Return to Hobie.com
Hobie Forums
It is currently Tue Mar 19, 2024 2:06 am

All times are UTC - 8 hours [ DST ]




Post new topic Reply to topic  [ 7 posts ] 
Author Message
PostPosted: Tue Aug 24, 2010 8:16 am 
Offline
Site Rank - Captain

Joined: Fri Nov 12, 2004 10:01 am
Posts: 76
Location: OC NJ
I know that polyester material is recommended for Hobie repairs by all those in the know. What happens when epoxy is used? I've searched in the forum here, but only seen warnings against using it, not the results. My last (professionally done) bottom job blew out pretty spectacularly last week and I'm getting advice from guys on the beach who swear by a surfers sun curing repair kit. I'm pretty sure that stuff is epoxy. They say they've used it for years with great results.

Thanks.


Top
 Profile  
 
PostPosted: Tue Aug 24, 2010 9:17 am 
Offline
Site Rank - Old Salt

Joined: Mon May 09, 2005 10:25 am
Posts: 4176
Location: Jersey Shore
I'm not a chemist, but my understanding is that epoxy resin will bond to (cured) polyester with no problems, but polyester resin will not bond properly to epoxy. So what that means is that you can do repairs on your polyester resin based Hobie Cat using epoxy, but if you later do any additional repairs to that same area, you must continue to use epoxy. So, its a much better policy to always use the same resin that the boat is made from - then you don't have to remember and there aren't issues. You also can't get a good bond using gelcoat over epoxy.

As far as your bottom job failing, I would guess it's almost certainly the result of poor surface preparation. The repair area must be properly "roughed up" and cleaned of dirt, dust, and grease prior to laminating.

Sun cure is polyester based, but I would not use it. It cures way too quickly. I would use a proper polyester resin to laminate fiberglass tape.

sm


Top
 Profile  
 
PostPosted: Tue Aug 24, 2010 10:13 am 
Offline
Site Rank - Old Salt

Joined: Mon Oct 09, 2006 2:34 pm
Posts: 621
Location: NC
From what I've learned on this forum you should use polyester for cosmetic repairs and epoxy for structural repairs/mods. Gel coat does not adhere to epoxy resin very well, if at all. Many people, including me, use epoxy to "glue" the boat together. I'm certainly not the most knowledgeable on this though.

_________________
James
86' Redline Hobie 16
Sail # 76909


Top
 Profile  
 
PostPosted: Tue Aug 24, 2010 8:27 pm 
Offline
Site Rank - Old Salt

Joined: Wed Jul 21, 2004 7:46 pm
Posts: 1457
Location: Santa Cruz
Epoxy for bonding, polyester for laminating and where any gelcoat will be applied later. That's a good general rule.

Edit:
Just saw your other post. The UV cure resin is probably polyester, but check it. Does it smell like "fiberglass"? If so, it's polyester. If it doesn't have a strong odor, it's epo. Search for amine blush to find out the problems with epoxy/ gelcoat. Not to mention, it costs a lot more.

_________________
Sail Revolution
Join us on our new FB Page!


Top
 Profile  
 
PostPosted: Wed Aug 25, 2010 7:38 am 
Offline
Site Rank - Captain

Joined: Fri Nov 12, 2004 10:01 am
Posts: 76
Location: OC NJ
Thanks guys -

Here's a pic

http://flic.kr/p/8viB8D

I think that when the job was done before, they didn't build up the keel. It looks like the surface gel cracked when there was some flexing. Flooded the hull pretty well!

I did fund an interesting page on amine blush http://www.epoxyproducts.com/blush4u.html


Top
 Profile  
 
PostPosted: Sun Oct 03, 2010 8:57 am 
Offline
Site Rank - Captain

Joined: Sun Jun 20, 2010 10:12 pm
Posts: 36
Okay, so then, polyester for delam fix? Is that what I am getting form this? :?:

_________________
Corey
82 H16 project complete


Top
 Profile  
 
PostPosted: Sun Oct 03, 2010 9:51 am 
Offline
Site Rank - Old Salt

Joined: Wed Oct 14, 2009 11:26 am
Posts: 317
I used West System Epoxy on the bottom of my hulls because it is much stronger and will hold up to abuse better. If I was filling in holes topside or something maybe would use poly. Gel Coat is also supposed to stick to the West System Epoxy.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 7 posts ] 

All times are UTC - 8 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Jump to:  
© Hobie Cat Company. All rights reserved.
Powered by phpBB® Forum Software © phpBB Group