What do do about a minor delam/bubble

Just noticed a small delaminated spot on a used longboard I picked up a few weeks ago. It’s right next to an old repair job on the rail, so I’m thinking it’s related to that. Rest of the deck looks completely fine. Total delaminated area is maybe the size of a quarter.

This is what it looks like when you press on the delam: https://imgur.com/a/MY8YYCK

This is what the rail repair job looks like: https://imgur.com/a/0AgZ4X7

It appears to be watertight, and the foam underneath feels dry and firm. I don’t care about cosmetics, just want to keep it from spreading. From a bit of research online, I think the options are:

  1. Do nothing and keep an eye on it
  2. Cut the glass out, fill the depression, and reglass.
  3. Drill two holes and inject resin as glue
  4. Drill two holes and inject actual glue (gorilla glue?)

I posted this question on r/surfing and was referred here. Any suggestions on the best move? Thanks!

Ohhhkay, first, stop playing with it, no matter how addictive it is. There’s a story behind that, but not right away

So- pluses and minuses to all of these

Do nothing and keep an eye on it

Cut the glass out, fill the depression, and reglass.

Drill two holes and inject resin as glue

Drill two holes and inject actual glue (gorilla glue?)

The first option really isn’t a bad one, depends on how long you intend to keep the board. Keep it out of the sun.

But then there’s  the second choice, which I’d avoid. There isn’t necessarily any depression in the foam, after all. If you very carefully cut the area out, ideally using a very sharp utility knife held so it’s an angled cut. Fill in carefully, using your choice of resin, resin plus thickener ( Cabosil, Aerosil, sugar, a lot of different things work and I have indeed used a lot of them) maybe by ‘buttering’ the back side of the original glass with your filler goo, stick in the original glass and clamp ( a band clamp or hold down strap applied gently, wax paper as a non-stick barrier) or lightly weight on top to get it flush, sand gently to perfectly flush or slightly concave, glass over the repair with a little light-ish cloth squeegeed ( 3/4 inch or so overlap onto the original glass), feather sand the edges of the new glass, hotcoat to fill the weave, sand, gloss, polish.

You see why I’d avoid it. It’s a lot of work, a lot of time. Done right it’d be strong, durable and nearly invisible. But if I was charging for the job I’d have to charge somewhere north of $100. Maybe well north. You get to the question of ‘is this worth it?’. You might want to, as an exercise in just how well you can do it. Me, I already know how- 

Then we’ve got the injection methods. I’d lean towards using the ‘clear’ Gorilla glue, resin tends to make this translucent area and it’s a lot harder than the original, the jury is still out on whether or not that tends to make more delam around the edges. I wouldn’t just inject it, I’d infuse it, on the one hole you have your injector and on the other you rig a small shop vac or similar, to get all your filler resin or glue in (it’s called ‘infusing’), stop it a couple of times to massage the stuff to the edges of the delam. Again, and especially with the glue I would use a band clamp, wax paper and maybe even a piece of sheet metal to keep things from expanding and making things worse. And again, I’d put some light glass over it and so forth, as above.  .

Good, strong, pretty easy and fairly unobtrusive fix. 

And now the story. You were warned. 

Back when, well, the first twin fins came out. Around the same time were the hollow boards, most were molded with a honeycomb material to stiffen, very much like aircraft construction, but there were some others- 

Hansen made some, foam skins top and bottom, with foam pylons in the main cavity, outside glass conventionally. I have no idea what the details were beyond that, whether or not they glassed it inside, I doubt it.  For equalizing purposes ( to kep it from imploding in cold water) it had this little hole towards the nose which was closed with what looked like the little plastic plug out of a squirt gun.

No idea what they cost, or if they made money on it, the setup must have been expensive. And I didn’t have one, somebody in our circle did, kid we called Lunga Louie for a long forgotten reason. We didn’t like him much. His parents bought him the thing.,And one flat day, we discovered you could do things with it. 

If you took the plug out, you could push the deck and it would ‘exhale’. Okay. You could  put your mouth over the plug hole and really suck out quite a lot of air. Heh-

We didn’t like Lunga very much, as I said. We sucked out quite a lot of air and put a lit cigarrette to the hole and it would take one long inhale, burn up the cigarette like what would happen sharing a smoke in the boy’s room in junior high. That was kinda fun, we thought we might give Lunga’s board cancer. 

But the best was when we discovered that if you thumped the deck, the board would do a really nice smoke ring. You now maybe see why I said don’t play with the delam, we probably thumped that board half to death, blowing smoke rings .

hope that’s of use

doc…

Wow, that is a hilarious story! I’m sitting here picturing these little smoke rings coming out and laughing my ass off.

Thanks so much for the detailed response and breakdown of all the different methods. I had seen the gorilla glue method talked about before on this forum but was skeptical, and most of the comments on my reddit post advised against it without really giving a good reason. You, however, sound like you really know what you are talking about.

I think I’ll go with the gorilla glue method – worst comes to worst I can always take it to a pro and have them cut it out and do a reglass. I’m not sure if I have the necessary equipment to do the infusion like you are talking about, but I’m thinking that instead I might be able to use another syringe over the other hole and pull the plunger out while I inject the glue. Thoughts? And for the clear gorilla glue, are you just talking about this: https://www.amazon.com/Gorilla-Clear-Glue-ounce-Bottle/dp/B074J7XQZT? Anything else I need to know before getting started?

Thanks again, I can see now why I was referred to swaylocks for this question!

Heh- ‘sound like I know’ indeed. On a really good day, maybe, with a following wind  and if the coffee was good .

The equipment to do the job, well, a shop vac and something to seal it a not all that well, a foam rubber washer for instance. Some putty, leftover pizza dough- 

Also, shop vacs can be big and awkward. These, however, are cheap and ridiculously useful for a lot of things. Bucket Head 5 Gal. 1.75-Peak HP Wet/Dry Shop Vacuum Powerhead with Filter Bag and Hose (compatible with 5 Gal. Homer Bucket)-BH0100 - The Home Depot . I find myself using one a lot, clearing drains, coffee grinders, the truck floor, you get the picture. 

I screwed up, what I should have steered you at is what the Gorilla people…I’m assuming they are people, for all I know they’re actually gorillas who do chemistry…now call ‘white’.  though I’d swear they called it ‘clear’ at first. Amazon.com: Gorilla White Waterproof Polyurethane Glue, 2 ounce Bottle, White, (Pack of 1): Home Improvement . It’s a water catalyzed expanding urethane foam adhesive, chemically very similar to surfboard foam,  and the white goes off to a white color like newer foam, while the ‘original’ cures to a pale yellow brown which isn’t a bad match for older, what I call ‘suntanned’ foam. Also handy around the house, loose joints in wood and so on.

There is enough moisture in seacoast air that it can make an opened partial bottle of the glue go off all by itself - ‘water catalysed’ really comes into play here, you get some foam on the top and the rest is unusable. Squeeze it so all the air is out and then use the handy resealable cap it comes with, you have a better shot at keeping it for a while. . 

hope that’s of use

doc…

If it really bothers you; cut out the delam in a symmetric circle.  Use a  50 cent piece or a silver dollar to mark a perfect circle.  Cut the glass with a Stanley knife.  Using resin, glue the piece of glass back down into the hole.  Sand the surrounding area and patch with two pieces of 4 oz. one slightly large than the first layer.  As far as the rail ding goes;  Sand with 150 until it is cleaned up and less noticeable.  Put a couple of pieces of 4 oz. over the ding.  If you don’t knock any chunks out, you won’t need to fill anything.  Hotcoat and sand.  Be careful thru the process not to sand off your pinline.  No reason to create extra work.  Lowel

If it really bothers you;  a Stanley knife. Using  the hole.  Sand two pieces of 4 oz. Sand with 150 until it is 4 oz. knock and sand.  Be your pinline.  No reason to work.

Haha!!

I

ve done a ton of delam repairs and used to chase delams with a razor blade but now just use a trim router. If you have one it will make a cleaner cut and not aggrivate any further delam. 

Awright, a couple of things have come up in this-

First, as I suggested, you want to use a sharp (new) utility blade to cut the old glass free as a single piece, ideally holding the thing at about a 45 degree angle or so so that the piece you cut off is fractionally narrower at the bottom of the cut than at the top.  This way you can reuse the original glass piece and replace it and it looks seamless, invisible.  . 

Any suntanned foam that sticks to the underside, any color in the glass , that’s your color match right there. Likewise, if your blank got painted, that often adheres to the underside of the old cloth. And unless you have the skills of a museum art restorer- and I most definitely do not - it’s the best and pretty much only way to do a repair of an airbrushed color. 

A saw or worse, a router, well, by its nature it removes material when it cuts and leaves a gap. Which makes the repair obvious, which isn’t what you want, you want invisible or as close to it as you can get. A blade doesn’t remove material.

Though I will note that this is why it’s worth going out and spending $2.95 on some new utilty knife blades, older ones with a little rust on them are not only duller (leading to mistakes, slips and injuries - a blade too dull to cut fiberglass still works Just Fine on meat) but in addition any faint rust on an old blade transfers to the edges of your cut, leaving a reddish brown to black scar when you reassemble it. You can, and I have had to after being an idiot and using an old blade, sand or scrape off the rust with the new blade you bought while cursing your own cheapness, but again, that’s removing material, which you want to avoid. It will show.  

Now, as to the shape of the cut. Lets take little side trip into camouflage. And veneering- 

You see, I do some hunting. Deer, ducks and turkeys are part of it. I have my Jungle Jim camo suit, pattern more or less matches the various plants around the places I go, though not many types of game have color vision. But more importantly, this stuff is baggy. It breaks up my shape, and Bambi and Daffy and Tom Turkey, they can definitely pick out shapes. I want to disguise  that shape.

Now, that’s animals. But we are trying to hide something from a human eye. So, we wander into what the people who hunt humans use, and that’s called a Ghillie Suit that orginated with deer stalkers in Scotland, generally a burlap-like fabric with a lot of grass, leaves and suchlike stuck into it, so that you don’t look like much other than a very irregular haystack or clump of foliage. While deer and game birds are pretty fair at picking out regular shapes, humans are really, REALLY good at it. You don’t want to have any geometric shapes in there at all. Nature may be geometric at the micro scale, but it isn’t when you’re standing any distance away. 

On to veneering. Let’s say you made a table, glued down a very thin layer (veneer) of very nice ( and expensive) wood over the cheaper or less desirable wood underlying it. But Uncle Fred got into the brandy and let his cigar fall on it, burning the veneer. Or the sheet of mahogany veneer you bought has a knot in it, you got it cheaper. But it’s right in the middle of the piece you want to use for the table top. You have to patch it somehow.

They make something for that. Two somethings, actually, a matched set of cutters/stamps of very irregular shape, one for the cutout and one for the patch, Or you get cute with a fret saw and after several attempts you have an oddly shaped hole and an oddly shaped precisely matching patch, which you glue up and it’s pretty much invisible, assuming you matched the grain okay (or the equivalent, see ‘why you save the old glass’ above) . The human eye doesn’t pick out the intentionally odd shape. 

This is the sort of thing you want to do when cutting stuff in a repair. Make it an odd shape, so it doesn’t jump out at you, and don’t surround it with a ring or border of filler where your saw or router made some of the original piece into irretrievable dust. 

And ya know what? It’s easier. Faster. And it looks a lot better. 

Funny how often that happens

doc…

As stated above;  A router cut is cleaner.   The all time best ding repair shop on Maui (“Gramps Rockin’ Chair Ding Repair”) used a router to cut out most dings.  But a router bit leaves a gap if you decide to glue down the original piece of glass.  A Roto-Zip is a finer/narrower cut if you can master use of it and don’t burn the glass.  Lately I have been using a “Fein or Oscilating” tool that can be purchased at Harbor Freight for about $30. If the old glass is not too thick, a sharp Stanley knife makes a more accurate cut for a reglue.   It’s a slow process, but you can glue down the old piece with resin and there will be no filler outline.  The pieces of foam that stick to the old glass will go right back into the holes they tore out of, so don’t scrape the old foam off of the piece of glass.  Ok Sammy from alabammy.  You can Troll now.