Any tricks for glassing on glass-on fins so that they can be removed and set in a different location?
It is an epoxy glass lamination over balsa. Would setting them with polyester make removal easier so that I don’t damage the glass lamination?
I was thinking of doing a bit of a fill coat over the lam with epoxy so that there was a bit of a epoxy resin buffer between the lam and the glass used to set the fins. And try setting them with poly. I want them affixed just strong enough to surf, but practically be able to smack them with a hammer to get them off and not damage the lam.
How about setting them on a cloth pad lammed to the board shiny gloss that you can then get a knife edge under to lift the whole cloth lamination with the fin mounted onto it? it would cause a little bit of a mess from areas where the bond was too good to the primary board gloss but lams do peel up from glossy surfaces pretty well.
I reckon your idea sounds about right…you will have seen how the fin base rips into the fibre on fin breaks when done the traditional way, and how when you repair them, theres always a hole the shape of the base which needs filling.
Try filler coat first, give it a scuff, then set your fin…
Thanks Speedneedle. I’ve not read anything here ever about people glassing glass-ons with this intention. But I figured that it must be something that board makers have done, wanting to test and fine tune a thruster fin set placement.
I will try a few sample first for sure and see what I can figure out.
Any polyester glassers out there that have glassed glass-ons with this in mind?
On a surf trip I lost my side fcs fin.I had no extra fcs fins but my friend broke his board that had glass ons .The plug was still good so I put tape over the plug and glassed on a new fin.It came off pretty clean & easy after I ground down the glass on the sides.
Try putting tape under bottom of the fin and glass away.
Thanks Ian, actually that sounds like it might be a great idea. I was hoping to salvage the fins if I decide to move them. In the past when I did this once I just junked the fins grinding them off, but I sort of had to because the base seemed attached well and I did not want to damage the lam badly.
Also that is very much like GTFDs idea. Thanks guys.
I change my glass ons from time to time and prefer boards with glass ons so I can change them without the routered hole for boxes. I use a dremel blade and cut into the base glass/roving until the fin begins to wiggle. I then slap the fin on the side and pop it off. Grind it town, and put the new fins where you would like them. Mike
I used to do glass-ons regularly on Compsands…It was’nt a matter of using polyester instead, though the Gel-time of poly helps to prevent drain-out of he roving fillet in the leading and trailing edges at the bases…To overcome that in epoxy I would use a pinch of chopped fibre thickened resin at those points, applying a pinch, then the rovings and shaping the blob in the fingertips.
I would reinforce the base area prior to lamination with patches both in the interior under the skin and in the outer lam directly on top. These outer patches would need a little blending before application of the fins. The reason for the patches was that the glass-on fin would frequently lever up the skin at the base. This is a classic problem with glass-ons, even in PU/poly of course, but is a particular concern with compsand.
And, use big wide fibre pieces, coming a long way onto the bottom off the fins.
It is possible to grind off the rovings without trashing the fins…its necessary to get a long way in towards the fin before cracking it off…definately not a simple whack with a hammer, or else you risk delamming the skin.
I’ve started using a hot glue gun to position the fin and then when you grind off you don’t need to do anything under the fin, I got the trick from here. Also makes setting the positions really easy.
To overcome that in epoxy I would use a pinch of chopped fibre thickened resin at those points, applying a pinch, then the rovings and shaping the blob in the fingertips.
depending abit with your resin viscosity, a trick I have done is to wrap some cellofane around the base and the squeeze the thing into shape and squeeze out any bubbles at the same time. If you get it right you can pull off the cellofane after cure and hardly need to do anything else to it, just some light sanding to get any resin blobs out of the way.
I also use hot glue to position the fins which probably makes it easier to pop them off once the roving has been cut. I dont hit anything with a hammer although a nice rubber mallet would do the trick. I use the palm of my hand. I don’t do very much grinding of the roving base. Maybe a little depending on the situation. I use a thin cutting blade on the dremel tool to cut under the fin with very little or no damage to underlining foam. Like Speedneedle mentioned. I recently cut fins off and used them on another board. Mike
Instead of putting the fins on before the hot coat, put the fins on after the hot coat. That way if you want to move them you won’t rip into the base glass. I’ve done this a few time…on purpose, and some not on purpose. The fins will stay there until you want them to come off. And if you hit a rock or something hard, they will snap off without damaging the lamination cloth.
“I’ve not read anything here ever about people glassing glass-ons with this intention. But I figured that it must be something that board makers have done, wanting to test and fine tune a thruster fin set placement.”
Hey Glenn,
On occasion as a Grommy at work, I would be subject to the whim of travelling Pro’s during the Bells contest…yeah, grinding off and re-positioning fins on brand new boards.
Whatever way you look at it , its hard work for a 1/8" difference, but, moving plugs is harder!
I’d like to see same-template tabbed fins offered in three different placement set-ups…sigh, guess I’ll have to do it myself…
I do them similar to resinhead on the hotcoat for pu/pe. There’s nothing worse than repairing a busted-out side fin which took the rail out with it. My procedure is: Stick fin on and align with hotglue gun, use resin/cabosil fillets, single layer of 6 oz each no more than 2" on the bottom either side of the fin, glassing only to the rail edge on sides never over it. You can do this on epoxy with poly, just sand the glassing areas with 60 grit first.