07.13.08
Glasswork
After more weeks than I care to remember, all of the hardware for both the VW donor chassis and the Bradley kit car have been refurbished and inspected. I’ll need to purchase some basic hardware items to replace some of the bolts, nuts, screws and washers that rusted to the point of being unuseable but about 80% of what came with the car was salvageable.
The next job is to restore all of the fiberglass parts. As many readers may not be familiar with the procedures and materials used to do basic fiberglass work, I’m going to add quite a bit of detail to the description. To begin, there are 25 pieces of fiberglass (or ABS plastic) that must be reconditioned:
(1) Main Car Body
(1) T-Top for Main Car Body
(1) T-Top Liner (For Headliner)
(4) Upholstery Shells (For Areas Surrounding Small Rear Windows)
(1) Center Console (ABS)
(1) Glove Box
(1) Defroster Shroud (ABS)
(2) Door Panels (ABS)
(1) Hood
(2) Headlight Buckets
(1) Trunk
(2) Gull-Wing Doors
(2) Bumpers
(2) Seat Buckets
(2) Seat Bucket Back Panels
(1) Glare Shield (Goes On top of Dashboard)
Some of these parts just need to be cleaned up. This usually consists of having the old upholstery stripped and the upholstery cement removed. The Glare Shield and Seat Bucket Back Panels would fall into this category. Other parts may need structural repair or reinforcement (my rear bumper took a bad hit on the left side) and most, if not all, will need cosmetic work (filling, sanding, contouring, priming and painting. There’s an order to doing this work and cleaning up the parts comes first. All of the old upholstery and rubber cement needs to be removed from all of the fiberglass parts — down to the bare fiberglass in some cases or down to the gel-coat in others. Once the parts are cleaned up, structural repairs are next. This may require removal of gel-coat or paint in damaged areas because you cannot perform an adequate structural repair over gel-coat or paint — you have to get down to the raw fiberglass. Once the structural work is done, then the cosmetic repairs can be done.
The method of fiberglass work that I use is called Moldless Composite Construction and, as the name implies, no molds need to be made to repair any of the parts or, for that matter, even to fabricate new parts. We’ll demonstrate this latter concept by scratch-building an overhead center console for the T-Top without building any molds. Moldless Composite Construction was developed by the German sailplane industry but was popularized in the U.S. by Burt Rutan, designer of the Vari-EZ, Long-EZ, Defiant, Voyager, and numerous other experimental and factory-certificated aircraft. The technique was recently used in the construction of Space Ship One and its mother ship — White Knight. The techniques are easy to learn, the materials are readily available and the methods produce strong and lightweight structures. If you’re not familiar with the techniques and would like to get some hands-on experience as I describe them, Aircraft Spruce and Specialty sells a practice kit, a demonstration video and all of the materials that you will need. You can purchase similar items from Wicks Aircraft Supply or The Composite Store (in Tehachapie, CA). Other techniques and materials may be equally applicable here. However, I’m most familiar with the procedures developed and the materials recomended by Burt Rutan — so those are the techniques and materials that I am going to describe.
Back to Step 1: — Cleaning the Parts
You’ll need to strip all of the upholstery and backing foam from all of the fiberglass parts, including the main body of the kit car. Ripping and shredding works well for the bulk of the material but remove the fabric with sufficient care that you can trace patterns on a roll of art paper. Be sure to mark the outline of each fabric piece along with the locations of any folds and seams that have been stitched into the fabric. If the fabric parts aren’t in too bad a condition, you might want to save them for use as models when you are making up the new upholstery. My upholstery was so deteriorated and soaked with pigeon and cat urine that I just made paper patterns and got rid of the original material as fast as I could.
Once the foam and fabric have been removed, you’ll need to remove any excess upholstery cement. A lot of this cement may have partially deteriorated (oxidized or powdered) and trying to fasten new upholstery over the old glue is a waste of your time. Also, if any structural repairs are required for the part, you will need to remove everythng (foam, cement, fabric, bondo, paint, primers, gel-coat…) right down to the bare fiberglass — on both the inside and outside of the damaged areas.
Upholstery cement is basically just a special formulation of rubber cement. As such, Acetone is the best solvent to soften (not remove) the old glue. You can use mineral spirits, but acetone works better. Make sure that you use the proper safety precautions when working with acetone (butyl rubber gloves, respirator with organic vapor cartridge, no open flames nearby, etc… Read the precautions on the can.) I use a paper towel to saturate the old glue with acetone to soften it and then use a single-edged razor blade to scrape the glue off the fiberglass. Once all of the glue has been removed, I sand the entire part with 60-grit aluminum oxide paper. This helps identify any glue that I might have missed and roughens up the part so that the new glue will adhere well. Removing the old glue takes time — it took me about 5 hours to do each of the seatback shells, for example — but it’s a lot easier and more pleasant to repair and upholster a clean part than a messy one.
To date, I’ve got the two seatback shells finished and the glare shield about half-way done. I’ve also got most of the headliner shell cleaned off and I’ve cleaned up the glove box. (In the original Bradley instructions, the glove box is glued to the back face of the dashboard with a structural adhesive. The joint was not glassed over with fiberglass tapes, as it should have been. Bradley left the installation of the glove box as an option, for builders who might prefer to install a radio in this location. I found that my glove box fell off after a couple of whacks with a rubber mallet. The adhesive was very brittle and the glove box popped off easily without any damage. Once on my workbench, I was able to sand off the old structural adhesive in short order. I’m going to use a flocking kit that I obtained from Woodworker’s Supply to flock the inside of the glove box. I’ve done this before and it comes out looking very professional — even for first time users — and it sure beats the carpet that was originally used.)
After you have all of the glue removed from all of the parts, you’ll be ready to start the structural repairs. In the next blog entry, we’ll do a couple of easy ones to introduce you to the materials and procedures.
