Are more expensive epoxies better?

[Reefmagnet]

Originally Posted by mikedefieslife

Scales don't work on boats. Even small movements cause massive changes in the weighed figure making it impossible to be precise enough for small amounts . Most people are probably only using small amounts unless they undertaking a big repair or construction, in case they will probably be on land.




But mixing is normally by weight. Very few epoxies and 2 part paints that I've seen list the both weight and volume mixing instructions.

At very small volumes, it doesn't matter (imo). However, some epoxies do have a large variation in volumetric mass between epoxy and hardener. I always mix by volume and when there is a difference that matters (looking at you, West), I have a spreadsheet table that calculates the appropriate volume mixing proportions.

[StoneCrab]

Originally Posted by garyfdl

I've used Progressive Epoxy Polymers for years. Prices are good and Paul Oman's customer service is top notch. He will return call and emails if you have questions. The web-page is nothing short of bizarre, but once you wade through it there is tons of good information.

Marine Epoxy Links - Wooden fiberglass boat repair

I was considering buying from Progressive Epoxy Polymers but was put off by the website. Gives me a bad feeling about how trustworthy their product would be if they do business with such a mess of a website.

I was glad for your comment and appreciate the other testimonials which give them a thumbs up.

They even sell the copper flakes to make your own "copperbottom" antifouling at a fraction of the cost of the trademarked product. Feedback that I've read on that wasn't all positive.

The only other website which is comparable is the website for the Austrailian aluminum dingy manufacturer who build the Delos dingy Maggie. www.oceancraft.com It seems like an awesome dingy but I couldn't get past the website confusion. If you ask questions the responding emails are basically the same style. I never knew if the question was actually answered. With the AUS/$ exchange rate right now, it is tempting.

[Thumbs Up]

I used E-Bond epoxy. Over 40 gallons to repair my boat. They sell a west system clone and a Mas clone. I used the 5:1/3:1 extra slow. Costs less than $50 a gallon. They have all the engineering specs on their website and shows that structurally it compares to West. Epoxy resin is mostly all the same I think but the hardeners can be a lot different. Never had any problem with it. It does blush (so does west). With critical repairs I wouldn't trust "no blush" not to blush so need to treat for blush anyway. E-bond resin is about $200. for five gallons.

[thinwater]

Originally Posted by mikedefieslife

... But mixing is normally by weight. Very few epoxies and 2 part paints that I've seen list the both weight and volume mixing instructions.

The gravity is listed in the SDS. In practice the correction factor will be about 8%. I doubt either figure is that accurate.


I've used a scale on a boat. I guess it depends on the boat, but if it's moving that much I doubt you can work. Just sayin'.


I stopped using the pumps a decade ago. Any batch size, any product. Good scales are so cheap now.

[Chotu]

Another good trick to mix a small batch for 2:1 is using the caps.

[skipmac]

Originally Posted by Chotu

I’m sorry, but it’s nearly all the same stuff. It’s just BPA (the resin) and an aliphatic amine hardener. Only the tiniest of tweaks are made.

Actually there's a little more to epoxy than BPA. Basic epoxies are BPA reacted with epichlorohydrin. Epi is extremely toxic and I believe people that develop epoxy sensitivities do so because of the small amounts of unreacted epi in the end product.

There are other types of epoxy made by reacting epi with glycols or phenols.

Don't have the experience with the various brands that others posting on this thread have but I can say from experience in the chemical industry that sometimes the tiny tweaks can make a big difference in the product.

[Chotu]

Originally Posted by skipmac

Actually there's a little more to epoxy than BPA. Basic epoxies are BPA reacted with epichlorohydrin. Epi is extremely toxic and I believe people that develop epoxy sensitivities do so because of the small amounts of unreacted epi in the end product.

There are other types of epoxy made by reacting epi with glycols or phenols.

Don't have the experience with the various brands that others posting on this thread have but I can say from experience in the chemical industry that sometimes the tiny tweaks can make a big difference in the product.

Nope. The epoxy allergy is on the hardener side. The aliphatic amines are the part that you become sensitive to. There aren’t really any unreacted compounds in the end product to worry about. I’m SEVERELY allergic to epoxy. As in anaphylactic reactions so severe I typically have to go to the hospital. Even at this level, the end product (after 2-3 months) is safe for me to handle and be around. If there is liquid hardener around anywhere, it becomes airborne. This causes my lungs to stop working. Or.. if there is 5 or 10 year old end product around that gets abraded and the polymer gets ripped up, it releases enough amine to give me an anaphylactic reaction when that dust gets on my skin. If I were to breathe that, I’d have a good chance of dying. No issues with the BPA resin side.


Otherwise, yes, the BPA side is a touch more complex. System Three Silvertip is one of the phenol types. However, the epoxies do all work just as well as each other, which was the question. They all polymerize properly and the independently tested final physical properties of each are available to anyone in the form of spec sheets. Elongation, etc... all that is there for anyone to see and compare.

To answer the op again, they are all the same in terms of quality, except non blushing is easier to deal with. West was the original boat epoxy. Like a64 said, they made epoxy user friendly for the public and did all the advertising and marketing of it (which is why people consider it “better “ than polyester and vinylester when they are simply different tools). They also developed the literature on best practices and did a lot of testing. That’s what you’re paying for. The actual product isn’t really any different.

[skipmac]

Originally Posted by Chotu

Nope. The epoxy allergy is on the hardener side. The aliphatic amines are the part that you become sensitive to. There aren’t really any unreacted compounds in the end product to worry about.

On a practical basis there are always some unreacted ingredients in any chemical compound because it is impossible to get the exact number of molecules of each component in the original reaction. Specs on good quality epoxies indicate the level is very small, typically on the level of 1 ppm but that is a level considered hazardous. Whether or not that is enough to contribute to allergic reactions I cannot say but allergists seem to think it might be. https://acaai.org/resources/connect/...n%20irritation.

Don't disagree the hardener could be the main cause but depending on the epoxy there are at least five completely different chemicals used in hardeners. Would your reactions be the same whether the hardener is a aliphatic, polyamide or amine based hardener?

[capt.rob]

I agree Fg ( fiberglass coatings) in St. Petersburg Fla. has everything you need even kevlar in any quantity and will ship. I started using there products back in the 1970's buying by the drum when I had a marine repair business,they have consistantly been xlt. with everything you possibly may want. I also learned epoxy is epoxy I would simply buy standard epoxy rezin then add either thinner for penetration or cabosil, talc. or other filler for glue and and putty, there are also diferent hardners to controll set time. Just be sure if you are adding thinner or filler materials it's best to add them after the epoxy is mixed and don't make it a fast set like 5 minute unless that is what you need, slower cure times lead to a better saturation and stronger bonds.

[Chotu]

Originally Posted by skipmac

On a practical basis there are always some unreacted ingredients in any chemical compound because it is impossible to get the exact number of molecules of each component in the original reaction. Specs on good quality epoxies indicate the level is very small, typically on the level of 1 ppm but that is a level considered hazardous. Whether or not that is enough to contribute to allergic reactions I cannot say but allergists seem to think it might be. https://acaai.org/resources/connect/...n%20irritation.

Don't disagree the hardener could be the main cause but depending on the epoxy there are at least five completely different chemicals used in hardeners. Would your reactions be the same whether the hardener is a aliphatic, polyamide or amine based hardener?

The unreacted bits in this case have a lot more to do with our “pour it in a mixing cup and mix 2:1” methods I think. Nowhere near precise at the molecular level as in your line of work . Likely a lot higher unreacted components than the ideal. Still, after 2-3 months, all hardener is gone. Be it by evaporation or just degradation in contact with the air. I can touch epoxy after a few months of cure time. I can’t tell you why the unreacted hardener is gone by then. Just that it is.

To answer you question in the last paragraph, I don’t want to find out!! Ha ha ha.

[skipmac]

Originally Posted by Chotu

To answer you question in the last paragraph, I don’t want to find out!! Ha ha ha.

To be sure. I don't use tons of epoxy but enough and have for years. Used to be pretty careless but now I wear gloves any time I mix up a batch. No problems so far and I don't want to start.

Originally Posted by Chotu

The unreacted bits in this case have a lot more to do with our “pour it in a mixing cup and mix 2:1” methods I think. Nowhere near precise at the molecular level as in your line of work . Likely a lot higher unreacted components than the ideal. Still, after 2-3 months, all hardener is gone. Be it by evaporation or just degradation in contact with the air. I can touch epoxy after a few months of cure time. I can’t tell you why the unreacted hardener is gone by then. Just that it is.

Well epoxy hardening is a chemical process crosslinking the molecules into a solid matrix so I'm guessing all the stuff that cause sensitivity are locked into the matrix and not available as free molecules to stimulate the allergic reaction. But sand it and you've got all that stuff in fine particles in the air.

Sorry for the thread drift but I think for all reading this it bears to keep in mind that epoxy can be nasty stuff and you should always handle it properly. Gloves and if large quantities or in a poorly ventilated area wear a respirator.

[Chotu]

I’d second skipmac’s warning regarding epoxy. It’s often thought to be more benign and not as much of a health risk as other resins because it doesn’t smell as bad.

Couldn’t be farther from the truth!!

It’s highly toxic and a strong sensitizer. It’s not a question of if, but when you’ll develop a sensitivity or allergy to it. You get X number of exposures until it happens. The less exposure you get, the slower it will take you to get to X.

I was very careful and still got enough to keep me off Epoxy for life.

Use your gloves, breathing apparatus, keep it off you and clean with vinegar.

[mikereed100]

Originally Posted by Chotu

Use your gloves, breathing apparatus, keep it off you and clean with vinegar.

This is a point worth repeating. All too often we clean up with acetone, which just facilitates absorption through the skin.

[s/v Jedi]

It is about 2% of users that develop the allergy. I see no data on the amount of exposure being a factor but that seems common logic

[icemate]

Peace of mind and not wanting to do any project twice, I started with West Systems and stayed with West Systems.
When I bought my sailboat I sand all the bottom paint of and put 3 coats of West Barrier Coat on the entire hull. Then 2 coats of bottom paint (Offshore) of different colors. After 10 years and many haul outs there was not one blister or blemish on the entire hull. I use West for every repair and never regretted it. Time is money and doing it once with West makes sense.