So i will be the first to admit my glassing skills are not quite there yet but I am learning as much as i can for a part time garage shaper. I recently finished a 6'-6" fish. The board is dark brown and white. I pigmented the lam coat on the board a dark brown. I then attached the fins to the lam coat as i have done with other boards in the past. The way i was taught was to temporarily secure the fins in place on the dried lam coat then lam on the footballs of cloth with laminating resin. Everything seemed to be going ok until i went to the hot coat. The cloth from the footballs did not disappear and are now very visible ont he finished board. The stregth seems ok but I am worried for the longrun strength of the fins. I have done the fins tis way before and have not had any issues. Not sure if it's the dark pigment color or i didn't prep it correctly. Any help on this would be greatly appreciated since I really don't want this to happen again and I can learn from it. Thanks
I don’t think that would affect the strength of the original lam at all. Depending on how much you’ve sanded past the cloth it shouldn’t be a problem. There’s not much strength in the hot coat. Plus, the fin rope is quite strong.
The rails on the outside of the fins generally have less of a problem vs inside the fins. The outside rail usually has more cloth due to the lap, and it’s closer to the rails which have a rounded shape. The inside of the fins have a much weaker structural foundation. The area surrounding the inside is flat and plus it takes more impact from surfing.
what I’ve found happens in glass fin problems is more about the foam. The glass can feel loose after you’ve hit something, but in reality it is the foam underneath it giving away or the areas surrounding the fin. so no matter how strong you glass it, it never really can be that strong with certain foam densities. For example, if your board is EPS, its helpful to route into foam under where you want your fins and add a bit of qcell resin to create an internal support structure for weaker foams. Kind of like how the fcs fusion boxes were designed geared more towards eps foam.
i never really looked at the fin that way and the strength of the foam compared to the glass. makes sense. thatnks for the insight on that. the fins are very sturdy right now.
i never really thought about moisture on the glass. that could be the case. i have a box of old scrap that i use for repairs and fin footballs. good chance that it got a bit wet. i think i will toss all the scraps just in case.
i have noticed on another dark colored board that there seemed to be a bit of crystalization on the cloth at the rails. i put that to the dark color, thought this was a similar condition. i heard somewhere that you need to put resin on those areas before you put lam the cloth to stop the crystalization.
On a side similar note, would there be an issue with laying up the fin football cloth with hot coat vs. lam resin?
If this is a PU board you can try to sand your hotcoat back down to the cloth. Hit it with some straight styrene and then re-hotcoat immediately. It looks like the cloth was not totally wetted out during the intitial lam or it was sanded a bit too much.
Nope. You mashed the cloth when you preped it for the hot coat. You need to let the resin cure more, and you need to use fresh sharp paper. Next time hit the area with mome styrene before the hot coat. if it goes invisible then you are ready for the hot coat. if not you need to back off, let it cure and resand the area.
All of the above. "Roving" = fiberglass rope or strands from mat. Wetted out and placed at the base of the fins. You might have used damp cloth, but your own statements tell me that you used hotcoat resin to lay up the cloth and that you sanded the piss out of it. The styrene and hot coat immediatly fix might do it. Give it a try. If you didn't use roving or rope they are gonna break off anyway.
Sanding green fins or laps will give you that "always seeing the glass look". The darker the board the worse off. sand paper should cut the fiberglass, not mash it or tear it off the area. The best results always come from a board that has cured a bit and fresh sand paper. When you use lighter grits with a semi green board you run into the problem of mashing more than heavy grits. But if the glass is rock hard it will grind away with most any grits. Then it's just a problem of how long do you want to sand.
One of the problems with fins and laps prep is it is an after thought for most. Meaning: you are looking around for a little worn out chunk of sand paper laying around the shop to "just get the job done".. usually something in a 100-220 grit. Most of the time it's a little torn sheet that's been laying on the floor, or table that gone through hell sanding the bumper of your car, or the back of it has been used as a micro epoxy mixing station.
Always use fresh paper with lot's of bite, when you feel it mashing...change it out. You know what I'm talking about, you know what a fresh load of sand paper feel like on your sander, keep that feeling all the time. The cheaper the paper, the more times you are going to change it out. The better the paper the longer it lasts.
Don't make me say it....Always use quality _ _ Products.
Didn’t want to say too much the first time because I wanted to hear from the “experts”. Somewhere the finish on the cloth was compromised. Water will wash off the finish, or perhaps the finish isn’t the right one for the resin. It could be caused by a multiple of problems, and stuff like this will show against darker colors more. My first thoughts are that fin lam looks like crap, over worked and too small, and Ray is a great laminator, and a good guy too. Huie’s inputs on right on too.
When your doing a fin lam what you should strive for is continuity and balance on both sides, so when the board is viewed from above they look the same. Cut all the cloth at the same time, and keep it as clean as possible, and stay away from the edges or it will fray. Hope you guys add some more.
Hey Ray, remember how many fins Wells used to do at a time working at Fibrecraft, after he finished at Hobie’s? 16 down racks, sometimes all with 3 fins, and one pail of resin. Didn’t realize those were the good old days…
All good comments but I would have to go with ghettorat first because it has happen to a whole panel with me. There’s a simple method to figure out if the cloth had a bad finish from the manufacture. This is what you look for;
When you wet out the glass it should go clear as resin is absorbed into the weave. As the resin starts to kick within the 8 to 10 minutes a whiting or shatter effect starts to appear like the pic below. If that is the case the fiber glass finish is bad and there is nothing you can do but don’t buy fiber glass from the same lot number. If the fiber glass stays clear after the drying process then the advise of the other Swaylockian brothers here would come into play.
Hope that’s helps narrows the trouble shooting down my friend.
You never want to use Hot Coat for any Laminating work, it is weak only use Laminating resin for bonding and glassing. Than Hot Coat on top it lets you sand to to finish.
hey, thanks for all the comments. i dont have a lot of experience as of now with glassing so i am trying to learn everyday. i can see where it was a combo of a lot of things. chances are, i sanded the hell out of the fin cloth with old paper. i did use rope so thats good. thank for all the help. i will remember all this on my next board. the fins may not be the prettiest but the board works really well so i just wont show anyone the bottom. thanks again.
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i did use rope so thats good.
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Not really. There IS a better way. Cloth only, cut and laminated on a 45/45 bias. From 1960 forward, I've never had a fin break OR crack, using that method. It's a method not well suited to ''production'' but is far stronger than using roving or rope.
