Fin box time

Tonight is going to be fin box night, and I was wondering if there are any pitfalls to watch out for? Also, when using cabosil, does it have any other property other than colouring and thickening? In other words, could you just use a pigment with lam resin? Cheers guys Peaman (nearly there now)!! P.s I don’t know whether any of you guys have surfed over here in the U.K but it sometimes a bit hit and miss. However, one of my favourite breaks is going off today, thought you might like to check it out - www.croydesurfcam.com Have fun!!

you just use a pigment with lam resin? Yes, that is the way I do it. Additionally, depending on how much tail rocker you might want to elevate the tail a bit so that your router cut is close to being level to the floor. You don’t want your resin to continually flow to the back of the box. Also, I like to set the fin box before filling the router cut with resin. If you just set your box in there and fill the router hole with resin, it will cause the box to float a bit, throwing off your fin box placement. To avoid this, I just take a little bit of lam resin (just enough to fill the very bottom of the router cut) and mix it so it will kick pretty quickly, say about 8 to 10 mins. Don’t worry about yellowing because you are going to pour your pigmented resin over it. This quick batch is just there to keep your box where you want it. I like to remove the little cross bar in the middle top of the fin box and place a fin in there in the center of the box, so the weight of the fin is centered over the middle of the box. Mix the little quick batch, pour in the router cut then place the box with the fin it in the router cut. That way you have the fin as a guide positioning the box. Once it has set, then you fill the hole with your pigmented lam resin/cabosil mix. On this mix (the pigmented one) you don’t want to mix it real hot. You want to avoid a lot of heat in your router cut. This will cause the sides of the box to expand a bit. As the batch cools the box contracts back and you will have a seam along the edges with no resin (that is why they put that little cross bar in the top of the box to begin with). If this does happen, you can just come back after your rough sanding and fill it in with some more pigmented resin. Good luck.

Man that break looks like a LOT of fun. How consistent is the swell? Where on the coast is it located? About the fin box, real important, before doing anything, clean off the finbox with a rag soaked in acetone. Often there is an oily film that you can’t see that stays on in the moulding process. Cleaning it with the acetone allows for the strongest possible bond with the resin. Also I add a couple of layers of glass to line the finbox slot before wedgin in the actual finbox. This allows for a better fit. Have fun.

I’m not 100% sure on the fiberglass cloth in the bottom of the router cut. I use to do this, then was told by others that a setup without the cloth is stronger. You are not really working the resin into the cloth and not bonding it (or laminating it) to the sides of the router cloth. All you are doing is making it more difficult for the foam to absorb the lam resin. Maybe some of the more experienced ones may chime in. But I vote for a No on the cloth.

hmmm. Interesting. The benefit that I can see of using a layer or two of cloth to line the slot would be to “fill in the gaps” so to speak. In other words the box is never a 100% snug fit, so the cloth would provide that extra few milimieters to bond to the surface of the slot. OR…I could see that if your fin box was spot on, then maybe resin would be all that you need. I am far from an expert so maybe those with mor experience can chime in.

I’m not 100% sure on the fiberglass cloth in the bottom of the router cut. > I use to do this, then was told by others that a setup without the cloth > is stronger. You are not really working the resin into the cloth and not > bonding it (or laminating it) to the sides of the router cloth. All you > are doing is making it more difficult for the foam to absorb the lam > resin. Maybe some of the more experienced ones may chime in. But I vote > for a No on the cloth. …on long boxes I tack the bottom and sides with lam in a slow cook-off(very slow).I then apply a layer of glass to the sides only just under the glassed surface.The tack holds the box in place,as well as the glass,then I fill with lam/pigment/DE and/or diaper-fiber and cabocel,using a 60cc syringe.Herb

hm so it appears to be a little bit of both. Once again, Herb is the fountain of information thanks

…on long boxes I tack the bottom and sides with lam in a slow > cook-off(very slow).I then apply a layer of glass to the sides only just > under the glassed surface.The tack holds the box in place,as well as the > glass,then I fill with lam/pigment/DE and/or diaper-fiber and > cabocel,using a 60cc syringe.Herb Forgive me Herb, but you lost me on the placement of the cloth. Are you putting it in on the sides fin box and bottom of your router cut, in the same manner (for example) as you would when you are setting up glass on fins (laminating panels of glass up the side of the box)? You are just not laying up the glass panel all the way to the top of the box? If so you must have a little squeege? And why such a slow tack? I understand that it would be stronger than a tack coat mixed to kick fast, but isn’t the majority of the strength coming from the fill resin (with your DE, diaper fiber, cabosil, or whatever)? Once again I don’t get it? Forgive my ignorance on this one, and again thanks for the info. Sorry to hear about not being able to build at home. That sucks, but who knows it might open up an opportunity to do things bigger and mo bettah.

Tonight is going to be fin box night, and I was wondering if there are any > pitfalls to watch out for? Also, when using cabosil, does it have any > other property other than colouring and thickening? In other words, could > you just use a pigment with lam resin?>>> Cheers guys Peaman (nearly there now)!!>>> P.s I don’t know whether any of you guys have surfed over here in the U.K > but it sometimes a bit hit and miss. However, one of my favourite breaks > is going off today, thought you might like to check it out - > www.croydesurfcam.com Have fun!! Instead of cabosil I would advise you to use a mixture of resin,pigment,and milled fibers. Maybe a piece of fiberglass in the bottom of routered hole but not wrapped around the box.Aloha Kokua

a big hint dont put your router back on the board between cuts without taking the lock off! ive done that before! made a nice hole in the board! good luck

…Mike d…You don’t have to slow tack it,but it’s cooler and will adhere better,and the filler will chain react the slower tack anyway.As far as the glass thing goes,I tack it to the sides(just to the sides not the bottom) of the hole not touching the box,this makes the routed hole tougher than sh*t,and have yet to have one come back.As far as the Cabocel controversy goes, you can use it or lose it,just don’t use goobs of it to thicken the resin,just enough to make a pasty-er mix…oh yeah squeegy…a popcycle stick.The tack should be thick ,but naturally,by evaporating the styrene out of the resin,not adding filler.The glass will stay tacked to the walls of the hole but will allow fibers to float out to the box ,mixing with the fill.get it? …Kokua…I’ve been using a mix of either milled glass, DE(A Noodle discovery),(which is a natural glass and works just as well as milled glass,a little dirty,but the pigment covers that right up),or my discovery,milled diaper filler.It could also be a combo of these things in lam resin,with a hint of pigment and cabocel to give it a good bind.It’s tough as all get out!Herb

what happens if you use sanding resin to fill in the seam? if using lam. resin, won’t it smear or discolor when grinding down the box?

what happens if you use sanding resin to fill in the seam? if using lam. > resin, won’t it smear or discolor when grinding down the box? …naw it’s too thick…but you can brush a little clear hotcoat over the residual before sanding.Herb…don’t use sanding resin.It can cause dislocation of the box.Herb

i had problems on my last box when i grinded it down. i used an angle grinder w/ a 50 disc to take out the heavy spots. then i switched to 80 to smooth it out. some parts were uneven and rough looking. what’s a good way to sand the box down smooth? need some suggestions

i had problems on my last box when i grinded it down. i used an angle > grinder w/ a 50 disc to take out the heavy spots. then i switched to 80 to > smooth it out. some parts were uneven and rough looking. what’s a good way > to sand the box down smooth? need some suggestions practice…or…you can put a few layers of tape around the area,and sand with a rough grit like 40,then when you hit the tape and just punch thru it,remove the tape and switch to 80.Herb