757 Fins and experimenting with CoreMat

[scientistblank]

So ever since I’ve seen the 757 online somewhere I wanted to try a pair. After searching I found that RFC had made some, but I’m a cheap industrial design student who has access to fiberglass and the basic knowhow of fiberglass layup so I set off to make my own set.

For the first panel I just decided to do a plain old solid fiber glass panel.

No glass panels around put I have plenty of acrylic panels around, and when waxed they work great.

A nice smooth edged piece of acrylic worked well as a squeegee

Lesson here. Mix more resin then you think you need.

 

So I had this super thin plastic sheating that another student had given me. Tired using it to help releasing the panel…don’t think the polyester resin agreeed with it.

Glueing on my paper templates for cutting, only room for a quad. btw daniel isn’t my name…it’s a friend’s

All cut out. Cut one set of tabs then realized it’d be nice to have the extra surface to clamp to when foiling

 

Foiling with the visual guide of FinFoil that user Hans is kicking ass with. I really like my IFT foiled FCS fins so I decied to do that same with these.

 

Quad Rear that got foiled 80/20

A certain youtube video said that 30 layers of 6oz fiberglass would give me the .25" I needed for the fin tabs…it didn’t…oh well more layers are easy enough to add. Also this lead to the tip of them being pretty damn flexible, since the fin turned out so thin.

Surfed them in my 7’ egg at a beach break that was putting out some 2-4ft consistant rights. Because of how flexible, at least this is my guess, they almost didn’t want to stop turning once they were started. No “snap back”, going to try to add some more layers + maybe some CF to the leading edge and tip (kinda blackstick like). Not too pivoty, certainly not much more than the M5/ GX set that I normally run, but on a 7’ egg I’m not really able to test that too well. Need to get a short board that takes a quad set, luckily just met a classmate who shapes, so I want to learn that as well.

 

Then I decided to expirement with some coremat. Used 20 layers of fb + the coremat.

This picture is at 10 layers put down, the coremat was placed there when I had 5 layers of fiberglass down . There is an extra 10 layers of fb on the tab area to make up for the coremat.

Just wanted to see if there was any difference on flex/ apperance/ layup ease between dead center and offset.

All layed up

I think for a hand layup I need to put some thin extra layers of FB or maybe roving along the edges of the coremat to help the transition.

Figured out via the air bubbles when it curred:(

Have them cut out but not foiled so hopefully they will be ready for this next week/weekend

 

[fins]

… GREAT stuff , mate !

 

  I’m STOKED someone ELSE is making fin panels , too !

 

 A few things I hope will be of use [just a few things I have noticed , tinkering as I have …]

 

 I call them 747’s [ named  after the shape of said [aero]plane’s tail …]

 

If you go to an ‘opportunity shop’  [ do they have the same name in america ? Second hand [ ‘op shops’ ] , here in OZ] … buy a large photo frame , for a few dollars. Make sure it has THICK glass. Why ? So , when you use the ‘paint scraper’ to prise the fibreglass from the pane of glass, you won’t break the glass…

No release agent or sprays of any type will be needed if you…

1. brush on a covering layer of lam resin onto the GLASS pane , prior to laying down any cloth

2. have masked off the outside areas with masking tape [as I see you HAVE done ! ] … only, if you also  make a ‘dam’ with the tape , for the resin to form an ‘edge’ , that the paint scraper will easily slide along. [ eg : Did you see my " panels [fins and art] "  thread ? … Also , my  ‘herbed tint’ thread?]

…like so…

 

I found that the ‘coremat’ stuff was a bit too thick for my liking , and that , when foiled , the edges protruded [ I sealed them with resin , after]. I preferred the ones I made WITHOUT  the mat , as I didn’t seem to save a lot in weight using the mat anyway , after foiling .

WAS it a tint you used ? It looks like a tint , in the little cups …but ,  it almost looks like a solid [pigment] colour you achieved , in the finished panel , yes ?

If you wanted it transparent [tint] , as opposed to opaque [pigment] , you can do that with tint…if you just tint , say , 10 layers , and clear laminate the remaing 25 or so  [ by the way ,  I use at least 33-36 layers of 6oz cloth , for fcs tab thickness ].

 

That written , however …the tab thickness will vary on occassion  , depending on such things as …

 

 what ounce of cloth you are using

  how many layers of fibreglass you lay up , at a time

  how much resin you use

  if you use a roller to lay it up ,

  how HARD you apply pressure to it [the roller]

 

  Okay , I hope this helps , mate ?

   cheers !

      ben    [ the fin tinkerer   ]

 

 

[scientistblank]

Yeah I’m pretty sure I went through your thread.

huh I thought the originals were 747’s for the longboard fins and the 757’s were the thruster and quad fins. Whatever

Yup made a sort of “dam” with the tape, and layed down a layer of resin before anything. The acrylic with just wax releases really good actaully, that’s what I did for the coremat panel, forgot to mention that.

Do you have any sources or just expierence on how much resin should be used for a x by x panel with 6oz clothe for FCS?

Yeah it was transparent tint, I should get some better pictures of it. Maybe I’ll try only tinting a few layers and see how I like the outcome of that versus tinting all. I didn’t bother to hot coat them yet because I know I’d probably be tunning them. But when they are covered in water they look the same as any transparent fin out there.

Next step is playing with CF/Armarid layers and getting some proper Coremat XM (the “hex cored” stuff). My friend said the regular stuff looked like I put a gram cracker in there so I want to make some brown ones with maybe some sparkles to make it look like sugar graham crackers

[hans]

Fantastic fins, well done! You can now start iterating and experimenting. I’m looking forward to see more builds!

This build perfectly illustrates the usage of finFoil that I originally intended.

Great job!

[fins]

" Do you have any sources or just expierence on how much resin should be used for a x by x panel with 6oz clothe for FCS? "

 

hi again !

 

…  I have learnt from   " just " experience , I’m afraid ?!  …no opinions or believe everything wikipaedia or google tells me , for THIS tinkerer !   [ some of the information there is questionable , I think  …the 'youtube ’ tab thickness thing you mentioned , being a case in point . Some people reckon they can get tab thickness with as few as 25 layers [?!] , I never have been able to …I’d like to watch them lay up a panel [? maybe they are using 20oz cloth , or something ??]

  what size was your green tint panel ?

 

  what size are each of  those 747s ?

 

how many layers of fibreglass cloth do you lay up , at a time ?

 

  I don’t know if your cups are measured in mls there [?] ,  but , as a rough guideline …

 

  for , say , a 4 x 6"   to a 5 x 7" panel , I’m using 25mls of resin each time I laminate

 for a 6" x 8" panel , I’ll use around 40mls , per lamination

 for an 8 x 10" panel , I’ll use 50-60mls each lamination .

 

This has been through trial and error , since 1999 [when I tentatively laid up my first fin panel [ I didn’t know ‘Sways’ existed , until someone told me via an email , in 2004. [ And , I never had a computer before then , anyway ! ]

 

 Again , as I said previously , the tab thickness may vary , according to the factors that I listed…

 

Well , I hope this [ and my last reply , also ? ] has helped you  ?

 

  cheers !

 

  ben

[batfische]

I had 747s/757s (I’m not sure which) on a rounded-pintailed quad board a asked about on a different thread previously – a 1982 or earlier Croteau, bought from the old golfball shaped Croteau store on 41st in Santa Cruz – and I remember these fins as being installe with a lot of cant, probably at least 6 degrees on the fronts, and likely at least 8 degrees, and 4-6 degree or more on the trailers, and what I remember is that they were super loose – but not as loose as twins of the period in Santa Cruz, which were slidey as banana peels.  I remember making cutbacks on the 747/757 board in almost random positions on the open face, because the fins were so loose you could do a lot of crazy, nonsensical things.

My own curiosity is about the history of these fins – who came up with them, who used them, and when.

Stretch has a shorty (the one with the Rolling Stones lips & tongue logo) with 747/757 fins above one of his shaping bays, and I think he put a good volume of them in boards back when he was a glasser/fin guy.

I’m dying to make a board like the first one I ever had, the one I mention above, so this is a topic close to my heart.

[fins]

good stuff !

 

  did you ever take photos [and dimensions ] of the board you mentioned ?

[batfische]

fins, not sure who you’re addressing, but if me then sadly no.  That board was stolen or otherwise disappeared from my folks’ back yard many years ago.  I wish it was still around to measure and contemplate.