I’ve known Jim Waggaman of Air Stream Studios for maybe 30 years. He helped me with my ’92 Dyna custom with Mike Maldonado, and I rode it to Sturgis in ’94. Hell, I rode it 400 miles in the rain with Dr. Hamster to the Billet Bar in Phoenix, from Los Angeles, for a drink. By the time we arrived we needed two and a hot shower.
Jim helped us with a last minute fairing in 2007 for the World’s Fastest Panhead, which set a record in Bonneville with a top speed of 162 mph. The fairing was built around an Arlen Ness custom fairing with a beanie helmet stuffed into the headlight hole for high tech aerodynamics.
When he sent me the initial shots of taping the seat and asked about a seat tech, I was all over it. Fiberglass and composite material pans are a pain in the ass to build, but nothing fits like a fiberglass seat pan. Nothing contours your bike as tight and right as a fiberglass handled properly. It basically uses you’re your bike pieces as the mold. In most cases you don’t need any fasteners to hold your seat in place. It’s fits like a glove. Let’s get started with Jim’s notes:
Initial taping is designed to create the ‘mold’ of the actual final shape and fit of the seat and create any barrier between the glass and the bike components.
It is critical all of the elements that will be under, (battery, oil bag, wiring) or around the seat (oil caps, oil bags) must be in place before taping and creating the seat base form. Sometimes covering some of these things with additional tape or pieces of cardboard helps simplify the shape. Plus, if you want some clearance between the battery or wiring and the seat, start with some cardboard insulation/spacing.
Always remember, the seat must slip on and off easily. So avoid creating areas or forms that are too complicated or intricate. Any hooked area could make the final fit and removal difficult. You want to try and make the fit ‘lock’ into the bike firm but not squirrely.
After all the initial masking is done, it’s very important to continue to layer all the areas. I generally put a minimum of 4 to 5 (the more the better) layers of tape. If you are careful with your taping procedure, you will be able to pull it all off as one sheet, when it comes time to remove it.
When you finally have the area ready to lay-up the fiberglass, you may want to do a rough drawing of the shape of the seat you desire on the tape with a felt pen. If you’re ready to start laying-up the fiberglass now is the time to spray the area completely with ‘Pam.’ It acts as a ‘Mold Release’ and allows the ‘set up’ rough fiberglass seat pan to be easily removed.
Polyester Resin & MEKP Catalyst,
Mixing Cups, stir sticks and 1-inch utility brushes
PAM ‘no stick’ spray as a mold release material
Rubber gloves
Acetone for clean up
Medium weight Fiberglass Cloth and Matte
All of these materials can be purchased at most all of Large ‘Box’ construction materials stores, i.e. Home Depot, Lowe’s, etc.
Cutting & Laying-up the Fiberglass:
After you have the area masked and prepped for laying-up the fiberglass you want to start cutting sections of the fiberglass cloth and matte.
Sizing the pieces is very important to the fit and makes the job go a lot easier. You’ll be cutting various different shapes; triangles, rectangles, squares of all different sizes. Look closely at the shape of your frame and try to cut shapes that will easily fit and wrap the areas you are trying to cover.
Once you’ve got the initial pieces cut and pre-fit ‘DRY’, cut several more of each one. Cut them in the quantity and in order you plan to lay them up. Remember you want to alternate the different cloths. First a layer of the cloth is applied, and then a layer of matte and so on and so on.
Remember the foam and the upholstery will hide the topside you are doing. The look of it does not matter. The bottom is the critical area. This area is the ‘fit & finish’ side.
The purpose for the matte is to add strength, thickness and rigidity to the seat pan. Depending on the weight of the matte you will probably need to ‘shred’ it (gently pulling it a part) slightly in order to get it to form to the contours of your frame more easily. I generally grip the piece in both hands and twist it and pull on it gently. You do not want to tear it apart. You just want to loosen the weave so it will be more manageable when laminating it.
It’s always best to try it before you actually start the project so you get the feeling of how to do it. You do not want to loosen the matte too much before you use it. You want to prep it, as you need it.
Now when you feel like you have all your materials in order and it’s time to start laying up the pan, you can start mixing your resin. I usually don’t mix more than approximately 4 ounces at a time, because you don’t want more than you can use and you want to work slowly.
The ratio of catalyst to resin varies. The ambient temperature in the area you’re working in will determine how much catalyst you will want to use in your resin. (Use the chart attached as a guide.) Generally you’ll want to use a little less catalyst than the recommended amount, so you have more time to work with it.
When applying the resin to the cloth use a 1-inch utility brush and a small body filler spreader. Do NOT put too much on at a time. You want only enough to saturate the cloth but not have it ‘sopping’ wet. Too wet doesn’t make it stronger. The strength comes from the cloth, NOT the resin. You do want the cloth to be completely saturated without any air pockets.
I usually start at one end of the project and work to the other slowly adding more resin, with the brush, as needed. Do not wrap the frame rails past the mid point of the tubing. If you do it could make it more difficult to remove the seat. When laying up the fiberglass always keep in mind how the seat will finally fit.
The first layer is the medium weight cloth. The next layer would be the Matte, then another layer of cloth and repeat with matte, clothe, matte, and two more layers of each. End up with a layer of cloth.
Remember the foam and the upholstery will hide the topside. The look of it does not matter. The bottom is the critical area. This area is the ‘fit & finish’ side.
Now once the glassing is done and has set-up (cured) and the pan is ready to be removed, you may want to, with your ‘Sharpie’ pen, draw the final shape you want onto the seat pan. This will act as a guide for the final trimming.
After removing the seat pan from the frame, do NOT remove the masking. In the event you need to patch some areas of the fiberglass.
Final Trimming:
When doing the final trimming, TAKE YOUR TIME. This stage is where you are creating the final shape of the seat. Pay attention to your proportions and symmetry. You want both sides to mirror each other.
To trim the hardened fiberglass use saws and or cut off wheels. You want to make smooth clean cuts. It’s best to fit and re-fit on to the bike while trimming. This helps to check the proportions, style, and the fit.
After the excess has been trimmed you’ll want to smooth the edges with sandpaper. I generally use 80-grit. Inspect the bottom for any rough spots and sharp edges.
Once the seat pan was trimmed and smoothed it was ready to be delivered to the masters at Saddlemen Seats for their seat structure process, which involved foam, gel, the Saddlemen spine slot, upholstery material and stitching. Hang on for that report.
Sources:
Air Stream Studios
Saddlemen Seats
