Association Forum - Gelcoat and cockpit scratch repair

Assn Members Area · Join

Home.

Association Forum

Ships Store

Cruising

Racing

Technical Tips

Photo Gallery - New

Boat Search - Updated

Manuals & Brochures

Swap Meet

Links

Officer Flag Line & Staff

Bylaws & Constitution

Members Area

Join the Association

Notice:
The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.

Association Forum

Username:	Password:
Save Password
Forgot your Password?

All Forums

Catalina/Capri 25/250 Sailor's Forums

General Sailing Forum

Gelcoat and cockpit scratch repair

New Topic

Topic Locked

Printer Friendly

Author

Topic

tingwc
1st Mate

Member Avatar

31 Posts

Initially Posted - 09/10/2006 : 06:08:27

Hi guys, my boat has numerous minor scratches on the sides of my hull.

I also have a lot of spider cracks/random scratches in my cockpit and on the deck.

I would like to repair these scratches but am unsure of where to begin. I've done some reading online and have a basic idea. I also bought Don Casey's book on Hull & Deck Repair but it doesn't seem totally clear to me.

My question is - is there a website anybody can recommend which shows step by step detailed directions (with pictures preferably) or a video which shows very clear directions? I've seen a few videos for sale online but am hesitant to purchase them without a recommendation. From my research, I think I know how to fix these cracks but without knowing for sure 100% I'm afraid I'll damage my boat permanently... please help!

Wallace Ting
Queens, NYC
1988 WK

Edited by - on

Frank Hopper
Past Commodore

Members Avatar

Pitcairn Island
6776 Posts

Response Posted - 09/10/2006 : 14:54:31

Hello Wallace,
When I was a boy my mother explained "patina" to me; signs of age are to be respected and admired for what they represent. Go sail.
If however this is something that you really must do
then practice what ever you are going to do
before you do it to your boat.

Edited by - on

ct95949
Captain

Members Avatar

Aruba
300 Posts

Response Posted - 09/10/2006 : 22:46:38

Hi Wallace-
I do not 'repect and admire' cracked gelcoat, in fact I don't like it one bit.I usually wait until the off season with my boat in the yard to make repairs.Don Casey's book is an excellent source as well as many threads on this site.I would experiment with different types (paste,liquid,spray,etc.) and brands .Don't worry about ruining your boat, gelcoat and epoxy are very forgiving materials.If you make a mistake just sand it down and try it again. I mentioned epoxy because you may want to make more in depth repairs or upgrades before applying gelcoat.I buy epoxy from West Systems by the gallon because I use it so much.Don't hesitate to try these projects, they're easier than you think.

Edited by - on

Ericson33
Admiral

Members Avatar

USA
892 Posts

Response Posted - 09/11/2006 : 13:28:52

I have read up on this quite a bit in the last couple of years, I would not use epoxy for the repairs if they are not structural. There have been many discussions about the use of epoxy and gelcoat, I tend to lean towards polyester resin sense gelcoat is a colored polyester resin. and your boat is made out of it.

The hardest part of fixing a scratch or crack is getting the gelcoat color the right shade, everything else is pretty easy to do. Fist lets start with the small hair line cracks in the gelcoat.

Get a can opener and scrape out the gelcoat to make a (V) shape in the crack. This will allow for the gelcoat to bond with the older gelcoat. Next I would start by using a white gelcoat, and mixing in some black and yellow to the white, this will give you the UV dull look that the original gelcoat has taken because of sitting in the sun. Mix up 1oz at a time tell you get the color you are looking for. I would take NON hardened gelcoat and place a dab on the older gelcoat to check the color, You will get close but it will never be perfect. Be sure to write down your formula to get your color, then you can make as much as you want over and over.

Once you have a gelcoat shade that looks good follow the directions for the hardner and apply the gelcoat into the (V) that you made. Have the gelcoat at least 1/16 to 1/8" above the older gelcoat. Once hardened (about an hour) then you can lightly sand the new gelcoat down to the surface of the old hull or deck. I used 600 wet and dry and a good flat sanding block, compound, then polish it out to a shinny new surface.

If you have an area that has allot of spider cracks in the small area I would just grind that area down and fix the whole spot. Keep this in mind, and it was mentioned above, Fiberglass is one of the easiest materials to work with as far as repairs go. If you mess it up, you can always grind it out and start over.

Small cracks are caused in the finish coat because of many different reasons, First is do to too much gelcoat that was thickened on one area, you will find this around risers in the glass, small curves, ect. Second is do to loads on the glass, most of the time you will find this at the bottom corners of the cockpit, and around tight radius curves, Gelcoat doesn't like 90 deg. bends. And the third reason is because the hardware was not installed correctly. to install hardware the factory usually just locates the holes, drills them thru the glass and attaches the hardware, on gelcoat you really need to drill out the top of the glass on a 45 deg chamfer you only need to do this a small amount but it lets the gelcoat have a opening angle back towards the top surface.

Everything mentioned above is from reading repair manuals and working with the gelcoat first hand. At first it tends to be a huge job, and can take a good amount of time to fix, but after the first couple of scraches you to will become very comfortable with working with the gelcoat. It really is fun to work with. Remember to work in a well ventilated area as the MEKP (gelcoat hardner) is very toxic.

As for videos I really like this guy and how he works with the glass. I don't own a video but look thru his site, there are many usfull tips and tricks
http://www.fiberglass-repair.com/

Edited by - on

tingwc
1st Mate

Members Avatar

31 Posts

Response Posted - 09/11/2006 : 15:30:17

Thanks for the responses guys. I feel a lot more confident about tackling this project.

Capri25, do you recommend a particular type of gelcoat? I went to west marine and saw about 7 or 8 different brands, gelcoats, resins, epoxies, etc... I know you said to stay away from the epoxies if it isn't structural, but there are still tons of things to choose from.

If you (or anyone else for that matter) could provide a link to a big gelcoat paste, I'd appreciate it.

PS - I did some research and found something called Poliglow - apparently this is a way to wax/clean the gelcoat to make it shine again. Am I safe to assume that after I've repaired the scratch and sanded it down this is what I apply? Thanks!

Edited by - on

Ericson33
Admiral

Members Avatar

USA
892 Posts

Response Posted - 09/11/2006 : 16:08:58

There are several different kinds for different repairs as you mentioned. You can buy Gelcoat that does have a wax built into it, so you don't have to cover the resin with PVA - Poly vinyl alcohol, or you can get the wax so the gelcoat will set up when applied. I would use the non wax kind this way if the scratch (side of the hull is so big that you need to apply 2 or 3 coats of gelcoat to fill the gouge you don't have to sand the gelcoat to apply more. There is also gelcoat for making moulds, and the paste. I think the paste has some kind of microballoons mixed into it for really large patches, this makes the sanding easier. Start off with a pint of gelcoat at first, and just buy some more if needed, It will go a long way.

Gelcoat Products you will need:

http://www.westmarine.com/webapp/wcs/stores/servlet/producte/10001/-1/10001/72277/0/0/gelcoat/All_2/mode+matchallpartial/0/0

http://www.westmarine.com/webapp/wcs/stores/servlet/producte/10001/-1/10001/50195/0/0/pva/All_2/mode+matchallpartial/0/0

I will let someone else tell you about the polyglow as I have not used this product

Edited by - on

StSimon
Captain

Members Avatar

USA
298 Posts

Response Posted - 09/11/2006 : 18:14:33

If it's information on how to do this job and many others, I would recommend Jamestown Ditributors "How Tos" page. They sell West System products which are first rate. Here's a link.

http://www.jamestowndistributors.com/userportal/how_tos.do

Heres the job I did on mine. If you look closely you can see the hairline cracks as well as the ladder's holes that needed to be filled to install the swim platform and longer, retractable ladder.

The first step was to grind out the cracks. You want aproximately a 12:1 bevel to allow for good adhesion. An angle grinder works best, but it could be done with a dremel or power drill and the right attachments. I heard of the can opener method but have never tried it. I don't believe it could give you the proper bevel though.

Next comes the filler. I wish I could remember what product I used. Sorry.

The filler is now sanded.

Next comes the gelcoat. I did just as Chris wrote. I mixed up small amounts and spread a finger full on the transom. I did however put in the hardner and driied each attmpt with a heat gun. You will not get the true color until it dries. You can sand them off later. I sprayed on two thick coats. This is after the first.

And here's the (almost) finished product. It still needs to be washed and the Poli-Glo applied.

Good luck on your project.

Edited by - on

britinusa
Web Editor

Members Avatar

USA
5404 Posts

Response Posted - 09/11/2006 : 19:01:02

Nice work Andy.

paul

Edited by - on

Ericson33
Admiral

Members Avatar

USA
892 Posts

Response Posted - 09/12/2006 : 10:10:37

Andy, What did you use to spray the gelcoat?

Edited by - on

StSimon
Captain

Members Avatar

USA
298 Posts

Response Posted - 09/12/2006 : 11:30:31

I would think any gun would work as long as you had a big enough tip or the gelcoat is thinned out. I just used an airbrush gun with thinned gelcoat.

Edited by - on

Happy D
Admiral

Members Avatar

921 Posts

Response Posted - 09/13/2006 : 18:50:23

In my opinion, gelcoat will adhere to epoxy, no problem. The key is to prepare the surface correctly. The bond is mechanical when putting gelcoat over cured polyester or epoxy so the bond is the same either way. West Systems did a gelcoat adherence test using epoxy and gelcoat for use below the water line. [url="http://www.westsystem.com/ewmag/22/polyester.html"]Here is the Article[/url]
Nice looking work Andy!
Andy, what did you thin the gelcoat with?
Where did you get the swim platform and the ladder? I like it

Looks like exactly what I would like to build. I was thinking about using some old rigging cable for the side supports instead of tubing but I'm still thinking about it.

Edited by - on

Ericson33
Admiral

Members Avatar

USA
892 Posts

Response Posted - 09/13/2006 : 19:32:40

Dan, Polyester resin will chemically bond with existing polyester resin if it is ground out. Polyester resign will not chemically bond with epoxy. I have read the test from West systems, and they have gotten the polyester resign to stick to the epoxy but there is no chemical bond. I always try and go back to the "what if" question. First if its not structrual, then why use a product that is (1) more expensive, and (2) might not bond.

Edited by - on

Topic

New Topic

Topic Locked

Printer Friendly

Jump To:

Association Forum

Notice: The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.