Fiberglass/Epoxy question.

I am getting ready to apply the fillets and fiberglass to my NE Dory. I have all the cloth roughly cut and set aside. I have never used this material before an I am a little confused as to the timing of events. After I lay down the fillets, then place the cloth in the compartments and wet it down with epoxy. The manual stated to trim the cloth at the joint between panel 1 and 2. When do I do this? Do I wait for the epoxy to cure completely or come back after a few hours while the epoxy is still somewhat malleable?


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RE: Fiberglass/Epoxy question.

   I am about 75% complete on my dory build. I have found that if you wait 2 to 3 hours just so the cloth is slightly tacky, you can trim with a razor knife with a new blade. My boat build is taking place in florida so that is my kick off time for my epoxy. Good luck and enjoy the build.

RE: Fiberglass/Epoxy question.

 It's very slick if you can lay the glass down while the fillets are still curing, but this is pretty advanced and complicates what is normally for novice boat builders two completely different steps.  For example, I did these two steps on two different days.

Step one, make your fillets nice and smooth using the proper radius tool, then smooth them with a glove and denatured alcohol.  Make sure this step is successful as anything less than ideal can lead to a lot of frustratingly unnecessary sanding.  You can consider this a successful day in the shop, turn out the lights and sleep soundly.

Once you're happy with the filleting step, then proceed with glassing the inside bottom.  If your bulkheads are already in place, this is complicated enough.  On some of CLC designs, the interior is glassed with no bulkheads in place, which makes it a much easier process.  On others, each station gets glassed separately.

Masking tape should be applied on the edge where the interior fiberglass reinforcement stops for that particular step in the process (which can be unecessarily tricky if fillets aren't cured yet).  When the resin-soaked fiberglass has gelled, but not cured hard (2-4 hours into curing time depending on hardener and temperature), it's easy to run a razor knife down the edge of the masking tape, liberating the edges of the fiberglass cloth and masking tape, leaving a beautiful, clean line of glass that will disappear under subsequent coats of epoxy.

Keep in mind that at worst, using the two step process, you will need to rough up the fully-cured fillets with some sandpaper for a mechanical bond to accept the epoxy wetted out fiberglass step some time later.  This is easy compared to A) Sanding fillets that got messed up before they cured because you wer laying down the fiberglass layer and B) Messing with both the filleting process and wetting out the fiberglass process on the interior all in a single stage.  This can be a very long and unpleasant day for a novice boat builder, detracting from the fun of what should be a series of successful processes.

My $0.02, your mileage may vary...  Good luck!

RE: Fiberglass/Epoxy question.

CaptainSkully thanks for the input. The manual states that this should be 1 step. It is really good to know I can separate it into a 2 stage procedure if I need to.

   

RE: Fiberglass/Epoxy question.

   I didn't worry too much about getting a neat trim job along the edge of the bulkheads. The thwarts will entirely conceal that area. But you should try to do a very good job of trimming along the top edge of the first strake. That will always be quite visible. As stated above, trim the fiberglass cloth while it is still incompletely cured. It should be dry to the touch but still flexible. If you trim it too early, you risk pulling the cloth away from the hull; too late, you risk getting slivers of blue tape entombed forever and/or lots of sanding.

 

RE: Fiberglass/Epoxy question.

 

 

A couple questions:

Cap'tScully: If one separates the steps of filleting and fiberglassing, what kind of preparation is needed to prepare fully cured fillets for subsequent application of epoxy? I'm wondering about amine blush & any need to wash / wipe / sand to ensure a good bond.

HH: You're a fan of PeelPly I can tell! Does using it for filleting (and elsewhere, as in fiberglassing inner trunk surfaces for as smooth a surface as possible) eliminate the need mentioned above when the procedures described are being performed separately? 

With the news Friday of the debut of CLC'S Waterlust sailing canoe kit, and my leap of faith in purchasing one that afternoon, I'll be paying more attention to what's being posted here.

It's been 45 years since my first adventure into boat building. There have been a few dreams since then that have brought me to buying plans for various craft and even a few sheets of marine ply. With skills and knowledge acquired in the meantime, and with sources for expertise such as this forum being a keystroke away, I'm confident this new endeavor will be more presentable as well as long-lived.

It'll be a few months before I can look forward to beginning to join the components of my kit to one another. In the meantime I'll be running thru the build sequence manual looking for areas that suggest a little more detailed explanation would be helpful.

Then there's all those videos to explore....

 

  

RE: Fiberglass/Epoxy question.

As relates to one step or two step fillet taping, when we built my Peeler Skiff, we followed the manual and did it in one step. That may well be the best technique for experienced professional builders, but if I were to do it again, I would wait until the fillets had set before applying the glass tape. The remainder of the build taught us that amine blush does not seem to be an issue with the MAS formulations that came with the CLC kit, especially within the first 24 hours.

I very much agree with masking and then trimming the selvage off the tape when it has set up but not yet hard. Otherwise, sanding the tape selvage smooth is a real pain in the posterior.

Cheers,
Dick

RE: Fiberglass/Epoxy question.

   I guess I have assumed that the reason for doing it in one step is to get a better bond between the epoxy of the fillet and that of the cloth. That should make the hull a little stronger.

RE: Fiberglass/Epoxy question.

I believe that you're right. It probably was the original reason. Amine blush used to be a serious issue when using epoxy. I do not believe it is now. I know I was very pleasantly surprised when I used the modern MAS formulations. In olden times, we used to wash it off with warm water and detergent, rinse, and let dry before adding another layer. Sandin it off with some of the epoxy worked too.

The one step process is much faster if you have a lot of skill and experience. Most of us do not and are more likely to do a better job with two steps. I think that building a boat every few years is just not enough practice to get really fast. If anyone has experience that disagrees with my opinion, please chime in.

Cheers,

Dick

RE: Fiberglass/Epoxy question.

Hi Guys!

I just came in from my shop for a break and a snack. My back is hurting a bit but I am very happy. My intention tonight was to just lay down the fillets, get them nice and smooth and place the cloth tomorrow. I worked till I was satisfied with the fillets, I was surveying my work and thought “how hard can it be”. So I decided to try the small compartment at the stern, I figured that one is mostly hidden by the seat so if I make a mess I can hide it. That compartment went easy, and I realized why the CLC folks said to do it all in one shot. The still tacky fillets hold the cloth in place for you. Spread it out, get it nice and tight then lightly press the cloth into the fillets and away you go! I am just waiting a bit for the epoxy to stiffen up in the cloth so I can trim it all back, then it will be bedtime!

   

RE: Fiberglass/Epoxy question.

Good work. We measured and cut the tape and wet it out with a tack brush on a plastic sheet over plywood. Then we layed the wet tape on the fillets. Are you waiting for the fillet to firm up before laying the tape? We had difficulty smoothing the tape without affecting the soft fillet material. That's why I would use two steps in future.

RE: Fiberglass/Epoxy question.

I waited just a bit till the fillets were about the constancy of silly putty. I went through with my gloved had wet-ted down with alcohol like the manual stated and smoothed the fillets. Then by just lightly pressing the cloth into the fillets they would stick pretty firm. I was still able to pull it up and re-position if I needed to. The only drawback I could mention was, it was a long work secession form start to finish. I started around 10:30, it took till about 3:00 to get the fillets and cloth all down. I then gave it a 45 min break to stiffen, Back out to the garage to trim the excess and remove the blue tape before it became a permanent part of my boat. It was around 5 that I got to bed.

   

RE: Fiberglass/Epoxy question.

   Just a few things I would like to say as I read this thread. The first thing is applying all your work and cloths in one coat is called a chemical bond, and a lot stronger. If done in two separate coats the layers could and most likely will separate if you don't prep the surface correctly., this is called surface bond. We are trying to get the cloths as smooth as possible and no air bubbles, next to impossible without Peel-ply. I have made over 1000 things using composites. Never have I left out Peel-ply. Some of my projects require the use of cloths and materials that will cost me over $20,000, and I can't afford a screw up. The Peel-ply is the ONLY way to make your cloths smooth without the use of a vacume machine, and building boats you can't do it this way. I did a search on Youtube and this guy was using a card- I use a squeege to smooth out the cloth. Look very close at your cloth and push out all your air and extra resins. Wait unill full cure, when you remove be carefull not to peel up your cloth. Yes you should allways sand between coats, but now you have a surface that is much smoother now and the less chance of a sand threw.

Here is part one of the video, part two will play next.

https://www.youtube.com/watch?v=p8XgQGojepY&index=13&t=3s&list=PLVWnERGbVWT4Q_x08EniIa-B9v8oGuoiY

Fibre glast video

https://www.youtube.com/watch?v=raxYTCIkD54&index=14&list=PLVWnERGbVWT4Q_x08EniIa-B9v8oGuoiY

Just my way of using composites, everyone in here has a method that works well for them, because we all made mistakes and learned what works the best.

Now off to reproduce a very famous car worth 5,000,000 million dollars using carbon,kevlar and honey-comb with vacuum baging.

Google- Troutman and Barnes Special, white car with number 8 on her. When in the show at Pebble beach everyone goes crazy because of her history, the first scarb Carroll shelby raced in. The rest is history.

 

RE: Fiberglass/Epoxy question.

Interesting thread, this'n.

Seems all Peel Ply's not created equal!

http://www.powerdevices.com/com/content_data/131883_Hysol_EA_9895.pdf

As for T&B, I remember seeing original Scarabs race at Meadowdale International Raceway & Elkhart Lake as a kid in grade school. Jim Hall & Hap Sharp too in Jim's Chaparrals.

Off topic I know... this is a forum about boats, right?

 

RE: Fiberglass/Epoxy question.

Just a short comment about a chemical versus a mechanical or surface bond. If we were talking about polyester rather than epoxy, I would be in complete agreement. One of the important things about the epoxy resin we use is that it is a superior adhesive. Because I'm the curious sort and because my daughters and grandchildren will be out on the ocean in the boat I built, I have actually tested various configurations of filleted plywood joints. As long as the joints were taped within the 12 hours I waited, the joints were stronger than the plywood. I really had no way to measure the relative strength of the  one-step versus two-step filleted and taped joints because after the plywood fractured, I no longer had the means to further stress the joints. I do believe that the issue is moot because a boat can be no stronger than the first component to fail --- the plywood.

That being said, if one waits too long to tape the joint allowing the epoxy surface to start to oxidize, one should probably sand the surface before taping. If one is using an epoxy formulation that is prone to amine blush, one should be very careful to clean and sand the surface before taping. With boats, safety is always the best policy. For my next build, I'll probably tape when the fillet has firmed up (similar to Mike's technique), but before it has fully set. I do however plan to test joints with fillets containing chopped glass fiber, rather than taped. I really don't enjoy taping and if the sample fillets don't break before the the plywood and are easier than taping, I might just try them. I will definitely try Peel-Ply.

Cheers,
Dick

RE: Fiberglass/Epoxy question.

A few thoughts...  First, millions of boats have been built with the fillets curing first, then the glass added later.  All of the above cautions about amine blush and sanding the fillets is valid.  As long as the bond is stronger than the 6mm plywood, you're golden.

Second, in my experience, properly wetting glass cloth is easy to do with a squeegee.  In the past, I've used peel-ply for carbon fiber applications, but it was an expensive additional material needed for the build and it was very difficult to peel off.  Not pleasant for the small part I made, I can't imagine an 8'-12' boat.

Third, if you're at all contemplating laying down the glass cloth shortly after doing the fillets, I highly recommend cutting the cloth into shapes that fit nicely into their compartments and carefully setting them aside, making sure to not tweak the weave before you start filleting.  Wrestling with cloth is fun enough without adding tacky fillets to the mix.  

Also, there are two different styles of fillets we're dealing with here.  The first one is the large, dramatic fillet between the bottom and the garboard plank.  The second is the very small fillet between the first plank and the second.  Since the bottom is not rebated, it has a very different relationship with it's neighboring plank than the first and second planks do.  Now this depends on how high up you're glassing and where the glass gets terminated.  Also, fillet and masking tape locations need to be taken into account if you're planning on pursuing the single step method.

Another factor might be whether the interior is one large area free of bulkheads or if the glass will be done between the bulkheads, station by station.  Long, easy fillets in an unobstructed interior would be considerably different than all of the additional fillets with bulkheads involved.

I will definitely be revisiting this discussion when my Passagemaker is stitched together.  Thanks for bringing this up.

Note to Mikeflys, while there is certainly nothing wrong with pre-build research and questions, I just want to prepare you for the fact that even with what is obviously careful prep, there will still be questions you'll have late at night with epoxy kicking while you frantically post on the forum ;^)

RE: Fiberglass/Epoxy question.

Cap't said:

"there will still be questions you'll have late at night with epoxy kicking while you frantically post on the forum ;^)"

Somehow a vision of keyboard - let alone touchscreen - combined with epoxy is unsettling. Use speech-to-text & all bets are off as to the relevance of any answers you get for unintelligible questions posed!

Have a plan! Better yet, two or three!

I like the pre-cut cloth idea....

RE: Fiberglass/Epoxy question.

I pre-cut my cloth leaving several inches of overlap to be trimmed later. I had a bit of trouble with some of the pieces from the weave coming apart. I also had a problem with a fairly large section of the cloth I was sent having a tear right down the middle when I un-folded it from the package.  I so far have been able to cut around this tear. I hope I can pull this off when I go to glass the bottom of the boat.    

RE: Fiberglass/Epoxy question.

Yes, cut your cloth a few inches wide on all sides.  Also, you can use masking tape to stabilize the selvage until it's wetted out, then peel the tape off sideways (perpendicular to tape).

RE: Fiberglass/Epoxy question.

 

Yes, cut your cloth a few inches wide on all sides.  Also, you can use masking tape to stabilize the selvage until it's wetted out, then peel the tape off sideways (perpendicular to tape).

Great idea!!!!  I will remember that.

 

   

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