Why do we like West System Epoxy?

I ran out of resin. The place I bought the last gallon from (for $76), Viking Boats, is out of business, so I needed a new source. While I was in Annapolis for jury duty, I stopped by Chesapeake Light Craft, figuring they must move a lot of epoxy and would have reasonable prices.

CLC doesn’t sell West System. They recommend MOS epoxy, because it doesn’t produce the noxious fumes and amine blush like West System. Since I am already into West System, I decided I didn’t want to change brands (change hardners, change pumps, change filler). So I went to West Marine. The MOS epoxy was something on the order of $130 for a gallon of resin. The gallon of West System I bought was a mere $95.

So okay, West System is a little cheaper, but not having to worry about fumes and not having to wash away amine blush is a step saver that would seem to make the additional cost worthwhile. And are we really that frugal (even you Scottsmen)?

So, I got the West System, which I have often seen recommended on paddling-related pages. Why are we still using this stuff? Does West System have other advantages for boating?

Chip Walsh, Gambrills, MD

Who is we?
Silvertip for me.

use MAS …have for quite a long time…

Best Wishes


What fumes? When I was a boy, epoxy
fumes would burn the skin right off. I developed an epoxy sensitivity with the “old stuff,” but I have never had a problem, breathing or contact, with West.

Question about amine blush…
I’ve only built one boat kit, using the MAS epoxy (not “MOS”, by the way), so I have no experience with West System or any other that might produce the amine blush. So, my question is, how much time and effort goes into dealing with this particular issue during the course of building a boat?


I love the smell of epoxy
I mean, I really love it. I think fumes and amine blush come with the territory for all epoxies. I think the person you spoke with at CLC was telling a fib. But what do I know? I’ve been huffing alot of epoxy.

I have used MAS for over ten years after I was sold on it by a friend for less blush and low fumes. Be careful of generalizations. MAS slow hardener will not blush (also takes a long time to cure). MAS medium hardener may blush, treat it as if it did. MAS fast Hardener will blush.

Blush is a waxy film on the surface of the hardened epoxy and will interfere with adhesion of epoxy re-coats and applied finishes. It’s not a big deal as long as you remember to remove it. Builders using epoxy that blushes have successfully used it for decades by removing the blush after the epoxy cures.

Fumes are a concern to me and MAS has low fumes when compared to some other epoxy mixes. You can wear a vapor mask when using an epoxy with higher fumes and it is a good practice with all epoxy.

With all that said about MAS, I visited the West Systems research center/factory in Bay City MI with a mutual friend. It is a very impressive facility with extraordinary research labs and equipment that I doubt MAS or System Three can match. I was very impressed with their scientific approach.

My advice is to learn to use one brand/system. You can buy by cost, blush tendency, fumes—they will all work as long as you mix to their correct ratio, observe the temp. range of that mix (or apply heat) and remove blush.


Another vote for Silver Tip
For my current project (a Bear Mountain Enterprise) I’m using Silver Tip epoxy from System 3. So far, I’m most impressed with it.

I used System 3 Clear Coat for a previous build (a Pygmy Coho) and really like using it, but the Silver Tip is even more clear in color.

My current build is being documented here:




I like both…
System 3 and West epoxy. I prefer System 3 because of the 2:1 mixing ratio. It makes mixing small amounts(less than a pump)much easier as I can eyeball them.

I like Raka. probably no real advantage for West System brand for boats in particular, but I do know the Gougeon brothers certainly know a thing or two about epoxy AND boatbuilding (just check out their excellent book “The Gougeon Brothers on Boat Construction”…)

I used MAS for my boat
Had no problems with it at all.

I don’t recall spending that much for a gallon. Only $90/gallon for resin if you buy direct from MAS on their web site, although there will be shipping on top of that.

Anyway I think “we” like West Systems because they are established, and well known, being one of the first to offer their products at retail.

I’ve used them all
MAS, West, East, System 3, Raka. I’m currently sold on US Composites, less expensive than the others, but it WILL blush. Apply successive coats before cure or wait and wash off.

If I were building a bright finished stripper I would probably go back to Raka or MAS.

Blush is more prevalent in the
fast cure epoxies as far as I’ve found. Cleaning off the blush can be a pain and I always worry that I don’t get it all off. Since I use the fast cure for small areas cleaning it off isn’t a big deal but with a hull I’d suggest using an epoxy that doesn’t blush. The slow cure West systems doesn’t seem to blush too bad but it’s still not worth messing with. I’ve used Raka and liked it but I did find that it was difficult to saturate the fiber glass.

Hi Chip,

I’ve used both West Systems and MAS. West is a great epoxy with a lot of R&D behind it, but I still stick with MAS for several reasons. Here’s my comparison. Keep in mind I use the epoxy to build strippers, so an easy and complete wet-out is probably the highest priority.

West Systems has a honey color, kicks-off faster, gives off some really strong vapors, is more viscous, and you don’t have the option of mixing fast and slow hardeners.

MAS epoxy is almost colorless with the slow hardener, it gives you much more time to work before it kicks-off, it’s vapors are nowhere near as noxious as WS, is a lot less viscous, and you have the option of mixing the hardeners to adjust your cure time.

With WS, I ended up with very strong headaches even while wearing a good respirator. With MAS, I still wear a respirator as a precaution.

With WS I was always rushing to remove the excess epoxy before it kicked. With MAS, I have a lot more time. I live in Miami, FL and the temps. down here don’t help.

You don’t have to get new fillers/additives, the WS fillers will work perfectly with other resins. MAS Slow hardener is truely blush-free, and you can mix-in up to 30% Fast without blush. For cloth wet-out, it’s best to just use the Slow hardener.

Check out Defender.com, they have good prices on MAS.

Hope this helps,

Pedro Almeida

West’s superiority
West epoxy and other 5-1 and 6-1 ratio epoxies have a much higher water resistance. They were developed for the boating industry and meant to stand up to constant water immersion as on boats that are docked or moored. They are also superior under stress tests. Aircraft buildiers use 6-1 ratio epoxies and most industrial hi stress applications also use 5-1’s and higher.

2-1 epoxies will absorb water under scientific testing but no problem for people making light weight dry stored craft and perform fantastic for most normal use.

I use RAKA and was happy to find anything half the price of WEST. 2-1 is very convenient and they have an nice no-blush hardner. I do give WEST a lot of credit for starting the epoxy building revolution. Anyone remember ClarkCraft boats and epoxy? I think they were the first 2-1 home use stuff.

Clark Craft is still around:

Amine must be washed off
The lore, at least, is that we need to wash off amine blush before we put any coating on top of it. Theoretically, the amine interferes with the overcoating’s ability to chemically bond to the surface.

So, anytime you are putting a coating over epoxy, and that includes a second layer of epoxy or whatever you are putting on top of the epoxy to prevent UV degradation, you need to wash down the existing layer of epoxy with soap and water. So, figure out all the recoatings you do, and add effort and time for washing and drying between layers, and that is how much extra effort the amine causes.


West Marine??
Next time you want West Systems in Annapolis go to the TruValue Hardware store at Hillsmere/Forest Drive. Getting epoxy at West Marine is crazy expensive. Don’t see how got $125/gal MAS resin at CLC, it’s $89/gal on the site, plus hardener it’s up around $165 for 1.5 gal mix.

The thing to remember comparing West 5:1 to MAS 2:1 is that you end up with less total mix per gal of resin with West.

Raka has worked fine for me at about 2/3 the cost of MAS/West at $98/ 1.5gal mix

MAS aroma
I wonder if they have cherry cough drop aromatics added to it. It doesn’t smell like any other epoxy out there. New Jersey is kind of the head quarters for artificial flavoring industry,maybe someone decided a fruity epoxy would sell?

Comparing Epoxies
Here is a link comparing a number of different popular epoxies under a variety of conditions.