Epoxy and fiberglass

Is there a way to gain experience with epoxy and fiberlass without ordering a kit ifrst?  I have no experience in this, but want to build the Lighthouse Tenderly kit.  I don't want to spend all that money and end up destroying the build with a bad fiberglass and epoxy job.

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RE: Epoxy and fiberglass

  Fiberglass cloth is cheap, and can be had from almost any home supply or hardware store.  You'd want to get cloth similar to the kits - 4 to 6 oz, woven.

Two-part epoxy isn't too cheap, and you'd need a fair quantity to get some decent testing/learning done.  Probably two quarts. And definitely get slow reaction epoxy.  Managing set-up (hardening) time (which is very temperature dependent) is a very big piece of learning good glassing.  Having 30 minutes or more of good working time is nice - 10 minutes or less gets very challenging.   And maybe some wood flour or cellofil to test the "mustard" and "peanut butter" consistencies you'll need to become familiar with gluing together pieces and doing filets.  You can get epoxies and fillers locally or mail order or from CLC.  One thing to do it to NOT confuse epoxy glassing efforts with polyester resin glassing efforts.  That is an entirely different animal.

You can test on any sort of wood - cheap plywood is fine, but a key will be to ensure you learn to do some corners and curves, and that some of the work is other than horizontal.  Horizontal flat surfaces are easy.  Other things not so much.  You'll also want to learn and practice the filet process.  The more you learn the better you get, and the less sanding you have to do, which is a significant time savings.  Good technique is less about puttin the epoxy on the cloth, and much more about getting the glass to lay flat while prepping the work, figuring out how to get good edges, smoothing filets, etc. 

I've learned a lot as I've done my kits. I find doing a decent job challenging and I'm far from expert, but with care I've had (almost) everything turn out well.  All the CLC and other instructional videos are VERY helpful.  So are CLC live demos, if you can ever make one.  They usually do demos at all boat shows they attend. 

So, practicing with cheap materials is a great idea.  But rest assured, you can do it.

RE: Epoxy and fiberglass

   I forgot to mention:  Why practice on something you plan to throw away?  Maybe up the stakes a bit and try to build a scooter for the kids, or bird feeder or bird house or do the roof on a dog house?  That will allow testing multiple glueing, glassing and filet techniques (and maybe even paint and varnish while you are at it) and no loss if things go a little sidways in the process.

RE: Epoxy and fiberglass

   Thanks.  I'm thinking about buying the materials needed from CLC and practing on some plywood like you recommend.  I'm not familiar with wood flour or cellofil , but will look it up.  I'll also check out the videos you mentioned.

RE: Epoxy and fiberglass

   Consider the Stitch and Glue class with John Harris (designer of the Peapod) in August at the Woodenboat School in Maine. The link is under the boat building classes on this website. This class is what I would call a "skills" class. You will spend a full week dealing with epoxy and fiberglass, building skills and learning lots of tips and tricks. Best of all the kit used is the Lighthouse Tender Peapod!

I took the class a few years ago...fell in love with the boat and built one



RE: Epoxy and fiberglass

   Thanks, but flying to Maine in August probably won't work for me.  I met a guy last year while rafting who built his own whitewater dory.  He's friends of some of my friends.  I'm going to try to contact him for help and advice.

RE: Epoxy and fiberglass

I started building a wood duckling about 10 months ago.  I'm almost done (have taken multiple long breaks, obviously)!  To my surprise, most of my delays have been due to alignment of the pieces (stitching and alignment of the deck/hull) or dumb mistakes I've made (like leaving a dollop of epoxy on every stitch hole, resulting in endless sanding) and have had nothing to do with epoxy and fiberglass.

As a first-timer with very few relevant skills, my biggest concern was whether I'd be able to get good results with epoxy on large sections of fiberglass cloth (on the hull, primarily).  I've only glassed the inside of the hull so far (about ready to glass the outside), but I found the large areas of cloth surprisingly easy to wet out/fill.

I struggled with fiberglass tape/epoxy in two critical areas, though.  Maybe this is peculiar to my (weak) skillset, but my advice would be to focus on these areas:

1. Puzzle joints: I was under the impression that I could get smooth puzzle joints that would need just a quick dust-off by using smooth plastic sheets (and weights) on both sides and adding lots of epoxy (enough to make sure I didn't have voids).  I ended up with really thick (but smooth!) epoxy that I had to sand a lot.  The ~50 lbs I put on each joint were not enough to squeeze out the excess epoxy.  I ended up sanding through the plywood veneer on at least one bottom/side panel because of this.  i wouldn't worry so much about getting a smooth surface since you'll have to sand anyway.  I'd just make sure to (a) get enough epoxy into the joint to prevent voids in the epoxy between the wood pieces and (b) keep the two pieces of wood flat/aligned so you won't have to sand through at least part of a veneer to get a smooth joint.

2. FG tape on fillets: Applying/shaping the fillets was mostly pretty easy, but but things got squirrely a few times when I added tape to the (not-yet-cured) fillets and tried to saturate it without pooling or bubbling.  As the (unthickened) epoxy starts to cure, it becomes really easy to pull strands from the ends of the tape and drag them all over the place, making a difficult mess to clean up.  I feel like viscous epoxy and vigorous brushing also led to strand pull-out mid-tape, which got very messy.  In general, I'd recommend working the epoxy into/out of the tape only until the epoxy starts to cure.  Working with multiple small batches, working quickly, and working at lowers temps would seem to help a lot.

One major caveat: Only apply epoxy when the temperature is stable/dropping since you might otherwise get outgassing/bubbles due to expansion of air trapped in the wood.

RE: Epoxy and fiberglass

All the major epoxy manufacturers used to sell trial kits. These had something like 10 ounces of epoxy, some fillers like cab-o-sil, phenolic microballoons, woodflour, etc. as well as a few scraps of glass cloth. They were sold at substantially less cost than buying the individual items would have been. The idea was to let new builders work with the stuff a bit and lose their nervousness about the unknown. Unfortunately they've stopped doing that. I guess it wasn't cost effective.

But, if you're a first-time builder and you are absolutely going to build that boat, you can get a similar effect. I don't know of a single first-time builder, myself included, who did not end up needing to order more epoxy. So instead of trying to avoid this the first time, embrace it and plan on needing more. The smallest amount sold is a quart of resin and a pint of hardener. That should actually be more than you need to cover the first-timer shortage, leaving the rest available for practice. Throw in a yard of 4-oz cloth and a small container of woodflour and you'll be able to practice your mixing, wetting out, cutting cloth (straight and bias-cut), filleting and all the stuff you want to get right before you start the boat. Since you'll probably need to buy the extra resin anyway, you won't be spending any more than you otherwise would. Any leftovers will last years and be useful for touch-ups, repairs, modifications or other projects.

On a completely different subject, you can avoid the problems with fillets that HerbieRidesAgain mentions by wetting out the tape before you apply it. Roll it up, put it into a tall narrow container and pour the epoxy over it. Give it a chance to soak in for a bit, then hold the roll in your gloved hand and squeeze and massage it until it turns transparent. At that point, simply unroll it onto the still soft fillet and gently rub it into place with the edge of a gloved finger. Spread any excess epoxy onto the adjacent wood. The result is a perfectly wet-out piece of tape over a smooth fillet with no bubbles.





RE: Epoxy and fiberglass

   Thanks for all the great advice.  Watching a few videos has really helped my confidence too.  

RE: Epoxy and fiberglass

Lazlo, that last paragraph of yours ("On a completely different...") is worth its weight in gold.  Thank you.   - K

RE: Epoxy and fiberglass

   Some of the experiences identified here are typical of every first build. No cure for inexperience, but experience. Take a small project and play. Try a small purchase of epoxy and watch the how to info CLC and West systems offer. John Harris did a video long ago about fiberglassing that offers the best advice you can get. Be prepared and deliberate. Use a slow cure hardner to start and keep epoxy batches sized to your limits. In the end it is just dirty work that leads to magic.

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