I had help from my friend Danny, an experienced boat builder, but for the most part, I was working with fiberglass for the first time. Writing guides from the beginners point of view has yielded good results in past Instructables, so I am doing this one in the same style. As a result, there might be information in here that will seem obvious to the experienced fiberglasser, but that same information might be valuable to someone who is just starting out.
Step 1: Background
If the fiberglass is applied on a flat surface, it hardens into a flat sheet when dry and will act like any other rigid material.
However, if the fiberglass is applied over a form, say the ribs of a boat hull, then it can be used to create strong, lightweight volumes that can take on virtually any curve, contour or shape.
Because it can be used to create rigid curved surfaces, it's a process that is generally reserved for specialized building projects. See the following steps of some specific Instructables to see what I mean: step 11: Create subwoofer retrorockets and midrange 'eyes', step 16Fiberglassing your beaver, Creating a fiberglass snowmobile trailer and trebuchet03's amazing video/Instructable on making a fairing for a human powered vehicle. When you need to make something that is rigid and curved, fiberglass is definitely the way to go.
Working with fiberglass comes with a whole new set of terms and lingo that it might be useful to know. I can't say that I will be using all of these words in my Instructable, but they are good to know anyway.
Fiberglass - very thin glass fibers that are treated like threads in a textile
Woven vs. Chopped Mat - woven mats contain fibers that are aligned and woven together like fabric, while chopped mats are made up of randomly aligned short fibers held together using a binder.
Resin - resin is the syrup like liquid that wets out the mat and then dries hard. It's activated by a hardener or second part.
Polyester vs. Epoxy Resins - polyester resins are cheaper, heavier and older then epoxy based resins. Polyester resins are activated by adding around 1.5% - 2% of total volume of resin that you are mixing of a hardener (MEKP). Epoxy resins come in a two parts that are mixed in more equal ratios )generally between 1:1 and 1:4). Epoxy based resins are stronger, have better adhesive properties then polyester resins and are more resistant to cracks and water. The major drawback is their price.
MEKP - Methyl Ethyl Keytone Peroxide - polyester resin catalyst (hardener)
PVA - Polyvinyl Alcohol (film mold release)
Cabosil - the white silica filler being mixed in (trade name - aka Aerosil or fairing filler)
Tool - negative mold used to make parts
Micro Balloons - air filler encapsulated in silica glass (creates a lattice matrix structure in resin)
Gelcoat - provides a high quality finish to composite tool surface
Composite - material made from two or more substances (in this case fiber glass and resin)
Exotherm - reference to the heat generated/required by the resin to cure
Pot - Catalyzed batch of resin
Pot Life - Working/usable life of pot. After this time, the chemical reactions between catalyst and resin "take off"
**Much of this list is copied from Trebuchet03's fiberglassing glossary which originally appears here.**
Working with fiberglass is actually one of the more hazardous processes out there. The small fibers from the mat can cause skin irritations and tend to get all over the place. Fumes from the resin and cleaners that are used can cause long term damage and are full of all kinds of nasty VOC's (things that mess up the brain and the baby maker). And then there is the large amount of very fine dust that is created when sanding. It's not that working with this stuff is deadly, it's just that it must be dealt with in the proper way and using the proper precautions. When working with fiberglass you should be wearing:
- Painters suit (to keep the itchy dust off)
- Working in a well ventilated workspace (preferably outdoors)
Aside from the resin and fiberglass itself, some other tools are required.
- Power sanders
- Sanding pads and sandpaper
- Mixing bowl (a disposable plastic container is fine)
- Mixing stick (piece of scrap wood)
- Measuring tools - pumps that dispense the resin and the hardener in the correct ratio or a measuring cup
- Disposable paint brush
- Solvents for cleaning
There are tons of good tips already published right here on Instructables. Here are just a few.
Mixing Polyester Resin by Trebuchet03
Handy Tricks (for removing fiberglass from skin) by TimAnderson
Epoxy Laminating Systems by freemanmfg
Fiberglass Tools and Tricks by unclesam
Using Paper, Resin and Fiberglass to be the Master Chief! by Dr.Professor_Jake_Biggs
Here are some companies that sell fiberglassing supplies.
US Composites has a wide range of resins.
West System is a good source for marine resins and fillers.
System Three has tons of marine application resin
TAP Plastics has many locations in the bay area and stocks a wide range of resin's fiberglass mat, and the tools needed to work with it all. They also have some informative .pdf's located in their FAQ section.
Check out your local store to get an idea of what you'll need and then see what's online. If you don't happen to be next to a major retailer of fiberglass supplies, it could be a good idea to order online since the price of resin varies wildly depending on where you get it.