Porous Gelcoat

D

dclagett

Well-known member
Joined
Aug 9, 2016
Messages
498
Fluid Motion Model
C-26
Last year I decided to fix a number of minor scratches in our dark blue hull that were there when we purchased the boat. After the yard completed the repairs I noticed hundreds of very small white dots around the repairs. This year as the yard was buffing the hull more of these dots are showing on areas of the hull that were not repaired. The yard was not using an aggressive compound, just 3M cleaner/wax. I did some research and found that these dots are probably air bubbles in the gelcoat. I have had 4 other boats with dark hulls and have never experienced this problem.

Has anyone experienced this problem with their gelcoat and if so what did you do about it?

The boat is only 3.5 years old and I guess I am looking at either painting or wrapping the hull.
 
I just finished repairing scratches on our 2014 R27 as well as giving it a full polish and wax. No spots like you describe were found. It came out beautiful!

Maybe you could post some pictures?

Curt
 
It sounds to me they got too aggressive with the compound... but I am no expert.
 
Sounds like it could be small gelcoat blisters to me. One out of four fiberglass boats can be expected to get them. Sometimes the blistering is very small but sometimes the blisters are big. If you had some photos, that would help.

Here's an article that goes into the cause and some treatments for gelcoat blisters if that's what they are:

http://www.boatus.com/magazine/2013/Jun ... isters.asp

Here's some highlights from the article:

Fiberglass hulls blister because the shiny exterior, the gelcoat layer, is not 100-percent impermeable to water. Seeking equilibrium, the water on the face of the gelcoat is drawn to dry voids on the back side – air pockets in the original lay-up or adhesive failures between laminates (particularly between the gelcoat and first layer). This attraction is intensified by loose soluble materials in the laminate, with which the water combines into larger molecules, too large to pass back through the gelcoat. Worse still, the solutions created are acidic, which can attack the resin and release more soluble material that attracts yet more water. The pressure that necessarily builds is released by expanding the volume of the void, pushing the gelcoat into a dome.

Blisters might signal a major defect due to either inferior materials or poor techniques when the hull was built, but absent a blistering history with other boats from the same builder, you should be slow to draw such a dire conclusion.

Blisters also occur because an inattentive worker may have failed to apply the gelcoat uniformly; because fluctuations in the mix from the resin sprayer may have created spots of soft gelcoat; because features in the mold may have induced thinner coverage; because the gelcoat may have been sanded to excess by the owner or yard; because chemical stripper may have been used on the bottom; because contaminants in the water may have attacked the gelcoat; or a dozen other reasons.
 
Sounds like the Gelcoat repair was too thick creating air bubbles in the finish that eventually POP or the tops of the bubbles are "CUT" by compound or even wax polished aggressively.

I find pinholes hard to repair, the gelcoat mix is too thick to penetrate those tiny holes. Have to dig out every hole and taper (crater) where the gelcoat will fill evenly and have something substantial to stick to.

It's been at least 8 years since I've done any fiberglass/gelcoat. Getting ready to hit some minor repairs on the Livingston Tender, then I'll attack the Tug...I have about 30 spots on the tender that are simple gelcoat repairs (blimishes) and 5 that are in the glass (up front where the tender was obviously nosed into the dock...

The glass repair is probably minor and would hold up if I simply applied a thin layer of Gelcoat, but I want to do some glass repair for practice, figure I can't hurt the Livingston...

I have heavy spider cracks on the weaver mount support in the transom of the Tug...I haven't removed the gelcoat to inspect the glass...I don't think the back support for the mount is sufficient for the job, holding that tender at cruise and in seas...Has anyone repaired these areas???
 
Red Raven – I requested last week to become a member of the user group that allows posting pictures, however I do not have that capability currently. I will post when I can.

Irish Mist – I am not an expert either, however having fiberglass boats since 1959 and having to compound several of them, I have never run into this problem. I believe if your gelcoat is consistent throughout its thickness aggressive compounding should not be a problem until you run out of gelcoat.

Scross – I have never seen or heard of blisters above the waterline, and these spots are way above the water line. Also, over the years I have seen many blisters on hulls and my spots do not resemble blisters. I wish I could post a picture to show folks.

TexasEye – the spots on my boat are on the original gelcoat not in the gelcoat repair area. Also, spots are beginning to show up where no repair has been done.

Thank you all for your responses.

I have looked around other boating forums and found that other boat manufactures have had this problem. After some research and studying my hull it appears that my gelcoat may be honeycombed with very tiny voids. The spots or voids diameter are approximately somewhere between a human hair and a small paper clip wire. They are white I believe due to the cleaner/wax getting into the voids and drying. I think what has happened is as the boat has been buffed over the last 3 years the outer layer of gelcoat has been worn down exposing the voids.

Again, I have never seen this on any other boat I have owned and I have had 4 boats with dark hulls ranging in age from 5 to 10 years old. These boats have had much more buffing than my current 3.5 year old tug.

As soon as I can post a picture I will. If someone has a different explanation or a way to remove/dissolve the cleaner/wax in these voids It would be much appreciated.
 
dclagett":2gjglgm8 said:
Red Raven – I requested last week to become a member of the user group that allows posting pictures, however I do not have that capability currently. I will post when I can.
Click to expand...

Sorry I missed your request. Just approved it and PM'ed instructions to get set up.

Cheers,

Bruce
 
Sounds like air bubbles in the gel coat when it was applied. You are just opening them up to the surface now. I think cleaning the compound out will be easier than filling the tiny holes (without opening each one of them up).

Where are you DIY guys getting gel coat scratch repair material that matches the dark blue Ranger color? Thanks.

Todd
 
Todd,

The only problem with trying to clean them out is they are so tiny and there are hundreds of them. I was hoping some type of solution would dissolve the wax in the voids and the wax residue could then be washed out. I would then need a wax that does not turn white when it dries or I am back to the same problem.

I just received the ability to post pictures today and will try to post a picture tomorrow when I get back from the boat.

Dick
 
Todd2":2a1sqwiy said:
Where are you DIY guys getting gel coat scratch repair material that matches the dark blue Ranger color? Thanks.

Todd
Click to expand...

Richard in the parts department at RT sent me some of the gel coat they use at the factory (mine is hero red). I use multiple coats with a very tiny artist brush to build it up for thin scratches as it is not a paste. I mix it with clear gel paste for deeper holes or scratches. Note: You need to use a MEKP catalyst to activate it and coat it with a wax solution once it starts to set as it will not fully cure if exposed to oxygen. You can get all but the matching gel coat itself from West Marine or other Chandlery.

Curt
 
For all those that are interested I have just added 2 pictures of the white spots in my album. If you look closely at the pictures you will see my fingers reflected in the image. I took the pictures within 6 inches of the hull so this should give you a reference for the size of the white spots, they are very tiny.

I had several experienced fiberglass professionals look at the hull and they agree that the gelcoat white spots are voids in the gelcoat filled with cleaner/wax. The pros say my options are: not to look at it too closely, have the hull painted, or have the hull wrapped.

The dark tan gelcoat around the cabin, which oxidizes more & quicker than the hull, does not have the same problem. It has been buffed, I think more than the hull since I can get to it easily, and has not showed any tendencies for developing visible white spots.

The areas of the hull that have been repaired using the factory dark blue gelcoat, which have been sanded and buffed after being sprayed on the hull, do not show any visible white spots. So all I can assume is that some anomaly occurred when the original gelcoat was sprayed in to the mold.

Since none of the respondents to this thread have seen this problem it must be rare on our Tugs.

Thanks for all your responses.
 
Wow! Nope, I have nothing like that!
 
"We had two very knowledgeable gelcoat guys look at our problem on the portside hull. They both said the the gelcoat suffers from a problem called "porosity". This creates very small pin holes in the gelcoat that somehow gives it a very dull and faded look". This is a quote from a post in 2016 ."Repainting Cost" sounds similar to your issue. I would speak to Ranger Tugs about your findings. Is there a 5 year Hull warranty?
 
Thanks Brian for finding that thread. I plan to go through my dealer to contact RT and try to get resolution to this problem.
 
I'm interested in your solution. I have pin holes in the gel of our C26 , some orange peal where the gel is thick and a honey Comb pattern in the Gel were it looks very thin. So far the wax is not filling the pin holes. The hull has a nice shine but there are a lot of blemishes in the Gel. I am proactive with maintenance of the Blue Hull. If I could do it over I would have purchased a white hull. Its harder to see the imperfections in the Gel.
 
Brian, I have contacted my dealer and they are willing to help resolve this problem. I will let you know what happens... Dick
 
Dreamchaser. Wow! That's worse than I was imagining. You can get the old white out of the pores with a wax and grease remover, and maybe a brush. However, in order to fill them all, I think it might take spraying thinned gelcoat over the area and sanding/buffing it down. Glad you are getting help from your dealer. Don't forget to come back here and tell us how they fixed it. Thanks.

Todd
 
My C28 is claret red and has the same problem on the visor. There in no pitting on the hull but it is covered with waterspots and drip line stains. I've had it professionally detailed and recently compounded and waxed it myself. Within a few days it looks the same. From an angle its nice and shiny but head on the water spots and hazing are quite visible. Options are wet sanding with 400 and working up to 1000 which is a lot of work, Repainting which is a lot of money, Wrapping in vinyl which only last a 2-5 yrs but still $2000-$3000, or living with it.
 
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