Build in foam and polyester. Epoxy
adds day between grinding, sanding
and fairing. With the first dab you are married to epoxy
. Go walk around a marina, and count on one hand how many production boats are made in epoxy. How many hull to deck
joints are made in epoxy... How many bulkheads are tabbed in with epoxy...
As boaters, we have had epoxy foisted on us. Polyester and vinylester are better than good enough to do most jobs that don't involve Wood. That is not to say that Epoxy isn't better, or even the best. I even prefer to work in it... But it is the opposite of fast building speed, and should not be in the vocabulary of anyone on a budget
. It is hard to get romantic about building in foam and polyester, where laminated wood is beautiful. Most things involved in building a fiberglass boats don't involve beautiful laminated wood, mainly space man suits, respirators and itching.
Spray your paints and primers.
Spray your fairing compounds.
Pick a batten and stick with it. I like a fir batten that is longer than the boat, (built a 90 footer once... Fragile!) If there is a crew big enough to use it. With 2 guys I like an aluminum
1x1 box tube. Any deep low spots can be pulled... With the corner of the batten or box tube and be "real close" compared to the fill and pray method. Another good eyeball method, is tacking a pink builder
string to the hull and stretching it tight. If you have a smooth curve, it will touch the whole way. If you have a low spot... it won't touch the whole way. Mark out the boat so it looks like a road map. Most low spots look like texas
. When you fill the last low spot and hold the batten up, it normally turns out that the batten was seeing the low spot as a high spot, as its a transition point and all of a sudden the planets have aligned and trumpets sound from the heavens... (This may be overly dramatic, depending on how many weeks you have been sanding
Duratech's easy sanding primer. Use it. Gelcoat
is cheaper, it does not lay down as nicely. A dump gun for spraying gel coat works great. You can go from 80 grit to 800 grit wet sanding if you do your part. It'll build 20mils wet on wet. Adtech's P77 fairing compound, is a polyester compound that kicks off entirely faster than it needs to... But works very well. It has a 6 minute sanding cycles instead of... Tomorrow like that of epoxy. I haven't found a polyester equivalent to Awlgrips Awlfair, but in small batches you can do what needs to be done with ATC's polyfair and the like.
I would think long and hard about shooting PPG instead of Awlgrip. Quite a few sport fishing
boats are done in PPG and Imron instead of Awlgrip, as you can sand, cut in and buff a repair without having to re-shoot the whole boat. Also spend some time on the design so the toe rails have a break point so the hull can be sprayed at each go. I would wrap stainless down the stems, and corners of the sterns (or do a sugar scoop stair case that breaks at the boot top...) for the same reason...
If you want it to go fast, the key is to start out with 320 grit finish in mind and don't pick up 40 grit unless you are planning to bury it with bog. That means if one of your crew, works within a 1/4 inch, or doesn't "See it." They mix glue, and don't spread glue. The hold the air hose, and don't spray primer.
I'm being serious, because if you have one on the team that doesn't work with 320 grit in mind and absolute cleanliness as though they were building the space shuttle... They will add 3 weeks of fairing because it looked so good they did not need to put a batten on it! One man, who knows where the putty needs to go can fair a boat faster than 3 who can't "See it."
Anybody can bog a 1/2 inch over the whole surface and eventually get something smooth-ish. The goal is to build it straight and fair, glass it straight and fair. Sand the glass with a batten in hand and skim some 1/8th inch low spots. Long board it once from each direction and spray high build primer knowing where the low spots are.
Don't think about anything but 320 grit! Close enough when setting the framing is a fools errand if you want an awlgrip job that you can see yourself in.
For cockpits, showers and built in pieces... you can build with flat panels that are perfectly smooth and flat before they are cut out and assembled, you can save a lot of time by making the tabbing narrower than the land of the 3 inch pvc pipe... and when you pull the bog over the top, there is no grinding or sanding of the flat surfaces as they come up into the fillet, and no reason why you can't go wet on wet while the tabbing is still green. You can also use structural fillets with long hair, mat, and pull a very thin layer of easy sanding stuff over the top.
Large curved surfaces are actually easier to fair than large flat ones, as you can see a twist in a flat panel that is hard to find with a string... a curve is harder to see an imperfection in. I think flat panels that are tortured into a curve in one plane only, are the easiest to work so your long board or string and batten land at the same plane along plumb frame work no matter where on the frame work top to bottom. I think a lifted deck
line is easier to fair a house into and keep straight on account of that single
dimensional curve. The radius of the deck beams changes to follow a straight string, rather than following the sheer as it goes. Doing the bow out of a flat panel where the framing changes from athwartship to fore and aft also makes things a bit easier for mounting hardware
Where ever the batten breaks at the deck line from curved to "Can't curve any more" is a good spot to start going fore an aft. Raised toe rails and short bulworks work well, as they don't necessarily have to stay the same height on the run... Which means you can put the shear you want on the boat in the Toe rails and let the deck go where it needs to for the house to be straight forward to build. Your rub rails should follow the tops of the toe rails not necessarily the shear clamp.
I ran a Kurt Hughes
for a summer with the curved sides over the edge of the deck for aerodynamics. I like a toe rail of some variety, as you can set a screwdriver down on the deck, and if you drop something it might stay on board. I also think that boats should have rub rails. Sure most cats don't have them... I guess most cats don't come near docks.
I like Barbour Plastics 2 7/8's rigid black plastic half oval rub rails. They are like greased owl snot pulling in and out of a slip, which means you'll have the second cat that is possible to dock
and work off of pilings without needing fenders with microfiber covers. (
) They are heat formable, so you can bend them down to the sugar scoop stern. 1/4 inch machine screws counter sunk every 6 inches is more than enough to hold them on. I cast the threads in epoxy for them, rather than put nuts and leak points on the inside of the boat. This also does away with the need for sealant
behind it, so if you tear things up it is replaceable with a heat gun and a screwdriver instead of 5200 removal
. Why repaint when you don't have to...
Outside corners (Toe Rails... cabin
sides... Ahem) are most easily done, by building the fiberglass structure with a larger radius than the one you want. Pull bog out to a square corner and get it perfectly smooth and square. Then run a router down it that cuts the radius you want. Rub red scotch brite on it, and spray primer. Or you can take a short board and a cut out piece of plywood
on as a radius gauge and sand fiberglass, bog, and keep hitting fiberglass forever more.
You can speed up your fairing process in the cockpits by increasing the diameter of the fillets in the corners. Use a 3 inch PVC pipe to pull them instead of a 1 1/2. It is much easier to sand out smoothly, and you can use the PVC pipe to take the edge off. With 1 1/2 you have to sand from the panel into the fillet to keep it straight. At 3 inches, no one can see a wiggle in it.
I have a 3 1/2 inch diameter shaper bit, that fits a custom base plate for a hand held porter cable router that does magical things to shape large diameter corners. Hand shaping and sanding those works... If you have a long board just shorter than the length of the corner of the house, stem, transom... And don't mind working 8 sided, 16 sided, 32 sided. Or you can run ever larger series of routers down it until you get what you want.
I use an 8 inch mud hog, and a hutchins orbital inline sander to do the bulk majority of the work on flat surfaces. If the 8 inch won't fit, I use the inline. If the inline won't fit I pick up hand board until I'm in finish primer, then the dynabrade comes out. I use 3M gold production paper on sticky back. If you have enough horsepower in your air compressor
you can go from 80 grit, spray primer to 320 and let it chew. 3M's black dust guide coat is worth its weight in gold. On hand boards, try Mirka's HD screen
paper. 3M makes 4 1/2 inch wide boards that are worth their weight in gold, just triple check that they are flat and true when you get them. I reject them from time to time...
Take the excess resin off the surface while glassing. Mush down any built up piles of cloth. Work within an 1/8th across the whole panel. If you have to fair out the whole panel an 1/8th to meet a high spot, any idea of speed of construction is over with before you got started. If the cloth has to overlap, make a trough for it to lay in so it is a low spot, not a high spot.
If you have to use epoxy, you can speed up the process by using Adtech's Proseal. It is a heavy, white compound that is loaded with filler. It kicks incredibly fast, and builds up enough thickness that it will hide Biax in one pass. It doesn't shrink and show the weave like a straight resin coat does. Doesn't work all that great on verticals, but on a table top it is great. ADTECH Plastic Systems
For the construction, if you make full size templates and patterns out of MDF (Or MDO if you can't control humidity in the shop) and use a spiral down carbide router bit with double guide bearings you can make as many of the pieces you want at once if you rig up a decent size router table. If there is a goof up in the panel, the Adtech P77 mentioned above will fix the troubled spot in the pattern in 6 minutes. I use carpet tape to hold things together. Perfect patterns, make for perfect fits... and it doesn't matter how many you need to build as they will all be the same. Don't under estimate Swanson #1 trim screws either, particularly the 1 7/8ths length. You can assemble quite a bit, and leave the screws in place.
One thing that needs to be noted, is that storage
space in the shop is important... It doesn't do you any good to make 3 of each panel, if you don't have room to store it during assembly, or if it will be a week till the next one gets put together. Lost
pieces, mean you are back on the router table.
You can buy pre-made rounded corners out of plywood
from World Panel, for doing interiors. That way you start with a few flat sides of plywood, cut a rabbet down them and glue them up. Quite a few folks are vacuum bagging linoleum counter top material down to plywood to veneer over...
Wiggle board is good stuff too, but over perfect frame work. If you want a large diameter round wall, you can do it... But it needs to have straight frame work. Flat panels make life easier, if they don't need a high grade finish.
I don't think high gloss paint
belongs in an interior
, a sheet rock texture, or just a shade smoother is perfect to my eye. Most custom boats are wallpapered or soft walled everywhere possible because even a sheet rock texture that looks fair takes an extra couple hundred hours to attain.
The stuff needs to be flat and true but building a gelcoated shower
stall in place... that shapes to the hull, were "two" of the dumbest things I've ever built. Fiberglass drop in showers, will save you several weeks worth of work, so walk around Lowes Hardware
and see if you find one that you like. Put it inside the boat before the deck goes on. Without forced air and a huge exhaust
fan you can't spray the inside of a custom shower
, in place and see what you are doing. Climb inside a 55 gallon paint
drum and start spraying awglrip. The overspray is nuts. Rolling and tipping over your head
, doesn't work very well if you need the floor painted, at the same time.
Make all plumbing
accesses and wiring
chases 4 times larger than they need to be. Also mock up any locations where wiring
will need to go and make sure it can be maintained, or even assembled. Back up shower drains, sink drains, and water
tank access so they run to the center of the boat and make all panels removable that can be. Drop in fiberglass liners have made folks shy away from trim rings on screws... Build it so it is maintainable without a sawzall.