replacing slot gasket....

[chalky]

A recurring thread, but can anyone help? I have just replaced the gasket on 3434 with 50mm mylar and sikaflex 292. It was perfect upto the point of retracting the board. I now have some shedded strips of mylar, a part used tube of glue and a cut finger. What else can I try? Will a sail cloth gasket stick to a plastic hull? Fed up and wanting to go sailing. Sensible offers for a nearly finished Baggy T considered, all it needs is a slot gasket, how hard can that be?

[Not that hard (Guest)]

It’s not, and you were warned about that daft ‘glue’.
 
1) Clean all the sh*t* off, properly.
2) Get new appropriate width Mylar gasket (50mm sound feasible)
3) Mask off the area you’ll be gluing on the hull and Mylar.  You should be gluing up to approx 10mm from the slot in the hull, not right to the edge.  Glue less if you think you can get away with it and still have the gasket stick.  Do not glue right up to the ends of the slot either, about 50mm there.
4) Rough up the hull and gasket with sand paper.
5) Clean area to be glued with acetone.
6) Allow all to dry.
7) Apply decent contact adhesive (Evostick?) (thin layer) to hull and gasket
Remove masking tape.
9) Allow glue to dry
10) Apply gasket to hull.
11) Repeat the other side.
 
Leave the cloth gasket alone, it’s no longer 1982.

[cookie (Guest)]

Having not had the pleasure of having to do a slot gasket for plenty long enough and having used it enough an adhesive sealant like Sikaflex would probably be the first thing I'd go for. It's hardcore enough to stick the flap on a Moth mainfoil so don't see why it cant hold some mylar. It does need a primer though...

 Be careful with contact (evostick) adhesives as the stuff they sell you in BnQ is solvent free and absolutely rubbish. The 'proper' stuff comes in green tins and can generally be bought from your local tool counter.

Daggerboards are lovely.

Cookie

It’s not, and you were warned about that daft ‘glue’.
 
1) Clean all the sh*t* off, properly.
2) Get new appropriate width Mylar gasket (50mm sound feasible)
3) Mask off the area you’ll be gluing on the hull and Mylar.  You should be gluing up to approx 10mm from the slot in the hull, not right to the edge.  Glue less if you think you can get away with it and still have the gasket stick.  Do not glue right up to the ends of the slot either, about 50mm there.
4) Rough up the hull and gasket with sand paper.
5) Clean area to be glued with acetone.
6) Allow all to dry.
7) Apply decent contact adhesive (Evostick?) (thin layer) to hull and gasket
Remove masking tape.
9) Allow glue to dry
10) Apply gasket to hull.
11) Repeat the other side.
 
Leave the cloth gasket alone, it’s no longer 1982.

[cookie (Guest)]

Oh, a PS. Sikaflex does however take a reeeaally long time to go off properly. Count it in days, rather than hours...

[chalky]

Thats the clearest set of instructions I have seen yet and thats pretty much what I did,except the glue was a bit closer to the edge ( 10mm gap would leave next to nothing bonded to the hull, the total width of the keel face is 50mm). The mylar was stuck to the boat like the proverbial to a blanket but it is the tight bend that did the damage. Perhaps a 1982 solution would suit a a boat of that era?
 
Now a dagger board would lovely, I would convert the boat overnight if they were allowed. Double standards allowing fixed or cassette rudders but bannging dagger boards and there varients.

[Jane Wade]

I am reliable informed by a sailmaker that some classes (505s amongst them) still use sail cloth gaskets so maybe not 1982 for them...

[not that hard (Guest)]

If you’ve still got the keels on the boat then the sailcloth probably is the solution. It does really need keelband to hold it on, but if you have a keelband you’re laughing, no glue required.  Fix the front, then tension it with a line to the stern, then fix the edges moving aft.  Cloth gaskets usually have an overlap whereas mylar ones generally don’t.
 
The problem with sikaflex is when you need to do the job again, and you will need to replace a gasket every couple of years.  As you’re about to find out it’s an absolute b********* to get off.
 
The 505 is more early 70s than 80s, could even be 60s I’m not sure, bit before my time.  Proper 505s are sailed by hairy men, with big sideburns and orange stretch suits over kapok lifejackets.  They should not be used as a technology guide, adding a stupid big kite doesn’t make them modern.

 

[chalky]

the boat has never had any banding screwed to the keel therefore someone stuck some mylar to the bottom in a way that worked or it has always been a problem. off to buy some sail cloth and use some more expensive glue. Removing 3 m of glue 10mm wide at a later is not a problem compared with rebuilding the ribbed boat....

[sam293]

dont bother with sailcloth, it wont do as good of a job as mylar does.

just stick it on properly with the right adhesive this time


you should be able to get something called trade grip, a 2 part very stickey glue from your local jewsons / trade supplier

and to prep, key it with 80 grit sandpaper!! then loads of acetone.

apply a fair bit of glue but not too much, and wait till its no longer stickey.

oh and for getting that S**ty sikaflex of, just use a bit of heat first and it should peel of niceley

[Tim Gatti]

Hi John - sorry to read of your problems. N3227's mylar slot gasket is stuck on with 'normal' Evo-Stik' (red tube) which certainly isn't solvent free!
But it sounds like the issue is more about the razor sharp edges of the mylar catching on the centreboard as you retracted it - is that right?  Is that what caused it to shred?
Even the slightest imperfection in the surface of the board can snag the mylar and pull it into the slot and split it - especially when the gasket is new and really stiff and if you are testing it 'dry' i.e. out of the water so without lubrication of any sort.  So it's worth checking for any minor snagging points on the board.
For this reason I always wet the board or, failing that, use a bit of WD40 or Silicone spray to help ease the board back into the slot when I am checking things out in the workshop.
I couldn't possibly comment on the relative virtues of Sikaflex or Evo-Stik - each will have their supporters, but I will say that I don't think you need to go to a sailcloth gasket.
Tim

[chalky]