Repairing Cracks

[Wayne Johnstone]

Hi all,

I am looking at repairing some cracks in one of my Fibreglass boats, what is the best way to go about doing this?

 

[Kez]

Hi,

Your pictures showed what appeared to be crackings in the gel coat. This is what I do to repair gel coat cracks.

1. Wash the entire boat with soap and wipe with a compatible solvent to remove any oil,

2. Use a Dremel with a fine bit (not a cutting bit, it is too coarse) like a diamond grinding bit, open up the cracks to about 1/16" to 1/8". I try not to cut into the glass underneath.

3. I learned this tip from this forum and it is very important: Where the crack terminates, make a larger diameter hole like 1/8 to 3/16". I have found that it is not necessary to drill the hole through the glass. A rounded area in the gel coat will work. This serve to distribute the stress so that the crack will not propagate. A forum member suggested this tip and it is very useful.

4. Fill the crack with either Bondo, or a mixture of micro ballons and resin. I have tried using a color matched gel coat to fill the crack. It work somewhat OK but I cannot make the repair invisible without repainting.

5. Block sand, prime and touch up paint.

I have repaired a few boats and the crack has not reappeared, yet.

kez

 

[glenng]

#3 the practice of stop drilling is to prevent cracks from spreading. Does not matter if you drill all the way thru the glass or not. It is much harder for a crack to cointinue from a radius.The drill needs to be no larger than 1/8" but you do need to know where the crack terminates.to be sucessfull.