I have only done a few glass on fins, and that was back when I was brand new to surfboard building. Mostly I use fin boxes.
So I have a single fin board that I am building, and a fin I made, and my question is this: at what point do I glass the fin on? In other words, how far do I finish the board, and how far do I finish the fin, before glassing it on? How much work on the board and the fin takes place after it is in place?
Hello; the fins go always on the laminated (bottom) stage.
1-laminate the bottom
2-laminate deck
3-hot coat deck and laps
4- flip over; sand laps.
5-locate the fins and glass ons.
6-hot coat bottom and fins
7-sand all the board
8-finish
tips:
-let the fin/s rough to have better adhesion.
-use at least 50 layers of 4oz for a single fin. More in several cases of bigger fins.
-if you want a gloss polish finish; do a double hot coat or double gloss to not have burn through and quality finish.
Anytime after laminating the bottom and before you hotcoat the bottom. Even if you mortise the fin. If you mortise it in you would still want to put a few strainds of rope at the base and a couple of layers of cloth on either side. The strength is in the mortise and since the fin is glassed already, you don’t need to run those layers of cloth all the way up to the tip. The rope and cloth are there just for flow,smooth transition and to seal the mortise. If you don’t mortise it, then just follow normal procedure for a glass-on.
OK, time for another glass on fin question: Do you hot coat and gloss coat the fin while you do the bottom of the board, i.e. the board is flat so you are applying resin to a vertical surface (the fin), or do you wait, and put the board rail up in the rack, so the side of the fin is a horizontal surface to work on, then flip and do the other side after the one side is dry? It seems difficult to get the resin to lay flat on a vertical surface, but I guess boat builders do it.
Have seen it done both ways. Most common though is all at one time , bottom up. Work quick and start with both sides of the fin first. Spread the bottom and then come back starting with the fin and pull excess resin off. Then tip it all off starting again with the fin. Babysit it.
I usually baste everything on the bottom, (fins, laps, nose area extra and build a hard edge out the tail if needed) then hotcoat the bottom but don’t hit the fin. Then I flip it hot coat the deck and the fin with it pointed down. It keeps the sanding if runoff to a minimum… I also gloss all my boards so I sand the crap out of the fin area to make sure it’s all smooth and flat then hit it with styrene before the gloss.
Hello Huck; as mentioned in the other comment; I put the sequence of the process.
There is no advantage in the hot coat stage to do it other way. The resin would be filling the mesh of the fibers so the vertical situation is not a problem; if you find a problem with the dripping is that you are using too much resin.
In the gloss stage you can do it whatever way but is not too much advantage to put the board on rails to do it.
The way I mentioned is the way that most of us do around the World in the glass shops. Again; you can do in other ways or repeat process etc but there is no advantages.
OK thanks very much for the responses, I finished up today. I just put a final coat of epoxy on, and calling it good, but might do some polishing after it cures awhile.
The fin was shaped from the same wood as the board, then it got 6 layers of 6 oz. fiberglass and epoxy resin each side, but with lots of sanding / shaping.
The fillet was strands running lengthwise, when it dried it just wasn’t quite enough, so I mixed chopped glass with resin and made a thick goop, then built up the gusset a bit more. Sanded when it dried with sandpaper wrapped around a dowel.
Finished up the fin along with the bottom of the board, just put the resin on thin and kept my eye on it, which you have to do with epoxy anyway.
If I understood correctly, do you say that you made the wood fin then put the fiberglass to to seal it only or did you put those layers also to hold the fin to the bottom?
Did you put the strands on top of those layers?
Is that board to be used in good surf?
The fin was glassed before attaching to the board with epoxy glue then a fiberglass gusset. It has a tab at the base which pressure fit tightly in a slot in the board. There is a birch inset around the fin. I can only hope to ride some good waves with it, surfing is currently banned in my area for now and into the indefinite future.
Cheater!
I have always tacked, fileted and roped at lam.
Grind laps and fin, then hot coat.
However on routed (short based) fins extra strength is required.
Check you PM
