After reading some of the postings about glassing I figured I’d throw in my two cents worth. I worked at the Westport Shipyard (producers of 100’+ motoryachts) for 15 months, first as a small parts laminator and then for the last 6 months in large parts. I’ve also been reading a good technical book called Composite Materials: Science and Engineering, 2nd Edition, by Krishan K. Chawla. I’ve also had the distinct pleasure of pestering Rob Brown at the Boarding Factory in Westport, WA with lots of questions about shaping and glassing. He’s shared quite a bit of info with me and for that I’m very grateful. On the issue of air bubbles in your glassing, use lots of resin and work them out with your squeegee. Twice, maybe three times, pulling harder from the center to the ends and lighter from the ends to the center. I highly recommend a large and small squeegee for glassing. Like at least 10-12" wide on the large one. It makes things go so much faster, leaving you with more time to finesse those laps. Also, for clean laps I’m really taking the time to make sure there aren’t any strings hanging down off the cloth after I’ve cut it and after I’ve glassed it. Sometimes you’ll pull them out when squeegeeing so I go back and pull them off and cut them with my scissors. I now babysit my board, little squeegee in hand, while it’s kicking and go over the bottom of the rails constantly so I don’t get drips. You won’t get air bubbles on the laps if your seams are smooth and this makes it way easier than sanding them later, which I usually do but it doesn’t take as much time. Sharp curves necessitate cutting the cloth in a few places, like the nose and tail, and overlapping the cuts. I’ve been able to wrap my glass with 6 oz cloth over my tails when I’ve only touched my tail rails with a swipe of 180 grit paper. Temperature and humidity have effects as well. Don’t glass below 55 degrees F. Higher temps mean faster kick (gel) times. The best way to determine how much MEKP to use is to kick off a batch of one ounce resin cups (not wax cups though!) at certain temps with certain MEKP levels and record them. Not a good idea to go below 1%. I usually go 2% on the bottom and maybe 1.5% to 2% on the deck. (This equates to about 15cc’s to a quart for 1%, but watch it because it’ll go off in your bucket first. It’s best to get your mixed resin onto your board ASAP.) Humidity affects are increased as it approaches 90% or more. I’ve seen polyester resin turn from red (using red MEKP) to purple because of humidity. Not a good thing. Water is bad to both resin and glass. We had a couple rolls of 24 oz roving at the yard that were rendered completely worthless because it had gotten wet, probably from being left on the floor. Also, air bubbles will form if the temperature in the room is rising while you are glassing. If anything have your stuff at room temperature and cool things down, never up, while glassing. I use a 6" pneumatic orbital sander and buy my discs at an automotive paint store. I use 3-M self-adhering discs (80, 150, 320 grits) and to date I’ve never had one fly off but they are pretty easy to take off the pad when done. My only problem with the orbital is that I have a bad tendency to grind through the glass a little bit in places, especially around the nose and tail. From what I hear those Makita variable speed sanders with medium and soft pads are worth their weight in gold for sanding boards. That’s what the major manufacturers use so what the hey! Sorry about the length, Vaya Con Dios! Mark “Mad Dog” Pearson
Mark: Good info you’ve put together here. I’ve got a quick question for you on gel coat repairs. I’ve got a 22’sailboat that is in great shape considering it’s almost 30 years old. I need to fix a couple of dime size or smaller gel coat chips that are down to the roving. What is the routine repair sequence for these? Opaque surfacing resin then sand and polish? TS BTW, this baby is up “For Sail” if anyone is interested in a Venture 222, swing keel, dinette, sleeps 4 and 10 hp. motor mount. North Sails main and jib on trailer ready to go. Pics if you want to see. tom>>> After reading some of the postings about glassing I figured I’d throw in > my two cents worth. I worked at the Westport Shipyard (producers of 100’+ > motoryachts) for 15 months, first as a small parts laminator and then for > the last 6 months in large parts. I’ve also been reading a good technical > book called Composite Materials: Science and Engineering, 2nd Edition, by > Krishan K. Chawla. I’ve also had the distinct pleasure of pestering Rob > Brown at the Boarding Factory in Westport, WA with lots of questions about > shaping and glassing. He’s shared quite a bit of info with me and for that > I’m very grateful. On the issue of air bubbles in your glassing, use lots > of resin and work them out with your squeegee. Twice, maybe three times, > pulling harder from the center to the ends and lighter from the ends to > the center. I highly recommend a large and small squeegee for glassing. > Like at least 10-12" wide on the large one. It makes things go so > much faster, leaving you with more time to finesse those laps. Also, for > clean laps I’m really taking the time to make sure there aren’t any > strings hanging down off the cloth after I’ve cut it and after I’ve > glassed it. Sometimes you’ll pull them out when squeegeeing so I go back > and pull them off and cut them with my scissors. I now babysit my board, > little squeegee in hand, while it’s kicking and go over the bottom of the > rails constantly so I don’t get drips. You won’t get air bubbles on the > laps if your seams are smooth and this makes it way easier than sanding > them later, which I usually do but it doesn’t take as much time. Sharp > curves necessitate cutting the cloth in a few places, like the nose and > tail, and overlapping the cuts. I’ve been able to wrap my glass with 6 oz > cloth over my tails when I’ve only touched my tail rails with a swipe of > 180 grit paper. Temperature and humidity have effects as well. Don’t glass > below 55 degrees F. Higher temps mean faster kick (gel) times. The best > way to determine how much MEKP to use is to kick off a batch of one ounce > resin cups (not wax cups though!) at certain temps with certain MEKP > levels and record them. Not a good idea to go below 1%. I usually go 2% on > the bottom and maybe 1.5% to 2% on the deck. (This equates to about 15cc’s > to a quart for 1%, but watch it because it’ll go off in your bucket first. > It’s best to get your mixed resin onto your board ASAP.) Humidity affects > are increased as it approaches 90% or more. I’ve seen polyester resin turn > from red (using red MEKP) to purple because of humidity. Not a good thing. > Water is bad to both resin and glass. We had a couple rolls of 24 oz > roving at the yard that were rendered completely worthless because it had > gotten wet, probably from being left on the floor. Also, air bubbles will > form if the temperature in the room is rising while you are glassing. If > anything have your stuff at room temperature and cool things down, never > up, while glassing. I use a 6" pneumatic orbital sander and buy my > discs at an automotive paint store. I use 3-M self-adhering discs (80, > 150, 320 grits) and to date I’ve never had one fly off but they are pretty > easy to take off the pad when done. My only problem with the orbital is > that I have a bad tendency to grind through the glass a little bit in > places, especially around the nose and tail. From what I hear those Makita > variable speed sanders with medium and soft pads are worth their weight in > gold for sanding boards. That’s what the major manufacturers use so what > the hey! Sorry about the length, Vaya Con Dios! Mark “Mad Dog” > Pearson
…Great Information…Thanks …Also, Rob Brown deserves thanks and respect for what he has done for the Westport surf community!!!..He shapes great sticks(ALL KINDS) and is a top level glasser…Now if he could only remember that I don’t want any milk in my Americano…
Mark:>>> Good info you’ve put together here. I’ve got a quick question for you on > gel coat repairs. I’ve got a 22’sailboat that is in great shape > considering it’s almost 30 years old. I need to fix a couple of dime size > or smaller gel coat chips that are down to the roving. What is the routine > repair sequence for these? Opaque surfacing resin then sand and polish?>>> TS>>> BTW, this baby is up “For Sail” if anyone is interested in a > Venture 222, swing keel, dinette, sleeps 4 and 10 hp. motor mount. North > Sails main and jib on trailer ready to go. Pics if you want to see.>>> tom I worked for many on the east coast building everything from canoes to 48’ sportfisherman’s. For gel coat repairs if you can find a little gel coat that come close to matching the color you are repairing mix it with some cab-o-sil and make a paste. The consistancy of the paste should be like toothpaste. Add a little catlayst and trowel it in. It tends to srink a little and is easy to sand if you put to much. But, don’t go overboard. Hope this helps. h2ofxk
BTW, this baby is up “For Sail” if anyone is interested in a > Venture 222, swing keel, dinette, sleeps 4 and 10 hp. motor mount. North > Sails main and jib on trailer ready to go. Pics if you want to see. Tom, R U still in TX? Planning a trip to SoCal soon? I would be interested in the boat if I didn’t have to go to TX to get it. Goofy Foot
BTW, this baby is up “For Sail” if anyone is interested in a > Venture 222, swing keel, dinette, sleeps 4 and 10 hp. motor mount. North > Sails main and jib on trailer ready to go. Pics if you want to see. Tom, if you are still in Texas, my father may be interested in your boat. If you’re in SoCal, I may be. Got pics? Now here’s another gel-coat question: Why doesn’t anyone use it on boards anymore? Was it mainly the weight factor that shoved it out of the board glassing community? I’ve been thinking about doing a little vintage-repro gelcoat job on an old board…and maybe on a new one too…any thoughts??? Thanks…deeb…
Deeb: The guys above who are in this business can correct me if I’m wrong…but I’m not so sure we aren’t already using a type of gelcoat process. Boatbuilders just go at it in the reverse order. Mold, mold release agent (wax?), spray opaque colored gel coat, then the heavy mat layup. The gelcoat resin is then wetsanded and polished as surfboards are done. This is a hand layup type process and I’m sure there are some injection or other pressurized layup processes. The 2 part automotive paints and other epoxy paints would work for you on the restoration or cover up jobs. I’ve been using a white base epoxy and using the Evercoat pigments to tint it on a couple of boards. There is just no way around having to spray this finish on however. Good luck. Tom The sailboat pics: http://y42.photos.yahoo.com/bc/ecommerceguild/lst?.dir=/Venture+222>>> Tom, if you are still in Texas, my father may be interested in your boat. > If you’re in SoCal, I may be. Got pics?>>> Now here’s another gel-coat question: Why doesn’t anyone use it on boards > anymore? Was it mainly the weight factor that shoved it out of the board > glassing community? I’ve been thinking about doing a little vintage-repro > gelcoat job on an old board…and maybe on a new one too…any thoughts??? > Thanks…deeb…
If you haven’t gone through any layers of glass the gelcoat mixed with cab-o-sil sounds pretty good. At that point it’s just like filling in dings with bondo on a car. Except that gelcoat is a pretty hard material, unlike bondo with is meant to be sanded. Another thing you can use is a polyester based putty that’s lighter and easier to sand than bondo but I’m having a devil of a time trying to remember what it’s called. Polyfill maybe. Have to double check or give self swirly. You’d have to sand it down and then run a medium coat of gelcoat over it. Also, on the subject of production boatbuilding and gelcoating, at the yard we did all wet lay-up. By hand of course. You’ve got your mold which is finished with either tooling gelcoat (harder than regular gelcoat, which is harder than polyester resin, and usually comes in black or bright orange) or some good stuff called Durakote (gray). We waxed our new molds with a special green wax called Partall Paste #2 from Rexco (800) 888-1060 and sometimes we waxed stuff with TR wax (white). I really like the Partall though. Wax on, leave for about 15-20 minutes and buff off. If you don’t let it dry to a haze though you can kiss your mold goodbye. Also, for a new mold at least 4 to 5 different waxes with a 4 hour flash time in between waxes. This ensures your part will release the first time with little to no damage. So you’ve got your mold waxed finally. If it’s a gelcoated part then that’s next. We had a special gelcoat gun much like a resin gun but it’s an external mix, meaning the catalyst and gelcoat are shot together outside of the tip. Somehow it works when everything’s going right. Usually we let this kick. Then we would use a special resin from Reichhold called Hydrex at about 3% MEKP, and skin it with a layer of 1 to 1.5oz mat. After this kicks we hand sand any burs or hairs off and begin our laminate schedule (which always leads off with another layer of mat.) In fact almost every time we let a laminate kick and had to come back over it again with more material (which happens on a daily basis) you have to put down mat first. It acts like a sponge and wets out the roving from beneath. So lets say your part is done. Then you grab a thin putty knife with one of the edges sharpened down to a bevel (usually using sandpaper) and pop the part, if it’s small that is. Bigger parts we use lots and lots of 2x4 wedges, rubber mallets, and for the soles and decks a sledgehammer to pry it off the floor. I used to help lay up those decks right on the concrete floor of the shop. It’s kind of weird. We also had a 10’ or 12’ by 50’ glass table that left some really cool finishes. I think for surfboards gelcoat is a little too hard and brittle. Not to mention it’s thicker so it’s harder to wet your cloth out. Also, it’s quite a bit more expensive than your sp249a laminating resin. I was considering using vinyl ester resin but the stuff we had at the yard was thicker and had some funky drain out problems. You had to mix it hotter than polyester to get the same kick off times but then you still had the drain out so you had to mix it even hotter to prevent that. And sticky, like maple syrup! And I’m not even interested in working with epoxy. Even though epoxy has the best mechanical properties of all the adhesives it’s toxic and you run the risk of getting sensitized, not a pretty site or feeling! Vaya Con Dios! Mark “Mad Dog” Pearson