LokBox and Fins Unlimited 10.5" installation.

General Discussion
1

Hi folks, I’ve got a request for help here…

I was expecting a sort of installation manual to come with my order of fins and boxes, but all I got were catalogues.

As some of you will already know if you’ve been following my attempt to build boards #1 and #2 in record time, I don’t have time to wait for them to arrive; basically they need to go in tonight if they need doing before glassing, or some time tomorrow if they need doing after. I’ll be putting the sealer coat (RR2000 and SP microballoons) on the first board in about an hour or so.

Can anyone point me to an installation guide for LokBox (side) fins and a 10.5" Fins Unlimited centre box? I’m somewhat lost without some kind of clear instructions. I have seen a thread on the surfermag forum where someone cut through the glass to do a freehand install of the LokBox system, but I’ve been told it’s actually better and probably easier to install them before glassing.

I could wing it and I’m fairly confident I’d be able to figure it out, but I’d rather not need to if at all possible.

I have absolutely no idea how best to go about installing them, I saw a few useful tips on here, like Kokua suggesting someone use a mixture of resin and milled fibers (chopped up rovings pulled from the glass cloth?) to install the F.U. box.

Apart from that though I’m kinda stumped.

Do they go in before or after glassing / sealing (microballoons)?

Even as far as what parts stay and what parts get sanded off I’m at a loss.

I’m not just new to shaping, but to anything to do with fins (rental boards don’t take much setting up)

Some specifics…

I assume that I remove the bar that crosses the box in this picture in order to fit the fin. (Like I said - new to ALL of this) So if I take it out and then fit the fin I’ve bought to use in it, I can use that to get the fin box at the proper angle?

Is the bar functional in some way that I shouldn’t take it out before installing?

Also, am I right in thinking that the lip around the box will be sanded down all the way?

Does it get sanded down to the red line leaving the tabs in place, or to the blue line sanding them off?

I hope someone can shed a bit of light on this before too long as I really need to make a start on anything that needs doing before glass asap. Otherwise I’m going to have a bit of a problem getting started with this.

Cheers folks.

2

Never done a finbox, but if it’s anything like the FCS you sand down to the blue line.

Here’s a thread,

http://www.swaylocks.com/forum/gforum.cgi?post=220899

I would put 2 extra patches of 6oz on when you do the bottom lam as GL says, and use the chopped glass-resin mix when you fit it later. Fill your routed hole about a third(?) full and then place the box in. If you put insulation tape around the routed hole it saves having to sand off the excess so much.

Oh, and routing through that 1/2 inch stringer is going to be slow with your dremel router attachment, do it in steps to make it easier, so first cut maybe 6mm, second pass 12 mm etc till you get the depth you need.

I would fit it after you hotcoat the bottom myself to fit into your schedule.

Glass bottom, wait for b-stage, flip, glass top, wait for b-stage, hotcoat top, wait for hotcoat to set fully (wiping drips to underneath as it sets), flip, grind laps on bottom (surform and sanding block), tape off centre line, hotcoat bottom, wait for set, route hole, install fin box, wait for set, grind off excess fin box.

Oh, and you’ll probably have the resin draining into the foam when you install the box, so you’ll need to top it up as you go, or top it up afterwards. You can sort of seal the edges with the slurry again before you pour the resin in, but don’t use too much as the microballoon mix can exotherm. Prob best to seal, wait to set a bit and then put the resin and box in.

3

I’ve done about 10,000 of them so I’ll try to help, but it’s not easy to describe the method(s) in type but I’ll give it a shot.

Bigshot, now comes the part where I recite the age old saying “your only as good as your tools”. I’m assuming you do not have the Jig, but what about a router? And if you have one, do you have any experience with it? Lokbox can be put into the foam, or through the glass before the bottom hotcoat. Fins Unlimited center boxes are designed to go in AFTER the bottom hotcoat. You have to cut a hole 10.5 inches long and 1 inch deep for that center box. Without some sort of jig it would be downright scary to attempt in the foam. Besides that you would then have to figure out how to glass around the raised part of the box. You better plan on doing it after. The little triangular pegs on the ends and sides of the FU box are designed to sit flat onto the hotcoated surface. If you get the box in to this depth, you then grind of the “resin rim” until the box is flush to the bottom of the board. The little plastic bridge should come off automatically when sanding… provided you got the box all the way in to the little triangular pegs on the front and the sides of the box. You’ll notice that the pegs on either end are positioned dead center in the middle of the box lengthwise. This is to help you center the box on the stringer. As far as setting the angle on this center box, there is no angle. You want it in straight so your fin ends up straight and not leaning to one side or the other. This requires that you cut a fairly perfect hole, or at least the bottom portion. The box is flat on the bottom, and needs to be seated to the stringer. If your hole was cut well…meaning the bottom portion of the hole is flat, you won’t need to install the box with a fin in it. You just seat it to the bottom of your hole. Fins Unlimited recommends wrapping at least one layer of 6 ounce glass around that center box. So the width of your hole needs to be wide enough to allow this layer of glass to go around the box. You’ll use the end pegs to line the box up on the stringer, as there will still be a bit of side to side movement of the box inside the routed hole. All this hinges on the fact that you rout your hole properly meaning equal distances from the side edges of the routed hole and the center of the stringer. Do you have a way to do this?

4

You could use this same method as in this pic but you’ll have to be very careful…

Position the center box where you want it fore and aft on the board, then trace around it. The hard part will be the stringer at the front and rear of the hole. If your using a 1/4 inch bit, take small depth passes back and forth across the stringer until you have routed through it about 1inch deep. Then rout just inside your traced line all the way around the hole you’ve traced for the box (1 inch deep). At this point you can then start to nibble away at the sides of the stringer for the whole length of the hole. Once you’ve gotten the stringer width down to about 1/8th, you can then grab the stringer with a pair of pliers and tweaking side to side…snap the rest of the stringer off. Problem with this method is it rarely leaves the deep portion of the cut on the stringer flat. You may be able to clean that up with a few passes of your router. Tape off the hole all the way around to avoid getting resin all over your hotcoat around the box. With a pen or pencil make a mark on the tape on the center of the stringer on either end of the hole. Then tape off the cavity of the box. It is recommended to tape off the cavity portion of the box with a piece of 1/2 tape that fits perfectly inside the resin rim of the box. The triangular pegs on the ends will be used to line up with the marks you’ve put on the tape on either end of the routed hole so you get the box centered side to side. You then install the box with straight laminating resin with white pigment mixed in. Cut yourself a piece of 6 ounce glass about 2.5 inches wide, by 12 inches long. Lay that centered over your routed hole, then push the box into the hole and the glass will go in and fold up around the sides of the box. Press box in until the little pegs are flush, then using gloves, you’ll wipe the resin away at the front and back of the box which will allow you to see your line up marks you’ve put on the tape in regards to the little pegs on either end. Push the box to either side with your gloved finger to line up those triangular pegs perfectly with your centering marks on the tape. Whew, say that 5 times fast…

5

"Is the bar functional in some way that I shouldn’t take it out before installing? "

Absolutley. The plastic bridge keeps the cavity from pinching due to getting hot while your resin goes off. This way when your all done suprise suprise your fin fits…

6

The box is designed to be ground down to the blue line in this pic (pegs will completely disappear)-

7

You can install the lokboxes into the foam using the method in this pic -

It will require that you can cut a clean hole freehand that ends up with a tight fit for the boxes. If you make a sloppy rout you will use excess resin and the whole deal will get pretty hot, especially when using epoxy resin (no bueno). Provided you can get a fairly clean rout, your depths are 3/16ths for the flange portion, and another 1/2 from there for the cavity portion. Once you’ve pulled that off, Pour resin into your routed holes and fill up the cavity portion of the hole about half way, then press the boxes in slowly until they are flush with the foam. Resin will come out around the edges of the boxes. Paint a light film (no globs) of resin over the flange portion of the boxes and squeegee off the excess around the boxes on the foam. Let gell. you should have received small pre-cut stickers when you got the boxes. Apply these over the cavities to keep resin out while you glass. Cut 2 oval patches minimum 1 inch larger in diameter than the boxes themselves and place over the boxes and under your full layer of glass your using to laminate your bottom. A small slit through the glass on the edge of the resin rim (while glassing) will aid in removing bubbles on top of the boxes while glassing. After laminating your deck, and hotcoating both sides, you’ll then be ready to install your Fins Unlimited center box. When you sand the board the Lokboxes will automatically open up with no razor work necessary. Hope tha helps, gotta go now, todays my day with the missus and she’s rolling her eyes and tapping her foot at the moment lol… Cheers Jim

8

Howzit Jim, I take the bridge out before installing the box. Before I started doing it I had a few times that after grinding down the box it actually releived the stress and the middle of the box separated from the filler. Another reason is I put a fin without a slot pin in the box during the install to make sure the fin will be perfectly perpendicular when finished. If you look closely some of the boxes bulge a bit where the bridge is and when you grind it off that’s when it can pull away from the filler. With a fin in the box you have the right width and the resin can’t pinch as the resin heats up. Just my way of doing it.Aloha,Kokua

9

Hi kokua, I actually have a homemade jig that I use for the same purpose. Easy to make out of wood, but I just used fiberglass. Your method is great and ensures your box being straight and cavity dimension. Unfortunately most production guys just tape them off and set ‘em in. Cleanly cut hole get’s the fin pretty straight most of the time. I’ll try and post up a pic of my jig tomorrow or sumpin’…

10

Everything I know about installing a center fin Channel is from Swaylock’s. I like what Lokbox has said so far. I have a home made router jig from Swaylock’s posts that works great. A little strip of glass in the hole and some filler/fiber mix and were “Good to go”…Make sure you sand the box before install or wipe it down real good with Acetone. Those tabs on Fin Unlimited boxes are really cool.

So…

What about center fin boxes with out the cool little tabs??? Any takers???

Thanks

Ray

11

  1. make your self a jig, no matter what power tool you have to cut slots for boxes. I have a nifty home-made mahogany ply two-piece fro Ofishl’s, another for Futures, a single-piece for the long FU, and another single for the shorty FU.

  2. Make the jig and slot you cut a snug fit. This minimizes the amount of resin you use to stick the box in, which cuts waste, and it reduces the chance you’ll melt foam or the box First box I ever set was melted in by too-fast resin. Bad thing.

  3. Dunno why FU wants glass around the side of their box. The idea that glass cloth or chopped fiber strengthens the install IS A MYTH. The install strength (how difficult it is to pull out) is ONLY dependent on the bond between (a) the resin and on one side the box, and (b) the bond between resin and the foam. Might someone may disprove this and I’ll learn something…?

  4. It’s easy to see the FU boxes go on the sanded hotcoat, than the little tabs or whatchamacallits get sanded off.

  5. I use a big old fin in the FU box to ensure it goes in straight and vertical BECAUSE… sometimes the bottom isn’t flat (vee or concave) and the router follows that to some extent. Thus the tab across the center of the box gets cut off early in the game. Another reason to use a wide jig that “averages” across the bottom. When you do this you’ll appreciate a snug fit cuz there won’t be a lot of resin flowing around, and possibly into the box. You really don’t want that and I tape them closed to prevent it. Don’t trust myself to do a really clean sanitary install.

12

“Dunno why FU wants glass around the side of their box. The idea that glass cloth or chopped fiber strengthens the install IS A MYTH”

Not true. Anytime you cut a hole into a surfboard, and don’t line it with glass, you risk seperation of the box from the edge of the hole when the board flexes and/or the fin loads the box side to side. Forget the chopped fiber that does nothing at all. That 10.5 box does not flex. Neither does their 8.5 box. But your board does. While I agree with the whole tight rout thing, that only applies to smaller boxes like Futures or Lokbox that run a 6" fin max…the FU box can have a fin as big as 12" in it but the box is only 1" deep. Doesn’t work on paper. Go ahead and cut that corner by not using glass (should save you a whopping 5 minutes), and you’ll be repairing that box down the road. Especially if you let a beginner surfer ride it up onto the sand. Want to guarantee that your FU box NEVER breaks? Put it in with glass around it…then after the board is sanded come back and cap over it with a piece of 6 ounce, and have a good nites sleep. Cheers

13

Bookmarked thread!

Thanks JJR

14

I would tend to agree with Lokbox on this one.

I recently repaired a nice Harbor 8’ single fin for a friend of mine who had an encounter with a rock while in Scotland. The fin was ripped right out of the box, which had a big chunk taken out of it, but there were only the smallest of hairline cracks in the bottom glass near the front edge of the box.

It had been installed with glass around the box (in the hole) as well as a patch over. I did the same thing with the new one I put in, and can only hope that it would stand up to a hit as well as that.

15

Great thread. I just want to recap to make sure I understand this (I’m doing my first box install—actually first surfboard, glassing and all):

  1. Laminate bottom (in my case 6oz)

  2. Laminate top (in my case 1 4oz then a 6oz)

  3. Hotcoat top

  4. Hotcoat bottom

  5. THEN route my slot (I’m using the 8.5" FU box on a 6-0 single fin)

  6. Fill the whole (1/3 full?) with resin. My board will be yellow pigment—should I use yellow pigmented resin to fill the hole to match the rest of the board?

  7. Wrap a layer of 6oz cloth around the box and push it into the hole.

  8. Let the resin set.

  9. Sand off the lip and the tabs off the box.

  10. Begin sanding process of rest of board.

So one question: Everyone says to put a 6oz patch (or two) over the box. When in this process would this get done? Would you put it over the hotcoat? Doesn’t seem right, but what do I know, it’s my first board.

I’m just trying to make this come out the best possible. I got a few pennies invested for it to come out crappy.

Thanks for the help!

Mark

16

Forgot a step:

  1. Surf!
17
Quote:

Great thread. I just want to recap to make sure I understand this (I’m doing my first box install—actually first surfboard, glassing and all):

  1. Laminate bottom (in my case 6oz)

  2. Laminate top (in my case 1 4oz then a 6oz)

  3. Hotcoat top

  4. Hotcoat bottom

  5. THEN route my slot (I’m using the 8.5" FU box on a 6-0 single fin)

  6. Fill the whole (1/3 full?) with resin. My board will be yellow pigment—should I use yellow pigmented resin to fill the hole to match the rest of the board?

  7. Wrap a layer of 6oz cloth around the box and push it into the hole.

  8. Let the resin set.

  9. Sand off the lip and the tabs off the box.

  10. Begin sanding process of rest of board.

So one question: Everyone says to put a 6oz patch (or two) over the box. When in this process would this get done? Would you put it over the hotcoat? Doesn’t seem right, but what do I know, it’s my first board.

I’m just trying to make this come out the best possible. I got a few pennies invested for it to come out crappy.

Thanks for the help!

Mark

You can use whatever color pigment you like. Most use white as the standard color, but these days with all the colored glassing coming back I see all different colors. Your spot on with your steps dreaming of indo, and your fiberglass patch (cap) that goes over the box would be applied after sanding and before glossing. You have to hotcoat this patch, then sand/feather it in flat then gloss the bottom. I prefer to use a grider with 50 grit to take down the rim of the box and switch to a medium pad with 60 or 80 when I get down to just hitting the hotcoat around the edges of the box. The grinder with 50 grit shaves the rim down fast and cold, whereas a sanding machine and a soft(er) pad could heat up the area where the box meets the board and that’s the last thing you want. Cheers

18

Thanks Lokbox. Sounds good.

So after I sand/grind the lip off the box, I would tape off the cavity, and then put on the patch of 6oz. So I guess I would lam it, then hotcoat it?

Also, I wasn’t planning on doing a gloss coat, and it’s not covered in Glassing 101 — do i do it the same as the hotcoat?

19

Correct. You tape it off, but make sure to hotcoat it right away within 5 or 10 minutes, then a few minutes after the hotcoat gells, you use a razor blade and cut the tape back out cleanly right on the edge of the tape. Wait too long and you won’t be able to cut it. Once you’ve feathered in your patch, smooth it to 120 grit, then just gloss the patch(I use hotcoat resin) and overlap the edge of the patch with your resin by maybe an inch or 2 past your feather line. Let it dry for a good few hours (unless your using suncure) and that edge will blend in and disappear with some 220, then to whatever grit you desire to finish.

20

Thanks. Sorry for my ignorance, I just need to get one thing clear: the way you’re describing it, it sounds like I only put hotcoat over the fiberglass patch, not laminating resin THEN a small hotcoat. Which is correct?