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PostPosted: Sat Jul 20, 2013 5:57 am 
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Hello All,
I have a leaking hull that I wish to repair and am trying to decided what resin I should use.
The hulls appeared to have received temporary or poor fixing from the previous owners as it appears that car body filler was used and this is peeling off.
I popped into the local chandlers and they recommended West Systems but reading this great forum others mention to use polyester resins etc.

What would you recommend for this particular job?

Thanks,
SRG

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PostPosted: Sun Jul 21, 2013 5:08 am 
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You really ought to use polyester resin. It's what Hobies are made of and polyester will stick to polyester hulls better than epoxy. If you go over it with gel-coat, the gel will stick to polyester better than it will to epoxy too.

I've used an automotive polyester product called Bondo with great success. The previous repair on your boat may have gone bad because the owners didn't mix the proper ratio of catalyst to resin.

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PostPosted: Mon Jul 22, 2013 7:07 am 
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For a bottom job, polyester. Be sure to prep the surface really well if you want the repair to work.

sm


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PostPosted: Mon Jul 22, 2013 12:28 pm 
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Thank you for your replies.
So it looks like polyester is the way to go.

I have watched a number of videos (youtube) and read a number of articles regarding fibreglass work and resins.

So would I be about right with the following process?
1) Do a soap test to spot leaks (Guess this may not be necessary if doing a complete bottom job but no harm)
2) Sand off the old filler and coarsely sand for (keying) the remaining good working area.
3) Clean thoroughly with acetone.
4) Wet in fiber glass strips with Polyester laminating resin (the stuff that does not cure completely) waiting for each layer to become tacky, building up the bottoms. How many layers is generally required for this process?
5) Wait for last layer to become tacky, it wont cure completely in air. (maybe use a polyester finishing resin)
6) Apply a gel coat to seal and thus cure and harden the underlying resin.
7) Progressively sand to a nice finish and polish.
8) Go sailing.

I have just read the West System literature and this states that epoxy is far superior and may be used on polyester fibreglass hulls.
Indeed a number of other articles are recommending this too. Some quoting epoxy resin superior strength something like 2000psi as opposed to 200 for polyester and that it requires less prep work etc.

My head is buzzing and it hurts ;-)

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PostPosted: Mon Jul 22, 2013 1:15 pm 
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I would use epoxy, regardless of it being a spot repair or a larger area that required a lay-in of glass cloth. The epoxy will give you better working time and is generally less brittle.


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PostPosted: Mon Jul 22, 2013 2:37 pm 
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Oh my i am as confused as ever with which way to tackle the bottom job! :-)

Something else I would like to throw out there is the fact that I am heading on vacation to the south of France shortly and intend to take the Hobie for some fun in the Mediterranean.

What should I use as temporary fix for this leaking hull?
Could I use something like epoxy putty, such as JB weld or similar?
The fix doesn't need to be that pretty or long lasting as I intend to crack on with the bottom job on my return, I just need it to plug this leak for now.

Thanks,
SRG

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PostPosted: Mon Jul 22, 2013 2:45 pm 
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If you are sure it is not a structural matter, and just need to plug a small hole or crack, you can do so effectively with GOOP.

However, you really need to be sure that you're not dealing with something that could lengthen or open up on you under stress.


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PostPosted: Mon Jul 22, 2013 7:17 pm 
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Whatever you use (I still lean towards polyester based on my research and experience doing two bottom jobs) just go ahead and knock it out before you go to France rather than doing a quick fix, spending time remediating the quick fix after you get back, and then fixing it properly. Perhaps you should just lay up the glass, give it a preliminary sanding, go to France, then repair any new dings and finish the job after you return. It seems very inefficient to put a temporary fix on it just to do it over again.

By the way, where in France are you going? I've been to Marseilles a couple times and had a blast. We thought the little town of Cassis just a few miles down the coast was a great place to chill.

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Last edited by MVD on Mon Jul 22, 2013 7:19 pm, edited 1 time in total.

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PostPosted: Mon Jul 22, 2013 7:19 pm 
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Vinylester resin. How's another option !

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PostPosted: Tue Jul 23, 2013 3:43 am 
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Some reasons to use polyester...

- It is the same material that the rest of the hull is made from (by far the number one reason).
- Its less expensive than epoxy (particularly important for a bottom job that is just going to be beat up from being dragged around).
- It's easier to work with than epoxy (easier to mix, less likely to have a "bad batch", cures more quickly).
- It can be gelcoated if desired.
- It is more UV stable if left un-coated.
- If the surface is properly prepared, it will be totally structurally sound.

I would not use JB weld, marine tex, or any other "temporary" repair. A quick repair probably won't hold up and could easily fail the first time the boat is dragged on the beach or sailed. Doing a decent bottom job only takes a few hours (especially if you aren't concerned about gelcoating.

sm


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PostPosted: Tue Jul 23, 2013 2:19 pm 
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Thank you all for your replies very helpful indeed :-)

MVD, Cassis is a great place indeed, stayed there a couple of times once on our honeymoon, traveling around Europe in a bright orange VW Westfailia bay camper (about 17 years ago). I know how to treat a woman ;-) All our friends were doing the all inclusive thing for theirs and I thought bugger that!

Then again last year for a night or two when traveling from St Marie Del A Mar which is in the Camargue to Agay which is close to St Raphael.

We are heading back to St Marie Del A Mar this year with friends and family so should be a blast.
Looking forward to visiting Beauduc Beach to release the Nobie :-)
http://www.camargue-en-provence.com/beach-beauduc.html

All the best and thanks again!

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