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View Full Version : small repair./ best thing to do?



spanky2002
11-28-2002, 04:26 AM
for the last few months or so i had been getting water in the boat. i first thought it was a leaking live well, only to discover i have a small crack in the bottom of the boat. i noticed small stress cracks where the boat sits on the outside runner. i then lifted the hull to see about a 1 inch crack in the gel coat. it didn't look like it was bad enough to take in water but it was. i filled the boat with water and i had a slow drip from this crack. so what do i do? do i sand away the cracked area and fill it with resin and then paint it or put a put a gel coat finish on it? i am trying to find the easiest but yet best thing to do while on my back. i don't have the equipment to flip her over.

bulldogdaddy
11-28-2002, 07:03 AM
believe me,i'm new at the resto,repair work,but nothing ever seems easy doing this,but from what i've been told and reading,if you have a crack in the bottom,it might be in the glass to.if it is you'll need to get down to the glass and bevel the edge so the new glass can adhere to it.anyone with experiance correct me if i'm wrong!also are you sure that the transome is'nt leaking?

Rickracer
11-28-2002, 09:15 AM
....for at least 2 to 3 inches on either side of the crack. Not having worked with gelcoat, I usually try to find some paint that is really close to the color of the gelcoat to seal and finish the repair. The bad news is that you need to do a repair on the inside too. :eek:

Jacob
11-28-2002, 03:05 PM
These repairs are not difficult, but they are a pain in the a$$. I use a die grinder to remove the portion of cracked glass from the hull. after getting all of the cracked glass removed and a good even bevel, I clean the surrounding area from the inside with some coarse grit sandpaper. I lay my fist layer of cloth from the inside, it serves a backing for the rest of my repair, next I use matt to fill in the rest of the void from the outside. I have done the repairs without flipping the boat, but get ready to get full of resin. I mix my resin pretty hot when doing over head repairs, it will gel quicker helping it stay in place while you work out the air bubbles. You can try to use a thin piece of cardboard to tape over the repair while it cures to help keep the shape of the hull. Before I pick up the resin I usually place a layer of matt over my layer of cloth from the inside, A repair can never be to strong. After it cures I sand it down till the repair blends with the contours of the hull. After sanding the glass down I cover the area with body filler for my final finish, I sand the body filler with a fine grit sandpaper giving you a smooth good looking repair. Good Luck :cool:

Techno
11-28-2002, 07:00 PM
Your hull is cracked clear through to let water in so a gel fix isn't going to work. The other thing is the cracked gel is like a tattle tale for the stress or flexing the hull is doing.

On my crack/s/s/s/ I foamed one side with expanding foam and the other with saw dust filled resin. The foam worked but was hard to get it to stay on without falling off first. The sawdust/resin worked well and sanded easy too. I used a flap sanding wheel on an angle grinder.
I sanded the inside to the gell coat and then repaired from the inside. Flipped since I could ( I might as well paint....) Sanded off the "sealer" and fixed that side.
The foam "sealer let me do whatever on the inside and still maintain the form that I needed to keep. Stop sanding when you see white gel.
A bandage method for patching the outside is to lay up your laminate on a sheet of plastic, then slap that on the already repaired spot( you've already sanded the gel off). Smooth the plastic out against the hull and tape or hold it. You still have to sand it.
The other thing not mentioned yet is something caused the hull to crack. You need to discover why it cracked so you can fix it properly. If you hit something there's the cause. If there are signs of other failure on the inside this could lead to the real cause and you can eliminate it.

Check out my site for what can happen to a simple crack if left. I didn't know it was cracked but it spread real fast and started to reproduce itself on the other side. One weak point puts strain on another location. The cause of my crack was a bad stiffener, this allowed the wide pad to flutter. If I had repaired the cracks but not found the cause it would have happend all over again.

spanky2002
11-29-2002, 12:50 AM
how much of a bevel do i need in the glass? i don't know the cause of the crack yet but i found that the two middle runners were not touching (supporting) the hull at all. it seems like if that's the cause then wouldn't both sides be cracked? maybe the previous owner did hit something. oh one more thing, in a different location of the boat there is a chip about 1/2 inch but goes to the glass. can i fill it with just resin and then paint it or should i use a body filler?

Techno
11-29-2002, 09:53 AM
There is a ratio which I forgot. But if you bevel back about 1-2" is fine.Rickracer said 2-3" so the more the better. I went back about 4-6" on my hull. But I had some serious cracks.
The point of beveling is to increase the surface so there is more surface to join together. A 1/8" thick hull -only 1/8" surface to join, bevel it back to 1" and there is 1" of surface to join together. Your changing a butt joint into a lap joint so to speak.

If the runners are the cause then the reason why the other side didn't fail is it didn't have the time yet. It could have been the other side that went. If you can post a picture then someone can probably say if it's supposed to be like that or not.

The little chip could be smoothed down and repaired with a gel coat repair kit. Gelcoat is just pure resin with a coloring agent in it. Should be in the resin area of the boat store. Saves the step of painting. They also have the pigment too.
Body filler is resin with talc- talc absorbs moisture so shouldn't be used. Although I've used it on my dash.

Rickracer
11-29-2002, 10:44 AM
....you really don't wanna use body filler anywhere under a boat, unless it's resin based, and uses fiberglass (OK, or talc) as a filler. But please , not Bondo. :cool:

Racemore
11-29-2002, 01:37 PM
It is resin with a colorant but it has talc for a base.This keeps it from being translusant,The solids keeps light and moisture out.If you ever use just resin and nothing to cover it will absorb sunlite and will become brittle and crack.The generally leads to delamination.If you can repair the inside by beveling and relaminating mat,roven,mat, roven etc untill the area is repaired the bottom repair is cosmetic and can be filled with marinetex,resin with cabosil,airosil,or talc(baby powder) then sanded and left or colored.I use pigment in the filler to get close to the color desired.Most important is an inside repair is by far the best because the outside damage remains a small area and water won't hydro the patch off.An outside repair is beveled out an gives the water a starting point to rip the patch off leaving a big hole.If it is the only way,then it isn't the wrong way.:cool:

Racemore
11-29-2002, 02:14 PM
I know you are a Bum by your profile.Is this because you can't learn?Not to bust your balls but talc absorbs water in your diapers,it absorbs resin in gelcoat.it is the base in polyester gelcoat.Do you think we should just junk all the boats using talc based gelcoat?You have alot of great ideas so I know you learned them somewhere.If my old friend that taught me about mixing talc with resin to make a filler that if applied to clean prepped fiberglass panels was wrong then the doors and hoods on 35 years of Corvette restos would be laying all over town.Not to mention all the boats that I have done with 0 problems.If you will indulge me please take a little resin,mix a little talc untill it's thick,and mek,stir and leave the paint paddle in it and let it kick.After you find out that it is bad ass **** then go through it in a lake or pond close by and leave it all winter.When the ice melts or you can go boating again pull it out of the water.It will be every bit as hard and bonded as it was.:cool: Get a Job:D

Techno
11-29-2002, 04:07 PM
Profiling my profile Hmmmm?

I didn't know gel had talc in it. This means that gel and body filler are about the same thing. Body filler is polyester resin thickened with talc. The talc thing was from an auto paint site and if I remember it does absorb moisture so isn't a good thing to apply to steel. Water vapor does penetrate gel coat, I think that is the cause of osmosis blisters. It doesn't sink boats since it's water vapor not water. If it did pass clear through the hull it would be able to evaporate. Even epoxy isn't water proof, 3 coats = 98%
For your test you could use just about any filler and get the same result. I personally only use epoxy when it counts. But I don't limit to a particular thing but use whatever seems best, if gelcoat was the best for something I would probably use it. Just haven't found the need for it.
I never use poly for anything for wood, only epoxy. Poly doesn't bond to wood. Any one who doesn't believe this I leave it to them to check into themselves, but one point is they don't use it for wooden boats, they use epoxy.

I do think they should stop using that crappy gelcoat. But you don't have to throw out all the old boats just to make me happy, after all my boati is coated with it.

Heres my dash with the bondo. This is only the surface,which is all it's meant for. You can see the poly/milled glass goo that was used. Barely visable under the wheel location. Under the goo was glass/resin. Just a step in the filling process. Everything gets coated with either epoxy or epoxy paint so I don't think the bondo to be a problem in this case. The wooden dash was built and sealed with epoxy so the poly doesn't touch any wood.

Which do you prefer, perfumed baby powder or the original unscented?

Racemore
11-29-2002, 05:27 PM
I agree epoxy is the best thing going although vinylester is excellent.I don't know why bondo is so bad but it is.I have a 1970 rayson-craft daycruiser.When i started stripping it I found holes where there were cleats and they were filled with bondo.it was soft and I could dig it out easy,it sucks.Don't think that my baby**** will do that because it won't.Also if you do the experiment I said do make enough to spread between to pieces of plywood(fir plywood)or take 2 paint sticks and stick them together with it.I'll bet you you will not seperate them without destroying them.it will seperate the plywood first.I would have definitly used it on you dash.I did a 23 Eliminator that had the motor brackets set on the tunnels and we moved them out over the sponsons,the transom was sucked in bad where the brakets were,I ground the suface with 80grit and spread it across most of the transom because it was so wavey.It has 2 225 promax's on it and runs 96mph all over the river and is like a rock.I do layup glass to bring a bad surface up but in small areas I won't think twice about it being 1/2" thick if it's over a solid surface.Try it,you'll like it.:cool:

And yes water does cause osmosis even through gelcoat if it is left in it for extended periods of time BUT without gelcoat a boat would delaminate and fall apart in 5 years.something has to sheild it from light and moisture.Epoxy will work and is the future i'm sure.;) :cool:

Techno
11-29-2002, 10:13 PM
How does the talc putty sand? That the only reason I used the bondo.
I'll know this spring if the bondo is going to soften. I had it upside down over grass when I painted so should have absorbed.

Racemore
11-29-2002, 10:52 PM
Yes it sands very well.Does smell like a baby,guess you could get unscented.It does suck up a little so when I'm filling and area alot I mix it with gel without wax to assure the best bond,also white gelcoat and the light gray powder makes a good base for white color.On my boat I mixed yellow+red gel to get a close orange to the original color so if it is scratched through the finish gelcoat it hardly will show.:cool: If i can get some pic's put on a disk or scanned i'll show you a couple of projects where I gelcoated aluminium and wood 3 color,1 base and 2 splatter.he asked for it,he got it and it has held up for 6 years now.:)

Alan Power
11-30-2002, 01:46 PM
I've seen this come up a few times lately, Lloyd's specification for boatbuilding specify 1:12, that's bevel back 12 times the thickness of the laminate. I normally use 6 or 10 depending on where the repair is, on the bottom of the hull 10, on the deck or topsides 6 or 8.

Hope this sheads some light,
Regards; Alan...:)