cutting cloth for swallow tail?

Folk’s - I’m going to be glassing my swallow tail and want clear deck, pin lines and a single color on bottom (resin color). My qquestion is: how do I want to cut the cloth so that I get a clean even cut lap for a swallow tail? TiA for help! I think I’m going w a opaque turquoise light blue…

That’s a good question Jim and I was typing the exact same one when I saw you already did :),

Being in the process of building a 5"5 Lis inspired, I checked the archives, but all the photos are gone, so explanations without photos can be pretty confusing on this specific task, I guess we just need to see one way of doing it.



I’ll tell what I do. I don’t lap inside the crack. Either on the top or bottom. I cut the glass flush with the inside of the crack. Tape and lam as usual. When I hotcoat the bottom I put roving around the halo of the crack. Kind of like a fin halo. Clean it all up. Flip it over and make patches that fit inside the crack where the glass didn’t overlap into the crack. Get it all nice and smooth. Usually have to ‘fix’ my f-ups in there at this time, too. Hotcoat the deck.  Mike

Folk’s - I am trying to figure out how not to get a blank spot by the buttcrack once I do my colored cutlap…do I want a upside spade type thing? Well, lap da sides first, and then bring over the center chunk? Sorry, but I’m a bit lost? Mike- I might just try what ur saying bcuz I cant figure this out…perhaps when I come over we can figure it out? Anyone.

good luck on your Fish! One thing I can say is: get your outline lined up to get your rocker setup where you get the rocker #s setup right…and ur off to a good start! Turn ur rails over nicely, and the fish tail cut out is a --bit**! Do urself a favor and buy the microround rasp from foam ez at the very least…trust me, it helps!!!

I might have to invest in a glassing vid?or ask a glasser for a tip? I really am bent on hopefully doin a cut lap w color/ clear deck! Any tips would be MUCH APPRECIATED!

Hi Jim. With my method or the method I tried to describe the butt crack area on the deck will be clear.  The colored laps will lap up onto the deck on the rails. Use patches with clear resin to fill in the missed spots in the crack. Mike

I see…an Idea I’m thinking might work - would be to cut the part inside crotch a bit longer ( to tape line), also to cover the cut laps on rails…we’ll have to set it up first. I’m thinking it should work?

The game plan is to have a even 2" boarder around a perimeter if you will…I’m pretty we’ll have to tape and mask the deck off …prob use painters paper and whatever…I think whatever we do, we gotta be sure it meets the tape line I think?

I do know one thing, I want a shot of Tequila before we start! Lol. Thanks for your .02

I dunno, but something tells me that I’m going to have to cut a center piece to over lap the rail laps…but hit has to line up w the side cut laps…I suppose if it aint perfect, the pin lines should hide it! Lol

Thanks for the advice Shapaholic, the shape is pretty much done here, just need to finish the foil on the tail. It went pretty smoothly for a first Fish,even tho I am not expecting my board to be the best fish ever made, I am still happy with the result so far, will post some photos when I’ll be done with the shape.


Did you consider doing a foam stain on your board? And then glass it clear? It could help having a clean color job and then a classic glass job without having to deal with colors in the lam + cutlap that seems to be a little ambitious for a first glass job, I am not saying you cannot do it tho;)




to foil tail out on my Fish I just took a surform to trim the chunky edges down from inside out in crotch (deck side)…take care NOT to chew into the center…and take care towards the tips…be very light handed! Take ur drywall sanding sponge to shape it sum…finishing touches w 150 drywall sanding screen…take it to the crotch (inside out)… prop the tail up off da stand and look at the tail tips on top! Make sure it looks even…sand w sponge to even it out…hope this keep in mind, a fish is a crude animal! It’s a simple design; parallel outline, flat deck, low fuller rails, a smooth low rocker, a moderate accelerated tail rocker…not too soft rails…harder in back behind fins…softer a bit in front of wp, goin back to thin out nose…eagle beak nose. Atleast that’s what I think. I could be off a bit…

I don’t want a foam stain, but rather a cut lap w color. Fyi -I’ve done a clear glass job before - which was kinda heavy… I geuss I’m bent on doin me a clear deck, colored cut lap…not sure if that’s the right term? I know i should probably do a simple clear job, but it’s not what I want. Im think n if I get the right cuts w cloth - that’s probably all it would take.T c

1.0 Tape off the butt perimeter just like the rails. Lap what you can from the bottom and foam stain the rest. Cut along the tape line. Cover later with a clear patch and clear deck lam.

2.0  Tape off the butt perimeter just like the rails. Make diaper patches and stick them in the crotch when you fold over the bottom laps.  Use your colored lam resin to glue it all together just like the rails. Cut along the tape line.

Practice making the diaper patches until you get the shape and size that will fill the gap between your bottom laps.  Varies with the size and shape of the butt and crack.  If you do item 2.0 take the time to smooth out all the inevitable lumps, folds and weirdness around the diaper or else you will increase your chances of sand-throughs.

A diaper patch looks like an hour-glass with the narrow part going in the crack…

I dont have pics of the process but I’ll try to explain the way I do it as best as I can. Assuming you know the basic steps of a normal glass job. Tape off deck where you want the color lap to be. Flip and lay out cloth on bottom as usual. First cut out your rail lap length so it will lap over your taped off line on deck. Make sure you don’t cut it short. Once you have your rails cut and have cut your nose cloth proper now comes the tail. Three cuts is what you’re going to do. First is in center where crack is. Cut all the way to the stringer. Depending on how the crack is near the stringer (round or V ) you may need to make small cuts at either side of stringer to get the cloth to rap around correctly. Other two cuts are at the tips of the tail. Now take your hand and rap one side of the crack cloth around and make sure it goes past the lap line. Cut off the excess where the crack cloth meets the rail so you dont have it all layered up. There will be a triangle shape where the cloth doesnt cover closer to the stringer. You have to take a scrap piece of cloth and cut to the shape of that area making sure its also past the lap line. When you get to the tail when glassing you’re going to add this triangle shape piece to that area by hand and smear resin to wet out. The key is to get all cloth wet out and make sure any exposed foam gets colored. Even if you dont have cloth covering in small spots due to bad cuts, make sure you stain those areas with your resin. You can go back and add cloth with either excess colored resin or clear resin like doing a ding repair. If you’re doing a single color and not a resin swirl you can save a little of the colored resin for that area and lam it on after the bottom is tacky. You would just flip the board over and glass it on. I have done both ways. Now let it cure to just past tacky to cut the lap. If its too tacky it’ll just pull the cloth when you go to cut and will gum up your razor. You want it to sound like a zipper when cutting the line. I wont go into detail on cutting line here. Im just explaining the tail issue. As for the  raised lap edge, there’s many ways to deal with that. I normally us a file and knock down the lip. Some people use a thimble or hard roller to press into foam. Do not baste with resin, it will mess up your color lap if you are also coloring the deck. If not then baste with clear sanding resin and sand the lap when cured. Now lay out first layer on deck cut to apex all around rails and tail. Next lay the second layer down and make sure its past the tail a bit to allow positioning for the crack. I position the cloth at tail with slack in the middle. Its not tight across from tip to tip. I make the center droop down to get as much coverage as possible before I cut. If you are looking at eye level with the tail think of the shape of a " M". The center of the M where it goes down being the cloth over the crack. Now cut the center to the stringer and then cut the tail tips and so on to fit the exposed areas. Then cut rail laps after dealing with the tail. Once the deck is glassed you can go back and resin a wedgie piece in the crack with either colored resin or clear depending on how well you did. If you plan on doing a colored deck, just repeat the bottom process of taping off the line first then lam. I hope this helps some. It took me a couple goofs to get it right.

Yes, either of the methods sound like it’ll do it. That said, I don’t care for foam stain at all…it just doesn’t do it for me. I like that good old fashioned quality look of a proper done cut lap resin tint job… it’s not too hard to realize it after seeing the pros boards sitting on the glass n stands drying! It’s a site
I can’t get out of my head! Bluefin - I am thinking a similar color of your fish, but a bit lighter, and opaque…a part of me tells me to swirl resin around to hide any blemishes the etc…I’ll jot this stuff down, drink a beer and go for it!gentlemen - THANKS AGAIN!!- Jim

I just re-read what you said - LeeV , and it sounds like a EXCELLENT way to get the crack chunk where it goes blank w out color to meet up w side rail cut laps…thanks MUCH! Foam stain is cool and all, and I know ur showing options…I dunno, but I like how the resin color looks so much nicer. But then again, ive seen sum excellent jobs w paint or foam stain…t c

thanks MUCH -Bluefin! And nice looking boards there! I will try this stuff out -you gentlemen shared! I cant wait to get done to hopefully catch south swells hitting mid August! :slight_smile: t c --Jim

Mr. Shapa,

I can appreciate you wanting a pretty glass job, but I’m just gonna throw out that if this is your first time glassing - or first time in a long time - you may want to consider sticking with a clear glass job.  Doing a proper colored lam on a fish is not a trivial matter.  Especially if it’s just tinted.  (Opaque would be slightly more forgiving.)

There’s a reason people just paint their blank and glass clear.

Just my 2 cents; wish you success with whatever you decide to do.  I know you’ll have fun.

Kind regards,


Newschoolblue - ty for the headsup! But I’m going ahead w opaque color lap job. Also, the board is a ‘test r’ , and whatever - so it doesn’t have to be perfect. That said, if I can learn something from it - that’ll pave the way for boards to come. My only hope is that my lam is free of a big void…I decided ill tape and mask off the entire deck w plastic if need be.I also have back up, tecate beers! Maybe a few malt beverages also.:stuck_out_tongue: after this board I plan to do a clear board, but paint the foam w pure white latex, and possibly airbrushed perimeter?

The reason for opaque/color is to block out any filler, or blemishes from when my board flew off da stands… I had a few small holes to patch w red devil light weight spackling…

I say go for it. I myself dont like being told I cant or shouldn’t do something cause its too hard. Doing it is how I learn even if I goof it up. The next time will always be better than the first. My first SUP was a 12 footer and also the first time using epoxy. I was told dont do it its too big to start with. I closed my ears and did it anyways. Came out nice. Learned a shit ton. Was nervous as hell too. Good luck with your board.

When are you attacking this glass job??  LeeV doesn’t mean do a foam stain, what they are saying is, when you wrap your lap in the buttcrack,there will be spots the cloth doesn’t hit,in these spots you just spread your colour while your tucking your laps and then patch with clear after it kicks and you have cut your lap.

then sand your clear patches smooth so your deck layer lays nice and flat over it.

Usually when you try doing coloured patches you will see them where they meet the main cloth thats also coloured because you will have a double up of colour.

The clear patch way is the easiest and looks the cleanest, unless one of the pro guys chime in and tell you their secrets.

Unless you do Blue fins way where your lap goes into the buttcrack, which looks nice too ,but from what i gather you are wanting your cutlap to trace your entire swallow tail shape??