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fitvit
United Kingdom
94 Posts |
 Posted - 22 May 2016 : 21:44:25
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Before I start hacking into my hull, can someone just confirm that my google led research is right. I'm going to grind the two outlet rings out off the bottom of the hull and remove the valves for the old sea toilet.
Then I'm going to make the two small holes into one large hole, sand down to taper the edges, clean up with acetone, cut 4 overlapping layers of biaxial fibreglass cloth (each layer being 4cm larger than the last) wet each cloth with polyester resin and roller them on one by one, waiting for each layer to dry before doing the other one. Sand down to smooth finish, primer and antifoul?
Then do the same to the hole from the inside of the boat.
jojo 
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stratford4528
United Kingdom
414 Posts |
Posted - 22 May 2016 : 22:34:30
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| What I would do is put 1 flat layer on the inside and let it harden. you then have something to push against when working from the outside |
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fitvit
United Kingdom
94 Posts |
Posted - 22 May 2016 : 23:11:33
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How long does it take for a layer to harden?
jojo
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cliveshep
Thailand
1324 Posts |
Posted - 23 May 2016 : 01:38:22
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In 20 deg ambient temperatures it'll take maybe 15 minutes to stiffen up.
You have the method exactly right except I'd not link the holes, the more of the original hull material you leave intact to bond to the stronger the job.
The other thing is after you've ground down the outside give it a coat of resin to seal all the fibres. You don't actually need to do anything else to it, under the hull it won't need anti-foul, all you need to do is make sure all the work area has a coat of resin over it.
Polyester resin won't stick to acetate tape, so wedging down some hardboard covered in parcel tape (Sellotape) over the holes inside will support the outside work until it stiffens up when you can remove the hardboard and the bricks or whatever you weighted it down with and do the inside which will chemically bond to the still curing outside.
Finally living the dream!
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Edited by - cliveshep on 23 May 2016 01:42:03 |
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df
United Kingdom
5994 Posts |
Posted - 23 May 2016 : 08:14:58
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You can also partially re-activate the original grp with liquid styrene for a better chemical bond, styrene is the solvent used in polyester resin.
I'd be tempted to finish the outside with an epoxy filler as polyester still absorbs some water.
NBAS--The communal colostomy bag of the boating community.
Visit leomagill.co.uk |
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Deano
United Kingdom
1843 Posts |
Posted - 25 May 2016 : 16:50:06
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I'd be tempted to get some "Oh my word" else to do it and go down the pub to drink some beer!!!
But If I had to ..... leave the holes as two.... the sheet of wood on the outside is a good ploy, or you may just end up with a sticky mess on the floor!!!!
Four layers sounds a bight light...... I'd start with a big circle of glass and get progressively smaller, pushing each one into the middle of the first....
I'd also do it all in one go, not waiting for each layer to harden up..... life is too short!!!
Just ensure you get as much air out between the layers and make sure the glass is fully wetted out...... stipple it with a brush..... it goes transparent when fully wet.
Dean - Boating on the Great Ouse.
Freeman 32 "Liberty"
See the photos http://www.flickr.com/photos/54758027@N00/ |
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fitvit
United Kingdom
94 Posts |
Posted - 03 Jun 2016 : 17:19:05
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Do I need something to activate the polyester resin or use it straight out of the tin?
jojo
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Deano
United Kingdom
1843 Posts |
Posted - 03 Jun 2016 : 17:52:44
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Polyester resin is generally sold with "Catalyst" ....usually in a little bottle.
It is mixed with the resin just before you need it.... usually in such a small ratio that it is almost impossible to measure in small quantities..... 1% to 1.75% ....???? How you measure that in a jam jar is anyones guess.... I usually drip about 6 drips in.... then a few more just in case!!
If you overdo it..... it will cure very fast and probably get very hot too, maybe even catching fire!!!! .... it will also be very brittle and make a crap join.
Dean - Boating on the Great Ouse.
Freeman 32 "Liberty"
See the photos http://www.flickr.com/photos/54758027@N00/ |
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fitvit
United Kingdom
94 Posts |
Posted - 03 Jun 2016 : 21:53:23
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Do I need to sand a wider surface area than this to glass the 2 holes or do you think this is big enough. 
jojo
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df
United Kingdom
5994 Posts |
Posted - 03 Jun 2016 : 22:41:12
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I,d clean to a bit bigger than that, you can get a handy catalyst dispenser from east coast fibreglass that gives an acurate measure or find a pipette (1-20ml is a good range and use 100-200ml of resin at a time).
If below 15 degrees use about 3% by volume much warmer drop to 2%, much over 23 degrees go down to 1.5% and youll get about 15-20 minutes working time.
NBAS--The communal colostomy bag of the boating community.
Visit leomagill.co.uk |
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fitvit
United Kingdom
94 Posts |
Posted - 03 Jun 2016 : 23:01:41
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Well this is is what it looked like when I finished this evening. I'm hoping to fibre glass it tomorrow if I can find the "Catalyst' which must be in my spare bedroom somewhere Do you think the surface area needs to be bigger still? Do I need to fibre glass underneath too? I was told by someone at the boat yard today to just 'gel coat' the outer hole? 
jojo
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cliveshep
Thailand
1324 Posts |
Posted - 04 Jun 2016 : 00:47:19
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More than enough, I can't see if you've tapered it at the hole edge but certainly enough spread. The boatyard man is a cowboy to tell you to only glass inside and gel-coat outside, the correct repair is inside and out, sandwiching the existing and bonding both sides through the holes. The gel coat would stay "tacky" anyway - he should know that. It cures when covered, as in a mould.
My comment stands, after cleaning down the repair outside - a gentle sanding if it's a bit "spiky", give it a coat of resin to seal it. You can paint at your discretion, some people don't like seeing light filtering through a translucent resin - it makes them nervous.
As for catalyst - the resin will not go hard without it so do find it as polyester resin is a 2-part mix to cure.
Finally living the dream!
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fitvit
United Kingdom
94 Posts |
Posted - 04 Jun 2016 : 01:09:24
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Yes the edges are tapered. How long after cleaning with acetone can I start classing it?
jojo
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cliveshep
Thailand
1324 Posts |
Posted - 04 Jun 2016 : 07:04:38
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Straight away - acetone evaporates almost instantly.
Finally living the dream!
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fitvit
United Kingdom
94 Posts |
Posted - 04 Jun 2016 : 23:31:07
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Almost there! Ive had my inner beast mode engaged today and pulled a 12 hour shift working on the boat. Ive finally put the window back in using arbmast (horrid stuff) so there's a bit of a clean up job still needed, I got rid of the rest of the yellow gloss and fibreglassed the inside of the holes. I used some sellotape as suggested to make the hammock so even though it looks sunken on the inside it is flat on the outside. I'll have the leave the outer hole until next week. Once the hull side is done, would I paint it with two pack (I've got some for the hull) before it gets antifloulled? 
jojo
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cliveshep
Thailand
1324 Posts |
Posted - 05 Jun 2016 : 01:50:42
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If you do outside while inside is still curing it is a stronger bond - don't prevaricate!
Good job!
Painting it in 2-pack is fine, not necessary but stops you looking at a glowing hole later when it's in the water!
Finally living the dream!
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Topic |
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hole repair confirmation.
