Hobie Cat Forums

It is currently Thu Sep 18, 2014 11:28 pm

All times are UTC - 8 hours [ DST ]




Post new topic Reply to topic  [ 6 posts ] 
Author Message
PostPosted: Fri Oct 21, 2011 9:25 am 
Offline
Site Rank - Captain

Joined: Mon Oct 18, 2010 11:25 am
Posts: 26
Location: Glen Lake, MI
I recently acquired an ‘85 H18 for parts and it came with a set of fiberglass rudders. First can anyone confirm whether they’re EPOs? They’re black w/ white fibers showing, weigh about 4lb 4oz, no flex.

Image

If they are in fact EPOs, I think I’m pretty clear about the general refinishing process thanks to Jeremy’s video, but have a couple specific questions. What’s the fix for this crack above the mounting hole? It doesn’t flex at all when pressed, but I don’t trust it. And the rudders look like they were previously drilled and filled with what looks like bondo. Should I drill out that old hole and fill them both?

Image

Also, the tips look like they were patched long ago. Should I grind/sand that all off and build it back up? If so what do I use? Epoxy w/ chopped glass? Strips of glass mat? Thanks, Pete

Image


Top
 Profile  
 
PostPosted: Fri Oct 21, 2011 11:29 am 
Offline
Site Rank - Old Salt

Joined: Mon May 09, 2005 10:25 am
Posts: 2568
Location: Jersey Shore
They are definitely EPOs (original version from the '80s).

For the surface, I would give a light sand with 80-100 grit paper. Then apply one or two coats of epoxy. Allow it to fully cure (min 24 hours) and then wet sand up to 600 grit. EPOs are made using epoxy resin (hence E P O), so you only want to use epoxy resin for your repairs. You could also shoot them with a coat of black spray paint to protect the new epoxy (otherwise it has a tendency to turn yellow from UV.

For the crack around the pivot hole, I would grid out all the loose material with a dremel tool. Taper it back at a minimum 10 to 1 taper. Then laminate new glass to build it back up. You could try using 6oz glass, but you may have to go lighter to get it to wrap around the curve. Use as many layers as necessary to build back up to the original thickness. I would also suggest you fill in the existing hole with epoxy and re-drill it since it looks like it has ovalized.

For the dings in the tip, use marine tex or thickened epoxy resin.
sm


Top
 Profile  
 
PostPosted: Fri Oct 21, 2011 1:39 pm 
Offline
Site Rank - Admiral

Joined: Sun Jun 21, 2009 7:32 am
Posts: 296
Too bad spray putty only comes in polyester. It's one of the greatest time saving inventions for body work, or working on boats.

Once you get them to sanding primer stage, if you want to really get the shapes as good as possible, use spray on guide coats when doing final fine sanding before paint. Eastwood sells it in different colors to contrast with whatever primer you use.

http://www.eastwood.com/ew-guide-coat-b ... 12-oz.html

Of course, this step if just if you really want to be picky.


Top
 Profile  
 
PostPosted: Thu Oct 27, 2011 8:23 am 
Offline
Site Rank - Captain

Joined: Mon Oct 18, 2010 11:25 am
Posts: 26
Location: Glen Lake, MI
Thanks for the suggestions, guys.

So I got at them with my Dremel tool using a combination of the small sanding drum and this one, which worked great for removing all the old filler:

Image

I cleaned off all the old filler. Based on the layers present, it looks like the holes have been drilled a filled a couple times. Looks a little like swiss cheese. Any concern about it's durability once they're properly filled and re-drilled? And around the cracked pivot hole I ground out all the cracked glass and foam. Should I just use thickened epoxy to fill the void before I laminate the corner with glass mat? Is there any other reinforcement I should put in there?

Image

Image

Ordering all the supplies today and hope to get started as soon as they arrive. Not much longer up here in Northern Michigan before it's too cold to work out in the garage. Will epoxy still harden at 40 degrees? Thanks for the continued advice. -Pete


Top
 Profile  
 
PostPosted: Thu Oct 27, 2011 12:41 pm 
Offline
Site Rank - Old Salt

Joined: Mon May 09, 2005 10:25 am
Posts: 2568
Location: Jersey Shore
Looks good. Only suggestion might be to increase the taper. You really want between 10:1 and 15:1 taper if possible (so if the thickness of the glass is 1/10 inch, you would want to taper back between 1" and 1.5" if possible). This increases the bond area between the existing and the new glass.

I think filling in the void areas with thickened epoxy is a good one. I would use masking tape to build up a trough to pour the epoxy into. After it cures, file/sand it to he desired shape. Then laminate your glass.

Epoxy will cure at 40 degrees, but you will probably want to use a fast hardener to reduce cure time.

I wouldn't use glass mat. I'd use glass cloth. It's stronger and will be easier to conform to the curvature of the rudder.

sm


Top
 Profile  
 
PostPosted: Thu Oct 27, 2011 2:21 pm 
Offline
Site Rank - Captain

Joined: Mon Oct 18, 2010 11:25 am
Posts: 26
Location: Glen Lake, MI
Great, thanks. In terms of the taper, I didn't want to remove too much material until I knew I was on the right track. And will do on the fiberglass cloth vs. chopped strand mat.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 6 posts ] 

All times are UTC - 8 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 1 guest


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

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group