Spider Cracks: The Guide

Spider crack DYK

Spider Cracks are a thorn in many boaters side. They seem to appear out of nowhere, and for no reason. Fixing them can involve more than just slapping on some gelcoat, however, and that is where we come in!

The first step needs to be ensuring that your spider cracks are just that, and not a sign of a soggy core, or a broken support. If the underside looks solid, and the surface is steady, then a spider crack is just a spider crack.

For properly fixing a spider crack, you will want to open the cracks to properly fill them. Usually, the easiest way to do that is with a Dremel. Once you open the cracks to a good size, you can lightly sand the surface and wash it down with soap and water, or Acetone to get the surface clean.

From there, you will want some Gelcoat Putty. Gelcoat putty is sold in many sizes, and only requires you mix in a 1-1/2% ratio of MEK-P Catalyst. Once mixed properly, you can use a putty knife to work the putty in the cracks. Once dry, you will sand to a nice, smooth surface and you are ready for the last part.

Now that you have a nice, smooth surface, you probably notice your white patch is still, well, white. Now you want to apply some gelcoat over the top to cover your patch. We can match gelcoat to a sample you provide, or you can check out the stock colors we have. We even have a brushable gelcoat that just requires you to brush it on and be done.

So, there you have it! Your patch is done, and that pesky spider crack is gone, and your boat is good as new! If you have any questions, you can call our technicians or comment in the section below. We are here to help!

FGCI New Product Spotlight: Spider-Crack Repair Kit

spider crack kit-1Here at FGCI, we look to make common problems easy to solve and make difficult projects doable for the do-it-yourselfer. With that being said, we are introducing an easy solution to a very common question we get; “how do I fix spider-cracks?”

Let me introduce our Spider-Crack Repair Kit, including everything you need to fix those pesky cracks:

  • 1 – Cordless two-speed dremel tool, complete with bits to bore out the cracks
  • 1 – ½ pint of Gelcoat Putty to fill in the bored out cracks
  • 1 – 1 oz MEKP bottle to catalyze the putty (see catalyst chart for amounts)
  • 1 – 9” x 11” sheet of 80 grit sandpaper to sand down the repaired area to a smooth finish

Now your spider-cracks are fixed and the surface is ready for the matching gelcoat (not included) to make your repair un-noticeable and the area look like new.

Now, before you simply fix them, you want to make sure the reason the cracks are there isn’t because something is just broken underneath the fiberglass, causing flexing. Make sure you inspect the surrounding area for softness to ensure it’s not flexing too much, causing further cracking.