Third Coast Boatbuilding: Fiberglassing the Drift Boat

Talented woodworker, Chris Schoenberg of Third Coast Craftsman (now Boatbuilding!), has had good luck so far with his wooden drift boat boatbuilding project. This week’s video, however, shows that not all skills can be assumed – like the fine art of fiberglassing that we know can be trickier than expected. As can easily happen, Chris ended up a few hands and a few mixed epoxy cups short of a smooth, straightforward job applying the fiberglass to the wooden boat.  His disappointment is palpable and you know from his reaction that he will never again underestimate the work and prep that goes into fiberglassing.

What tips would you offer to a novice about laying down and wetting out their first big fiberglass job? Everyone has special tips and techniques and even Chris has a cool tip for us hidden in today’s video of the week. Leave your comments below.


15 responses to “Third Coast Boatbuilding: Fiberglassing the Drift Boat

  1. I don’t understand why people fiberglass hull sides when the intention is to finish the hull bright. If you ever incur a bruise that gets beyond the fiberglass, and you want the hull bright, it makes it almost impossible to blend in.

  2. Suggest the heated environment was also big factor in the problem. Epoxy wets fiberglass (esp the fiberglass made for epoxying) rather well. Once it starts to gel it may be moveable but won’t work into the glass well.
    Anything more than a minimal epoxy application “floats” the glass cloth off the wood surface, and that applies to runs in particular. It’s very easy to apply too much on first coat. Glassing the hull of a 30’ cold molded boat we learned that heat is not your friend, and trying to more than dampen the glass on your first coat is not your friend. I sympathize deeply with his disappointment. We mixed larger batches of epoxy, and poured it into metal paint roller trays to dissipate the exothermic heat (metal conducting heat away and broad top surface to release heat). We found rolling and smoothing MUCH easier to control epoxy amount than pouring or brushing and smoothing (which we discovered by failing on our test section). Yeah, three person job…mixer, roller, smoother. I cringed when I heard “warmed epoxy”…we were using coolers with ice at one point to suck exothermic heat away. Not to sound like a know-it-all, we didn’t know any of this til we had messed things up a bit, testing. And so it goes…

  3. chris; I did a very similar project on a 13 foot strip boat this month and knew it was more than I could do in one sheet of fiberglass on the bottom. I did the bottom in 3 sections, lapping them from over a little from transom to bow, starting from the transom. yes the laps show but no one is going to see that anyway, and it may be stronger. it made the whole more manageable.

  4. You mentioned that filling those deep countersinks was a pain, but the pain seems self-inflicted. I could understand if you were using wood plugs for cosmetics’ sake, but given the non-traditional appearance of thickened epoxy, you could have just driven the screws a little past flush – not only eliminating two unnecessary steps, but also leaving more plywood (for strength) under the screw heads.

    On your “lessons learned”:
    -Agree with pre-epoxying the boat before applying fiberglass (to avoid the wood’s porosity drawing up the resin and starving the glass) – but it doesn’t need to be penetrating (any low-viscosity will do) and doesn’t need to be scuffed up. Epoxy adheres to any non-blushing epoxy just fine.
    -Disagree with pre-glassing the panels. Your first thought (they will be much harder to bend) was correct, and (depending on the amount of bend) it can also cause some delamination.
    -Disagree with your conclusion about epoxy mixing. Pumps are the way to go for accurate proportioning. Also, given all you’ve done to warm everything up, the larger batches could have started to congeal in the pot unless you were using a VERY slow mixture.
    -On a related note, epoxy isn’t paint and is very forgiving of a wide range of application paces (except as noted in the previous point). As you noted in the end, you could easily have glassed it in separate shifts – again, no issues adhering new epoxy to set epoxy.

  5. Been there. Anybody who’s honest with themselves will say the same. Fiberglass is equal parts art and skill. The sheer number of variables you have to contend with make it really hard — ambient temperature, humidity —both of the underlying substrate and the environment you’re in — the pot life of each batch, elimination of air pockets, too much epoxy, too little epoxy, how many times the butterfly flaps its wings in the Amazon, etc.

    I am by no means an expert, but a fairly experienced DIYer. Sounds like you learned some valuable lessons. One thing I didn’t hear was a comment about getting the glass to lay down over the edges — where the sides meet the bottom. Fiberglass does not like 90 degree (or anything close) edges. You will never get the glass to sit on the wood flat, despite how much you roll it out. Also noticed you didn’t have a fin roller. This is a great, cheap tool that will help you get out the excess epoxy after the initial lay-up. Finally, I didn’t see any kind of respirator on you or your wife. These are absolutely necessary when working with VOCs. You’ve only got one set of lungs and a good respirator is cheap in comparison. Especially when you’re in a small, enclosed space, a respirator is essential. I use one whenever I’m working with epoxy or two-part marine paints, etc whether I’m inside or outside.

    My advice is to start small next time. Take a 2x4x1 piece and do all the prep (sand, wipe down, removal of surface oils, etc) that you will do on the finished product. Go through the entire process on that small piece and learn on that.

    When you move to the boat, attack in sections even over multiple days. Even professionals lay out a bottom in at least two longitudinal pieces. Doing this allows you to slow down (fiberglass always feels like a race against the clock for me), catch the inevitable runs, and generally approach it in a more relaxed manner.

    For a first timer, it looks fantastic. Good job! Get a respirator!! 😉

  6. We use epoxy grout in our tile business. As soon as I heard “heated garage, warmed epoxy, etc., I was shouting STOP, STOP! Epoxy has two diametrically opposed characteristics and they are tied to each other. You get runny epoxy when warm and very reduced working time. Or you get stiff epoxy when cold (and sore muscles working it into grout joints) but much longer to work with it. In the end, the results look the same. When we are doing a job in the summer time with no A/C in the house, we start as early as possible and keep everything epoxy related, including tools, in cool places. Your build looks cool and great they you are sharing the pros and cons.

  7. I new you were going to have issues:
    1. Epoxy is “exothermic”….do not heat resin or the garage. You dramatically reduce pot time.
    2. Small sections at a time works well. Then feather the overlap area for the next section.
    3. Make resin spreading tools from 3 or 4inch pipe on the end of a broom handle. The curved surface makes spreading resin and forcing it through the weave much easier and a long handle makes it less messy. Those small squeegee’s are a pain.

  8. I Agree with Martin, I would have thinned a little with acetone on the first coat and then you are not fighting the cure time so you can mix bigger batches.

  9. It sounds like you have identified what you did wrong. I cringed when you said it was August and you heated the garage with only one person helping. Glassing is where you want a group, next time for a group is when you turn it over or load it onto a trailer the first time. Cold beer helps to gather a group 🙂

  10. Some personal philosophy suggestions:
    Take your wife out and let her buy a new dress. Comment on how good she looks before choosing one. Then take her out to a favorite restaurant and thank her for helping on the boat.
    Some technical suggestions:
    When you stop having failures in your life, then worry.
    Do not beat yourself up when failure happens. Learn and be brutally honest about why it happened.
    The larger and newer the project – the more failures. Keep the overall goal in mind, but focus and adapt to changes.
    Stay conservative and break large projects into smaller ones to learn as you go.
    Epoxy is miracle stuff – but requires experience. The Mona Lisa has (23?) layers of paint and it took Da Vinci many years to complete. Creative enthusiasm must be tempered with some humility.

  11. Chris, thanks a million for sharing your experience. For what it’s worth, I’m sure other first timers (definitely myself) will avoid some of the pitfalls you identified. Really appreciate your candid and honest evaluation of what went well, what didn’t. It’s still a beautiful boat 🙂

  12. In my 20+ years of building wooden drift boats, my preference would be to epoxy the bottom, then screw on a sheet of 1/4″ UHMW plastic. In my experience as well, glassing the sides is a waste of time and an addition of weight. AND it’s difficult. Too difficult to be worth it. If one wants to glass the bottom only, I normally lay the dry cloth on bare plywood, then roll it on with an epoxy roller (that won’t dissolve). Use a disposable paint pan to roll out of ( to keep the epoxy as cool as possible). Make it a sparse coat so that it maintains contact with the wood surface. Then, when the first coat starts to tack, do another coat. The second coat should lay down smoothly. If you plan to skid over rocks on whitewater rivers, you will probably need another layer of cloth.

  13. Do what Clarence says,”Take your wife out and let her buy a new dress. Comment on how good she looks before choosing one. Then take her out to a favorite restaurant and thank her for helping on the boat.” This is the best advice I have ever seen on these forums 🙂

    Few people know more about building drift boats than Greg Tatman. His suggestions are not theoretical they come from years of practical experience.
    If you can incorporate any of his ideas you will be years ahead in in your building.

  14. I agree voc is pretty nasty, wear a good respirator mask, keep the room and epoxy cold , have the glass cut and fitted it will probably move anyway but start in the center swiftly soaking the glass rolling not scraping the bubbles out, getting the hard bends at the chine to not bubble is a real problem, remember you could and should put additional tapes along those vulnerable areas as well as the bow and stern,
    Bright finish for the bottom makes no sense, pick a waterline, if it stands proud of the fairing so be it , you’re gonna be painting it over the years anyway.
    Just got the glass as smooth as you can , clean any runs and bake the boat, you’ll learn no big deal screwing up here or there, we all done .messed up;)

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