Vinylester Resin or Epoxy, How To Tell

[unbusted67]

Originally Posted by minaret

Believe me, cost is not a factor in this decision. Our yard charges top dollar, our clients can easily afford any material we choose to use, and labor makes up 95% or more of the average bill. Clients are billed for materials with the usual markup, we would actually make more money using epoxy (mostly because jobs would take much longer but also because materials would triple in price). We choose to use poly strictly because its often the better material for the job. And it allows us to get our clients out the door with pro results much faster. Ever seen a thruster tube fail? I've glassed in a great many, never done one in anything but poly. Done lots of roll stabilizers, major keel repairs/rebuilds, huge holes in boats, etc etc. All in poly, all with zero failures. Poly not bonding well to poly is a myth which is propagated on this forum far too much, and it does boaters a disservice. Just learn to prep properly and save yourself a whole lot of time and money.

Sort for the confusion. Actually was confusing vinylester with polyester resin. So polyester cures quicker than epoxy. I didn't realize that.

[colemj]

Originally Posted by Krogensailor

I've built enough to know what my nose tells me, this **** stinks and is def not good for you. Neither is the epoxy, but one is worse than the other in my estimation.

Don't be fooled by your nose. Epoxy is much more dangerous to your health than polyester.

Mark

[motion30]

Originally Posted by colemj

While not really a "downside", vinylester resin is not as easy to work with as polyester - requiring much more careful prep work and not as accommodating of the curing environments and conditions one often finds themselves in.

Mark

I guess thats like still driving a 65 chevy because it is a simpler car to use. technology has vastly improved since the invention of polyester resin

[unbusted67]

Originally Posted by colemj

Don't be fooled by your nose. Epoxy is much more dangerous to your health than polyester.

Mark

I've heard that. When poly kicks it lets off ketones, particularly methyl vinyl ketone which is toxic stuff. Vinyl lets off vinyl chloride which isn't so good for you either. What is it that is toxic in epoxy? Is it amine?

I think its worth noting that none of this stuff is exactly great for the environment either and isn't known for decomposing. Then again wooden boats are and we clear cut forests on their behalf for years so I think I will stick with fiberglass construction.

[ssanzone]

Originally Posted by unbusted67

Sort for the confusion. Actually was confusing vinylester with polyester resin. So polyester cures quicker than epoxy. I didn't realize that.

yes and no...

epoxy cures extra slow, slow and fast based (209, 206, 205).

poly cures at a rate relative to the amount of actuator.

-steve

[nimblemotors]

At 45F degrees, 'fast' curing epoxy takes all day.

[AbaftAndBaffled]

Originally Posted by unbusted67

I've heard that. When poly kicks it lets off ketones, particularly methyl vinyl ketone which is toxic stuff. Vinyl lets off vinyl chloride which isn't so good for you either. What is it that is toxic in epoxy? Is it amine?

I am blissfully ignorant of the science behind the chemicals but I haven't found anything talking about methyl vinyl ketone. I know that the catalyst to poly/vinylester is methyl ethyl ketone peroxide, which you definitely don't want to get in your eyes...

[smj]

Originally Posted by Krogensailor

I've done a lot of work with both epoxy and poly/vinylester. I've used epoxy almost exclusivly in boat building project's. Don't see why I'd use anything else. It is by far the strongest, most water resistant, best primary and secondary bonds. And it doesn't make me want to vomit when using it. I have a fair amount of use with poly in that I designed and build a hardtop for a factory five Shellby Cobra. I've built enough to know what my nose tells me, this **** stinks and is def not good for you. Neither is the epoxy, but one is worse than the other in my estimation. And as to money? I think its false economy to make that an issue. If I use a gallon of epoxy it cost, worst case from WM a hundred bucks, versus $25 for poly. When putting in a bulkhead I don't think $75 saved is worth the trade off. Now when you get up to using 5+g And your interested in thickness, poly is the way to go. Strength/waterproof/structural,,,epoxy. I've a friend who spent weeks getting the bottom of his 50er stripped and ready for barrior coat, he used vinylester, given that its a bit better than poly. Crazy logic to me. After all that $$$ in labor, and the same amount of labor to roll out,,,use epoxy. My Dad told me decades ago use bronze screws in boats, period. I would 'save' money and watch the damn thing fall aprt. For the sake of $25 I lost whole projects., Just my thoughts.

I agree with all you've said.

[neilpride]

Guys there is life outside of West System, and cheaper!!! my last 2 gallons come from system 3 if i remember well the name brand , wonderfull stuff , the only small problem is a 3 to 1 ratio and no mini pumps, guess what, no problem, i pay 40 $ for the gallon and catalyst, even the microballons and silica are sold by the pound, 5 $ for a kilo of microballons , same stuff as west system brand, even i found this epoxy very strong when mixed with fillers , easy to work with it, easy to sand with the right filler , so far so god i love it, i stop working with West long time agoo, expensive stuff...

Epoxy is more strong than poly, it bond better to wood,is waterproof, and i found it better for especific projects,, still working with Poly to, mainly laminate build up or in areas where is better to have the same material , flexing or because epoxy dont make sense there as Poly can do the job, so both resins are good , boatbuilders are still using Poly for their hulls, is cheap and is easy to work with it, with some layers of vinylester or epoxy the water barrier coat is a plus, i found epoxy safer in the mix ratio, and newby people doing horrible things mixing MEK with Poly, both resins are okey in the right project....

[psneeld]

Originally Posted by Krogensailor

I've done a lot of work with both epoxy and poly/vinylester. I've used epoxy almost exclusivly in boat building project's. Don't see why I'd use anything else. It is by far the strongest, most water resistant, best primary and secondary bonds. And it doesn't make me want to vomit when using it. I have a fair amount of use with poly in that I designed and build a hardtop for a factory five Shellby Cobra. I've built enough to know what my nose tells me, this **** stinks and is def not good for you. Neither is the epoxy, but one is worse than the other in my estimation. And as to money? I think its false economy to make that an issue. If I use a gallon of epoxy it cost, worst case from WM a hundred bucks, versus $25 for poly. When putting in a bulkhead I don't think $75 saved is worth the trade off. Now when you get up to using 5+g And your interested in thickness, poly is the way to go. Strength/waterproof/structural,,,epoxy. I've a friend who spent weeks getting the bottom of his 50er stripped and ready for barrior coat, he used vinylester, given that its a bit better than poly. Crazy logic to me. After all that $$$ in labor, and the same amount of labor to roll out,,,use epoxy. My Dad told me decades ago use bronze screws in boats, period. I would 'save' money and watch the damn thing fall aprt. For the sake of $25 I lost whole projects., Just my thoughts.

backyard boatbuilder and mechanic no doubt...read what the big yards and pros use for different repairs...if the biggest project you ever did was on your boat...I can see why you don't understand.

Poster Mineret has vast experience over the owner repair guy...I follow his thought process myself and have seen the same widespread in experienced yards....many boatyards are not well versed in big glass repair projects.

Epony has its place...just not everyplace....

[colemj]

Originally Posted by neilpride

Guys there is life outside of West System, and cheaper!!! my last 2 gallons come from system 3

Yes, haven't used West in a while. FGCI sells all types of epoxies (there are many types) for less than System 3 even. You can fine-tune the epoxy to the repair and conditions you need.

Mark

[OceanSeaSpray]

As someone quite rightly pointed out, you will be able to distinguish between polyester and epoxy the minute you start grinding into it from the smell of the trapped solvents. Production GRP boat: it will be polyester with 95% confidence.

When it comes to bonding to old laminate:

You must use epoxy to bond to epoxy, probably not applicable to you.

You can bond to polyester with polyester resin, but results can vary. Some laminating resins have waxes to help with mould release. Wax remains can contaminate the surface and cause bonding issues, and some resins just don't like each other. Not all polyester resins are made equal for bonding to cured laminate, I wouldn't take anyone's word or dogmatic "do" or "don't" statements here.
Clean the surface with thinners, grind it with a 16-grit abrasive disc to get a get key, wipe it wet with thinners again and try glassing on top. Try glassing something that will give you some leverage so you can try tearing it off a week or two later. You will get a pretty good idea of bond strength.
Don't "push" your polyester with too much catalyst, a slower cure will give more time for the solvents to "soften" the old laminate and create a good bond. Polyester curing rates are very sensitive to temperature, you will have to experiment a little.

If you need to bond to timber, plywood etc like bulkheads in your project, then you should really use epoxy for these jobs. Polyester tends to bond very poorly to timber, even when it looks ok at first.
And remember, once you have used epoxy somewhere, only epoxy will bond to it again and with great difficulty if fully cured.

I wouldn't consider vinylester. Too sensitive to environmental conditions, especially ambient humidity.
The best epoxy resin I have used all around is International HT9000.

All the best with the job!

[GordMay]

Greetings and welcome aboard the CF, OceanSeaSpray.

[minaret]

Originally Posted by unbusted67

I've heard that. When poly kicks it lets off ketones, particularly methyl vinyl ketone which is toxic stuff. Vinyl lets off vinyl chloride which isn't so good for you either. What is it that is toxic in epoxy? Is it amine?

I think its worth noting that none of this stuff is exactly great for the environment either and isn't known for decomposing. Then again wooden boats are and we clear cut forests on their behalf for years so I think I will stick with fiberglass construction.

Styrene monomer is the main solvent released by poly. It's surprisingly non toxic for its smell. You probably ingest some from styrofoam cups and containers already. Yes, the amines are the main toxin to worry about with epoxy, much more toxic. Ever seen anyone get sensitized to poly? Not possible, but it happens with epoxy often.

[minaret]

Originally Posted by OceanSeaSpray

As someone quite rightly pointed out, you will be able to distinguish between polyester and epoxy the minute you start grinding into it from the smell of the trapped solvents. Production GRP boat: it will be polyester with 95% confidence.

When it comes to bonding to old laminate:

You must use epoxy to bond to epoxy, probably not applicable to you.

You can bond to polyester with polyester resin, but results can vary. Some laminating resins have waxes to help with mould release. Wax remains can contaminate the surface and cause bonding issues, and some resins just don't like each other. Not all polyester resins are made equal for bonding to cured laminate, I wouldn't take anyone's word or dogmatic "do" or "don't" statements here.
Clean the surface with thinners, grind it with a 16-grit abrasive disc to get a get key, wipe it wet with thinners again and try glassing on top. Try glassing something that will give you some leverage so you can try tearing it off a week or two later. You will get a pretty good idea of bond strength.
Don't "push" your polyester with too much catalyst, a slower cure will give more time for the solvents to "soften" the old laminate and create a good bond. Polyester curing rates are very sensitive to temperature, you will have to experiment a little.

If you need to bond to timber, plywood etc like bulkheads in your project, then you should really use epoxy for these jobs. Polyester tends to bond very poorly to timber, even when it looks ok at first.
And remember, once you have used epoxy somewhere, only epoxy will bond to it again and with great difficulty if fully cured.

I wouldn't consider vinylester. Too sensitive to environmental conditions, especially ambient humidity.
The best epoxy resin I have used all around is International HT9000.

All the best with the job!

Wax in resin is to promote surface cure. Has nothing to do with mold release, and is never used for laminating. That's why it's called "finishing resin".