Commonly Asked Questions and Assumptions of a First Time Builder

I would like to share the things I’ve learned as a builder and shop technician that are valuable to a first-time builder or mold maker. As a technician working with fiberglass products there was a few assumptions that I had about using the product that turned out to be incorrect or misguided. During my years of building, repairing, mold making, manufacturing carbon paddles, milling cedar and spraying finishes I have come across hundreds of first-time builders or D.I.Y. repairs alongside the many shop projects. Through this lens I have a greater comprehension of the whole industry of fiberglassing, prototyping using composite, material experience and knowledge as well as the most common errors and assumptions of working with fiberglass. Since I also began with these assumptions and lack of experience, I am able to honestly reflect on many years of being the technician and sales representative in a unique shop like BoatCraft.

To begin with, it cannot be understated the value of talking to an industry professional (of any industry) when sourcing information and the complex understanding that individual has to help a builder with specific information, guidance, warnings and techniques for the best result with the least amount of wasted time, product and money on a project or repair. I must state this so clearly because so many clients have begun sourcing information from Google and Youtube, and these platforms are great for basic information and ideas about projects, however the credibility of the information has always led clients astray (including myself on personal projects).

There are excellent Youtube tutorials from fiberglass manufacturers like West System, Easy Composites and Smooth-On, since the technicians from the company are doing product advertisement and using quality materials and processes on video. These companies, just like our Youtube channel Timber BoatWorks, must accord to the proper processes, product uses and materials information because they are directly linked to the success of using their product or process and must be responsible for claims and promises made using their product. Youtube tutorials and product guides directly from a manufacturer, shop or industry professional are highly valuable and are the most accurate sources for a new builder.

Other videos are builder project videos, where the builder may be experienced (maybe experience as a mechanic or woodworker) or it may be a personal project for the first time, and they are also learning as they document the process. This information must be taken with a high level of scrutiny, because these videos often use products, materials and processes that are not standard, correct or proper to the project they are doing. I have had many (hundreds) of conversations where the individual is looking for a product, tool or construction process that is incorrect. Not incorrect in that we are personally motivation to sell a different product, but that the material (plywood, resin, adhesive, mold making, gel coat, paint, etc.) would not be sufficient due to chemical incompatibility (ie: home paint delaminating from being submerged under water, pressure treated plywood not being able to stick to fiberglass, etc.) or materials that cannot survive in a marine outdoor or winter unheated environment. There are also incorrect information on tools (HVLP sprayers and fiberglassing tools) or layup process are not correct for fiberglassing (tools that leave textures, are expensive or are not chemically compatible with the product) and finally the lay up (composite, plywood, plastics and fiberglass) are not strong enough for the intended use, not sufficient for winterization or outdoor applications, the plywood is home grade and delaminate or that chemicals cannot bond to other chemicals (ie: gel coats onto plastic, paint onto vinyl, gel coat onto rubber, truck liner onto submerged aluminum, etc.)

BoatCraft is always willing to give advice on constructions, repairs and builds so that the products that you purchase are durable, long lasting, chemically compatible and capable of handling the outdoor in winter environment. We will always intend to help builders with guidance for the highest level of durability without having simple issues that arise from quality issues of material (home grade or pressure treated plywood) and adhesive incompatibility (bondo brand, paints that cannot be submerged, resins that cannot stick to plywoods, construction adhesives in marine environment.) Our aim is to have a repair or build last without any issue, so that the money invested in the repair is long lasting and do not fail the user (ie: transom or hull issues while on the water.)

Another assumption that I had made about fiberglass products in general was that fiberglass resin (polyester resin) is similar in quality and strength but cheaper than epoxy resin. My assumption is that the only major difference was that one was used for river tables and hobby projects (epoxy) and that polyester resin was used in the industry for structural products (campers, trailers, hot tubs, showers, boats, canoes, kayaks, medical parts, heavy truck and trailer, automotive and aerospace.) This is completely incorrect, and shockingly laminating epoxy resins are significantly stronger than polyesters, saturate larger surface areas by volume and are less expensive to use than polyester. (see blog post on Comparing Epoxy, Polyester and Vinylester with Cost Analysis). The only benefit to using polyester is that the cure time is faster than epoxy, so for large scale manufacturers making parts in molds (hot tubs, showers, etc.) its most cost effective for them so cycle their molds every 90 minutes versus every 12 hours with West Systems epoxy. The cure time of the resin system makes its strength, so the hotter and faster the cure the weaker the bond, the longer and more consistent exothermic reaction the stronger the bond. Bondo Brand polyester fiberglass resin has a tensile strength of 5800 psi (see Bondo tds sheet attached) and West System 105 epoxy has a tensile strength of 7300 PSI and flexural strength of 11,800 psi (see data sheets attached). The strength is not similar on any metric. There is no benefit of using polyester resin over epoxy, even when dealing with a polyester product, because epoxy bonds to polyester better than polyester bonds to polyester (by their own TDS numbers!)

The other assumption I had made is that all fiberglass cloths were similar, and they were based on price and thickness of the product, which is also incorrect. The difference between cloths and matting will increase strength, clarity, durability, how many layers must be applied and overall cost when saturating a thicker mat. The thinner layers of woven fiberglass cloths the more interactions between those materials per square inch, which in combination with your resin strength will dictate durability and overall strength. The thicker cloths like chopped strand, have large unwoven fibers, which means that more layers have to be applied. One layer of a woven cloth will be 6 times the strength of one layer of chopped strand mat, therefore, 6 layers of mat would have to be applied to have the same strength as one layer of woven fiberglass e-glass or s-glass. The lamination thickness for one layer of woven cloth is less than 1/16^th of an inch, one layer of chopped strand is 3/16 inch per layer. This is always chocking to clients that come in to discuss their projects, because the volume of polyester resin ends up being 3 times more than they anticipated because they are choosing chopped strand mat to save money. Saving money on weaker fiberglass ends up costing them in resin saturation cost. The saturation area of a gallon of polyester (fiberglass) resin is 12.8 square feet at 1/8 inch thick (one layer of chopped strand mat). The saturation of a gallon of epoxy through a 6-ounce e-glass is 95 square feet. Shockingly higher than polyester.

What I’ve learned about the industry standards is that what is best practices for a manufacturer for their profitability and their productivity are not always best for a repair or build. Hot tubs and shower surrounds have become very thin and damage easily, power boat gel coats are lasting 2 years before beginning to spider crack. For an individual that is doing a repair, specifically on newer products, we always want to resolve any issues so that this repair does not have to be redone every few years. This is partly the speed of the manufacturers production, as well as quality control, but this has left so many of our clients with short lifespan expensive products that are not lasting and need repair. BoatCraft will always offer the longest-term solution, we do not want to use poor quality or random adhesives (jb weld, bondo, pl premium), where they will fail and cost the builder a second project. It is so hard to know what is a quality material or product, with Amazon, Canadian Tire and Princess Auto major contributors to the industry carrying so many variations and differing qualities of product. Once concern with these volume purchasers is they often discount and sell out of date product, when it comes to polyester resin there is a 6-month shelf life from manufacturer, so if they are doing a fire sale on resins be very careful that they are not expired. Weve had dozens of calls from builders that have purchased from Amazon or Canadian Tire with on sale product that was expired that cannot be returned.

I have also learned that cost saving and frugality is a very limited perspective when it comes to projects, because often the projects are already in a state of disrepair sometimes for years or decades before the project is started. For example, it is very common for a client to buy a used boat from Kijiji or Facebook for a “great price” and the boat “needs a little work,” but this is often times a much larger project than anticipated. These types situations are very common, but what is not understood is the cost of rebuilding a floor and transom in a boat, even using cheap plywood and polyester resin is between $1000-1500. The great price boat is not accounting for the repairs, parts, materials and time for these projects. For a professional repair from a fiberglass shop a floor and transom rebuild with gel coat floor is $6000. To rebuild a floor and transom will take a budget builder 20-40 hours of labor and about $1500. Even for a used fiberglass canoe ($300-500) that needs to be stripped and new gel coat or marine paint needs to be applied, will take 20 hours and about $500 in materials. We have had so many conversations were the new project ends up being way larger than anticipated in cost and labor than the inexperienced individual thought when making the Kijiji purchase. BoatCraft is always willing to have the conversation about the project and different approaches for budget building and repairs, but it is most commonly misunderstood when it comes to cost and labor of the projects.

When it comes to mold making, there is some important assumptions and solutions to share, specifically about the Youtube level of explanation to actually successfully building a limited run single part polyester mold. I’ve worked and build successful one part, 2-part compression and vacuum bagging molds for BoatCraft and learned some valuable lessons about mold making. Part of this education is in the blog post https://boatcraft.com/blogs/news/tips-on-mold-making-with-tooling-gel-coat-and-polyester-resin, but there are a few things to add about the lay up and tools to avoid. When it comes to spraying tooling gel coat onto a plug surface, it is crucial to not use a sprayer with too large of a nozzle size. Tooling gel coat, like regular gel coat must be thinned using styrene (NOT ACETONE) to spray through an HVLP sprayer. It is easier to use a sprayer with a smaller nozzle (1.2-2.0 mm) with thinned gel coat than a regular “gel coat sprayer” with a 2.8mm or larger nozzle. The amount of pressure to atomize gel coat is quite high, but when adding a massive aperture the gel coat gun sprays orange peel (or alligator) that has to be resurfaced. Use a smaller nozzle and apply 2-3 even coats of tooling gel coat. This will stop any orange peel, areas of thick and thin gel coat and spraying so thick that it cracks when it cures. Gel coats shrink 5-8% when curing. When applied too thick the gel coats crack.

The other large issue with first time mold makers is they are applying polyester resin too thick too quickly onto the surface which leads to warping, twisting and melting of the plug surface and the parts are not the desired or expected shape. When saturating fiberglass cloths its crucial not to pour thick layers of resin onto the fiberglass because resin cures at 175 degrees Celsius. Depending on the plug (initial surface for female mold) this much heat can warp plastics or deform metal parts, so the tooling gel coat will crack or lift off of the plug due to the heat and shrinkage of the resin on the back surface. Be cautious, this has caused me fits in the past.

Another view point that has changed over time is my understanding of building, or purchasing boats, has evolved to only value the intended purpose of the boat, and to not search for boats that do all minimum activities mediocre and nothing well. What I mean is, in the context of kayaks, people are looking for cheap, light, touring and fishing kayaks that can be paddled in the ocean, lakes, cold water, rivers and rapids. Sadly, no boat is perfect for every type of use and environment, so it is always best to prioritize what the individual’s main activity will be and then find a boat that suits that need. By establishing if the person wants to paddle in the mountains with overnight stays or coastal paddling, there is a type of kayak or canoe that is best for this. Fishing and recreation require a different hull design for stability when the boat is stationary. The inflatable kayaks offer one convenience of being packed down for storage, however, they miss every other strength of a kayak like lightness, hard surfaces for efficiency, stability and durability. This same methodology is applied to people fixing and repairing boats, knowing their intended use makes for easy recommendations on how durable they need to build the hull, or how much storage they require in a drift boat. Boats that are going to see heavy use and abuse, we have high strength epoxies, 3m 5200 adhesive, Kevlar and 1708 fiberglass fabrics to satisfy the end game of the boat.

The final comment that I can make is that its always a pleasure to help discuss and guide people in their projects, as well as build and refinish canoes and kayaks in the shop over the last years. There always seems to be a new project or a new idea of how to build or repair, and its been very helpful for Boatcraft to have the conversations and receive input from our builders so that we can serve and guide new builders in a better way. I have rebuilt a dozen cedar strip canoes, and done build tutorials on Youtube, gel coated many different projects, fixed completely crushed kayaks, build full carbon fibre paddles, educated and wrote build manuals for our Kayak kits Timber BoatWorks. Every project that comes in is a new test, a new challenge and no two boats are built the same, so there is a lot of adjusting to give these boats a second lease on life. No matter what the labor cost and time fiberglassing, I have thoroughly enjoyed building wood kayaks, repairing and refinishing boats and guiding uncertain builders to their ideal project successes.

BoatCraft has written technical manuals and guides for free, and Youtube tutorials on the Channel Timber BoatWorks for the soul goal of helping the success of a builder or paddler. We also link and blog many complimentary build manuals (under https://boatcraft.com/pages/west-system-user-manual)  from Timber Boatworks, West System and Transport Canada for free, to help guide and provide knowledge on boating, building, repairs and laws. This is a service in gratitude and appreciation for the marine fiberglass repair, first time builder or paddler to demonstrate our knowledge and voluntary promotion of truth and trust of our building community. 

tds-3mtm-fiberglass-resin-05833-05834.pdf

https://www.westsystem.com/products/206-slow-hardener/