I'm in search of something to fill in small holes that doesnt require me to lug three gallons of resin/hardener, a giant container of 404 and all of the other accessories. Marine Tex is way over priced. I was looking at PC-11. Has anyone tried it?
Small and quick fix fiberglass filler
- Thread starter Project_Mayhem
- Start date
I use PC-11 for many things. It is just a 2-part epoxy filler like Marine Tex. Also like Marine Tex, it is a bit of a pain to sand and fair if you are finishing over it.
Mark
Mark
West Systems Six10 or TotalBoat Thixio, both are thickened epoxies that come in a cartridge that fits in a caulking gun. Use a good quality caulking gun, the epoxies are thick, especially when cold and the cheap $2 guns aren't up to the task. They are marketed as adhesives, but work quite well for filling small holes.
www.westsystem.com
www.totalboat.com
Six10 Thickened Epoxy Adhesive | WEST SYSTEM Epoxy
Six10 Thickened Epoxy Adhesive has a static mixer and is designed to bond to wood fiber, metals, composites, and masonry.
www.westsystem.com
TotalBoat Thixo 2:1 Epoxy Adhesive System
Thixo is a high-strength, two-part epoxy adhesive system that comes in a convenient cartridge. Dispense a bead of thickened, structural epoxy anywhere you need it.
www.totalboat.com
Marine Tex is great but pricey. I've used plumbers epoxy with great success a few times. It was the only thing that would stop a small leak below the waterline. However, it's slightly absorbent. Does PC11 absorb water/moisture?
I use the cast caulk gun from Home Depot. It's leaps and bounds better than the stamped ones.West Systems Six10 or TotalBoat Thixio, both are thickened epoxies that come in a cartridge that fits in a caulking gun. Use a good quality caulking gun, the epoxies are thick, especially when cold and the cheap $2 guns aren't up to the task. They are marketed as adhesives, but work quite well for filling small holes.
Six10 Thickened Epoxy Adhesive | WEST SYSTEM Epoxy
Six10 Thickened Epoxy Adhesive has a static mixer and is designed to bond to wood fiber, metals, composites, and masonry.
TotalBoat Thixo 2:1 Epoxy Adhesive System
Thixo is a high-strength, two-part epoxy adhesive system that comes in a convenient cartridge. Dispense a bead of thickened, structural epoxy anywhere you need it.
I love the idea of these products. How often do the tips need to be replaced? Is it hard like epoxy or soft like caulk?
The tips are a one time use. It hardens just like epoxy because it is epoxy. Inside the tube are 2 sections, one resin, one hardener. When the epoxy is squeezed out it goes through a mixing tube and is properly mixed. They have a long working time, about an hour so there is plenty of time to fill lots of holes.
The tip on six10 is a mixing tip, so it needs to be replaced after you finish your job, you install a new one when you need to continue using the tube, the tips are screwed on, the epoxy and hardener are separate inside the tube.
I used this product many times and it is a wonderful product, easy to use, good thickness, so it won’t run (obviously will if you put too much)
The tube comes with a mixing tip and you buy extra ones if needed, they come in packs of 2 last time I bought some.
I used this product many times and it is a wonderful product, easy to use, good thickness, so it won’t run (obviously will if you put too much)
The tube comes with a mixing tip and you buy extra ones if needed, they come in packs of 2 last time I bought some.
TB's Thixo isn't horribly priced and the tips are around $1 each when bought in a 12 pack. I think the convenience is well worth it
Good to know. Thixo comes with 2 tips and it is always disheartening to use one of them for a single small repair. I never seem to have enough damages or voids to make it worthwhile to use a tip. Buying a 12-pack makes it a bit more convenient for small repairs at various times.
I've never noticed it absorbing water. To me, it seems identical to Marine Tex, only cheaper because it doesn't have "marine" in its name.
Mark
I have dispensed small amounts of Thixo without using the tip. You obviously then have to mix it yourself but that's no big deal.
You don't "waste" a tip and you don't waste the amount of product stuck in the tip.
If only there were a vast database of information that you could easily search with a query like “epoxy mixing tips”….
Years ago I worked for a company that, among many other things, manufactured epoxy adhesives that utilized these mixing nozzles. We actually designed the mixing nozzles for the specific product and those nozzles were made specifically for the product it was sold for. There is actually quite a bit of science in the manufacture of these mixing nozzles - the quest for finding cheap, off-the-shelf mixing nozzles is not a good one.. Just my 2 cents worth...If only there were a vast database of information that you could easily search with a query like “epoxy mixing tips”….
dj
Depends on your aim. My boat's all-wood and I haven't had a fiberglass boat for about 30 years, but I've worked on plenty. I worked for Catalina for a bit back in the day doing layups and earned the odd cash working on other people's boats when I still had the back for it.
I’ve used PC-11 plenty of times over the years. It’s a perfectly serviceable filler, and no, I’ve never seen it take up water. If you mix it properly and put it on a clean, dry surface, it stays put and stays dry. It sands about the same as Marine-Tex - which is to say, you’ll be working a bit harder than you’d like, but it finishes fine.
Six10 and Thixo are good products if convenience is what you’re after. The mixing tips are single-use because the epoxy cures inside them. There’s no saving a tip once resin and hardener have met, no matter what brand you buy. If you’re only filling a couple of small holes, you can dispense without the tip and mix it by hand like Richard mentioned. That works, though the cartridge is really designed around the static mixer.
For small jobs, the only real question is how much gear you want to carry. The cartridge systems win on simplicity. PC-11 wins on price. A small batch of regular epoxy and a bit of silica gives you the most control, though it means carrying more supplies. Still, that's my preference. I carry the raw materials and mix whatever I need to suit the job. But, I also tend to spend a lot of time off-shore or in parts of the world where I can't always find fancy materials. I carry a couple of small bottles of System Three and a variety of fillers, and that suits me down to the ground for almost any repair that comes up.
If all you’re doing is filling a handful of screw holes, any of the above will work. I’d use whichever one you don’t mind sanding tomorrow.
Now, if getting perfect match with your gel coat is your goal, that changes my answer.
If you’re chasing a clean gelcoat match, straight epoxy fillers aren’t your best friend. PC-11, Marine-Tex, Six10 - they all cure harder and darker than gelcoat, and you’ll see the patch unless it’s under hardware or trim.
For a visible surface repair you’re better off treating the epoxy as the structural step, not the finish. Fill the hole with whatever epoxy product you like - PC-11 is fine for that - then fair it and come back over it with gelcoat paste that’s been color-matched. That gives you control over the final surface, because the gelcoat is what you’re actually blending in, not the epoxy.
If you try to tint an epoxy filler to match the surrounding gelcoat, you’ll rarely get it right. Even if you get close on day one, UV will age the two materials differently. Epoxy yellows over time; gelcoat does it in its own way.
So the workflow I’d use for a visible surface repair:
I’ve used PC-11 plenty of times over the years. It’s a perfectly serviceable filler, and no, I’ve never seen it take up water. If you mix it properly and put it on a clean, dry surface, it stays put and stays dry. It sands about the same as Marine-Tex - which is to say, you’ll be working a bit harder than you’d like, but it finishes fine.
Six10 and Thixo are good products if convenience is what you’re after. The mixing tips are single-use because the epoxy cures inside them. There’s no saving a tip once resin and hardener have met, no matter what brand you buy. If you’re only filling a couple of small holes, you can dispense without the tip and mix it by hand like Richard mentioned. That works, though the cartridge is really designed around the static mixer.
For small jobs, the only real question is how much gear you want to carry. The cartridge systems win on simplicity. PC-11 wins on price. A small batch of regular epoxy and a bit of silica gives you the most control, though it means carrying more supplies. Still, that's my preference. I carry the raw materials and mix whatever I need to suit the job. But, I also tend to spend a lot of time off-shore or in parts of the world where I can't always find fancy materials. I carry a couple of small bottles of System Three and a variety of fillers, and that suits me down to the ground for almost any repair that comes up.
If all you’re doing is filling a handful of screw holes, any of the above will work. I’d use whichever one you don’t mind sanding tomorrow.
Now, if getting perfect match with your gel coat is your goal, that changes my answer.
If you’re chasing a clean gelcoat match, straight epoxy fillers aren’t your best friend. PC-11, Marine-Tex, Six10 - they all cure harder and darker than gelcoat, and you’ll see the patch unless it’s under hardware or trim.
For a visible surface repair you’re better off treating the epoxy as the structural step, not the finish. Fill the hole with whatever epoxy product you like - PC-11 is fine for that - then fair it and come back over it with gelcoat paste that’s been color-matched. That gives you control over the final surface, because the gelcoat is what you’re actually blending in, not the epoxy.
If you try to tint an epoxy filler to match the surrounding gelcoat, you’ll rarely get it right. Even if you get close on day one, UV will age the two materials differently. Epoxy yellows over time; gelcoat does it in its own way.
So the workflow I’d use for a visible surface repair:
- Fill and fair the hole with whatever epoxy is convenient.
- Seal it and sand it smooth.
- Apply color-matched gelcoat paste over the top and finish sand/polish.
- That’s the way to make it disappear. Epoxy alone won’t get you there.
Do you such a thing it might also contain forums to discuss sailboats as well?If only there were a vast database of information that you could easily search with a query like “epoxy mixing tips”….
Sir, I have a feeling you're going to be a fairly active and valued member here. Once again, Welcome!
Both products have different advantages for sure. I ordered Thixo yesterday and have some PC-11 that I will attempt to use today to fill in some crushed fiberglass on the underside of the deck where a stanchion was pulled too hard. It's also going to adhere some G10 as a backing plate. I'm guessing that the consistency of the PC-11 will keeps itself in place upside down quite well while Thixo or Six10 might drip or at least have a higher potential to make a mess.
Is there a difference between different pigments such as pigments for household paint vs gel coat? Does one hold up to UV better than another
Are all tints the same?
No all tints are not the same. In fact this is an area of highly proprietary formulas.
You would need to know the manufacturer of the tint and their specific ID number to even begin to answer the question first above. Good luck trying to get that info....
dj
On pigments: paint tints, gelcoat tints, and epoxy tints are not interchangeable. They’re different chemistries meant to bond to different resins.
Gelcoat pigments are made for polyester/vinylester resins. They stay stable in UV because the polyester does most of the work. Epoxy-based pigments are designed to cure inside an epoxy matrix. Household paint tints are a completely different chemistry and won’t stay stable in resin at all - wrong solvents, wrong binders.
Even within the proper families, tints aren’t really universal. White from Brand A may not look anything like white from Brand B once you cure and sand it. UV stability also varies: the pigments themselves are usually fine, but the resin around them ages at its own pace.
That’s why when you’re trying to make a visible repair disappear, you get the structural part right with epoxy, then cover it with gelcoat paste that’s matched to the boat. That’s the only part of the sandwich the eye will ever see, and gelcoat is what will weather alongside the original gelcoat.
Trying to tint the filler itself is a fight you’ll lose over time. Epoxy yellows, polyester doesn’t do it the same way, and the patch will “print through” sooner or later.
If the repair is under hardware and never sees daylight, it doesn’t matter. If it’s anywhere you’ll look at twice, use gelcoat over the epoxy and tint that.
That’s the only way to get as close to invisible as fiberglass work ever gets.
Color-matching gelcoat is often looked at as voodoo, but it's just a slow, deliberate process. Nobody gets it right in one mix. What you’re doing is sneaking up on the color.
The basic process looks like this:
1. Start with a neutral white gelcoat paste.
That gives you a predictable base. Don’t try to rescue the boat’s existing color by starting with “off-white” from a different brand; that just adds variables.
2. Use proper polyester gelcoat pigments.
A primary set (white, black, yellow, red, blue, brown) is enough. A boat that’s been in the sun will almost always need yellow or brown—boats fade toward cream, not toward gray.
3. Mix tiny batches - teaspoon-sized.
You’re not making the final coat yet. You’re finding the recipe. I usually take a bit of gelcoat paste on a scrap board, add pigment with a toothpick, and note the proportions. When adding darks like brown and black, it really takes just the tiniest amount. I measure these by dipping a toothpick about a half-inch in the black and then mixing the gelcoat with that stick. That is "one" dose of black - not a precise measure, but close enough. The larger you make each batch, the more consistent you are able to make your proportions, but the more gelcoat you will waste. I don't worry about that too much. I just make each test batch about double what I will need for the final repair. I'm able to get consistent results with fewer attempts and that makes it cheaper, or about the same, in the long run.
4. Test-mix, smear, and let it cure before judging.
Gelcoat changes shade as it kicks. What looks right wet will be wrong once cured. I wipe a little onto a scrap of masking tape stuck on the hull. Most people skip this wait and ruin the match.
5. Adjust toward the hull one direction at a time.
Too bright - add a touch of yellow.
Too warm - a toothpick of blue.
Too brown - a dot of white plus a hint of yellow.
Never fix a mix with the opposite color - that’s how you end up with mud. If you add too much of a color to a batch, just scrap it and start over. You can dilute a mistake by adding more white, but that makes it hard to repeat the formula. Just be consistent and deliberate and you'll get there. But for god's sake, write everything down! There is nothing worse than finally getting it perfect and not remembering how you did it. I might have done this once or twice before I finally learned to write the proportions of each batch with a pencil directly on the gelcoat near the repair because otherwise I'll lose them or get confused about which formula is the latest and correct.
6. When your cured swatch vanishes at a glance, make the real batch.
If you have to, scale up the proportions and catalyze normally. I try not to have to scale up, though. I prefer my final batch to be the exact size as my test batches.
7. Apply slightly proud, then wet-sand and buff it flat.
The blend happens in the sanding, not the mixing. Once you feather the transition and polish it, the repair melts visually into the surrounding gelcoat.
A few practical notes:
- Expect the surrounding hull to be sun-faded. Don’t try to match the original color deep inside a locker. Match what’s actually on the topsides.
- Expect the first mix to be wrong. Everyone’s first mix is wrong. I can sometimes get it right on the third try, but it takes as many tests as it takes. If you're about 10 tries in and haven't figured it out, start over, ask for help, or both.
- Keep your winning formula for a few months. Expect UV to shift the match slightly over the first month. Good repairs settle in. If you're really particular, and it just doesn't look right after a month in the sun, you can sand off, adjust your formula, and try again. If you're that fussy, though, you're in the wrong sport.
- If the area is large or very exposed, I’ll often clear-coat the repair afterward. It evens out gloss differences.
I watched a fellow in Malta who did nothing but gelcoat repairs. He did them all in one shot - no test batches - and he didn't even wait for them to cure. I couldn't speak with him, but I talked to a couple of the lads who did structural repairs and they said he gets it perfect every time and that's all he does. Everyone uses him because he is fast and does a better job than anyone else. He worked about 2 hours a day and that was his entire livelihood. He left the docks in a Jaguar.
I tried to learn his secret, but it's a mystery. I assume he went home to turn lead into gold.
So, if you're ever in Malta, try to find that fellow. For us mere mortals, the slow way is the reliable way.
From the above, sounds like PC-11 would be fine. Some other options are:
WEST sells a patch kit that comes with small packets of epoxy & silica. Pre-thickened fairing compound like TotalFair can be appropriate for some purposes. If it's not critical, 5 minute epoxy in the little squirter tubes can be thickened in the usual manner. You can buy G-Flex in small bottles that let you mix up just a bit.
WEST sells a patch kit that comes with small packets of epoxy & silica. Pre-thickened fairing compound like TotalFair can be appropriate for some purposes. If it's not critical, 5 minute epoxy in the little squirter tubes can be thickened in the usual manner. You can buy G-Flex in small bottles that let you mix up just a bit.
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