DIY Cockpit Repairs Help Please

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Stuart Yendle
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DIY Cockpit Repairs Help Please

Post by Stuart Yendle » Tue Jul 26, 2011 6:19 pm

I've recently purchased a Glass Tahe Marine Revel at a reasonable price, some of you might have seen it advertised in Brookbank.

On further inspection the cockpit coaming was a bit creaky and there were some hair line cracks. I was planning on reinforcing them with some cut-offs when I glassed my wooden boat I am building. After a few roles last night it seems the cracks have got worse and the coaming is starting to shift a little.

As a complete novice to the world of fiber glassing I was hoping for some advice. I thought I could buy some carbon Kevlar (I know it's expensive but I only need a small amount, plus it looks quite nice) and reinforce around the inside of the deck where the coaming joins the deck and while I'm at it reinforce the inside hull under the seat. I was then thinking of getting some fiberglass tape to reinforce the outside under the coaming lip where the coaming joins the deck.

Does this sound like a good plan?
Would it be a good idea to add some sealant/adhesive around the cracks prior to glassing?
Do I need to sand down the crack before glassing and with what?
Some advice on what I need/shopping list please and how I go about doing it?

Here is an article on Gnarlydog News blog where he does a similar thing and from what he says it seems to be a common problem? http://gnarlydognews.blogspot.com/2011/ ... blems.html

Pictures of the damage can be found on my blog here: http://seakayaking-stuart.blogspot.com/

Any advice would be great, thanks.

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Mikebelluk
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Re: DIY Cockpit Repairs Help Please

Post by Mikebelluk » Tue Jul 26, 2011 8:19 pm

Urgh.. unfortunately that looks like a well bodged repair Stuart.
I think you're going to have to get a Dremel and grind out a load of the cracked up gelcoat and filler until you get back to solid glass, and then re-glass it with a couple of layers of 2" tape on the inside.
Or you could completely remove the coaming, tidy up all the gack, epoxy it back on and then re-glass it on the inside, and put a nice strip of bias cut Carbon fibre under the coaming on the outside.
M

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Stuart Yendle
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Re: DIY Cockpit Repairs Help Please

Post by Stuart Yendle » Tue Jul 26, 2011 9:04 pm

I think I would completely mess up both those options. Either way I have to get rid of that rough looking stuff under the deck? that's the gel coat and filler is it? Glass fiber wouldn't stick to it is that right? I thought this was going to be so simple. Is there anywhere that does this sort of stuff?

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Re: DIY Cockpit Repairs Help Please

Post by Owen » Tue Jul 26, 2011 9:29 pm

I wouldn't use a dremel, far to harsh, use a knife, remove what loose stuff you can. With the kayak upside down, pore some made up resin onto the cracked area. You want it to run into as much of the cracks as possible, even pull them open if you can. Once that starts to go off, start putting tape over the whole area. Just use glass tape I wouldn't bother with anything else. If the old repair is epoxy then you're better off using epoxy as well otherwise use polyester resin.
Then turn the kayak over and again with a knife clean out the cracks in the gelcoat. Make up some Flowcoat (gelcoat + wax) with some filler and pigment. Use a razor blade to scrape the flowcoat into the cracks so that it's flush with the surface. Use wet and dry then t-cut to finish.

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Noah nig
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Re: DIY Cockpit Repairs Help Please

Post by Noah nig » Tue Jul 26, 2011 10:35 pm

Hi Stuart,
it looks like the coaming has parted company with the deck. The front resin bond fails when spray decks are pulled off.
The back doesn't break because the seat is attached to it.

I had this happen to mine. Tahe Marine were contacted and they offered to repair it or replace the boat, as it was under a year old.

I opted to repair the boat myself, they sent me some resin to do the job.

I carefully cut the coaming off with a hacksaw blade.

I then half glassed on to the coaming a 50mm rim of fibreglass tape. I then used the thickened resin from Tahe Marine to re attach the coaming.

When this was set I then glassed the other half of the tape to the under side of the deck.

To finish off I painted gel coat under the deck, covering it with cling film to get a smoothish finish.
Finally wet and drying it to a smooth finish.

Tested it by lifting the kayak up by the coaming.

Apparently Tahe Marine have changed the resin mix now to stop this happening..

Sorry no pics taken.

Nigel
http://www.h2gocoaching.co.uk

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Stuart Yendle
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Re: DIY Cockpit Repairs Help Please

Post by Stuart Yendle » Wed Jul 27, 2011 8:32 am

Thanks all.

I don't really fancy cutting off the coaming, It's only really a few cracks it hasn't come completely off. I've also had an input from GnarlydogNews via email with complete instructions. All pretty similar answers. His option would be to dremel out the old epoxy or sand with into a shallow recess around the damaged area and simply layer up some thin glass strips overlapping the cracks, same as Mike. I think I'll get online and order me some glass strip and epoxy and let you know how it goes, I'll try to get some pictures on my blog too.

Another thing what is wet and drying?

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Re: DIY Cockpit Repairs Help Please

Post by Bod » Wed Jul 27, 2011 8:44 am

Stuart Yendle wrote:

Another thing what is wet and drying?
Ooh a question I can answer. He means sanding down with wet and dry paper.
John B.

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TechnoEngineer
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Re: DIY Cockpit Repairs Help Please

Post by TechnoEngineer » Wed Jul 27, 2011 9:31 am

...and with progressively finer grades - starting at 100-200 ish, then 400ish, 800ish, finally 1200. And then use T-cut to really polish it.
XL-Burn-3 / Monstar / Kodiak / My Videos

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Re: DIY Cockpit Repairs Help Please

Post by tg » Wed Jul 27, 2011 9:38 am

Hi Stuart,
Stuart Yendle wrote:
As a complete novice to the world of fiber glassing I was hoping for some advice. ...
I'll add; try a few small practice pieces. Just so you get used to how 'the magic' happens.

Tim
"I sink therfore I am".

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MikeB
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Re: DIY Cockpit Repairs Help Please

Post by MikeB » Wed Jul 27, 2011 10:10 am

Stuart Yendle wrote:I think I would completely mess up both those options. Either way I have to get rid of that rough looking stuff under the deck? that's the gel coat and filler is it? Glass fiber wouldn't stick to it is that right? I thought this was going to be so simple. Is there anywhere that does this sort of stuff?
Might Rockpool be able to help?

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Jim
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Re: DIY Cockpit Repairs Help Please

Post by Jim » Wed Jul 27, 2011 3:51 pm

Firstly - forget carbon/kevlar cloth or tape, it is more difficult to wet out and completely un-necessary for this repair. It's like trying to run before you can walk when walking would more appropriate even if you could run....

Secondly - Gel coat is thick polyester resin with pigment in, there are no fibres in it so all you have is brittle polyester - it is used to make a pretty surface. Unfortunately if it is too thick it can chip away in chunks, and this is the sort of area where is it likely to be either thicker or thinner than elsewhere on the boat. It is therefore not really advisable to make a structural repair just onto some weak brittle stuff that may break away at some point in the future. So local gouging of the gelcoat is probably advisable, although if you do the main structural part inside perhaps not essential. In fact the area around the cockpit has probably had some bonding paste used sparingly (hence it failing) which may be thickened polyester or thickened epoxy if it is an epoxy boat.

What I would do (and this may not be pretty) is chip or gouge away the gelcoat in a V along the cracks - anywhere more falls away off keep going until it seems sound. If this was an area on show I wold say avoid scratching away from the V, but it's mostly hidden and a nightmare to work under the coaming so feel free to abrade generally making a key in a adjacent gelboat. If it was a neat gelcoat repair only I would say to make the V using just 400 grit wet and dry paper (dry), but for this feel free to use 240 or 120 grit even use alu oxide if you need to. Also abrade the inside of rim/under deck if you will be adding tape there (recommended).

For the outside, because you have created a groove and assuming you are using epoxy resin, I will go further than Owen and suggest first moistening it ever so slightly with resin using a small brush - not wet, just slightly moist. pour off a little of the resin you have mixed up and add a little filler powder to it - various makes have different names but something like 'microballoons', 'high density filler' etc. will be suitable - the packaging will tell you which powders are good for strong joints (colloidal silica for example is not structural and just used for thickening cheaply). Mix it up a bit thicker than peanut butter and then use it to fill the groove flush (a wooden tongue depresser is probably a good filleting stick to use, they are often included in small repair packs) rather than pouring in resin and hoping for the best (that could get quite messy). Now without waiting around put the filler down and go back to your resin (you have to work quicky to avoid the resin curing in between - if it is really hot consider mixing up seperate batches as you need them so you can work more slowly) gently brush over the filler (don't mess it up!) and out to the width of a strip of tape, this time making it properly wet, but not puddling. Next you want to lay some glass tape onto the wet resin and filler - don't try and do the whole circumference in one piece, it will be a nightmare - use 6-8 inch lengths with about and inch of overlap (cut the strips before you mix resin), carefully smooth it down with a gloved hand (at this point I usually take the marigolds off leaving just my latex undergloves on so I can feel what I am doing better). The final part for the outside is to carefully paint resin onto the glass to make sure it all turns from white to clear (so you know it is wetted out - carbon and kevlar don't change colour you need a sixth sense) - in places you may needto gently stipple the resin into the tape (load brush and gently tap with the ends of the bristles).

If your filling was good there may be some filler extruded through on the inside, if so scrape it flush with your stick, I will assume there are no hollows inside to fill, if there are proceed exaclty as above, if there aren't go directly to the part where you paint resin on and then lay the tape etc.

You might want to add 2 layers inside and/or out, any more would be overkill.

It might be that the texture of the resin and tape in the inside (or outside is going to be annoying to you. I haven't tried this myself but you could try mixing some resin with colloidal silica to thicken it and then painting that over as a final action before cleaning up. Alternatively let it cure overnight and then sand before painting more resin (or resin thickened as above) - note that you will get a waxy blush on cured epoxy that must be sanded off before anything will adhere properly to it.

Personally I wouldn't bother to do a gel coat repair and try to blend it in seamlessly - you have created a ridge where the tape is so it won't look seamless. If you wanted to try to polish it nice and smooth you could try using wet and dry on the epoxy (I never have, only polyester) but it might be a waste of time. To do an invisible gel repair (after you sand a V along the crack and fill with gelcoat filler or gelcoat with 2% wax and allowed it to set) you start off with 400 grit (no coarser) (working wet now - just water, warm if you like and some people add detergent to help clean it but plain cold water is fine) on a small block (custom cut to suit the repair) and rub with a linear motion until the repair area is flat - don't rush it, it can take a while. You now have a flat matt area, so you move up a number (finer) on the wet and dry paper (600) and rub the area linearly but at 90 degrees the the original area. Keep going until you can't see any of the scratch marks from the previous grade. repeat alternating grades and directions until you get to 1600 or superfine by why which point you won't be able to see any scratches - if it still has a dull look about it, use polishing paste to finish off and don't be surprised if the repair suddeny stands out as being better than the rest of the boat....
I do think gel repairing on top of this is a waste of time, but if you want to make it blend in a little better you could get some pigment for epoxy that is similar to the boat colour and add a tiny amount (it goes a long way) to each batch of resin or filler you make up - if doing the filler you may need more pigment to counter the colour of the filler powder. Then, like my keel and chine strips the repair will not be visible from a distance, but will be obvious enough close up and will save a lot of work!

Jim

Chris Bolton
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Re: DIY Cockpit Repairs Help Please

Post by Chris Bolton » Wed Jul 27, 2011 8:26 pm

Lots of useful advice on doing repairs with resin and fabric can be found about one screen down in the Almanac.

Do you know whether your boat is made with epoxy or polyester resin? If it's polyester, you can use either - epoxy will stick better but is less tolerant of mixing errors. If it's epoxy, you must use epoxy to repair it.

Chris

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Stuart Yendle
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Re: DIY Cockpit Repairs Help Please

Post by Stuart Yendle » Thu Jul 28, 2011 8:58 am

Thank you again for all the input. I've ordered some stuff and if I get time will get it done this weekend and let you know how it goes. Cheers.

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Re: DIY Cockpit Repairs Help Please

Post by Stuart Yendle » Fri Jul 29, 2011 9:03 pm

Just taken the seat off in preparation for tomorrows repair work and it's possibly not as bad as I first thought. It seems the coaming has come away from the cockpit lip. What looked like a crack in the deck/lip (third pic down in on my blog 'cracking up') is just the gel coat stuck to the coaming. This was my main concern. It seems my only main concern now is the two hairline cracks on either side of the lip itself (first two pics) and glueing the coaming back on.

As I have already bought everything I was thinking remove the coaming, the front and left side is already free, the right side still need a little persuading but behind the seat is stuck firm. Grind down any old gel coat and gunk and fibreglass the rim with a few layers of tape to fix the cracks and reinforce the rim. Then glue the rim back on with a thickened microfibre epoxy. Job done how does that sound?

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