Thread subject: Whaler Central - Boston Whaler Boat Information and Photos :: how to fix the spider cracks
Posted by franknall on 01/16/10 - 7:53 PM
#1
they are all over my 1971 whaler katama
Posted by Fishmore on 01/17/10 - 2:44 AM
#2
From the reading I have done (because I have the same problem) there are several ways to go about this. All involve removing the interior and rails.
1. Soda blast or sand the interior smooth and gel coat it again.
2. Sand it and fill any divits or holes then coat it with a high hide protective paint such as Ultra TUFF or Rhino coat bedliner or Line-X.
3. Grind out and fill in all cracks and divits with epoxy or polyester resin and then paint it with a top side boat paint or a two-part polyurethane boat paint.
4. Grind out and fill all cracks then sand smooth and add a new layer of gelcoat.
I am currently leaning towards item 2 and using the Ultra TUFF coating as I have read that the new gelcoat will just crack again.
Posted by kamie on 01/17/10 - 5:42 AM
#3
The best method for filling depends on the cracks and the finish you plan to put on top.
Photo's help to see what your looking at, so create a personal page, that way folks can help you out.
Posted by modenacart on 01/17/10 - 6:42 AM
#4
Sand or grind out the cracks. Fill with thicken polyester resin or a premium filler. If you are painting instead of gelcoating you can use epoxy. If you are gelcoating, make sure your filler is compatible with gelcoat.
Posted by DWinter on 01/17/10 - 9:20 AM
#5
I've repaired more than I want to think about and the proper way is to grind the cracks down to the glass usually with a Dremol tool, and refill with marine grade filler or gel paste. If you color matched gel paste (small repairs) Then sand and buff. Or just respray with gel, sand and buff.
Posted by marineresorts on 02/02/10 - 8:42 AM
#6
if you have spidercracks all over the interior it would be best to use a thin fiberglass cloth over the whole interior with poly resin. sanding cracks down or throwing some filler on them will work for a few months. but soon the cracks will return. all that work for a temporary fix sucks! and if you're concerned about weight of new gel and fiberglass, its not that bad. i have 15 pounds of fat that i need to lose. If i go on a diet and lose it, then that will offset my boats weight gain.
Posted by Blackduck on 02/02/10 - 9:34 AM
#7
If tight, the cracks are only a visual problem. No matter how you repair them, they will return. I would compound and wax, and live with them, repairing any that are really wide. We all start to crack by the time we reach 40.
Posted by 510racer on 02/02/10 - 10:44 AM
#8
Left exposed, any cracks in the gelcoat can and will allow water to reach the fiberglass and eventually lead to delaminated and compromised fiberglass. Wax will help, but because the cracks can move the wax barrier will also fail over time and is only a bandaid.
There are a couple of reasons gelcoat gets cracks.
1. The original gelcoat was put on too thick , a common problem with some boston whalers I have refinished (I have seen 1/8" or 125 mils +). Thick gelcoat cracks under minor flex where thinner will not. Also, gelcoat shrinks over time and exposure to the sun makes the effects worse.
2. The fiberglass under the gelcoat has been compromised, too much flex will cause the gelcoat to crack, these will typically be spider cracks.
In my opinion, the correct repair would be to re-gelcoat anywhere that has cracks.
First, You need to identify which problem caused the cracks.
If the underlying fiberglass has been structurally compromised and flex is causing the cracks, the area needs to be repaired and made structurally sound.
If the cracks were cause by shrinkage only and the underlying fiberglass is still sound.
First, sand any areas with cracks down to the glass, being careful to not to go into the glass at all. Its ok if you leave a mil or 2 of gelcoat unless there is any delamination or loose gelcoat. at this thickness the cracks in the gelcoat will not be a problem for the new gelcoat sticking.
Clean with acetone or laquer thinner.
You have two optons here.
You can gelcoat to 35 - 40 mils thick, sand out orange peel which will leave you at ~ 20-30 mils, then top coat with a paint of your choice.
Or,
Gelcoat to 35 - 40 mils thick, sand out orange peel working your way up to 1000 grit, followed up with compound, which will leave you at ~ 20-30 mils
It is very important that the final gelcoat thickness after sanding / polishing should be 20 - 30 mils, any thicker and you risk cracking over time. The thicker it is, the sooner it will crack.
Posted by spitnsputter on 02/14/10 - 7:03 PM
#9
Hi ...Ive got a 1971 nauset hull that has the spider cracks and i would like to send photos..I thought of pouring epoxy into these cracks then paint...but your saying gelcoat is the way to go?? Ive never getlcoated before ...but this whaler is worth it to me to do good job...The whole cockpit floor is as hard as a rock ...no sagging or soft spots..How do you send photos?? Thanks...
Posted by spitnsputter on 02/15/10 - 5:50 PM
#11
Thanks...i appreciate that...
Posted by ppandr on 02/15/10 - 7:55 PM
#12
Purist's....Keep an open mind on this idea
Would a Liquid Rubber product work to recoat/paint the exterior hull. My entire hull is spider cracked for the most part. Obviously the durability/hardness of the coating is softer vs. abrasion but it would be relatively easy to touch up and would surely seal the hull. This would be the same product used to recoat inflatables.
Posted by ppandr on 02/16/10 - 5:32 PM
#13
Any thoughts on the Liquid Rubber product? Actually someone makes a top coat for over the Liquid Rubber as well...also for inflatables.
Edited by ppandr on 02/16/10 - 6:07 PM