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PostPosted: July 3rd, 2014, 12:32 pm 
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Location: Freeland, Maryland USA
I want to duplicate an experiment I tried years ago - laying various plastic wraps, wax paper and other releasable materials atop resin. There were a couple of problems with that experiment - one, it was so long ago that I was probably using polyester resin, and two, I don’t remember the results.

I used four different types of plastic wrap, Saran Wrap, Cling Wrap, and…I forget. I do remember that two of them were kinda stuck, and that Saran Wrap was one of them.

I want to try that experiment again, using the various plastic wraps, wax paper, peel ply and etc, but this time using West System 105/206 on one batch and Gflex on another. I might try it first using just the 105/206; I hate to waste Gflex, and I could repeat the experiment using Gflex on only the release materials that proved to work with regular epoxy.

For the test bed I’m thinking about epoxying a scrap pieces of fiberglass cloth to a (clean and alcohol-wiped) length of vinyl siding, covering those “patches” with the various release materials and weighing the patch down with a large zip-lock bag of sand. Peel off the plastics (or maybe not) a day later and see what happens.

I’ve got plenty of scrap fiberglass cloth, epoxy, peel ply and wax paper and just need to pick up the various plastic wraps.

Any idea which plastic wraps are used in epoxy application successfully?

Or other commonly available plastics? I’ve heard that Xerox transparency sheets work, if only for flattish areas.

Any suggestions for changes in the experimental methods or materials?


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PostPosted: July 3rd, 2014, 6:30 pm 
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Joined: February 12th, 2008, 6:01 pm
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Location: North Bay, Ontario
I know waxed paper works and I use it for small patches to cut down on sanding. Also duct tape seems to work fairly well. Both of these leave a residue I guess but it sands right off.

Crazy carpet material (HDPE?) also works. Nothing sticks to that stuff.

Kinguq.


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PostPosted: July 3rd, 2014, 9:29 pm 
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Location: Lower Saranac Lake, NY
Professionals use release treated peel ply because it works. Untreated peel ply works fine if small patches are pulled off when resin is still green. Both let air and other outgassing through the weave. Films generally do not, unless perforated as in wet bag perforated film.

Secondly, peel ply upsets somewhat, conforming to curve-linear surfaces, conforming even better when patches are bias cut. Again, films tend to bridge on concave surfaces and ripple at the edges on convex ones.

The downside of peel ply is the imprint of the weave. Inside hulls, that;s fine. On outer gel repairs we gotta sand through 2000 and buff. Film can leave a smooth surface, but the edges generally end up needing sandpaper anyway.


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PostPosted: July 4th, 2014, 7:34 am 
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Location: Freeland, Maryland USA
Charlie Wilson wrote:
Professionals use release treated peel ply because it works

The downside of peel ply is the imprint of the weave. Inside hulls, that;s fine. On outer gel repairs we gotta sand through 2000 and buff. Film can leave a smooth surface, but the edges generally end up needing sandpaper anyway.


I am well short of being a professional when it comes to boat work, but since I started using peel ply a few years ago I need no convincing, and try not to start any epoxy work without peel ply on hand.

The very faint weave left after the peel ply is removed is easier to sand away than the crinkly results usually left by my attempts using wax paper or plastic wrap. I read (and have found) that peel ply largely eliminates amine blush (the blush rests atop the peel ply and is removed when the peel ply is take off).

My intention in this is to (re)discover which of the commonly available plastic wraps work best.

From the Repairing Royalex Chips thread:
Mike McCrea wrote:
(Peel ply release fabric would be much better than wax paper, but the grocery store doesn’t sell peel ply)


I think that a lot of folks who do their own boat repairs or outfitting use materials that are commonly available at hardware or grocery stores, and that most shade tree boat tinkerers do not have peel ply. I’ve been trying to convince one friend who regularly messes with small boats to order some for years now. (I also know that when he finally breaks down and orders some he’ll kick himself for not having done so sooner).

If I can find a brand or two of easily available plastic wrap that works “best” that at least will provide the better of bad options to using peel ply.


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PostPosted: July 4th, 2014, 6:29 pm 
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Joined: December 24th, 2008, 10:31 am
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Location: Jokeville
Have you tried using the shrink wrap (basically industrial grade saran wrap) that they use for wrapping pallets of....... stuff?
You can usually find it at moving supply stores. Maybe at your local uhaul store for example. One roll of that stuff you could probably build a canoe without any resin.


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PostPosted: July 4th, 2014, 9:52 pm 
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Location: Rattlesnake Pond ME
There are loads of shrink wrap in cottage country. If you have folks in your neighborhood that store boats overwinter, chances are the boats are shrink wrapped. The stuff seems to wind up everywhere around here.


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PostPosted: July 5th, 2014, 11:52 am 
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Location: North Bay, Ontario
This rang a bell and I remembered reading about a guy who used lexan film over epoxy to create a mirror-smooth, faired surface that required no sanding. Here are a couple of articles.

http://www.duckworksmagazine.com/03/r/a ... bottom.htm

http://www.duckworksmagazine.com/03/r/p ... /index.htm

I have not tried this myself.

Kinguq.


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PostPosted: July 11th, 2014, 8:27 am 
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I look forward to your results, Mike.

I have used a close weave, untreated nylon cloth sold by Sweet Composites as peelply many times. It is relatively inexpensive, but as Charlie indicated, it needs to be removed when the epoxy has cured to a green state. If it is left on too long, it can be difficult or impossible to remove.

I find that the cloth usually yields a better result than my attempts to use wax paper or plastic wraps have. Excess epoxy will come out through the cloth and in my hands at least, I am much less likely to get pleats or wrinkles, and I get a smoother edge.

The matte finish caused by the imprint of the cloth fibers is not cosmetically unpleasant on the hull interior. For exterior patches, where a smooth surface is desirable, I do not expect to completely fill the weave of 5 or 6 ounce/sq. yd. cloth with a single application of epoxy anyway so I remove the peelply when the wet out application of epoxy is green, and apply another coat of epoxy (without peelply) to fill the weave. If the first epoxy application is still green there is no need to worry about amine blush.


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PostPosted: July 11th, 2014, 11:03 am 
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The best test bed I could find was a scrap piece of vinyl siding, which will stand in nicely for the vinyl skin of an RX canoe. I wish it was something with more complex curves to test the “stretchability” of the plastic wraps, jut it’ll do. More on the usefulness of stretchability later.

I’m mostly curious to see which if any of the top films end up adhered to the epoxy, to see how the films flatten the would-be razor sharp seams that stand tall on fiberglass tape and how each smoothes out kevlar felt (which, I know, is a crap material, but it’s still what is included in most skid plate kits).

I’ve got bags of scrap glass tape and kevlar felt. Know I know why I kept it, and any other potentially usable piece of scrap material. It’s not that I’m cheap, it’s that I’m, um, experimental, or some subset of syllables therein.

I do have a couple of harder-to-come by films on hand; peel ply and a roll of mystery labeled “Porous Release Film” made (I think) for vacuum bagging. I’m going to omit some other “films” that have good reputation but limited availability - lexan film, Xerox transparencies sheets and etc

The films:
Saran Cling Plus
Glad Press & Seal
Glad Cling Wrap
Reynolds Wax Paper
Porous release film
Peel ply

The vinyl siding bed has been scrubbed clean, dried and alcohol wiped. Time to cut some fabric and film, and mix some epoxy.

Image

The Test: I painted a coat of epoxy (West System 105/206) on the vinyl siding, laid down pieces of kevlar felt and seamed edge glass and filled the cloth with an additional topcoat of epoxy resin in each test bed. I laid on the test films, smoothed each out with a gloved hand to eliminate what wrinkles I could and then rolled each film, pressing down with a short nap roller.

I weighed the “patches” down with Zip-lock sandbags, but removed them from the peel ply and (visibly perforated) porous release film while the epoxy was still green.

Image

I could immediately confirm that I do not like working with stretchable plastic wrap. I can barely get kitchen leftover containers covered without ending up like a transparent and frustrated mummy, much less achieve a smooth and wrinkle-free film atop epoxy and cloth.

If there’s a trick to using stretch wraps atop epoxy and cloth it needs more than two hands.

I removed the sandbags atop the peel ply and porous film after 4 hours, which was almost too long. They were starting to get stuck and just barely came off without tearing open the Zip-locks and dispensing sand on the test bed. I live in trepidation of that happening when using sand bag weights.

Results:

I left the various films on for 12 hours before pulling them.

All of the test films knocked down the seamed edge of the tape and smoothed out the kevlar felt. The glass was barely visible and the loose end strands disappeared completely, with no stray frays poking up like composite lancets, and the cut sides of the kevlar felt were beveled smooth along the edges and not standing abrupt. So far so good.

Saran Cling Plus – It released cleanly except for one small shard of Saran that was trapped in a wrinkle. The resin was hardened, but there were many (many) sharp wrinkles and crinkles that would necessitate a lot of sanding. Not a pleasing surface.

Glad Cling Wrap – Identical to the Saran Wrap in every way.

Glad Press and Seal – Far smoother with less wrinkles and crinkles than the previous two, but the resin still felt tacky. It either needed more cure time or that tackiness was sticky residue from the Press and Seal. I set the test panel out in the sun for a few hours and the Press and Seal test piece was even stickier. I’d guess that stickiness is residue from the top film. Nix that one - Press and Seal is best avoided for epoxy work.

Reynolds Wax Paper – The cleanest release and smoothest epoxy/fabric surface of any of the grocery store products, with only a few small wrinkles/crinkles. I didn’t see or feel any waxy residue, but I’d want to lightly sand and clean that area just to be sure; wax would be a horrible contaminat to leave in place before topcoating.

Peel Ply – As expected the best of the lot and the easiest to work with, leaving a very faint weave pattern from the peel ply fabric. No wrinkles, no crinkles baby butt smooth.

Porous Release Film – Very clean release, but the epoxy surface is almost as wrinkled as with the two “cling” plastics.

Summary:

All of the materials released after a 12 hour cure, with one wrinkle trapped shard. In the previous plastic wrap experiment years ago (using poly resin) I had clamped the films down and found a good bit plastic trapped in compressed wrinkles and crinkles, especially with the Saran Wrap.

For a flattish surface or a simple curve wax paper seems to be the best, or at least easiest to work with, of the grocery store products. However wax paper will leave sharp-edged pockmark voids if the area is at all resin starved and will wrinkle if “forced” to take too much of a curve.

For complex curves one of the stretchable cling products “might” work if laid in place with four hands stretching the material smoothly across the surface area. Or not, even taping down one side I have never had much smooth success trying to stretch plastic wraps, and the resulting wrinkles and crinkles were more of a PITA to deal with than using no release material at all.

Clarification: While the cling products “might” work with better stretching technique on the outside of a curve (ie canoe stems), on an interior curve like the chines plastic wrap would be a wrinkled and creased disaster to get into place. Wax paper would be easier to apply in that application.

The mystery “porous release film” (a reddish-translucent film perforated with small holes) was no better than the cling wrap plastics. I’m guessing it was intended for vacuum bagging.

Peel Ply – If you do epoxy work get you some.

By far the smoothest finish, wrinkle and crinkle free. The faint fabric weave sands far easier than jagged wrinkles and crinkles, and makes a beneficial mechanical bonding surface if left in place for additional epoxy coats. Cut on the bias or laid in multiple overlapping sections peel ply will wrap a stem curve, and it’s much easier than any cling wrap for working inside a hull.

The peel ply removes most amine blush, and I think some excess resin as well. I can’t prove this, but after using peel ply for a few years I have a feel for the least amount of resin necessary to fill the cloth, with any small amount of excess coming off with the peel ply.

Ah well, in for a penny, in for a pound. Before I put a year’s supply of plastic food wraps in the kitchen cupboard I’ll try a small test area using Gflex with each product to see how that sticks-to-damn-near-everything epoxy releases from the various films.

And if I feel energetic in a week or so I may try sanding down the wrinkles and crinkles to gauge the effort required, and topcoating with more epoxy to see what’s needed for a smooth surface.


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 Post subject: Untreated nylon cloth?
PostPosted: July 11th, 2014, 11:56 am 
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pblanc wrote:
I have used a close weave, untreated nylon cloth sold by Sweet Composites as peelply many times. It is relatively inexpensive, but as Charlie indicated, it needs to be removed when the epoxy has cured to a green state. If it is left on too long, it can be difficult or impossible to remove.

The matte finish caused by the imprint of the cloth fibers is not cosmetically unpleasant on the hull interior. For exterior patches, where a smooth surface is desirable, I do not expect to completely fill the weave of 5 or 6 ounce/sq. yd. cloth with a single application of epoxy anyway so I remove the peelply when the wet out application of epoxy is green, and apply another coat of epoxy (without peelply) to fill the weave. If the first epoxy application is still green there is no need to worry about amine blush.


I like that idea a lot. I often remove the peel ply when the resin is still green, especially when I have taped and papered the hull to catch any drips and dribbles and need to get underneath to strip the tape and paper.

And still green forms a better bond with a second coat of epoxy in any case.

What is the stock/style number for that untreated nylon? You know I am frugal/cheap, and the untreated nylon cloth is less costly than treated peel ply I’d use that in many applications instead, and I’ll need to order some material from Sweets soon anyway.

The Gflex test beds are in place and I’ll try to pull the films in 12 hours or so. In a “Duh” moment I realized that the Press and Seal is only sticky coated on one side, so I put it on upside down on the Gflex to eliminate the leftover residue.


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PostPosted: July 11th, 2014, 12:35 pm 
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Mike McCrea wrote:
pblanc wrote:
I have used a close weave, untreated nylon cloth sold by Sweet Composites as peelply many times. It is relatively inexpensive, but as Charlie indicated, it needs to be removed when the epoxy has cured to a green state. If it is left on too long, it can be difficult or impossible to remove.

The matte finish caused by the imprint of the cloth fibers is not cosmetically unpleasant on the hull interior. For exterior patches, where a smooth surface is desirable, I do not expect to completely fill the weave of 5 or 6 ounce/sq. yd. cloth with a single application of epoxy anyway so I remove the peelply when the wet out application of epoxy is green, and apply another coat of epoxy (without peelply) to fill the weave. If the first epoxy application is still green there is no need to worry about amine blush.


I like that idea a lot. I often remove the peel ply when the resin is still green, especially when I have taped and papered the hull to catch any drips and dribbles and need to get underneath to strip the tape and paper.

And still green forms a better bond with a second coat of epoxy in any case.

What is the stock/style number for that untreated nylon? You know I am frugal/cheap, and the untreated nylon cloth is less costly than treated peel ply I’d use that in many applications instead, and I’ll need to order some material from Sweets soon anyway.

The Gflex test beds are in place and I’ll try to pull the films in 12 hours or so. In a “Duh” moment I realized that the Press and Seal is only sticky coated on one side, so I put it on upside down on the Gflex to eliminate the leftover residue.


The fabric I have used is the nylon fabric listed on this page:

http://sweetcomposites.com/Polyester.html

The price is somewhat higher than I remember and it might have gone up since the last time I bought some, but if you are using it primarily for patch work, a yard goes quite a long way.

Your results are pretty much what I expected and in line with the results I have achieved using plastic wraps and waxed paper. Peelply costs a few dollars but if you anticipate applying fabric patches now and again it is well worth it. The only downside is that using a permeable fabric as peelply does require the use of a little bit more epoxy, but it makes it much easier to distribute the epoxy evenly.


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PostPosted: July 12th, 2014, 8:08 am 
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G/flex release film results

Almost exactly the same as with West System 105/206. All of the “films” released (although the upside-down Press and Peel was stuck pretty well) and the wrinkles, crinkles and folds in the cloth and epoxy below were identical to using 105/206.

I didn’t learn a lot in this experiment. All of those products work to some extent. I wouldn’t use Press and Peel, and my cling wrap technique needs work to achieve a smooth surface. The perforated wet bag release film I have is useless for my purposes. Using G/flex, or a mix of G/flex and 105/205 works equally well with all cover materials.

I’ll stick with wax paper for simple flattish patches and peel ply for the rest. And pick up some untreated nylon cloth from Sweet Composites for green epoxy pulls.


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PostPosted: August 19th, 2014, 3:51 pm 
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pblanc wrote:
I have used a close weave, untreated nylon cloth sold by Sweet Composites as peelply many times. It is relatively inexpensive, but as Charlie indicated, it needs to be removed when the epoxy has cured to a green state. If it is left on too long, it can be difficult or impossible to remove.


Pete, I have now heard conflicting stories about how green/cured the epoxy need be to cleanly pull that nylon peel ply. Given varying temps and humidity how “green” is green? A couple of hours, or the next morning?

I recently put skid plates on an RX canoe, bias-weave tape on the bow and dynel on the stern. I laid release treated peel ply over both and did not like the epoxy finish I saw when starting to pull the ply several hours later.

The next morning (@ 12 hours after the epoxy went on) the release treated stuff pulled cleanly and left but a faint peel ply weave in the dynel.

If the “green” pull on the nylon stuff is 10 or 12 hours later I could use that 90% of the time.


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PostPosted: August 20th, 2014, 6:38 am 
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I have generally had good luck pulling it off after an hour or two. I live in a somewhat hotter climate than you do and I am often working outside so the epoxy may cure more quickly.

As I start to pull it off, it any fibers at the edge of my patch appear to be lifting, I smooth it back down and wait a bit longer.


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PostPosted: August 21st, 2014, 8:42 am 
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On the other hand, Express Composites in Minneapolis sells treated peel ply for ~$8/ yard. Once you've tried the real deal, you'll never go back to untreated.


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