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  Topic Review (Newest First)
06-20-2006 06:59 PM
hellosailor "What's a good product to use on removing silicone?"
Elbow grease.

What is called "mechanical abrasion", scrape, chisel, or sand it away. There's an aerosol paint stripper called KleanStrip that will loosen most of it, but that's extremely strong stuff, read and follow the warnings if you use it.

"Next I plan on picking up some prep stuff to remove the silicone (as mentioned earlier) " There's a big difference between silicone rubber, and the silicone POLISHES that the prep compounds will remove. They remove waxes and polishes, they will not remove silicon sealer.

Real gel coat only hardens in the absence of oxygen, which is why it is normally sprayed inside a highly polished female mold and then covered with the other FRP materials. If you want to apply it over a male mold (the canoe) you'll need to cover with with something else like a PVA spray or it won't cure properly. Gel coat is also sensitive to thickness and the odds are it will CRACK badly as the canoe hull flexes under it. I've never heard of it being used on canoes.

"After the fiberglass is in there I'll attempt to feather it out and blend it to as level as possible without comprimising strength.
Does that sound like a good process/approach or am I missing something?"

What you're missing is that unless you follow the steps from an experienced materials supplier, you're going to have a very expensive mess on your hands. There's usually a reason for every material and process they suggest, and you can't just substitute for them. Fiberglass work is very much a matter of experience and patience, if you haven't worked with the materials and you take shortcuts, the result is going to be poor at best. West System aren't the only folks in the business, but they are a good place to start, they document the entire process and you can download most of it online FREE.
06-20-2006 06:15 PM
Faster The paints do require the proper primer, otherwise the paint won't stick to the fiberglass. They will cure to a mirror finish(without buffing/polishing) if properly prepared and applied. The finish depends greatly on the quality of the prep work. In fact, the paint finish can be soo shiny that it shows any flaws in your repair work and fairing.
Getting rid of any residual silicone is paramount. You need some nasty solvents, and multiple wipe downs to be sure its gone. This can also be an issue on boats that have had their gelcoat "restored" with silicone based products such as "penetrol".
For the canoe the water permeability is really a non issue. If the next project is trailerable, you could say the same. In any event, as noted above epoxy coatings are used as barriers in place of gel coat when blistered hulls are repaired.
Many of the better boat builders these days don't gelcoat their hulls, but choose to paint instead.

There is no structural strength in gelcoat or paint, but the 2 part paints will withstand more punishment than anything else.
06-20-2006 04:53 PM
natew I suppose I should have clarified *L* I was told that fiberglass if left untreated (I.E. no gel coat, paint etc,) will absorb some water because it's porous... no leak per-say but absorb water and deteriorate more quickly... Which would be stronger the gel coat or the paint?
06-20-2006 04:30 PM
sailingdog Epoxy-based paints are often used as osmosis barrier coats on sailboats, so an epoxy-based paint should provide relatively good protection to the fiberglass from water intrusion.

As to whether it will prevent your fiberglass repair from leaking...not necessarily. If you've botched the repair, no amount of paint will make it water tight.
06-20-2006 04:27 PM
natew that's amazing... I wasn't even aware of this paint stuff before... from what I'm seeing it does require a primer coat correct? does it require buffing and sanding/waxing after it's been painted?
06-20-2006 04:09 PM
Faster I'd still HIGHLY recommend you hone your painting skills on the canoe, and paint your next project as well. The long term results, especially if you use premium paint, (and proper primers) will outshine and outlast any after-the-fact gelcoat project. These days gelcoat just isn't done anymore. There's a better way to go.
Way less work and way better results.. for sure.
06-20-2006 02:14 PM
natew experiment is right *L* I'm going to re-do the gelcoat on an old twin hull fiberglass boat next that's why I'm thinking of doing the gelcoat here... I know it will be a lot of work putting it on then applying the plastic like layer then wetsanding it for hours but this is my experiment/practice run... not to mention time really isn't an issue for me since it's just an excuse for me to stay out of trouble *L*
06-20-2006 02:14 PM
Faster The poly paint will provide a decent barrier coat, but that really isn't the issue with a boat that is not always in the water anyway.
You can apply gel coat, but it will not cure to a nice finish like the paints will. So it's much more labor intensive to get a decent finish, and it is fibreglass resin, primarily, and is not impermeable to water. (again, not a huge issue on a canoe that is out of the water more than in it.) Fiberglass is permeable to water at a microscopic level, it's not going to "leak" without paint unless the repairs are faulty.
One part poly paint will likely do a decent job for you but will not withstand abuse, bumps and scrapes as well as the two-parts will. They are a lot less expensive, though, and may serve your purpose.
I would think that one part poly would be no more money than gelcoat.
06-20-2006 02:08 PM
Gary M Being a canoe I assume it will not be in the water all the time so gel coat is water proof enough. Gel coat after many years will admit some moisture which can develope into a problem for say a keel boat but not a canoe.

You will have trouble gettign a nice finish painting gel coat on. It would have to be sanded and buffed way more that it is worth. A pint of single epoxy paint would be about $30 and would come out nice and shiny.

Most epoxy paints are for use above the water line, but again if it is only going to be submerged for short periods that is probably OK. This is a learning experiment right?
06-20-2006 01:53 PM
natew just to make sure I'm reading everything correctly the epoxy paint will provide the waterproofing layer correct? so when I put it on it will seal in my fiberglass so It doesn't leak at all? The reason I ask is because someone told me that bare fiberglass is not that true?
Also, that paint seems quite a bit more expensive than gelcoat so why would I go the more expensive route? Basically, what do I gain by going with the paint vs. gelcoating?
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