Suggestions on fixing this crack

[sodaksker]

Is something that can be wet sanded and then polished out with rubbing compound or should I just live with it. I have about 6 of them down one side of my boat.

Thanks for any suggestions.

[BASSCAT7]

Those are fairly good sized stress cracks. They can be made less noticeable by wetsanding / compunding but cannot be sanded completley out as they go down to the resin/mat layer.
If these are on a mid 90's Champ there is a good chance they will come right back when you get into some really rough stuff or get bounced off a dock piling.

[sodaksker]

They are off the 94 champ that I have. I have some oxidation down that same side. The other side of the boat looks near perfect. The guy I bought the boat from claims that the side with the cracks and oxidation is the side that was exposed to the sun when stored under his leanto. Those big cracks, I figured were a little deeper. I'll wet sand and buff that side out and see how it goes. I am only going to do the top cap on that side. Any guesses on how long that will take to wet sand, and what grit would you rec starting with?

Thanks for all your help.

[BASSCAT7]

The oxidation is definitely from the sun hitting it, the stress cracks no. Those mid/late 90's Champs were prone to stress cracking like that.

To do one side on the top/cap side hull is going to take a good 4 hours to wet sand down taking your time.
You'll have to test the grit on the cracks, start with 800 and see if it will take them down smooth, if not drop down.
Whatever grit you start with, you'll need 2 successive higher grits to take out the progressively finer sanding marks, then the compound/buffer to smooth out the final sand marks.
Follow the post on gelcoat pinned at the top.

[sodaksker]

Thanks for the info basscatt.....just what i was looking for. I'll see if I can do some before and after pics and post later.

Thanks again

Rob

[pappastratos]

How long are these cracks ? both sides ? I saw a Pathfinder bay boat start cracking where hull starts turning in. They got worse. Looked like boat was going to break in half. Can you access the inside of these ? You need to make sure of the integrity of the hull espically if you have a large motor & run fast. Can be repaired from the inside if necessary.

[sodaksker]

They are just on the one side. Length is about 4-5 inches. They run from the corner of the top cap to the rub rail, just like in the picture posted above.

[MMosher]

Call em battle scars and go fishing. I freaked the first time I got em too. Stess cracks happen.

[pappastratos]

Ok, I thought they were on the hull,

[sodaksker]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by MMosher &raquo;</td></tr><tr><td class="quote">Call em battle scars and go fishing. I freaked the first time I got em too. Stess cracks happen.</td></tr></table>

I was bored and had some resin from a bondo kit. I tried to fill one of the cracks with that resin, with the hopes that I can sand it smooth later. Any thoughts on whether that will work or not?

[BASSCAT7]

Most stress cracks are really hard to fill in because they are so thin. To do it right, the crack needs to be opened up and V'd down so the resin will have some adhesion. Otherwise if you just attempt to lay the resin on the original stress crack there is a good chance it will not adhere to well and first couple of jolts will have it fall apart.

The other problem is that most stress cracks are caused by the hull flexing in a certain spot, usually near a radius like the splash well, where a console meets the hull or on the curve where the top cap meets the hull. The flexing can be caused by lack of bracing in the area which means the cracks will usually return.

Impact stress cracks are caused by whacking something, a dock post, etc. Those can be fixed and will not return.

[sodaksker]

Bcatt,

Here is a pic of the bondo resin that I put over the crack. I noticed that it looked like it was not bonding correctly. I could take my fingernail and chip it away. Could this be due to the fact that I did not prep the area correctly? The boat had fresh coat of wax on it. I had prepped the other areas for repair by sanding and then cleaning with mineral spirits. I had left over resin and just thought I would try it here to see what it would do and applied the resin without prep. My thought is that the fresh coat of wax kept it from bonding.

thoughts?

[BASSCAT7]

The wax will definitely keep any resin from bonding to gelcoat.

Fresh catalyzed resin laid on a stress crack is not going to work. To do it right, the crack needs to be opened up and V'd down so the resin will have some adhesion. Otherwise if you just attempt to lay the resin on the original stress crack there is a good chance it will not adhere too well and first couple of jolts will have it fall apart or peel off like yours did.
The crack is barely wide enough to get any resin to seep into it, on top of that, the resin is just sitting on top of a hardened gel coat surface. Without any sanding to the surface or V'ing of the crack there is nothing really for the resin to adhere sufficiently.
Any repair to a gelcoat surface needs to be prepped so the fresh resin or gel will adhere. Gelcoat is very hard, and slick and needs to be scuffed at the least for repair work to have a chance to stick.
When spraying new gelcoat on top of existing gelcoat, it needs to be cleaned extremely well to remove any surface contaminants, The Gel has microscopic pores that can hold wax/dirt/pollution and all this needs to come out.
Otherwise while the repair is curing ( heat is produced when the gel/resin is catalyzed ) these contaminants can migrate to the surface and cause the new repair to not bond solidly to the old gelcoat.
Ideally if spraying new gel, you want to clean the surface well with acetone which will remove all the contaminants, lightly scuff the surface then wipe it with Styrene to activate the old gel some to form the chemical bond with the new gel.