resin quantity for finbox installation ?

Can anyone tell me in mls [millilitres] the rough quantity of lam resin I would need to install a 12" fins unlimited finbox. The hole I’ve made is 12" long x 1 1/2" deep x 1" wide, if that helps . I guess I’d be about 1/2 filling it, as installing the box will make the resin level rise .

I haven’t done a box this size, and I forgot to write the quantity I used when I did the 10 " six months ago. [D’oh !]

Okay… thanks , crew. Your help as always is very much appreciated!

Ben ‘chipman’

ps - the quart / cc/ mls conversion… anyone out there know the equivalents, for this Aussie ?

Sorry can’t answer your question about how much resin to use Ben - Kokua would be the one to know for sure. But here’s a handy conversion page… http://www.sciencemadesimple.net/EASYvolume.html

Quote:

Sorry can’t answer your question about how much resin to use Ben - Kokua would be the one to know for sure. But here’s a handy conversion page… http://www.sciencemadesimple.net/EASYvolume.html

" well , dang diddly ang diddly, neighbourino…"

thanks for that , waxheadman! [HELPFUL , indeed ! ]

eg : -

1ooomls = 1000ccs [I always WONDERED if they were the same !!]

1000 mls = 1.05 ‘quarts’ [ dang, now it gets tricky eh ?]

That’s a handy one… I’ve added that to my favourites !!

My next question [re: the finbox] …

In my ‘enthusiasm’, I unfortunately hacked out an extra 1/2 " depth of foam more than needed. oops.

Should a coupla layers 6oz and resin before installing the box bring the box up to level with the hull ?

[NEXT time, I will be a bit slower and check and double / triple/ quadruple check the depth as I go. Lesson learnt!]

cheers then !

‘chip’

OUCH…

The quantity depends on the size of the hole and the size of the box. With an extra large hole, what a pain, I’d prolly recommend a Q-cell/cabosil batch, extra light, to put the box in, let it set, grind it down, and glass over the edge of the lip. I’ve gone to this on my finbox installs, works well. The back of the box should make GOOD contact with the stringer, that and the glass-over make it plenty strong. It is not like a side box where you cannot use the stringer for help.

Use a router and get the hole TIGHT, you will get better mechanical strength and save weight.

Using your hole dimensions, 12 x 1.5 x 1 = 18 cubic inches. You discovered that the hole is 1/2 inch too deep, so fill the void either when you install the box (with resin) or fill it before with a Qcell mix. My preference would be the former.

As I recall, the Fu box is 12 x 1 x 1 = 12 cubic inches. (Recalculate if I’m wrong). The void space to fill is 18 -12 = 6 cubic inches, and you want a little extra just in case, and for grins and screams.

6 cubic inches x 16.39 cc/cubic inch = 98 cc. (mix a little extra)

But how ya gonna measure just that amount? I usually just eyeball it and if there’s extra, there’s extra. If not enough, quickly mix a little more. I use chopped fibers to thicken. Your routed hole wants to be a pretty snug fit.

I pour a couple fingers of resin in a plastic cup and add whatever filler I have handy (qcell, microballoons) until it gets a bit thicker, then I catalyze it slow and spread it around the bottom & sides of the routed hole. Use enough that some is pushed out when the fin box gets pushed in. Not very exact, but it works.

If your hole is 1/2 inch too deep, you need about 50% more much resin, I’d think. Compared to having a pretty tight fit.

Howzit chipfish, I use 5oz cups and fill about 3/4 with the same mix I use for FCS installations and there's usually some left in the cup. I make up my mix the day before I'm going to use it and put into a plastic conainer ( like a butter tub) and put the lid on . This allows the air bubbles to disapate and makes the mixture really smooth and leave no air bubbles after it goes off. Aloha,Kokua

thanks for your help everyone !

I DO need to get, and learn how to use, a router… DEFINATELY !

98CC = 98mls, @ 50 % extra, I’m figuring 150mls should be PLENTY ! [I’ll get a wood fin ready for glassing , so IF I’ve got enough excess, kill two birds with the one resin batch, so to speak…]

        ben 

ps - waxfoot, that site you gave me is REALLY useful…THANKS!! [I just typed in 5 oz, this is the conversion… a good guesstimate on my part then ?!]

" 5oz = 147.8mls " [!!]

make sure you wipe down your fin box w/ acetone to get the mold release off it before you install, and tape over the hole in the fin box (unless you’re one of those guys who installs the box with a fin already in it so as to check the vertical alignment - which may not be such a bad idea if your hole is really oversized!)

don’t use too much catalyst or you will warp the fin box.

Better to focus on one thing, you’re not going to waste much resin, & what you have for installing the fin box will have filler in it, so not really perfect for wood fin making…

PS I’ve found that you can convert pretty much anything to anything by just typing it into a good search engine such as google. For instance just enter “convert ounces per square yard to grams per square meter” and up pops “1 ounces per (square yard) = 33.9057475 grams per (square meter)”

… how easy is that?

I used RR Epoxy when installing my 15" fin box.

My notes say I mixed up 3oz and had plenty left over.

hope that helps

a previous fin box install thread indicated it was MUCH more important to rough up the fin box with sand paper than to wipe it down, but I’m sure doing both is best. I would guess that the sanding the box (any surface that touches the resin) removes most of the mold release that the wipe down does.

hey guys im new to shaping and made a big mistake when installing the fin box. i forgot to tape it over!!some resin got in and it kicked before i realised what had happened, Iv tried sanding to fit the fin in but its just not happening for me. now i have this nice longboard which turned out good but got no fin!!! any suggestions on how i could fix this? i suppose ill never forget to tape the box again anyway!!

Well… that’s a mistake you won’t make again eh…

You could try to route out the slot with a dremel tool if the resin leakage didn’t get to the guide slot that runs horizintally- to fit the pin on the fin and screwplate-, failing that your options are to glass on a fin or route out the whole finbox and put in a new one.

ealadubh,

If you decide to route out the box try this. Just router the box in the middle from end to end starting with a small cut and increasing a little at a time until you just cut through the bottom of the box. You only have the full depth of the ends and then just the small depth of the bottom. You can then take a wood chisel and knock the halves of the box inward and pull out each half. Then clean up your hole and try again. This keeps you from having to router so much of the finbox material which is a pain. Kokua’s tip about mixing the resin for FCS and other boxes the night before is one of those things that help you get pro results!

Dave_D

cheers guys, the guide rail is ok just the bottom of the box so ill try just rout out the bottom of the box a little, thanks again