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View Full Version : Proper Wat To Deal With Stress Cracks



H20MOFO
09-17-2007, 08:01 PM
Sorry If This Has Been Done To Death. Lookin At A Used Hull ,gel Is Gone.(enougph) If I Get It ,it's Paint Time. I Painted A Boat Once And It Had Very Few Stress Cracks. But They All Came Right Through.

DUCKY
09-19-2007, 02:11 PM
Fiberglass.......
If you want the cracks to go away permanently, they need to be ground out and glassed over. You also need to find out what caused them to begin with and cure the problem. If the cracks are in an inside radiused corner, chances are the deck is flexing and needs to be supported. If the cracks are near a bulkhead or the like, chances are the wood is fit too tightly to the hull and needs to be relieved. If the cracks are extending from screw holes, the holes need to be properly ground out, glassed up and then when the new ones are drilled, you should use a countersink bit to bevel the entrance. Anyways, hope this infor helps, Good Luck!

GAWnCA
09-19-2007, 02:32 PM
Fiberglass.......
If you want the cracks to go away permanently, they need to be ground out and glassed over. You also need to find out what caused them to begin with and cure the problem. If the cracks are in an inside radiused corner, chances are the deck is flexing and needs to be supported. If the cracks are near a bulkhead or the like, chances are the wood is fit too tightly to the hull and needs to be relieved. If the cracks are extending from screw holes, the holes need to be properly ground out, glassed up and then when the new ones are drilled, you should use a countersink bit to bevel the entrance. Anyways, hope this infor helps, Good Luck!
Ducky, One other thing, I found, don't over tighten screws and if possible, use bolts with washers behind the nuts. My problems came from the previous owner(s) putting in oval head screws and then tightening them much. The screws weren't of the proper size, too big for the job.

H20MOFO
09-20-2007, 10:41 AM
Will A Single Layer Of Cloth Do It Or Will It Take A Couple? I Was Hoping I Could Just Grind Em Out And Fill Em With Some Duraglass. I Figured That Would Be Way Too Easy.

DUCKY
09-20-2007, 10:54 AM
While through bolting is always better, screws are fine in their respective application with the proper size pilot hole, and a beveled edge.
Anyways, cloth is a waste of time. You need to use mat. usually a layer of 2-3 oz mat is sufficient. Cloth is just for making things look good, and you have to use mat under it anyways.

H20MOFO
09-20-2007, 11:20 AM
Forgive My Ignorance I Always Get Them Confused Cloth Looks"woven" And Mat Has All The Strands Goin Every Which Way? Correct? So I Should Use A Layer Of Each, Or Just Mat? Thanks In Advance. ALSO, WHATS A GOOLD RULE OF THUMB AS FAR AS WIDE SHOULD I GO? IS 1/2' ON EACH SIDE OF THE CRACK (1" TOTAL) WIDE ENOUGPH?

DUCKY
09-20-2007, 06:28 PM
The "magic" ratio for properly repairing broken fiberglass is 12:1, so if the hull was 1" thick, you would grind a 12" radius from the break, or if you grind out 1/8", you need a 1.5" radius (3" total), but for a stress crack (not all the way through), you can probably cut that in half. The most important part is getting a good bevel to the ground out area. Too steep of a bevel and it will just break again.

H20MOFO
09-20-2007, 07:23 PM
Thanks Ducky. If I'm Getin It. If You Havn't Ground To The Bottom Of The Crack You Haven't Got To The Bottom Of The Problem. There's An 1981 21' Daytona On Spam I'm Not Sure What To Expect . Are Daytona's Glass Only Everywhere? Or Wood And Glass?

H20MOFO
09-21-2007, 07:04 PM
Thanks Ducky. 12-1. Kinda Funny Did You Ever Notice How Everybody Says The Stress Cracks R Just In The Gel Coat. Rumor Has It The Boat Im Lookin At Has Bottom Damage(painted Bottom,or Something) In General ARE Out Boards Are A Lighter Lay Up X-cept For The Transom? Any Help Would Be Appreciated