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First Time Fiberglass = Not So Great

Discussion in 'Strippers, Stitch-n-Glue, and Other Wood Composite' started by RoadRunner, Apr 18, 2016.

  1. RoadRunner

    RoadRunner Enthusiastic about Wooden Canoes

    Hey All -

    Been awhile since I posted, but I finally took the first-timer's leap and fiberglassed the outer hull of my Freedom 17' from Bear Mountain. While the base 2 coats are well in place and curing up, things didn't go very well in terms of cosmetics. After much consultation with Ron Frenette of Canadian Canoes / Bear Mountain, we decided that the core issue was that I didn't squeegee with much pressure, which allowed ripples to form and at least one major section of the cloth do bubble up a bit on the first coat (notice the cloudy spots in the close up pic - they are definitely raised when I run my hand across the surface).

    Naturally, I didn't catch this until well after things had hardened up, so the result isn't pretty (see attached pics.) Ron and I discussed how to approach this - he has some excellent prescriptions in mind - but I also wanted to hear what you guys had to say so that, when I start working on this, I'm armed with as much info as possible. Let me know:

    1. Any recommended solutions
    2. What steps to take
    3. Additional goofs to watch out for
    4. How to know if I've done things right (besides the obvious beautiful - if imperfect - canoe finish that I'm looking for).

    Thanks guys.

  2. OP

    RoadRunner Enthusiastic about Wooden Canoes

    One more point I forgot to mention:

    I took another look at the canoe, and I'm confounded by the fact that, while not as bad as the examples we discussed, the whole surface of the canoe is lacking a unified smoothness. Frankly, its a mess. Not expecting a factory finish by any means, but since we are going to focus on cosmetics as a next step, I'd like to better understand what I'm missing, and what I can do to get a reasonably smooth surface. Suggestions? Additional photo attached. Thanks.

  3. Dan Lindberg

    Dan Lindberg Ex Wood Hoarder


    It's hard to tell just what is bad/wrong with your job based on the pics, but at 1st glance it looks like too much resin.

    Assuming the resin is above the glass, take a carbide scraper and scrap the surface smooth, it will go fast.
    Then block sand it until very smooth, if there is exposed glass, you may need to apply more resin locally in those spots.

    Finally, that perfect finish you see and are looking for ONLY comes after the resin is block and fairing board sanded smooth, it's NOT from unsanded resin.

    The final sand should be with maybe 150 to give tooth to the varnish, put on at least 3-4 coats. Put it on with a roller and tip it
    to get that perfect finish.

    And use a good marine varnish.


    BTW - I apply wet out coats with a nylon brush, a little at a time, working the resin in with the brush, I apply fill coats with a roller. I don't use a squeege, but then I also use very thin, tight weave cloth. I only mix about 5 oz at a time, any more and the resin doesn't flow and I make hockey pucks.
    Last edited: Apr 18, 2016
  4. OP

    RoadRunner Enthusiastic about Wooden Canoes

    OK, that's helpful....Couple things to ask (I've made enough assumptions throughout this process, which is usually what gets me into serious trouble, so I'm asking everything I can think of to start doing things right):

    1. Some of the resin is above the glass, some areas the weave is still exposed. This is the case all over the hull, not just in the pics I have attached above. Is that what you mean "above the glass"? (just want to be sure I understand).
    2. Can you reply with a link to a carbide scrapper you recommend? I haven't used one before, not very familiar with the item.
    3. Same question for the fairing board. What specifically should I use?
    4. Good point about the varnish being what brings the finish I'm looking for. I guess I just want to get the resin / glass right so I can move on.

    Thanks again for your help.
  5. Dan Lindberg

    Dan Lindberg Ex Wood Hoarder

    Yes, where there seems to be a puddle of resin floating above the glass. The areas where then weave is exposed will need more resin. I'd do that 1st.

    1. Some of the resin is above the glass, some areas the weave is still exposed. This is the case all over the hull, not just in the pics I have attached above. Is that what you mean "above the glass"? (just want to be sure I understand).

    A regular paint scrapper that uses carbide inserts - - works great for removing the runs and high spots of resin.

    2. Can you reply with a link to a carbide scrapper you recommend? I haven't used one before, not very familiar with the item.

    This is a bit tougher, do a google for fairing board and you will see many examples of solid boards. And they have there place.
    I made one that uses belt sander belts, it's a 3/4" board that has raised ends at each end, such that it can be used as a solid flat board on one side and a soft flexable "board" on the other. A piece at one end is removable for changing belts, it just is pushed into a slot to hold and tighten the belt.
    3. Same question for the fairing board. What specifically should I use?

  6. OP

    RoadRunner Enthusiastic about Wooden Canoes

    Great info....Man, lots to think about. Just ordered the Carbide scrapper. Feeling pretty overwhelmed. Beyond correcting the overall inconsistencies w/ the hull, the big question remains the section with the raised or "floating" cloth in the first picture. Ron Frenette said he would be talking me through some sort of a patching job, preceded by much sanding in that area "almost down to the wood".....a prospect that kinda scares me to death. He also said something about "threading"....??
  7. Jim Dodd

    Jim Dodd LOVES Wooden Canoes

    I recommend those white "Cigar" type foam rollers. I find I get a even coat with rollers. No need to squeegee. If you feel you need to squeegee, follow with a roller, to erase the lines left by the squeegee.

    Wet out the cloth with a foam roller. Let it come to cure past the tacky stag, to the point, it will no longer move on the hull. Usually 6 to 8 hours, depending on the resin type.

    Apply fill coats 2 hours apart, until the weave is COMPLETELY filled. Applying fill coats close together, prevents runs. The tackiness of the previous coat holds the resin in place.

    Carbide scrapers are a must. as described above. I have the best results if used within 24 hrs of my finish coat. The resin is still soft, and scrapes easily.

    A ROS with about 80 grit, and then finish with 120 grit. If the weave of the cloth appears STOP and move to another area.

    Good luck. The next one will be better for sure !

  8. Dan Lindberg

    Dan Lindberg Ex Wood Hoarder

    Write it off as a lesson learned, the more you mess with it the worse it will become.
    As Jim said above, "the next one will be better", and there will always be a next one. :)


  9. Rod Tait (Orca Boats)

    Rod Tait (Orca Boats) Designer/Builder

    In addition to the carbide scraper, you might want to invest in a set of cabinet scrapers form Lee Valley.,310,41069 And from what others say, it definitely looks like a lot of resin. That first coat needs to go on smooth with excess resin removed with spreader after glass clears so that the glass is tight to the wood for a max. strength matrix. Once the first coat is setting up, I always use the the West System foam rollers to apply subsequent coats since they will give you a good even coat every time and it is always better to apply more thin coats than less thick ones which tend to run and sag.

    So I would also recommend scraping and sanding off as much as you can and then proceed to filling with more resin as needed. If you cut into the cloth when sanding, you can either stop and apply more resin or sand through the glass and patch. But unless the glass was not filled in first place and you can see white patches right now (referred to as starved glass), I would not go so far as sanding glass off and patching.
  10. Todd Bradshaw

    Todd Bradshaw Sailmaker

    Yep, as liabilities go, resin-starved glass tends to be substantially worse than flooded glass. The starved stuff doesn't have full strength or a very good bond and unfortunately, there is generally no way to go in after it has hardened and add enough fresh resin to fix it. It usually picks up just enough resin while being starved to seal out the addition of more, preventing you from being able to go back in and saturate it properly.

    There are various ways to do most of these building steps. I generally apply resin to the glass layer with a roller and then "comb" it down tight and uniform using an ethafoam slab about 1/2" thick as a squeegee. Filler coats are then rolled on thinly and tipped with a brush as needed to knock down any bubbles, and I'll generally apply enough to totally hide the weave, plus one more coat as a sanding cushion. Usually this will take five or six thin coats, applied as soon as the previous coat is stiff enough that I won't disturb it. I'll let it harden for about a week and then I use disk sanders or random orbit sanders to smooth it all out before varnishing, rather than long boards or scrapers. Everybody has their own preferences and methods but despite that, once your glassing layer is done (either inside or outside) it should be down tight and have a very uniform cloth texture like the inside of this boat (I don't fill the weave on interiors to save weight). In any case, I have yet to meet anybody who was born a great fiberglasser, and it takes some practice to get good at it.

    Attached Files:

  11. Mekong

    Mekong Curious about Wooden Canoes


    I don't know if this is a right thread to ask my question, but I do it anyway. If it is not, please ignore or direct me to the right one.

    I have plenty of fiberglass (FG) tape but not clothe. Can I use FG tape to glass the canoe hull (35 inches wide), by lay the tape across the hull (not along), strip-by-strip?

  12. Todd Bradshaw

    Todd Bradshaw Sailmaker

    You could do it, but they would need to overlap a bit. They would leave small stair steps that would need fairing and/or filling and just generally add a lot of extra work. Considering the cost of the resin and the hull, decent fiberglass cloth is a fairly small expense and it's probably well worth locating the real stuff for such a project.
  13. Mekong

    Mekong Curious about Wooden Canoes

    Hi Todd,

    Thanks very much for the advice.

  14. Jim Dodd

    Jim Dodd LOVES Wooden Canoes

    I agree with Todd.

    You could however use the tape on the inside. Again you'd need to over lap, and this would add weight, but strength also.
    How wide is the tape ?

  15. Mekong

    Mekong Curious about Wooden Canoes

    Thanks Jim,

    The tape is 4" wide.

  16. Chuey

    Chuey Curious about Wooden Canoes

    The Orca Boats man wrote basically what I was thinking as I read through this. Thing is, the glassing is the process that I still look forward to and dread at the same time. In other words, I'm not great at it. But.....I think I can put some words to the hows and whys of squeegeeing the resin. If these other words are just a tad bit different but hit the spot, then great.

    It was not long ago that I realized that the reason to squeegee the surface is to remove the excess resin because the glass cloth wants to float up into the resin. When you squeegee with a smooth, firm but not concentrated motion, the glass will suck down to the wood. This leaves a bumpiley finish. The more even you can get that finish, the better. In fact, on the inside, I've been leaving that finish with just a thin second coat. Others have said how to do "fill coats". Those fill coats are not as critical because the cloth will be adhered to the wood and you can easily correct any goofs after that has been accomplished.

    By the way, the wood under your epoxy work looks stunning!

  17. Jim Dodd

    Jim Dodd LOVES Wooden Canoes

    I'm going to assume you are glassing a canoe.

    Two thoughts, well several, but I will start with what I think are most important, if this is your first glassing job.

    One, have someone to accurately mix epoxy for you, while you glass, and that can maybe help out as well. Someone that has done this before would be best.

    In the books, glassing isn't that well described, in my opinion.

    Have everything lined up, before you mix that first cup of resin.

    After that first WET OUT coat of resin is applied, and squeegeed, allow it to cure, Past the Tacky stage. Then apply FILL coats with a FOAM roller. Here's the important step ! Apply your first FILL coat, and wait at least an hour or a little more. While this first fill coat is still tacky, apply the next fill coat. Keep this schedule with the next fill coats. This step nearly eliminates runs in the resin.

    Keep applying fill coats, until you are satisfied that the weave is Completely filled. This depending on the resin you use, can take from three, to six fill coats.

    Air bubbles may appear, especially when WETTING out the cloth. These are outgassing of air, either from the wood itself, or gaps in the wood joints. Keep a blow drier handy to warm these areas up. Then with a foam brush, wipe down the bubbles. As the hull cools these bubbles shouldn't reappear again.

    After you are done glassing, come back within 24hrs, while the resin is still green, or soft, and scrape, not sand, any imperfections, or runs. This is also a good time to trim any excess glass.

    DO NOT, apply resin, and go off to do something else !!! That's when bad things tend to happen. Runs, air bubbles, bugs. Stay with it, until the resin sets !

    I know this is scary, but you can do it ! Work at a good pace, and don't give up !

    I wish I could be there to help !

    Good Luck !

    Last edited: Jun 2, 2016
  18. OP

    RoadRunner Enthusiastic about Wooden Canoes

    So, I've been away for some time and I'm now getting back in the saddle.

    Man, this is all such great info. I'll certainly be studying this when I finally get to glassing the inner hull.

    I've finally fished scraping and sanding off the excess resin and I think I'm ready to apply another thin coat per the directive of Ron Frenette. He's been talking me through my mess of a job, and I'm looking forward to getting past this one once he gets back from vacation.

    As I finished sanding, I came across something that Im guessing is air bubbles. Pic attached. Question to you guys is how the heck do I deal with this? Do I continue to sand down till I remove the bubbles? The adventure continues.... 20160704_125155.jpg 20160704_125237.jpg
  19. Rod Tait (Orca Boats)

    Rod Tait (Orca Boats) Designer/Builder

    Looks to me like either air bubbles in the glass itself or air bubbles that have been sanded and now sanding dust is trapped in the tiny holes. Before adding more resin, blow the boat off and get close with air nozzle to see if you can clear the dust if any. If you don't have compressed air, then a bottle of dust off purchased from an office supply store will do. Do not wet it if you think it is sanding dust as it will just solidify with water or whatever. If you have to, pick it out with a needle while blowing air. If they do not go away, then take some alcohol and wipe down the area. If the whiteness disappears when wet, then it will again when more resin is applied.
  20. Jim Dodd

    Jim Dodd LOVES Wooden Canoes

    Great advise Rod.

    The white pin holes, aren't cratered like outgassing.
    Lightly sand before applying resin to give the surface tooth to hold the resin, and then blow off as Rod states.

    Keep with the resin as it sets, don't walk away, until it is past the tacky stage.

    Keep a hair dryer handy incase bubbles pop up. Warm them with the blow drier, and tip up with a foam brush.

    Then take the time to report back to us !! HA ! We'll want to know !


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