Discouragement is starting to set in

twitcherz

Seaman Apprentice
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Jun 11, 2020
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I was under the impression all gelcoat or paint on the inside of a hull has to be removed for a chemically strong bond. Problem is I just removed the gelcoat and 2 holes appeared. I now have a total of 4 holes to repair. My question is because gelcoat is pokyesyer based and I'm using polyester resin to lay my glass can I just smooth it out to Kay glass over or do I have to remove it all. I dobt want to fix 30 different holes if I dobt have to. Any help is appriacted as this is very discouraging
 

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JASinIL2006

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The gelcoat has tp go. If that’s all that is covering holes, you want it gone anyway?
 

GSPLures

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Just keep at it, no point in throwing money and time into it just to have doubts later. Once it is done you will know it is done right, unfortunately I know it is a lot easier to say then do.
 

twitcherz

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Okay I will keep removing all the gelcoat. Maybe this boat was a real thin layup to start with so anything I do would be better then what was here
 

twitcherz

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Would it be a good idea to cover the entire hull where I have sanded and grindedndown everything in a layer of csm and then 1708 ? Just to build up some structure and thickness again ?
 

twitcherz

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Would it be a good idea to cover the entire hull where I have sanded and grindedndown everything in a layer of csm and then 1708 ? Just to build up some structure and thickness again ?
Also wondering other then the repair I will have to make how far up should I remove and grind the white paint or gelcoat off.
 

JASinIL2006

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You only need to grind off the gel as far up as your repair will go. I can't see much point in going further.

Also, it's not a bad idea to lay down some layers of 1708 if you want to build up the hull where you ground it down. 1708 already has CSM on one side, so you really don't need a layer of 1708 and an extra layer of CSM; extra layers of CSM will add weight but contribute little strength. Just be sure to lay the 1708 so the mat side is down and the woven side is up.
 

twitcherz

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You only need to grind off the gel as far up as your repair will go. I can't see much point in going further.

Also, it's not a bad idea to lay down some layers of 1708 if you want to build up the hull where you ground it down. 1708 already has CSM on one side, so you really don't need a layer of 1708 and an extra layer of CSM; extra layers of CSM will add weight but contribute little strength. Just be sure to lay the 1708 so the mat side is down and the woven side is up.
Sounds great. As far as the rest of the paint on the inside of the hull it is a rough texture so if I just sand that smooth and rough it up after I would be fine to lay gelcoat over tip of that I'm looking for a smoother overall finish inside the boat when completed
 

GSPLures

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Sounds great. As far as the rest of the paint on the inside of the hull it is a rough texture so if I just sand that smooth and rough it up after I would be fine to lay gelcoat over tip of that I'm looking for a smoother overall finish inside the boat when completed
I would stay away from going too smooth on the deck. It will become very slick when wet.
 

twitcherz

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Not kn the deck but up the sides of the biat I mean. As it is pretty rough I just want the sides to look smooth. I think also my issue has been using a flap disk which is not helping me. I'm going to pick up some soft pads for my grinder and use some 36 and 40 grit paper to help with removing to much material. I will pick up today and post tonight on the difference I am hoping it will make
 

TCKibe1

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I would use an orbital sander to smooth out the rough gelcoat. It will leave a smoother more uniform surface with no digs or gouges like you get with a grinder. Just my opinion.
 

76SeaRay

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I am doing this now on my deck (top of bow not floor) using a orbital sander with 40 grit (6 hours today). It is working pretty good but it does take a bit of effort to sand it down. On large flat surfaces that are non-appearance, I use the grinder and a 3 inch belt sander. I had used a flap disk also but gave up on those really quick. I do have a lot of little swirl marks with 40 grit using the orbital sander and you have to be careful to not round off any edges too much with 40 grit. I am considering going back over it with 80 or 100 grit to smooth the swirls before the first coat of gelcoat but mine is probably more visible than yours. Not sure how much gelcoat will fill in the sanding scratches.
 

twitcherz

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My biggest problem has been removing to much gelcoat from the inside of the hull. I wanted to reinforce the side of the boat a little more where the meet the floor. I did get the soft backing pads and it made a huge difference I got the gelcoat nice and smooth and it remove alot of it without wearing through. I also spoke with a local boat builder who has done everything from 12 ft runabout to large Yachts. He did tell me that I could lay glass over the gelcoat as long as the gelcoat has been prepped properly and and the first couple layers have been removed to remove the wax and uv protection. This is where I'm at so far. Also got my material orders in and should start in the next few weeks as I'm very weather dependent right now.
 

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Emerger

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My biggest problem has been removing to much gelcoat from the inside of the hull. I wanted to reinforce the side of the boat a little more where the meet the floor. I did get the soft backing pads and it made a huge difference I got the gelcoat nice and smooth and it remove alot of it without wearing through. I also spoke with a local boat builder who has done everything from 12 ft runabout to large Yachts. He did tell me that I could lay glass over the gelcoat as long as the gelcoat has been prepped properly and and the first couple layers have been removed to remove the wax and uv protection. This is where I'm at so far. Also got my material orders in and should start in the next few weeks as I'm very weather dependent right now.

Your boatbuilder friend is right. There is no sense in grinding through polyester just to get to polyester.
 

twitcherz

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Your boatbuilder friend is right. There is no sense in grinding through polyester just to get to polyester.
Yes I agree. I also wish I would have known gelcoat is just pigmented poly resin with more binders and blockers in it. Oh well I suppose it's all part of the learning process
 

Emerger

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Yes I agree. I also wish I would have known gelcoat is just pigmented poly resin with more binders and blockers in it. Oh well I suppose it's all part of the learning process

Well, let's think about it. Every fiberglass boat begins its life as a lamination on top of gelcoat. A boat mold is first coated with gelcoat then cloth is laminated over the top of it. The problem people run into later is attempting to laminate on top of improperly prepared gelcoat. A boat routinely gets washed and waxed, then there are tons of products people sell to spray and wipe on after. It's all that gunk that will keep resin from adhering to it so it has to be sanded down but not all the way through. Making a repair is different in that you want to grind down as far as you can in order to get a good foundation to build a patch on.
 

twitcherz

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Okay so if I wanted to run fiberglass up from the bottom of the hull up the sides of the boat about 8" then in this picture I should be able to do that without removing anymore material. I just want to stiffen it up a little bit as there is not much there
 

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Emerger

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Okay so if I wanted to run fiberglass up from the bottom of the hull up the sides of the boat about 8" then in this picture I should be able to do that without removing anymore material. I just want to stiffen it up a little bit as there is not much there

It looks like you have sanded the entire surface of it so yes you'll be fine with that. Wipe it down with acetone before you lay the glass. If you want to add strength to it put a layer of chopped strand mat down first to smooth it out and then add a layer of woven roving on top of it.
 

twitcherz

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It looks like you have sanded the entire surface of it so yes you'll be fine with that. Wipe it down with acetone before you lay the glass. If you want to add strength to it put a layer of chopped strand mat down first to smooth it out and then add a layer

It looks like you have sanded the entire surface of it so yes you'll be fine with that. Wipe it down with acetone before you lay the glass. If you want to add strength to it put a layer of chopped strand mat down first to smooth it out and then add a layer of woven roving on top of it.
Excellent. Thank you very much.
 
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