Need advice on patching a hole

[a2theb]

Hi all - First post but been lurking for a while. I just picked up a new to me 91 Capri 2050. The boat is in overall good condition but there's a corner on the swim platform that was poorly patched that I want to redo. You know that myth about a guy using his wife's tampons to plug a hole? I literally got that boat. The patch job was so bad that the resin was starting to flake off and when I pulled on the cloth, it came off like old duct tape.

I got it down to the gel coat for the most part but I'm assuming I'm going to have to sand down past the gel coat to even start glassing. Do I also need to sand behind if I'm going be laying some chop mat? It's a tight reach from the engine hatch. Here's my plan of action and please let me know if it will work or any advise you can throw in. Thanks!

1. Sand down gelcoat to fiberglass around 3" from hole.
2. Soak chop mat in resin and fill from the inside, let harden.
3. Run strips of cloth against each axis, let harden.
4. Sand smooth, fill voids with Marine Tex and to level with gelcoat.

I'm not planning on gelcoating it since I will be repainting the hull above the waterline. Does this sound right? Also, can I get all my materials at the local hardware supercenter? And what grit size range should I be looking at getting when buying wet/dry sandpaper? Any advice would be great.

First two pics show the POs patch job, third pic shows what I removed including said tampons and last pic is somewhat cleaned up shot of the hole in question.

 

[ondarvr]

Re: Need advice on patching a hole

I love those pics, this is the reason for the myth of polyester doesn't stick to anything line of thought. It looks like there was little or no prep work, then a bunch cloth and resin was just slapped on the surface, it looks like there might be some type of white epoxy mixed in the patch also.

For the repair get a small grinder and use 36 grit to sand off all that "stuff", you will need to taper the area to be repaired out a few inches so you can build up some new glass. Yes you can get your supplies at the local super store, but if the boat will sit in the water for long periods of time you may be better off buying a resin for marine use, some of the big stores "may" carry it. Always make sure the surface is clean before doing any glass work and follow the directions on the can for that resin.

Don't use cloth as the first layer, always use mat or the bond will be poor.
You can use layers of cloth or roving in between layers of mat to build up the thickness you need. You can use epoxy to fair the surface, but it can be difficult to sand, so try to find a sanding filler, or just use gel coat. Gel coat won't stick well to epoxy, so if you use epoxy to fair it, skip the gel coat layer over it.

 

[tashasdaddy]

Re: Need advice on patching a hole

agree poor of no prep work.

 

[HighTrim]

Re: Need advice on patching a hole

Worth a read as well.

"http://www.boatus.com/boattech/casey/17.htm"

 

[bigmarc66]

Re: Need advice on patching a hole

I did fiberglass work this summer for the first time. I know this may seem silly or obvious but once that resin and hardener are mixed you start rushing.
1. Make sure you have no skin exposed, (I was itching for days)
2. Make sure you get a mask to cover your face, the fumes are very bad. If you ever think you might do fiberglass again, buy the good one, well worth it.
Those two seemingly obvious parts to fiberglassing are most important.

 

[maxum247]

Re: Need advice on patching a hole

Sand down to the fiberglass.

 

[flabum]

Re: Need advice on patching a hole

As for the patch:

Grind as you intend, put some masking tape over the hole inside to comform to the radius, 2 layers of cloth, 2 layers of matt and shape with waterproof epoxy filler such as this: http://www.westmarine.com/webapp/wc...RL=true&storeNum=95&subdeptNum=96&classNum=96

If access is good, remove the tape from inside, grind area including the new glass, and add 2 more layers of cloth.

 

[a2theb]

Re: Need advice on patching a hole

Thanks for the help everyone. I looked at the hole again today and it looks like it's going to be pretty difficult to do work on the inside. I can barely reach without getting my body all distorted and uncomfortable. I'll probably start this in a couple weeks. I'll post pics of the results also.