Hello,
I just made my first cutaway longboard fin in plywood and now I have a few questions i hope someone can answer.
I want to write some words on the fin and then seal it with ressin. Do I need to put some chemical liquid on the fin before I write on it? What pen or paint should I use?
I mean the wrong colour or pen will react badly to the ressin and catylist and maybe will smudge so the letters become blury…
Thanks!
Andreas
I’d seal the wood with laminating resin and then write your words on with a posca pen. Leave to dry overnight and then lay up your fibreglass over the fin. I ususally use a minimum of 3 layers of fibreglass on wooden fins on each side of the fin. I then hotcoat them before I start trimming the glass and resanding the foil.
Cheers
Rich
Thanks heaps Rich! Do i seal with just a paintbrush then? Maybe a silly question but what do i use for hotcoating? So its possible to foil the dried hotcoated fin? Perhaps i need a not so strong sandpaper but a more finer one? Supercool homepage you have gave me lots of inspiration!
Thanks again,
Andreas
Yes just seal with a brush and your lam resin. I presume you’re using polyester resin? To laminate the glass on again just standard laminating resin then when that’s dry use more of the same resin with about 1.5% wax in styrene solution added to it. Add the wax before catalysing and stir well. The hot coat is also applied with a brush. Let your fibreglass overlap the edges of your fin by about an inch or so, obviously one side, let it harden then flip and lay up your glass on the other side. If you want anise halo then after laminating the first side then wet out some glass rovings and lay them round the perimeter of the fin before you lay the cloth down to start the other side. I’m sure you should be able to find a thread if you search the archives with images. It’s not a difficult process.
Good luck and I look toward to seeing your end result.
Cheers
Rich
Www.thirdshade.com
I have been looking quite a bit online but you are the one who describes it best. Its ok to sandpaper or foil on the second layer of ressin then? make it nice for the hotcoating. Just one last question. I guess its different but how much ressin do i put on the second layer(together with the fiberglass roving)? If it turns out good i will definately post it here. Otherwise i just keep trying.
Thanks,
Andreas
Hi Andreas, you just laminate one side with your three layers of glass and let that harden. Do it on a flat board with a polythene sheet and allow the glass to lay out onto the board, like I suggested let the glass overlap the fin outline by at least and inch. Then peel the laminated fin off of the board and flip the fin over. You will find that the ovarlapping fibreglass leaves a bit of a sloping surface around the edges. To get the halo just bunch up a number of strands of glass roving. I always tape the end together to make it easy to hadle so it looks like a pony tail. Lay this into a bucket of catalysed resin and pull it through your fingers to get rid of excess resin - make sure its all gone clear. Then simply lay it into the sloping void around the fin thats been created by you first layer of glass. Paint the wood with resin and start laying each layer of cloth over the wet fin. Use a brush to help wet it out adding more resin as required. You’ll find that using a dabbing action with the brush will work best as it wont drag the weave like it would if you stroked the brush along the surfcae. Add next layer of cloth, more resin etc until its done. Then let it all go hard. You can trim close to the fin outline then with a tool of your choice - I use a dremmel with a cutting disc - they work great. After that just hotcoat the whole fin and let that dry. When I do this stage I insert a small screw in eyelet into the base of the fin screwed into your wood core so I can hang it up on a string. This allows you to hotcoat both sides at once. When thats dry and hard then you sand the whole fin including refoiling the leading and trailing edge. If you are lassing it on use course sandpaper - as rough as 60 grit is good as it provides a good key for the glass that you use to attach it to the board. If you want it glossy then sand to 80grit and apply your gloss coat.
The volume of resin I would mix for that fin would be about 50ml for the first side but about 100ml for the second as you’ll waste a fair amount when wetting out the rovings.
Sorry I dont have pictures of this but as you’ll find out its a little messy when youre handling the rovings and it would be difficult to take pictures when youre covered in resin!
Cheers
Rich
Thank you so much for taking your time to explain! With this from scratch to the end explenation i cant fail! I will get to it this weekend and then post to end result here.
Best regards,
Andreas
Hey Rich, great explanation. I just have one question. I’ve tried doing this process with a double-foiled centre fin almost exactly as you’ve described it above. But when it came to flipping the fin and laying the halo, I found that the slope of the hardened glass on the first side made it difficult to get the halo centred on the fin (running down the central line of the foil). Instead, it sat off-centre, leaving the foil at the front of the fin skewed once I’d glassed the other side of the fin. When I refoiled, I ended up sanding away most of the halo before I got it back to being even. Does this make sense?
How do you avoid this skewing when laying your halo?
Hey again! Everything went quite smoth my first fin is ready but then i ran into another problem. The holes i had to drill in the cutaway fin to keep the fin in the finbox was a pain to drill afterwards so now i know i have to drill the holes before starting to foil the fin.
Problem 1: Im not sure the fin will hold when i sqrew it in place in the finbox.
Problem 2: I need to laminate inside the holes to becuase the core is plywood. How to do this?
Also what kind of wax to mix with the styrene for the hotcoating?
Any advice will be greatfully appreciated:)
I just noticed this in “industry talk” - am moving it over here to “general discussion”
Hi Andreas
Not sure what you mean with your first question?
Problem 2 - never done this as all my hand foiled fins have been glass-ons, but I do think I understand your problem - when you drill your hole for your fin screw you are going through the wood core?
I would consider trying sealing the hole with superglue - It works extremely well for sealing the endgrain of timber. Failing that you could drill the hole slightly over size, fill the hole with resin with microfibre and when it’s cured redrill with the correct (smaller) sized bit - this one may be a little difficult as you will not have much space to play with.
The wax you need is wax in styrene solution - need to add about 1% or a little more. They will sell it where you buy your resin.
May be better posting pics along with questions in future.
Cheers
Rich
www.thirdshade.com