but haven’t got into that yet.

Mark, I’m trying to imagine me cutting that open weave Xynole into a thin strip, and see only disastrous results. The Dynel fabric has a kinda stay-together weave to it, and cuts/wets out well without undue fraying. The photo shows it on my cutting table, where it is opaque white against the green background cover.

We tried cutting that Dynel with a fresh razor blade against a straight edge and that was less satisfactory than using sharp scissors. Of course my scissor work, trying to make clean, even cuts even on Dynel or any other fabric, leaves a lot to be desired.

Even 1” wide Dynel sleeve would (perhaps) be easier to epoxy/peel ply/roller compress onto narrow vee stems as an abrasion resistant outer layer.

2” wide would be better, especially for something like the full length bottom vee on a well worn Mad River canoe. We have used wide E-glass tapes in that application; it was not worth the short lived abrasion resistance, and became a mess to re-treat deal with when too quickly worn, scraped and chunked away.

I agree about green pull peel ply, I just don’t see the reason. If I want to pull the peel ply while the epoxy is still green, for better chemical adhesion, the release treated stuff comes off just as easily.

And letting the green pull nylon stay on a wee bit too long in the mysteries of epoxy mix, heat and humidity has been a comical struggle at times. Think removing green pull peel ply over skid plates a bit late, with one largish fellow laying atop the hull to hold it down, and a one scrawny guy pulling #%$@& with both hands for all he was worth. Just nope.

About the release treated peel ply. The very sheer blue release treated peel ply (or vacuum bagging release fabric) is a PITA to cut cleanly, and worse to solo fly-away-weight lay in place. The heavier (white) finely woven release treated peel ply is easier to cut and manipulate. It leaves a very faint weave texture in the epoxy when compressed, which I guess is good for mechanical adhesion, and that fine weave imprint sands away easily for a smooth skid plate paint topcoat.

Like Recped I bought a couple feet of experimental: Dynel cord is used for reinforcing edges and tips on foam-core paddles. It is about 3/8" diameter with a hollow core so that it will flatten out when pressed.

I am lost as to how to use that Dynel cord as after-market paddle edging. It is wider than a shoelace, twice the thickness, and swells up even further when epoxied. I’m guessing it is laid-up inside/flush fitted during foam core paddle construction, maybe with vacuum bagging. Epoxying it as protection on an existing paddle would be thick bladed glump-splash-glump-splash with every paddle stroke.

I have used that Dynel cord in some other applications, where I wanted a cloth and epoxy fillet to round out a right angle edge.

I have two more sharp vee stemmed decked canoes that need Dynel skid plates, and will be experimentally trying some Dynel sleeve.