I'm almost to the stage of my speedster body where I'll lay out the fiberglass. This is the least authentic part of the car, while everything is a mixed bag, it will still be stock Model T. I think there are more reasons to glass over the wood than not, but I wanted opinions either way. I could varnish the heck out of it, like the 'old days' however it would be stronger and frankly a bit safer being glassed. Safer meaning less likely to pop apart after the normal flexing of the frame and what not, not in an accident. Yes I know this is my car, but others may have experienced things I have not thought of.
here it is, almost ready for sanding. The camera angle makes the rear curve look more proud than it is...
You already mentioned the authenticity issue so that aside -
If you plan to paint for the final finish, the fiberglass is an excellent idea as it will stabilize the surface making the wood grain less obvious as the wood goes through the changes of time, moisture, and stress movement over the years. Regardless of how nicely you prime and paint, the grain will start to show through after a few years of use if you don't use the fiberglass.
If you plan on a clear finish, the fiberglass can still add the stability but is less important to the overall appearance.
I was thinking painted sides and the plywood part of the top. Clear finish on the strips.
If there was an authentic read:period correct way of doing this, I'd consider it. Glassing covers up a multitude of sins, but it is on in its self to the purist. Hmm, which is worse, a water pump or a fiberglassed wood body? (runs for cover)
The purists will find a wide variety of things to be offended about. Worry about them if you wish but I got over them a long time ago.
Of course, water pumps are an inherently evil product of the devil. Any who use them should be shunned and cast out of the club.
I've done quite a bit of glassing over wood, mostly in boats. If you want the wood grain to show through, use a light fiberglass cloth (not mat or roving). If you care about longevity, use epoxy resin NOT polyester. Its more expensive but the glass to wood adhesion is MUCH better. polyester resin will usually separate from the wood after several years.
Since you asked, I would not use fiberglass at all. Wood is a thing of beauty, and it suits a Speedster well. More is less, especially when it comes to a Model T.
My "opinion"? I like original methods and material types to be used. While not the most common, all-wood-built bodies were done back in their day. They also sometimes used a linen type cloth covering and painted it. Either way can look good, and I think better than fiberglass.
But that is me.
Drive carefully, and enjoy, W2
Who cares when it comes to a speedster unless you are a purist. There are quite a few guys in the Northwest Vintage Speedster club who are running fiberglass Morton and Brett bodies made many years ago by Poliform. They are well-made and heavyweight construction, you bolt right onto your frame and away you go. The heart and soul of the speedster experience is the T chassis and running gear.
If you are going to "glass" your wooden body you owe it to yourself to do some research on various materials and methods. The best source that I know of is Gougeon Brothers, makers of West Systems epoxy. Their principal interest is building and finishing of wooden boats, but their products are popular for many other wood projects. Among the products that they sell are very clear epoxys that lend themselves to a clear finish to show off the beauty of the wood. You can even do this with some glass fabric over the wood. You can google them and find a world of information.
In addition to having lots of written information available, Gougeon maintains a hotline where you can call and talk to knowledgeable people who can advise on your particular application.
For pure durability and good looks, it's hard to beat epoxy resin and glass cloth, whether you do it as a clear finish or with a solid color.
I refinished (clear finish) the oak front door on my house about 14 years ago using West Systems products and it still looks like new.
Along the lines of the linen cloth angle mentioned above, it is quiet common to find on the inside of wood bodies the equivalent of #40 cheesecloth used to reinforce panels and joints. Something like that might give you an interesting combination of strengthening the assembly and period correct appearance (and aging over time) if such an effect interests you.
I think originally hide glue was used, but I apply with West System just as you would fiberglass and the results have been very good.
Chris, my 15 speedster is exactly what you propose. It is a true boat tail rather than bob tail like the Morton & Brett glass body shown. I used fine glass fabric and epoxy resin on both the underside and the top side of the timber lid, thinking it would make a stronger component. On the underside it worked well. You really have to look closely to detect the glass fabric, it is so clear.
Topside is a different story. Something went wrong and the fabric is clearly visible through a milky epoxy coat. Now I have to sand the glass fabric and epoxy back to the decorative timber and re-finish it with spar varnish as I did for the rest of the exposed timberwork.
Hope this helps.
allan from down under.
I'm building a model a boattail using cloth and dope like an airplane of the day.
I like the cloth and dope idea. The nice thing about using epoxy is the wood slat deck will show through and the few gaps will fill in. I'll poke around the boat forums to see if there is a good looking filler I can use. I had a couple splits come off when I was planing it smooth. Those'll need filling.
Where are you getting the dope? I only ever used the little tins of the stuff for covering paper and balsa planes.
I remember seeing bodies covered with fabric and then was involved in restoring a canoe. We used unshrunk canvas. After pulling it tight and tacking we wet it down and let it dry. It came out very tight and after painting with an oil based paint several coats the finish was smooth and water tight.
If it suits you to use epoxy, you can cut down on having another transition by using the epoxy as a filler, also. You can mix colloidal silica with the epoxy to thicken it to a peanut butter-like consistency. West System sells it as an additive for their product line. I'm sure other brands do, too.
If you want the very best finish (that has to be maintained every few years) go with varnish.
If you want a very good finish that will last without much maintenance go with glass and epoxy.
The picture below shows my boat which has been in our family for 57 years. Above the splashrail it has been recently varnished. Below the splashrail is glass which was put on in 1966 and never touched since. The wood was already somewhat weathered when the glass was put on. If the glass had been put on when the boat was new, the two finishes would be hard to tell apart.
When we restored our 1906 Moline back in the 1970's we had the old stick and plywood body to work with. They used to build a body frame and then cover it with criss cross sheets of thin wood and made plywood as they proceeded by laying the thin sheets of veneer wood in layers until they had a strong and rigid thickness.
I went to a boat builder here in Long Beach and he layered a thin sheet of finely woven fiberglass cloth and then coated it with resin. I then block sanded it with one of those 18 inch and 12 inch sanding blocks. That allowed me to get it very straight with no bumps or hollow places. The original wood was still there and could be seen when you removed some of the upholstery yet it was exceptionally strong and only a few pounds heavier than wood alone.
We let it dry for a year before we began priming and painting in order for the woven pattern to not show. We added new half round reeds to make the trim molding and glassed it on. Sanding around that molding where it attached was the most difficult part of the task.
It was not downgraded in judging because of the glass treatment and thought to be better to have save the wood than make it new. Originality always outshines redone.
Back in the wooden Lockheed days out near Empire Ave and San Fernando Road in Burbank, they covered their lovely wood shells with unbleached muslin doped on. Made a good base for the paint jobs.