resin and what is best

ok people this should get some dicussion. when i first started building my own IOMs. i used what ever i was comfortable with. not what was best. and the was polyester resin , you buy at the hardware store. then i found out about epoxy resin. now if you are good at it. you can thin the resin with acetone. this was great too. but after a recent visit too the fibreglass store. i found a new product(to me) called vinyl ester resin.
has anybody used this? has anybody any good information on it?
let the discusson begin

long live the cup and cris dickson


According to this link, it?s kind of in between polyester resin and epoxy. If I remember correctly Bob Sterne uses it in his models.

I have never used vinyl ester resin, but if it?s anyway related to polyester resin, I bet it smells to high heaven.

Are you thinking of switching from MPS?

<hr noshade size=“1”><font size=“1”>Moderator
Sherman Yachts</font id=“size1”>

vinylester stinks, forget it! Some (big boat) designers see vinylester as a half way house between poly and epoxy on cost and performance. Use poly on CSM and epoxy on rovings and you wont go far wrong.

Luff 'em & leave 'em.

We used to use vinylester on the outer layers of the fullsize cruising cats at work. It provides a better resistance to osmosis than polyester (not a problem for model boats)and can still be used with CSM where you shouldn’t use epoxy.

<font size=“1”>19 out of 7 people have trouble with statistics</font id=“size1”>

mmm, we use vinyl at work primarly, but don’t use it to seal foam, mmm, will eat away at it i think, or somethin bad will happen, donno, just dont do it. poly (gelcoat/flowcoat are both poly) is used to seal foam, flowcoat/gelcoat is used to protect stuff that you can see. (& vinyl is pretty old now). mmm, vinyl uses slow reaction catalyst whereas poly uses normal reaction catalyst.

I see said the blind man to the crippled nudist who put his hands in his pockets & promptly walked away.

Maybe a stupid question froma an amateur… Whats CSM?

You’re not alone in the acronyms Deckard. I currently use epoxy. It’s a bit on the pricey side, but I also am not chased away by the shear smell of it either. In fact, there’s hardly an odor to what I’m using. But then I’m not sticking my nose right down in it either.

AMYA #13417

Don’t forget to have fun!!!

Sorry, been kicking round boatyards too much… CSM= chopped strand mat = the type of fibreglass mat with random short strands
Hope that clears it up!

Luff 'em & leave 'em.

Oh… Epoxy does have fumes, okay they dont smell as bad as poly but they can make more of a mess of you inside than poly. Probally not a biggie to you guys, but using the stuff everyday can cause problems after a while.
Some epoxies stink to high heaven anyway, as anyone who’s seen a pot of Sp ampreg with fast hardener go off, watch the pretty smoke! not nice…

Luff 'em & leave 'em.

tell the truth. I use both poltester resin and epoxy. but thanks to a person who builds model submarine kits. i got the safety end. before i started using the mgs resin. when i use the resin i have a mask, with air filters, i use gloves, and we have a 2 thousand dollar air purifer. when i use it. i dont spend too much time in the shop. remember what you smell you breathe. and from two expert
“do you realy want to put a layer of fibreglass on your lungs?’” after that. i use the mask all the time, unless i am outdoors. now with that vinlyester? does it smell? is it strong?

long live the cup and cris dickson

Okay, now this is gonna sound bad-
most professional laminators/boatbuilders using epoxy and poly dont use respirators unless in a really confined space (like inside a locker on a big boat). As long as you have a well ventilated/air con’ed workshop or your outside you should be fine, dust from grinding the stuff is what you want to worry about more.
I dont have much experience with vinylester, but from what I have seen and heard of it I really can’t see the point in using it on models. It smells bad, but I guess its no worse health wise than poly as both are styrene based if I’m not mistaken.

Luff 'em & leave 'em.

You can get “LSE” vinylester resin. This is Low Styrene Emission and, and isnt as stinky as other types - its the styrene that gives the resin its smell. Interestingly there are no known side effects to styrene. I still think for models however standard polyester resin is fine. Its cheaper, easily available and in the quantities that a model builder uses should not do any harm although personally I always where a proper mask.

<font size=“1”>19 out of 7 people have trouble with statistics</font id=“size1”>

What Matthew says about the safety practices at professional shops it correct. 20+ years ago I learned about using a chopper gun from a guy that had been doing it all his life… along with smoking Camel UNfiltered cigarettes at the rate of about 2.5 packs a day. He would shoot pure resin onto the subject, and it would run me right out of the booth… to the sound of much laughter. NO, he never wore a mask… it was for “light-weights” such as me that didn’t know what was going on.

Same thing with the oven, they could walk into the oven and hook up the vacuum lines and stand around and talk… I was on a deep sea diving adventure… I had to hold my breath go in and work and get back out.

I strongly encourage anyone reading out there… particularly lurkers that are read-only… to not only take the precautions mentioned here seriously… but to further investigate and ask questions before dealing with any material that you are not completely familiar with, and use good sense. One thing I have not seen mentioned here that I am afraid of more than anything else is FIRE.

I keep a HAZMAT barrel and any and all rags, cloth, paper towels etc that come into contact with solvents, resins, paint and the like, are mandatory for that barrel because of the chance of spontaneous combustion. That barrel is always kept outside in a location where should it light up, it will cause no further damage.

Fighter Pilot Rule #3 <u>Respect the Threat</u>

Vinyl does smell, same as poly does, you can really tell when you’ve smell to much, your eyes start stinging then they start getting runny. but you should have your mask on all the time that you are working with it, i think with model boats, without proper ventilation, you should definately wear your mask with organic filters. i find that when we are laying up even the 32’s (in a big shed with air conditioning & an extractor) you still have to wear the mask. the other thing if your using flowcoat, dont get it in your eyes & don’t get catalyst in your eyes, that sends you blind in 6 seconds.

I see said the blind man to the crippled nudist who put his hands in his pockets & promptly walked away.

here is the truth quoted from one of the best boat builders in australia (& maybe the world).
Vinylester is S*** loads better than Polyester because Vinyl is 100% water proof. Vinyl is also a type of Epoxy but a special type, normal epoxy is 99.99% water proof. also, because of these facts, you don’t get the problems of osmosis, as you do with poly.
Vinyl is better than normal epoxy in 1 way, it takes a shorter amount to go off compareds to epoxy… (as i am finding out today, the epoxy bog i mixed up yesterday still hasn’t gone off fully, i mixed it to the right ratio’s as well, temperature changes aren’t good!!!). so there you have it, vinyl is better than poly in so many ways, if you can, use vinyl not poly, cept if your hot coating (coating balsa wood/foam).

I see said the blind man to the crippled nudist who put his hands in his pockets & promptly walked away.

In all due respect to your “expert” - Vinylester resin cannot and is not used as an adhesive - like epoxy can ! Vinylester is simply a resin that is and can only be used for laminating. It will not bond (glue) dissimilar materials together, it doesn’t work well as a bedding for mounting deck hardware, and if I recall correctly, it has less tensile strength and flexibility than epoxy.

Sorry - if I am going to spend nearly $50 (USD) for a quart of something, it better work for a lot of applications - not just for glass composite layups.

VINYLESTER: The vinylester molecule also features fewer ester groups. These ester groups are susceptible to water degradation by hydrolysis which means that vinylesters exhibit better resistance to water and many other chemicals than their polyester counterparts, and are frequently found in applications such as pipelines and chemical storage tanks.

So in this case, I would agree that vinylester is much better than “Polyester” - however - it is still an “ester” based resin. Also - if you look at the molecular makeup of vinylester resin, you will find it is no way an “epoxy” type of resin. See second paragraph below under “polyester”.

EPOXY: High adhesive strength and high mechanical properties are also enhanced by high electrical insulation and good chemical resistance. Epoxies find uses as adhesives, caulking compounds, casting compounds, sealants, varnishes and paints, as well as laminating resins for a variety of industrial applications.

POLYESTER: There are two principle types of polyester resin used as standard laminating systems in the composites industry. Orthophthalic polyester resin is the standard economic resin used by many people. Isophthalic polyester resin is now becoming the preferred material in industries such as marine where its superior water resistance is desirable.

Also, the “ester” groups cure via “catalyst” additives, whereas epoxies cure from adding a hardener.

OSMOSIS: All laminates in a marine environment will permit very low quantities of water to pass through them in vapour form. As this water passes through, it reacts with any hydrolysable components inside the laminate to form tiny cells of concentrated solution. Under the osmotic cycle, more water is then drawn through the semi-permeable membrane of the laminate to attempt to dilute this solution. This water increases the fluid pressure in the cell to as much as 700 psi. Eventually the pressure distorts or bursts the laminate or gelcoat, and can lead to a characteristic ‘chicken-pox’ surface. Hydrolysable components in a laminate can include dirt and debris that have become trapped during fabrication, but can also include the ester linkages in a cured polyester, and to a lesser extent, vinylester.

Use of resin rich layers next to the gel coat are essential with polyester resins to minimise this type of degradation, but often the only cure once the process has started is the replacement of the affected material. To prevent the onset of osmosis from the start, it is necessary to use a resin which has both a low water transmission rate and a high resistance to attack by water. When used with reinforcements with similarly resistant surface treatment and laminated to a very high standard, blistering can then be virtually eliminated. <u>A polymer chain having an <font color=“blue”>epoxy</font id=“blue”> backbone is substantially better than many other resin systems at resisting the effects of water.</u> Such systems have been shown to confer excellent chemical and water resistance, low water transmission rate and very good mechanical properties to the polymer.

<font size=“1”>Published courtesy of David Cripps, SP Systems</font id=“size1”>

Just want to keep focused on facts - [:-graduate] [;)]

Dick Lemke
F-48 #US-06
MultiONE #US-06
Class 3 Landyacht #US-196
Minnesota, USA

Sorry for two posts - but ran across this after previous post. It might give a better and clearer picture to the discussion of various types of laminates. In most cases, our boats are small, dry sailed and subject to much fewer issues than a full size boat. Yet - we seem to always try to compare big ones to our little ones. Again - technical post courtesy of SP Systems.

Guide To Composites
Resin Comparison Summary

The polyesters, vinylesters and epoxies discussed here probably account for some 90% of all thermosetting resin systems used in structural composites. In summary the main advantages and disadvantages of each of these types are:


Easy to use
Lowest cost of resins available (?1-2/kg)

Only moderate mechanical properties
High styrene emissions in open moulds
High cure shrinkage Limited range of working times

<u>Vinylesters </u>

Very high chemical/environmental resistance
Higher mechanical properties than polyesters

Postcure generally required for high properties
High styrene content
Higher cost than polyesters (?2-4/kg)
High cure shrinkage


High mechanical and thermal properties
High water resistance
Long working times available
Temperature resistance can be up to 140?C wet / 220?C dry
Low cure shrinkage

More expensive than vinylesters (?3-15/kg)
Critical mixing
Corrosive handling

<font size=“1”>Published courtesy of David Cripps, SP Systems</font id=“size1”>

Dick Lemke
F-48 #US-06
MultiONE #US-06
Class 3 Landyacht #US-196
Minnesota, USA

Sounds a bit more like it… When doing an osmosis treatment on an older polyester hull you use epoxy, as I’ts pretty much impermable to water (compared to poly anyway) and will bond to the old polyester laminate underneath. Totally irelevant to models but hey!

Slightly more useful facts though;

As a rule Epoxy will bond to cured polyester but polyester is pretty poor at bonding to epoxy. You often find modern racing dingys with a epoxy laminate in the hull with a polyester gelcoat outside. This is all very well untill you have to do a gel repair as if you don’t taper your repair well to the surrounding gelcoat you will find the gel you applied to do the repair will fall out whilst you are fairing it back…frustrating as hell… So only use poly gel on a epoxy hull if you never hit anything!
Poly gelcoats are used on epoxy hulls mainly due to epoxy gels having pretty poor performance under UV light, hence if you have a completely epoxy hull you have to lacquer or paint it to stop it discolouring and eventually breaking down on the surface. Again this is pretty irrelevant to models unless it lives in direct sunlight all the time.

Oh and another thing while we’re at it…P38/Bondo and other car body type polyester fillers soak up water like sponges…seal before you put in the water for anything longer than a quick test, as they will go soft pretty quickly. They also shrink back if faired soon after they cure, use epoxy with microbaloons/silica to fair large areas, harder to sand but you wont notice it after painting like you often can with a soft filler.

There you go, a load of semi useful stuff from a professional boat bum in training, learnt more in 4 years of kicking round boatyards than in 4 years of college and uni lectures!

Luff 'em & leave 'em.

could you use paint to seal bondo? say you have a good hull. but only have a few small dents. could you fill it with p38/bondo. then paint the hull? or would you have to resin the whole hull agian?

long live the cup and cris dickson

Yeah paints fine, anything to seal it really…

Luff 'em & leave 'em.