Join the discussion 31 Comments

  • JohnB says:

    Once again an informative and well produced video. Your instruction is clear and lucid, and diction and video presentation very good. Looking forward to Part 2.

    Thanks Andy.

  • Matt Hurley says:

    looking for the second part . I have some spider cracks I need to deal with this season.

  • Dan Lyle says:

    Your vids are great man! Very helpful!

    I have two questions for you…


    “If you’re looking to keep costs down poly resin with csm and 1708 biaxial glass will give all the strength you need, easily repairable and not hit the pocket book as hard as doing this with epoxy.

    I am restoring an old runabout… The hulls is in great shape but the topside is in pretty poor cosmetic shape. Lots of hairline/spider cracks and a handful of holes. Based on your quote above, am I okay using poly with csm to do the repairs or am I better off spending the extra money for the epoxy?


    I When I look at the topside of my boat I can’t figure out which product to use for what (fairing compound or resin)… Is there some crossover? Can it be an either/or type of thing? Can I use either product to address the same issue?

    Once again, I love your vids! You’re an amazingly talented guy.

    • Andy says:

      Hi Dan,

      Thanks for the compliments 🙂 It’s nice to hear from someone that enjoys the show!!

      Epoxy Vs Polyester choice: determine what you’re ultimate finish is going to be. Gelcoat or paint.

      If it’s going to be gelcoat you are limited to using polyester resins all the way through the job. There are poly based fairing compounds, fillers, etc. so you don’t necessarily have to use glass for everything (although I try use use as much glass as possible and only rely on other fairing products for filling pin holes and final shaping of a piece.

      If your going to finish the boat in paint, then you have the option of using epoxy based products. Even still I tend to do the glass work with poly resins and reserve epoxy products for the fairing, shaping, etc. Mostly because of the longer working times and cost. If you haven’t watched them already check out the series I did on the Glass Magic Runabout. I used poly for the glass work and because I was going to be finishing with paint decided to do all my fairing with epoxy. There are (3) videos to this series. Part 1 Part 2 and Part 3

      Polyester based products set up rather quickly (10 – 15 min) whereas epoxy based products provide more than double the work time. This comes in handy when doing fairing or working on larg(er) projects.

      Is there a benefit in strength of one over the other?? Well, epoxy is a stronger resin and has better water resistance than poly, BUT in my opinion it’s something that’s blown a little out of proportion for MOST repair work.

      Boats have been built with poly and glass for over 50 years (most still are). Many are still in service and other than the lack of maintenance on some sections of a boat, the areas that are “solid glass” (i.e. don’t have any sort of a wood coring) are still in great shape!!

      Hope this helps a bit 🙂


      • Dan Lyle says:

        Thanks Man! That helps a lot!

        I made my frist attempted at laying up poly and it went pretty well. It took a bit longer to cure then I thought it was going to. I mixed up half the amount (.5oz) for my second attempt and that seemed to setup quite a bit faster. Both attempts went well. I was very happy with the results.

        I did watch the three Glass Magic videos… They were great! After watching you reglass that entire boat I was tempted to do the same to my topside but I don’t think my boat is that bad off.


        “If it’s going to be gelcoat you are limited to using polyester resins all the way through the job.”

        Does this mean that all fiberglass boats finished with gel coat were built with poly?

        • Andy says:

          “Does this mean that all fiberglass boats finished with gel coat were built with poly?”
          ~ Pretty much; vinylester resin would be another option but that’s something that came into the scene a little more recently (10 yrs maybe?)

          Glad to hear things went well! When you catalyzed the resin (added the Mek-P) how was it mixed? For small batches I’ll add 10-12 drops of Mek-p per ounce of resin and stir really well. Usually gives me about 10 min of working time depending on air temp..


  • Dan says:

    I am using poly resin instead of epoxy… Do you have any suggestions for a filler that will work well with poly?

  • David Dodge says:

    Andy, you are a master teacher! I am facinated by your videos. I have an old ’74 Boston Whaler with lots of screw holes and some fairly deep spider webbing. I want to gelcoat over entire boat. Would you recommend filling the screw holes with epoxy? I know it’s not good to mix with polyester over the top. Or after prep like you showed, can I take care of all these problems with Adtech P-14 where CSM is not required? Can you ad color to the Adtech, or will the color added to the gelcoat cover up the difference? I would very much like you to do the same video with gelcoat as the end result. Maybe you have already done so and I over looked it. I’m buying materials (And if it helps get you sponsors, mostly the stuff you use) and getting ready to take the plunge. Never done fiberglass work before, but with your help, I’m a little less afraid than I was a week ago. I can’t wait for more of your videos. Thank you for helping the way you do. I see big things in your future. Hope you still have time to help out the little guys like me with more videos.

    • Andy says:

      Hey Dave, Thanks for the encouragement! On your project, if you want to re-surface the boat in gelcoat I would not use any epoxy or epoxy based fillers; strictly poly 🙂 There are fillers that can be used with poly resin, look over this link (specifically the dry fillers). The way I would probably deal with the SMALL screws is to fill with Adtech-14, dish the tops of each screw hole with a dremmel tool and go over top of that with a mixture of poly resin, cabosil and milled glass fiber.

      Seal over top of that mixture with gelcoat mixing either a wax additive or Duratec high gloss to allow the gelcoat to fully cure as well as the resin beneath it. By going over with the gelcoat mix it will also fill any pin holes / low spots that result from the milled glass. Sand the whole thing flush and call it ready for topcoating.

      Any holes larger than 1/4″ I would fill with Adtech, dish the top and actually lay in some csm like I did on one of the glass videos. For the final fairing of the surface over these repairs you can use the adtech rather than thickened epoxy. Works pretty slick and allows a quick turn-a-round.

      You can add color pigments to the adtech, but if you’re going to be gelcoating the entire area there is no need. Gelcoat requires a fairly heavy film thickness to cure, certainly more than thick enough to cover up / hide anything underneath it.

      I have plans to do a full gelcoat series this Fall / Winter covering everything from color matching for repairs to mixing, application and finishing. But unfortunately I just don’t have time with my job (the one that pays the bills 🙂 ) to dedicate enough time for proper / detailed vid’s on this topic. If I’m going to do it, I’m going to do it right so I am giving viewers answers rather than leaving them with more questions..

      I have no doubt that your projects will go great! Typically the hardest part of the project is just getting started 🙂 Just remember there isn’t anything that can happen that can’t be fixed. If you have any Q’s along the way send them my way along with a couple pics and we’ll figure it out.

      I’ve been seeing a BIG increase in viewer questions about their own projects (which is AWESOME!!) I think things have gotten to the point where it would be very helpful to start a forum type atmosphere on the site so people can bounce questions / ideas around and get feedback on their projects! It’s on my To-Do list for this Winter; just have to scrounge up the funds as there are monthly costs associated with the forum software 🙁 One way or the other it will happen!


  • David Dodge says:

    A very sincere thank you Andy, for all your help. I’ll be keeping an eye on your site for anything and everything new you have to share. By the way, I love your woodworking too, but right now, my focus is on the boat. A lot of other things are not going to get done because of that old boat. I’m doing it for my son. At least It started out that way. When I get it on the water someday, I’ll christen it in your honor. Probably make a toast to you as well. Thanks again.

    • ~Andy says:

      Hi Dave, you’re too kind 🙂 Make sure to keep me posted on the progress! If you haven’t done so already you may want to subscribe to my site so you get notifications when something new is added. You can do it a number of ways but the (3) easiest are to either click the RSS feed on the home page (if you use a RSS reader) if not enter your email address (this tends to be easiest and I don’t share it with anyone or send junk mail :-)) or lastly hit the subscribe button on YouTube!! If you’re on Facebook show that like button some love!! All of the various ways to do this are on the home page of this website. If you know anyone that might find what I’m doing useful spread the word! Every bit of support helps a ton!

      Thanks again! Good luck with the projects!


  • Dan Lyle says:

    Hey man,

    I ordered from Ad-Tech from Express Composites because of this article. I gave you props for the sale.

  • Chris Lynas says:

    Hi Andy
    Thanks for all you videos
    They have given me confidence to carry out repairs to my boat which I just acquired and is in need of a lot of TLC
    Though your not a popular man in my house hold as I’m watching each episode over and over
    Thanks again
    Chris in the UK

  • Pavel says:

    Hi Andy! Thank you for this wonderful video! Please tell me what kind of fiberglass do you use? Density, etc.

  • Don in Spokane WA says:


    Thank you for this website and videos.

    I have a Mckenzie style fiberglass drift boat. I invariably hit a rock on the chines each trip and take a quarter to half dollar sized chip out of the gelcoat. I haven’t had any structural damage as the chines are laid up very thick. I feel the need to repair these after each incident. A quick repair is what I have in mind with perhaps a more extensive gel coat repair every 3-4 years or so. Because I will always be hitting rocks, what would be the most durable immediate fix after each incident? I want to avoid chipping the repairs loose with every little impact.



    • ~Andy says:

      It wouldn’t look the best, but one option would be to use what’s called a Keel Guard. Other than that, if it’s only gelcoat that’s chipping off (no glass damage) you can do a quick and dirty repair with Adtech 🙂

  • Barbara says:

    LOVE your videos!! Very informative and very well done!! My “boat” Is a 23ft fiberglass motor home!! I have always wanted to restore an old car and this was the best that I could do!! It is in good condition for being 26 years old but the gel coat has seen better days and I need to make some of the repairs that you have described here. You have provided answers to many questions. Would you explain the problems that I may encounter with vertical repairs? I also have a large 12″ x 43″ window that I would like to remove and glass in the hole. What would you recommend as a good core material? It needs to be lightweight , yet strong. When I am done with all of the repairs, I plan to paint the entire unit with a good topside paint. That will include the metal truck cab. Are the paints that are used for fiberglass acceptable for use on metal also?
    Thanks for your help and keep the great videos coming!!

  • Connie says:

    I love your videos! My husband has put me in charge of all fiberglass repair work so I desperately need some advise as I’ve never done anything like this before. In the case of repairing screw holes in a transom where there used to be a fish finder, what would you recommend? This would be below the water line also.

  • Christopher says:

    Great videos I have revisited them many times,help for what I call a “soft restoration” of my 63 Pearson Electra.
    I have just re-cored my deck from interior. Epoxy over 20 weight cloth. What would you fair the area with? Area about 12’x6′.
    I was curious if you would still recommend p-14 for larger areas. Looking for the easiest sand and quick dry wouldn’t hurt as well, winters coming…

    Thanks so much for all you information.

  • Kenneth says:


    Thank you for doing all these great videos. I have questions after watching all you did and researching all I can find on the web about boat repair. The first question, in this video you repaired a large hole in the deck that was one just epoxed. After you chamfered the hole drilled it out and re expoxy it, you layed the csm in small to large layers. I was reading the same thing on the boat us site They acually said to lay up the mat the reverse of what you did with the large layer first then work for smaller peices, what do you think about that?

    Second, the spider crack you fixed on the deck. You use poly because of two reasons the flexabality and cure time of it. Dosnt epoxy cure fast when you put a layer of something over it and cant you still bend the glass to the walls radious like the poly?

    Third, after you did your test with proven you can adhear epox to poly and poly to epoxy including gel coat to epoxy, would you do all your repairs with epoxy if price was not an issue? What happend to the lab tests?

    Fourth, my dad had an 1980 grady overnighter and he hurt it on the trailer and needs to be patched. Is it non gloss gel coat on there or just painted? He wants to just make some epoxy peanut butter and slap it on there to call it a day. What do u think of that?

    Fith, i have my proline i need to take pics and send it to you to see how bad the spider cracking is on the port transon to port side. Not sure if it was hit or just structral and i need to do major glass repair. How can i send you a picture?

    If you can get back to me before the season starts that would be great. I see your a busy man!!


    • ~Andy says:

      Hi Ken, quick responses below:

      1) I don’t agree with this method of layup as it doesn’t make sense. Starting largest and going down means that all the glasswork is being held in place by the first layer of glass (none of the others are making contact with the surrounding area locking things together. Starting small and working up means that every layer is tabbing onto the surrounding glass; when done properly all of these layers of glass are also weaving in with one another. Logically it makes a lot more sense to me 🙂

      2) CSM does not become as pliable when used with epoxy. There’s nothing in epoxy to dissolve the binders in the glass (as opposed to poly or vinyl resins)

      3) Probably not as it would take too long for repairs 🙂 Some situations really benefit from using epoxy, others it’s somewhat of a waste (no real gain). Lab tests haven’t been done yet; only so many hours in a day and making these video’s is not my main job (more of a hobby really at this point). Have to pay the bills first!

      4) Sorry, can’t say with pics..

      5) If you would like some help with a project, please go to THIS PAGE if you haven’t done so already 🙂

      Thank you!

  • Ross says:

    Love all your videos and the concept of this site. It’s awesome!! Now like everyone else, on to my question! Would you consider a 3/8″ old hardware hole that goes through cored glass (1/8 skin, 3/8 balsa core, and 1/4 bottom skin) to be too large to over drill, bevel, and epoxy shut? The PO plugged them with 3m 4200 and they look like hell. I’d gelcoat the repair, and eventually paint over that when I have time.

  • Paul Mertz says:

    your site is great. i made a donation w/paypal and hope you can keep it going. my question is in regards to a screw hole that goes thru the fiberglass (when removing a snap that will no longer be used) if i ream it out with a drill as you did in the video, can i just fill it or do i need to reinforce it with fiberglass because it goes thru all the way. it is like your structural repair video, but i can only get to one side and it will be less the 1/4″ diameter. i have a whole row along the radar arch and other locations from old canvass locations from previous owners (44′ Defever trawler). your videos make me think that i can learn fiberglass repair and painting, rather than pay someone else. i do most work myself (rebuilt both diesels, swapped in new transmissions, wired in an inverter with battery bank, installing new simrad electronic suite) but now need to bring it back to cosmetic glory to finish the restoration. my ultimate goal is to take it from the east coast to alaska thru the panama canal. we all need dreams. thanks again

  • Rudi Winkelman says:

    On your new shop for insulation look into Rockwool.
    Made of basalt stone, no itch when handling, can lower insurance as will not hold water if leak develops, great fire resistance.

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