Mechie3
04-07-2020, 08:00 AM
Blwalker105 did this writeup 3.5 years ago, but it is buried in a thread with a non related thread title. Took me a while to find it, so I wanted to put it in its own thread with a title that will show up when searching. This isn't my work, I just copy pasted everything past these first three sentences.
I would like to encourage anyone wanting to attempt this mod that fiberglass work is a very forgiving medium and if you don't like your results, just grind them off and start over. If you are gutsy enough to build your own car, then this project is WELL within your reach.
Unlike other more expensive mediums, fiberglass work is relatively cheap; you only need a few basic materials and products to be off and running. The real secret lies in the combinations of these goodies.
Here is my list of the basic ingredients needed to complete any fiberglass project from these fender points, to hard point fillets, to panel layups. I get most of my supplies through USComposites.com (no affiliation) because it is almost one-stop shopping. The two exceptions are the adhesive-backed sheet wax which is used to create molds, dams and uniform panel gaps and the peel ply. Just go to eBay and search "Sheet Lining Wax for Carbon Fiber Molds". I recommend having 2 thicknesses: 1/16" and 1/8" inch. The thinner stuff is good for areas where you need minimum clearances and the thicker stuff is great for making uniform final panel gaps if you have to build-up surfaces for finish body work. A 12" x 24" sheet of each will probably last forever unless you do a lot of fiberglass work. Everything past the Peel Ply section is hardware store or Amazon available.
Resin
700 Vinyl Ester Resin - This product is similar to what F5 uses for the body itself. It is strong and very tolerant of mix ratios but has a relatively short shelf life of about 3 months, so don't buy large quantities. The recommended mix ratio IMO is inadequate: you will be waiting forever for it to cure. I use 16 drops hardener per half-ounce and it gives me about 30-45 minutes of working time. I give it a good long time to fully cure cause I hate clogging my sand paper. Plan on doing the 'glass work one day and sanding & shaping the next. You may have read about the addition of wax but I NEVER use it and see no reason to add the additional step of removing it later to prepare for more layups or body work. Wax is used to isolate the resined area of low-mass layups from the atmosphere to help them cure. If I have any areas that are still tacky 8 hrs or so later, I just use a heat gun to lightly warm (140-150 degrees F) them for about 4-5 minutes. In warmer climes, just placing them out in the sunlight for a couple hrs will get the job done.
Fiberglass
Style 7725 Highly Comformable Fiberglass Cloth - This is the best all-around cloth from my experience and I could probably make a pinkie ring for Barbie with it. There are probably places where thicker, hardware store stuff would work, but with this fabric, I just add layers for extra stiffness and strength. It's very lightweight so 2 or 3 plies will usually get the jobs done. Be advised that that more plies or layers you have, the less it wants to conform to tight radii. A couple yards will probably be more than enough for our projects.
Modifiers
Here is where the magic begins and the best part is that it is easy! I routinely use only 2 modifiers: 3M Glass Bubbles and 1/32" Milled Fibers. When I am making slurries or body fillers that have to be sanded down to existing gelcoat, these get the job done without having to resort to Cabosil as a thickener. Cab is great if you want something you can drill and tap later, but for our purposes it cures much harder than the surrounding gelcoat, making final sanding very difficult. The Bubbles and Milled Fiber mixes are easy to sand, shape and are very sturdy on their own. There were plenty of places on my plane where I simply sanded, primed and painted pretty large areas of these mixes and they held up to daily cruising speeds of 225 mph and +4 and -2 G's. (the plane could take +8 and -4, but the pilot couldn't :/). Stout stuff. More on mix ratios later. With these, you can also make the best body filler that money can't buy.
Peel Ply
This product isn't a strict necessity, but it makes for nicer layups by deleting the next sanding step in preparation for body work and it gets rid of those micro grams of extra resin. When cured, just peel it off and you will have a surface ready for body filler or additional layups without the need for any sanding. When doing layups, I simply cut pieces slightly larger than the resined area and apply them directly onto my wetted-out fiberglass as the top layer. Be sure to leave dry perimeters of at least 1" or you won't have anything to grab and peel. It can be found on eBay: something like "Airtech Econostitch Peel Ply 54" for about $4. Peel ply doesn't like to bend and shape itself around corners like the fiberglass, so you sometimes have to get tricky and cut relief slots and/or use multiple pieces to cover your layups. I also have to come back more often with my stipple brush to make sure the peel ply is staying attached to bends and corners until the resin starts to set up, but that is a small price to pay.
Visqueen
One of the first things I learned building my plane was how to prepare layups off-site and be able to carry them to the work area for attachment. If you've ever attempted to make multiple layer layups and transport them even 2 feet away, you will know it is almost impossible to have them keep their shape. The secret is to use a nice medium-to-heavy thickness Visqueen as the bottom and the top layers of your layup. More on this later.
Chip Brushes
I use 1" and 2" chip brushes from Amazon for wetting-out areas with resin and for stippling, then throw them away after each use. They are cheap enough to not have to hassle with cleaning them.
Scissors
Invest in a good, dedicated pair of scissors or shears. Fiberglass is tough on metal. Something like these: https://www.amazon.com/Wiss-W20-8-Inch-Inlaid-Industrial/dp/B005LBMFCY/ref=sr_1_8?ie=UTF8&qid=1479662502&sr=8-8&keywords=shears
Painter's Tape
Resin does not stick to either side of painter's tape, or wax paper, or anything greased or oiled, but will cure just fine while touching it. Use this to your advantage when making molds and dams for slurries.
Stir Sticks
Standard 1/16" stir stick/tongue depressors. Buy a big box for pennies. Use them for everything from the obvious uses to covering them in painter's tape for mold and dam sides, etc.
That's about it for supplies.
I would like to encourage anyone wanting to attempt this mod that fiberglass work is a very forgiving medium and if you don't like your results, just grind them off and start over. If you are gutsy enough to build your own car, then this project is WELL within your reach.
Unlike other more expensive mediums, fiberglass work is relatively cheap; you only need a few basic materials and products to be off and running. The real secret lies in the combinations of these goodies.
Here is my list of the basic ingredients needed to complete any fiberglass project from these fender points, to hard point fillets, to panel layups. I get most of my supplies through USComposites.com (no affiliation) because it is almost one-stop shopping. The two exceptions are the adhesive-backed sheet wax which is used to create molds, dams and uniform panel gaps and the peel ply. Just go to eBay and search "Sheet Lining Wax for Carbon Fiber Molds". I recommend having 2 thicknesses: 1/16" and 1/8" inch. The thinner stuff is good for areas where you need minimum clearances and the thicker stuff is great for making uniform final panel gaps if you have to build-up surfaces for finish body work. A 12" x 24" sheet of each will probably last forever unless you do a lot of fiberglass work. Everything past the Peel Ply section is hardware store or Amazon available.
Resin
700 Vinyl Ester Resin - This product is similar to what F5 uses for the body itself. It is strong and very tolerant of mix ratios but has a relatively short shelf life of about 3 months, so don't buy large quantities. The recommended mix ratio IMO is inadequate: you will be waiting forever for it to cure. I use 16 drops hardener per half-ounce and it gives me about 30-45 minutes of working time. I give it a good long time to fully cure cause I hate clogging my sand paper. Plan on doing the 'glass work one day and sanding & shaping the next. You may have read about the addition of wax but I NEVER use it and see no reason to add the additional step of removing it later to prepare for more layups or body work. Wax is used to isolate the resined area of low-mass layups from the atmosphere to help them cure. If I have any areas that are still tacky 8 hrs or so later, I just use a heat gun to lightly warm (140-150 degrees F) them for about 4-5 minutes. In warmer climes, just placing them out in the sunlight for a couple hrs will get the job done.
Fiberglass
Style 7725 Highly Comformable Fiberglass Cloth - This is the best all-around cloth from my experience and I could probably make a pinkie ring for Barbie with it. There are probably places where thicker, hardware store stuff would work, but with this fabric, I just add layers for extra stiffness and strength. It's very lightweight so 2 or 3 plies will usually get the jobs done. Be advised that that more plies or layers you have, the less it wants to conform to tight radii. A couple yards will probably be more than enough for our projects.
Modifiers
Here is where the magic begins and the best part is that it is easy! I routinely use only 2 modifiers: 3M Glass Bubbles and 1/32" Milled Fibers. When I am making slurries or body fillers that have to be sanded down to existing gelcoat, these get the job done without having to resort to Cabosil as a thickener. Cab is great if you want something you can drill and tap later, but for our purposes it cures much harder than the surrounding gelcoat, making final sanding very difficult. The Bubbles and Milled Fiber mixes are easy to sand, shape and are very sturdy on their own. There were plenty of places on my plane where I simply sanded, primed and painted pretty large areas of these mixes and they held up to daily cruising speeds of 225 mph and +4 and -2 G's. (the plane could take +8 and -4, but the pilot couldn't :/). Stout stuff. More on mix ratios later. With these, you can also make the best body filler that money can't buy.
Peel Ply
This product isn't a strict necessity, but it makes for nicer layups by deleting the next sanding step in preparation for body work and it gets rid of those micro grams of extra resin. When cured, just peel it off and you will have a surface ready for body filler or additional layups without the need for any sanding. When doing layups, I simply cut pieces slightly larger than the resined area and apply them directly onto my wetted-out fiberglass as the top layer. Be sure to leave dry perimeters of at least 1" or you won't have anything to grab and peel. It can be found on eBay: something like "Airtech Econostitch Peel Ply 54" for about $4. Peel ply doesn't like to bend and shape itself around corners like the fiberglass, so you sometimes have to get tricky and cut relief slots and/or use multiple pieces to cover your layups. I also have to come back more often with my stipple brush to make sure the peel ply is staying attached to bends and corners until the resin starts to set up, but that is a small price to pay.
Visqueen
One of the first things I learned building my plane was how to prepare layups off-site and be able to carry them to the work area for attachment. If you've ever attempted to make multiple layer layups and transport them even 2 feet away, you will know it is almost impossible to have them keep their shape. The secret is to use a nice medium-to-heavy thickness Visqueen as the bottom and the top layers of your layup. More on this later.
Chip Brushes
I use 1" and 2" chip brushes from Amazon for wetting-out areas with resin and for stippling, then throw them away after each use. They are cheap enough to not have to hassle with cleaning them.
Scissors
Invest in a good, dedicated pair of scissors or shears. Fiberglass is tough on metal. Something like these: https://www.amazon.com/Wiss-W20-8-Inch-Inlaid-Industrial/dp/B005LBMFCY/ref=sr_1_8?ie=UTF8&qid=1479662502&sr=8-8&keywords=shears
Painter's Tape
Resin does not stick to either side of painter's tape, or wax paper, or anything greased or oiled, but will cure just fine while touching it. Use this to your advantage when making molds and dams for slurries.
Stir Sticks
Standard 1/16" stir stick/tongue depressors. Buy a big box for pennies. Use them for everything from the obvious uses to covering them in painter's tape for mold and dam sides, etc.
That's about it for supplies.