I've never used Mas, but it can't be good enough to justify 2x the cost of other, really good epoxies. Raka's and US Composites' epoxies are both low-to-non blushing, 2:1 ratio, available with quite slow or quick hardeners, and have a good viscosity for laminating. They're thinner than West (btw, even West is cheaper than Mas, and that's saying something!), which means they take a higher filler loading to achieve the needed consistency for fillets or fairing goop, which also saves money since filler is cheaper than resin.

  I have used US Composites but not Mas, so can't directly compare. The cheaper epoxy worked fine and is massively, significantly cheaper. It definitely does blush. I think it's a good idea to scrub down with soap/water and a scotch-pad after the epoxy has cured. You can avoid that by putting on all of your filler coats while the first epoxy coat is still curing.

 I've used West Systems since the early 80's.  The Gougeon Brothers (West) basically made epoxy user friendly and everyone else copied them.  Still using the Iceboat I built with it.  No issues.  I've used MAS also with no problems in the last 10 years other than their pumps are not as good as West pumps.  I like West because when I run out I can just get it at West Marine which is just down the road.  Currently I am using Entropy to build a cedar surfboard.  No VOC's.  No pumps, just measure the 2:1.  Not sure about blushing issues.  Haven't gotten to the laminating stage yet though so I cant say anything about it yet.  Its all expensive, but for me, it seems I waste so much anyway its not that relevant in the long run when doing one project every few years or so.  Varnish is more expensive!  There are some great posts about the differnent epoxies and their attributes hidden on this forum.  Do some digging.

"About the same" is a relative concept. Here's a good comparison:

http://www.oneoceankayaks.com/Epoxresl.htm

My limited experience is that there's a much greater difference between the different formulations of any one maker (fast, slow, extra strong, etc.) than between the similar formulations of different makers- at least for a hobbyist like me. If I was doing this for a living, working under extreme time constraints, or had very particular spec requirements then they might not seem "about the same" to me.

Good luck,

Patrick

If I start with MAS for gluing and fillets can I move to West (or something else) for coating? Or if 1st coat is MAS can secnd coat WEST.

Entropy looks interesting

As long as the first epoxy is competely cured. Not just set up, but really truly cured, as in days or even weeks, depending on the conditions.

Entropy makes things fall apart.

Laszlo

 Laszlo - nice littoral pun on Entropy.  Entropy is being used more in the surfing and snowboarding industry but is also used in the boat building industry with great results.  And a snowboard is under way more stress than say a sea kayak.  Even a surfboard is more stressed.  It does not fall apart as Laszlo suggests.   Go to their site for info.

Bill is correct, I took shameless advantage of a pun that was handed to me on a silver platter. It was not meant as an opionion of the epoxy brand, which I have never used.

Laszlo

   Actually, you can mix different epoxies, even wet. Say, a fillet of West's fast, and a tape wet out with Raka's slow. Or start a hull lamination with brand X, run the cans dry, and finish with brand Y. The important thing is to thoroughly mix each brand in its own cup. The chemical cross linking happens in the cup, not on the boat. Indeed, if you mix the epoxies in separate cups, then combine them, the combined soup will still cure (as long as the epoxies are from the same chemical family, Bis-A in most cases I recall).

Unless the brand x additives are not compatible with the brand y additives. If you're as familiar with different epoxies as nemochad, you can mix safely, but if you're not, waiting for a full cure always works.

Laszlo

   I've used MAS, which came with my CLC kit, and now I'm using West Systems because it's available locally (I live near Los Angeles.) I've had good experiences with both. West Systems has a lot of accessories, and I'm using their quick hardener for the inside of my kayak...it's cheaper than the special clear hardener. The main thing, from reading the posts over the last few years, is to mix your resin for about two full minutes. MAS is not available locally except in commerical quanities, so I've had to have it shipped...so that's a drawback. MAS and West Systems have good websites with a lot of information. As far as I can tell, MAS is very clear, without blush, and the West Systems special clear hardener looks the same. I was surprised that the West Systems fast hardener did not have any blush, but the humidity was very low when I used it. Oh, and I wouldn't mix manufacturers and let the resin cure per manufacturer's specs before finishing.

 SurferBill said,  " I like West because when I run out I can just get it at West Marine which is just down the road."

Me too.

 Let me add one thing about the cost of epoxy and hardener. Let's say a kayak needs two gallons of mixed epoxy to finish it (just for sake of argument.) The mixing ratio with hardener and which hardener you use makes a big difference in the total cost.   

West Systems resin costs aboout $100 for a gallon, The West Systems special clear hardener is mixed 1:3 and costs about $90. So, you get one and one third gallon of mixed resin for $190. 

West Systems fast hardener is mixed 1:5 and costs $48. It is a good choice for colder weather curing on the inside of a kayak. So you get one and a fifth gallon of mixed resin for $148.

So, when doing a cost comparison of different brands of resin, make sure you're comparing the mixed quantities of the resin. When I used the MAS resin a few years ago, the resin was mixed with hardener at a 1:2 ratio. I just looked and CLC has the Number two economy kit on sale for $314, which gives you 2 and a quarter gallons of mixed resin along with some wood flour, cell-o-fill and pumps. It's a pretty good deal by comparison, but then I think you have to pay for shipping.

While I'm at it, I'll mention that the West System special clear hardener won't cure below about 55 degrees F (according to their literature), while the fast hardener will. If you're working in a cold basement it could be an issue.

MAS has a time to cure chart on their web page FAQ for all three hardeners. If I remember correctly, MAS slow hardener will cure in colder weather, but it will take two weeks. In a cold climate, you might want to switch to a faster MAS hardener.

Cheers

Another thing to keep in mind is customer service costs - not yours, but CLC's. They have a very strong vested interest in their kits and designs being successfully built. No success = no repeat customers. So, as many on this forum can attest, they will do what it takes with phone, e-mail, etc. to make sure that our problems are solved. But from CLC's point of view, that support is also a cost that comes right out of their bottom line.

As a responsible business in tough economic times they have to minimize that cost. One way is through kit design (precise CNC cuts, puzzle joints instead of scarfs, etc.). Another is through high quality manuals. Yet another is through recommending and selling epoxies that are tolerant of mixture errors, work in wide temperature ranges, wet glass out easily and don't blush.

So when selecting epoxies, keep the designer's recommendations in mind. There's a reason for them. If you have enough experience that you understand what you're doing and can make intelligent trade-offs (again, nemochad comes to mind) and/or are willing to experiment and accept the consequences, then by all means do so if you want. Otherwise, CLC is giving you a strong hint on how to build with the best chance of success. You should probably try it once and then go from there.

Have fun all, it's finally Spring!

Laszlo

Unlike Laszlo, I have used Entropy, and can recommend it without reservation, especially for omelettes made with Sriraca sauce.

 Greetings all!

A little off topic but just an add to the above posts.  Some time ago, I built a Ches 17 LT in my unheated garagage during mid-atlantic cooler weather.  In my haste to get the boat done before winter, I erred in mixing ratios of MAS epoxy to glue up the hull scarf joints.  After a few days, the joints were soft and seemed to stop hardening.  I contacted MAS and they assured me (not to worry) the joints will eventually cure.  They also suggested that if I could somehow get heat to the joints, that would speed the process. The fix: I  set up couple of portable shop lamps under the boat and draped a plastic tarp over the boat to create a tent.  After another 24 hours, the joints hardened.  Cautionary notes: plastic tarps + wood boat + heat = POTENTIAL FOR FIRE. Adjust placement of lamps to crete a warm, not hot, environment and don't leave boat unattended for long periods of time.  

Thanks

   I can get Entropy and RAKA for the exact same price because I recently set up distributor account for both. Considering they are the same price for either is one a little better product than the other? I obviously have some research to do yet and I would rather here it from someone with first hand experience with both than to go solely off the specs. 

   Crickets? Anyone??

Streetoutlaw wrote >> ...I would rather here it from someone with first hand experience with both...

Not ignoring you, just that people who have used Raka and Entropy are rare on this essentially MAS site.

Laszlo