Glass ons vs. Fin Box

i’m still working on my first board, i’m basically done shaping and i’m just waiting until i have enough money to glass it

What is easier to do? A big glass on single fin or a fin box for a single fin.

This is a 9’2" board and it’s my first board.

Thanks for any suggestions and advice.

unless you already know exactly what fin will work best on the board, and where you want it placed…do a box.

The only time you don’t want to use a box is if you don’t have enough tail thickness on a LB. Place it about 7" back or so depending on the thickness.

Go with the box.

Fixed fins perform better than the same fin in a box, but are a pain if the fin needs to be replaced or if you travel with the board.

Putting a box in is way quicker and easier than getting glass ons perfect, you can play with the fin position, use different fins and removing them makes travel less traumatic.

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The only time you don't want to use a box is if you don't have enough tail thickness on a LB. Place it about 7" back or so depending on the thickness.

Aloha Pete

I hope you don’t mind my clarification… but… it is actually ok to put boxes in boards even if the box comes through the deck.

If one prefers a box it must always be put in the correct location for proper fin/board function and as such, it might wind up coming through onto the deck on thinner boards.

Of course, if it goes through, one should put some glass over the spot after sanding. And maybe a logo laminate or some other cosmetic cover up.

If the tail is really thin, one might even have to modify the fin base a tad or run a rear tabbed fin. Or in an extreme case abandon the use of a box all together, as you noted.

Good luck on your new board Barrel!

Although I truely believe everyone should glass on fins early in their building career, simply for the experience and to see how they ride (around here you can’t even buy a boards without boxes or plugs), you’ll want a box for the versitility.

Although I have to say I prefer glass-ons for big, old school logs, retro fish, and even some “performance” shortboards if they’re designed for a specific break.

So make your next board an old school fish and do some plywood glass-ons… you’ll dig it!

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Aloha Pete

I hope you don’t mind my clarification… but… it is actually ok to put boxes in boards even if the box comes through the deck.

If one prefers a box it must always be put in the correct location for proper fin/board function and as such, it might wind up coming through onto the deck on thinner boards.

Of course, if it goes through, one should put some glass over the spot after sanding. And maybe a logo laminate or some other cosmetic cover up.

    I'm not normally compelled to reply to other peoples advice, but I would NOT recommend fitting a finbox to a thin tailed Longboard through the deck and then just patch it up!  The deck of the board, especially in the tail takes a lot of abuse and pressure. Apart from destroying the sprayed design or resin tint which you've put so much work into, going through the deck will destroy the integrity of the deck glasswork, resulting in deck compression and cave in. There is no 'one perfect location' for a fin box, as it (the performance of the board, and the customers prefereded position) is the result of too many other factors. Eg: ability of the rider and the surfing style. As well as size, positin and style of fin. I have customers who like the rear of the fin box to be 8" from the tail, some customers more. I used to set mine 5" from the tail but now I have gone glass on, and the rear of the base of the fin is 4" from the tail, and all these factors can and will change with different fins too.   

 If you don't know where you like to position you fin, or just want to be able to adjust your fin position (and therefore needing a fin box) but do have a thin tail, all you need to do is measure the tail thickness and only set the box into the board (as normal) to the depth you need, and sand off the excess during the filler coat sanding process.  If the tail is real thin, you will need to do it another way. You need to sand a bit off the bottom of the fin box (the side which goes into the board) and a bit off the top (the side which is exposed, where the fin slots in), otherwise if all the thickness is sanded off the top, the area between the top of the fin box and the screw slide channel will be too thin for the fin to tighten up. 

There is really no need for the tail of a longboard to be so thin that you physically can't fit a fin box.  If your experienced enough to want to go so thin in a tail of a Longboard, then you'd also be experienced enough to know where you like your fin, therefore fitting a glass on fin. 

A glassed on fin on a longboards seems to give a more powerfull turns, and seems to be smoother. I believe the reason to be because there is no movement between the fin box and the fin, like the fin box system.

If you know exactly where you like your fin and the style of fin, go glass on, BUT if you 're not sure or like the freedom of adjustment or ability to change fins, go with a fin box. 



I believe this forum is to exchange helpfull and beneficial information and techniques in board building. Not to offer 'patch up' and 'cover up' techniques to beginners .Whether it's between experienced craftsmen or beginners to boardbuilding. I hope I haven't offended 'BB' with my reply to his advice.   

NINEFOOTSIX

okay, thank you for all the help, i’m gonna put in a box

next question …

can anybody point me in the direction of some really good instructions to putting in a box?

any instructions on how to do it without a router? is it impossible to do it without a router?

Thanks a lot

Hey Barrel: is that you from surfline?

check out this site, (once again) http://www.surfersteve.com/fins.htm for instructions on installing a fin box with just a hand drill. or without a drill if you dont have that. does your board have a stringer?

Barrel, Take your board to a glassing house and get it routed. I assume that you’re doing it after glassing, and you don’t want to risk all of your hard work. The archives have lots of info on glassing the box in. As you progress, get a cheap router and make some templates out of plywood. Putting in a 10" box with a drill or dremel can be done, but I can’t recommend it. Cutting into stringers is a lot harder than it seems, and you need a very flat bottom slot to help you align the box to keep the fin true vertical.

Bill, your input is always appreciated and respected. Since this is his first board, thru-deck boxes without a router or much glassing experience didn’t seem like a good option. However, thru-deck boxes do work on thin tails if they’re needed. My opinion is that cutting 90% or more of the stringer away for a box on a thin-tailed board is asking for a break right across the front of the box. I’ve repaired many performance LB’s snapped like this. Boxes can be reinforced, but even changing a glass-on 3 times would be an easier task.

i did glass ons for my first board because i didnt want to spend a lot of money on a poorly shaped board. and with time and patience i think they came out ok for the first time. im happy with them:

yes they were difficult to get right, but i didnt want to deal with power tools and such as well as the high price tag of fin boxes on my first board. my next one i will probably use boxes though.

good luck!

Aloha 9’6

I assume by the hint of edge in your response to my post above, that you felt my advice was misguided. No problem, you are certainly entitled to your opinion. But lets see if I can expand on my comments such that they will make more sense to you.

I didn’t flippantly advise patching the deck, where the fin box routs through, nor is it some rank amateur solution to an unheard of issue. Since the fin box does rout through sometimes, either on purpose or by accident, one does need to glass over the spot to re-establish the integrity of the glass job in that area. And since most, beginners and even experts, who build boards will run into this occurrence sometime in their board building life, it didn’t seem irresponsible or a particularly bad idea to mention that patching it would be a good idea as opposed to not patching the rout through.

As you noted, the deck can take a lot of abuse, especially where feet stomp around on it. But generally on longer boards (which was the kind of board Barrel was building), with a fin box, the tail end of that box which might rout through, will likely be quite a bit further back then anyone is likely to be stomping on with any consequential regularity.

Additionally, this area once patched over with a couple layers of glass would not be weaker as you argued but rather in fact, much stronger! Including the box, which will now be well connected to the deck. Hardly the circumstances that would lead to, “deck compression and cave in” which you so confidently predicted. Truth is, rather the opposite will be true.

Depending on the deck color work or design, surely routing into it might screw it up as you mentioned. But that also depends a great deal on the skill of the craftsman doing the routing and cover up. And of course the customers sense of what looks good. Sort of an, “eye of the beholder” kind of issue. Those who have been making boards long enough (like 45 years or so) will testify that many “classic” resin, color work designs, from time past were actually created, simply to cosmetically cover up problems in the underlying foam or glass jobs. Wise board builders often have laminates made in various sizes to help deal with those occasional and necessary cover-ups. My hat is off to you 9’6 if your workmanship is so consistently perfect that you never have a need for such amateurish solutions.

I recall one day about 15 years ago when we had a typical bunch of laminated boards in the works at ProGlass when they burned the cane fields around the factory. A new hotcoater and rebellious character had decided, without asking, that he would remove the filters on the air intakes to the laminating and hotcoat areas. Instantly all the boards in the room were covered with tiny black ashes from the burning cane. Dozens of boards were covered with hundreds of small black specks that when you touched them simply turned to unmovable dust smudges stuck on the tacky lamination surfaces.

After hotcoating and sanding, we did some simple yet very tedious and creative pen work of small spirals, squares, triangles, stars, etc, etc to cover up and detract from the smudges. It was a huge burdensome task of many days and we were all thanking God that it was over! When…. Low and behold, the boards hit the retail racks and orders began pouring in for custom boards with exactly that cool new look we had created! Beauty is surely in the eye of the beholder!

You said, “There is no ‘one perfect location’ for a fin box” like as though I had said it. But I never said that there was “one perfect location” for a fin box. Those were your words not mine! Please don’t put words in my mouth. I only said that a box “must always be put in the correct location for proper fin/board function” Simply meaning that… If one is going to use a box of a given size, they are going to determine their preferred location to set that box in and that location is more important to the overall purpose and function of the board then whether or not one has to rout through the deck to achieve it. I certainly agree that there are many variables that can effect that “correct location” and it won’t necessarily be the same for everyone but that’s why we each have the freedom to determine that location and then place the box were we or our customer’s feel is best. Just like Barrel is also going to have to do soon.

If the deck glass is so sacred to you 9’6, that you feel it is terribly wrong to tamper with it, that’s terrific! More power too you. Enjoy the freedom to choose…. as will I and everyone else who makes and rides boards. I hope that is ok with you.

Sanding a bit off the bottom of the box is a reasonable suggestion. I wasn’t intending to provide every detail involved in the installation of a fin box. I like to leave room for others to add a few points too. Which I am glad you have decided to do. When removing some of the bottom of the box, I typically only do the tail end of the box and do it at an angle that compliments the deck. But sometimes that is not enough and the box will still rout through. Lessening the depth of the box is generally not a good idea for 2 reasons.

#1. The less vertical surface area and therefore contact with the foam there is (as in depth) the weaker the installation will be. Vertical surface or depth is necessary to prevent the box from flopping over sideways under high lateral fin stress. This was especially common in early sailboard fin box installations and can still be for surfboards, in powerful surf like Hawaii.

#2. Years ago Bill Bahne briefed me on the (original) design of the Fins Unlimited fin box system it relies on a slight taper in the sides of the fin slot. 2 degrees if I recall correctly. Fins are also supposed to be milled with the same taper so that when they are inserted in the box and began to be pulled down by the fin screw, these tapers merge and cause the fin to engage tighter in the box the more the screw pulls it in until the top of the screw tab or screw head becomes flush with the top of the box about the same time the base of the fin hits the bottom of the box. Many fins made for these boxes don’t have these tapers or the correct measurement to “fit” in the box properly. Removing any amount off the top of the box not only lessens the amount of surface area mentioned above but it also lessens the very important amount of tapered contact surface that the fin needs to tighten properly in the box. Like you also noted it can leave the fin insecure in the box. Especially since the wider part of the fins taper is at the top that must engage the highest top point in the box. Which if removed won’t be there to secure the fin! Lastly, on forward tabbed fins, it will leave it’s rather square forward edge and screw head, sticking up into the water flow, unless it is ground down at least as much as the top of the box has been shortened. This can severely weaken the screw tab which is a vulnerable break away area under the best of circumstances.

I find it amusing that you have determined for us all that there is no reason to have tails too thin for a fin box! I can think of a dozen reasons and hundreds of successful boards over the decades that have proved your confident statement to be quite wrong. Once again, this is much better left for everyone to choose on their own as they see fit in each circumstance.

You said, “If your experienced enough to want to go so thin in a tail of a Longboard, then you’d also be experienced enough to know where you like your fin, therefore fitting a glass on fin.” I don’t think there is any particular connection between those who might shape thin tails and those who know precisely where their fins should go. While I agree that most boards aren’t going to be so thin that fin boxes will pop through. But be it shaper error, beginners bad luck or chosen thin by calculated design, there is occasional need or circumstance where the tail will be thinner then the box and as such the box routing through the deck might be the outcome. My point was simply that it was completely ok, not to panic over it, and that there were simple ways to deal with it that wouldn’t detract from the integrity or jeopardize the proper function of the fin system and would in fact, even strengthen the installation. In the end, leaving nothing more then a small cosmetic cover up to do, if one so desired. Personally I find the Clark Foam stickers perfectly suited for this purpose!

You said, “I believe this forum is to exchange helpfull and beneficial information and techniques in board building. Not to offer ‘patch up’ and ‘cover up’ techniques to beginners”. Many believe this forum to be many things and in that, I suppose you have every right to choose what you think it is for also. You apparently think that it is not for instructing beginners in how to “patch up” or in“cover up” techniques. Well…… 9’6, when and where would you suggest that beginners learn about these things?? And who else but beginners, are going to be most in need of understanding these techniques?? How about maybe you leave it up to those learning to decide what they learn, when they learn it or what instructions they approve of. Share all the wisdom and techniques you have in your magic bag and do it as often as you like. But don’t discourage others from sharing their tips and techniques, simply because your limited view of things, doesn’t allow for approval of their advice.

Finally 9’6, do know that you haven’t offended me. Nor should you be offended by my comments in return to your comments. And hopefully we will have some other great discussions about surfboard building and design someday.

As you may have gathered, surfboard building is not my religion and nothing in it is sacred to me. It is simply my primary craft and interest among many. In which every issue and circumstance requires clear, unencumbered thinking and experience to creatively resolve the myriad of unique and mystifying problems and objectives typical of all hand made products designed to function at the highest levels of performance.

As I have said many times before, somewhat tongue in cheek……”the difference between good surfboard makers and bad ones is the quality of their cover-ups”.

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you need a very flat bottom slot to help you align the box to keep the fin true vertical.

I don’t mean to be contentious Pete. But on a Fins unlimited box the top tabs are what is supposed to level the box and set its depth, not the squareness of the bottom of the routed hole. If the box was supposed to touch the bottom of the hole it would nulify the effect of the tabs and there would be no need for them to have been molded on to the box in the first place. The box should hang in the hole from the tabs with the bottom of the box, clearing the bottom of the hole just enough to have the least amount of resin in the gap yet not touch.

Maybe you know this, but the original boxes didn’t have tabs and a tight fit side to side and a square bottom was how many established a box square to the bottom. I never trusted this method and always set the boxes with a fin in them to insure they were square.

Bill, your input is always appreciated and respected. Since this is his first board, thru-deck boxes without a router or much glassing experience didn’t seem like a good option.

I understand Pete, but when I commented, I didn’t know Barrel didn’t have access to a router. And while Barrel’s issues were a concern, I was thinking beyond him when I responed to your thin tail comment. I didn’t know how thin Barrel’s tail was but I didn’t want people to generally think that routing through the deck was so bad that they would be inclined to put the box in the wrong spot rather than rout through the deck.

However, thru-deck boxes do work on thin tails if they’re needed. My opinion is that cutting 90% or more of the stringer away for a box on a thin-tailed board is asking for a break right across the front of the box. I’ve repaired many performance LB’s snapped like this. Boxes can be reinforced, but even changing a glass-on 3 times would be an easier task.

I think weakness in thin tailed boards with boxes, has everything to do with the thickness (beam theory) or rather lack of thickness and change in flex. The stringer is inconsequential once it is down around 3/4" - 1/2" thick. A typical 2 3/4" board will have about a 1 3/4" tail at 12" up. So cut a 1"+ hole for a 10" box and you can quickly see that most boards don’t have much stinger left under the box anyway.

The rapid reduction and change in flex beginning or ending in front of the box depending on how you see it, and the stress riser created by the change in materials from a wood stringer to a plastic box, is way more than the small amount of remaining stringer under the box can reasonably offset. Plus the stringer left is on the deck side and the fragile point is on the bottom skin at the front of the box.

This was a huge problem in sailboards and they were much thicker. As you may recall “woodies” were added to each side of the box extending beyond the box and overlapping the stringer on each end. These were not hard to install, nor is capping the box with some cloth to lessen the effect of the stress riser and lessen the chances of the board cracking or breaking in front of the box.

Just to be clear, I think glass ons are superior, assuming you don’t need adjustability or easy removal. But installing them and finishing them out, I think, is harder then installing boxes and reinforcing them a bit if need be.

But I understand your points and they are well made. Hopefully, Barrel and others will find some value in our discussions.

Pete I just realized that your in Dana Point. My younger daughter just moved over there.

Bill,

Some great information there, thanks for sharing it.

Paul

yes it’s me … you caught me

I saw the stuff that surfer steve wrote, but I figured i could find something on this site with pictures. The more info the better!

I’ve been doing some searching and i think i’ll just cut it out by hand, I haven’t used a power tool yet so why should I now? I don’t work well with power tools.

Thanks for the input though, looks like you did a good job glassing the fins. I’m proud that you chose to do it the home depot way … you’re braver then me.

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Hey Barrel: is that you from surfline?

check out this site, (once again) http://www.surfersteve.com/fins.htm for instructions on installing a fin box with just a hand drill. or without a drill if you dont have that. does your board have a stringer?

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Thanks Paul!

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Bill,

Some great information there, thanks for sharing it.

Paul