Anyone using MAS Epoxy, well besides me?

[soholingo]

I went to the boat shop with the thought of getting some MGS epoxy. I hear the viscosity is low and dries hard. I get to the shop and there is LOTS of Wests Systems epoxy, everything except the graphite powder I wanted. On the shelf is this other epoxy MAS. Boat guys say they just got it in. Its in clear bottles so I can shake it and see this stuff is thin!!! So I started reading the literature on it. I know the viscosity is low and the literature mentions that it dries hard. I asked the staff and they say it dries hard. In addition they MAS branded cabosil and milled fiber, and I need both. The stuff also comes in a great variety of combinations. TWO types of base resin, resin and flash. The flash being available for use as an adhesive. Next there are three different types of hardners. Slow, medium and fast. I pickup a container of the slow and the fast. They have more sizes than West systems. In addition to the gallon and quart sizes, MAS comes in a HALF gallon size with the hardners available in 32oz sizes. And finally the prices are a bit less than west, and the cabosil and milled glass are sold in large quantities and are cheaper. The only thing they didn't have was the graphite powder.

Found the link to this stuff:
MAS Epoxies (http://masepoxies.com/index.htm)

Also you can adjust the cure times of the hardners by mixing them together!! So if the slow is taking to long then add a bit of fast. Mix the hardners first and maintain a 2:1 ratio... NICE!!! I am going out of town, but will report back on this stuff when I return...

So has anyone actually used this stuff?

Jay

[davidfee]

I've never heard of it. The website is a little lacking in the technical details (common for marine-grade epoxies). They don't seem to have published physicals for the cured resin system. The viscosity looks good. The fast hardener looks VERY fast... 7 minutes at room temp? Yikes!

It will probably work just fine for you. The best part is it's available in small quantities at reasonable prices... so you do not have to commit to a gallon of resin.

Good luck with it,
-David

[soholingo]

mixed up a batch of MAS resin and fast hardner, stirred it for 2 minutes, and at the end of that time the epoxy had a ton of bubbles in it, kinda frothy. I then mixed in the MAS cabosil, this stuff came out in tiny chunks, but broke up as I stirred it into the epoxy.

I poured the epoxy out onto the mold, and it seemed level fairly well, it didn't retain the frothy bubbles, and with the cabosil, it held fast to the sides. This stuff kicked in kinda quick, definitely within 10 minutes and it wasn't a gradual hardnening, this stuff started smoking and a lump formed in the epoxy. I touched the container and it was VERY WARM!!!

At any rate, this stuff is a lot more viscous than the hobby 1-1 based epoxy I am used to using. So far I like this stuff, its acting how I envisioned MGS acting. Tomorrow we will see how hard it becomes, and how easy it will be to sand.

[davidfee]

You won't see MGS kicking off in 10 minutes like that... the fast hardener is something like 45 minutes. And the transition from liquid to gel to hard is quite slow and gradual.

What kind of mold were you using?

Chunks in the cabosil usually means it has absorbed some water (not so great). It probably won't hurt anything though. I've got some which is that way and I still use it.

-David

[davidfee]

How much did you leave in the cup? Most fast epoxies will "exotherm" and boil if there is too much there in the cup.

[soholingo]

How much did you leave in the cup? Most fast epoxies will "exotherm" and boil if there is too much there in the cup.

That's what happened Dave. The epoxy in the cup exothermed and become solid rather quickly. I had never seen it happen so fast. As for the epoxy on the mold it was still tacky after 40 minutes. This stuff dries much shinnier and harder than the hobby epoxies I have been using.

The bubbles were still in he epoxy after it dried so I will have to work on how to remove them.

Dave the mold is simply a piece of balsa that's shaped like a servo cover, not very accurate, but it is allowing me to practice. I may have to use foam like most people do these days, and start using/making templates so that my shapes are consistant. Making a consistant shape is difficult and time consuming in balsa.

[davidfee]

The bubbles were still in he epoxy after it dried so I will have to work on how to remove them.

I usually use a wide, soft brush for applying the surface coat. This allows you to spread it thin and evenly, and it tends to pop any bubbles at the same time. Those disposable sponge chisel-tip brushes work pretty well. Acid brushes are ok, but the bristles are sharp and can scratch your PVA (if you're using it).

I'm thinking of making a vacuum chamber for degasing mixed resin, but you can go a long way by mixing less vigorously. If you mix more gently you will introduce less air and make fewer bubbles. However, if you've only got a 7 minute pot life...

-David

[shoe]

This stuff kicked in kinda quick, definitely within 10 minutes and it wasn't a gradual hardnening, this stuff started smoking and a lump formed in the epoxy.

I'd be concerned about the speed at which this stuff kicks. The last thing you want to be is rushed, that can lead to all kinds of errors.

I use MGS and have used both the 40min and the 4hr hardners (you can mix them to get something in between). I was very thankful I had used the 4hr stuff on the last wing I bagged as my 3yr old kept interrupting me (she was supposed to be down for a nap) and the process took much longer than expected. If I had been using stuff with a short pot life I would have been sunk.

The extra margin for error is helpful.

[soholingo]

There are differnt speeds of hardning. I look at it this way...

Fast is used for making quick repairs...
Slow is used for bagging wings, building molds and long term fusilage repairs...

I don't know why you would need or want a medium as you can mix the two together to get that sort of pot life...

Suffice it to say that if I wanted longer pot life, I would have used one of the other hardners...

[shoe]

Fast is used for making quick repairs...
Slow is used for bagging wings, building molds and long term fusilage repairs...


Sounds good, I guess I missed the part about the slow hardner. What's the pot life like for it?

If you're comparing this stuff to the resins sold in your LHS, there's no comparison (as it looks like you've discovered) now you're ruined, never to go back ;)

Keep us posted on how the cured parts turn out.

[davidfee]

Not all hardeners can be mixed, which is why you may want a medium in some cases. Also, different types of hardeners (reason not all can be mixed) will give different physicals for the cured system. You can take one resin and get a fast-cure room temp system, or a slow cure high temp system. Very different end results, both using the same epoxy.

MGS and this MAS are (I think) the only two companies I've seen advertising the "mixability" of their hardeners. There are probably others... but unless the manufacturer says it's ok, I wouldn't do it. You don't know what the end results will be.

-David

[soholingo]

Sounds good, I guess I missed the part about the slow hardner. What's the pot life like for it?

If you're comparing this stuff to the resins sold in your LHS, there's no comparison (as it looks like you've discovered) now you're ruined, never to go back ;)

Keep us posted on how the cured parts turn out.

All of this is my first go around with this mold making business. I don't expect to get anything usable out of this, but I just wanted to familiarize myself with the epoxy and cabosil.

As for the LHS epoxy, I think Dave has been telling me for the past year to get some "real" epoxy. I can't believe the difference, it seems as if the LHS has a serious racket. They could still charge the same price and put the good stuff in the bottles...

Jay

[lestingoy]

Looks like an old thread, but here we go anyway.

I learned of MAS at a wooden boat show outside New Orleans. Bought some and I have since used about 10+ gallons to make several large scale gliders and tugs. This includes the plug, molds, fuses, and wings. I think I'm getting to know it pretty well.

Everything you described is the learning curve with epoxy and layups in general.

You will always WANT to use faster cure than you NEED. The slower the better. Easier to work with, more chance for bubbles to go away etc.

I buy lots of slow, some medium and some fast. Fast is only to be used for small amounts, ie., 15 cc. max. It will kick sooo fast.

I like the mix ratio of 2 to 1. I use clear plastic cups. I draw a line arbitrarily on the side with a sharpie. Pour in 1 shot of hardener to line. Pour that into a old Wendy's salad plastic bowl (cookie plastics from the grocery store deli work well too - flat, shallow pool, not deep) then do two shots of the resin.

Don't bother with the little squirt spouts from the MAS guys, like West, they are slow and you'll be pumping away for most of the night with larger projects. Cups work great.

Start small. Make small parts & molds and learn what you are doing. Hell, I've got to re-learn every time I go to make a plane, especially with a lag of about 6 months to a year between projects....

MAS works well. Equal to or better than West. Slightly cheaper, better/easier mixing ratio, slightly thinner.

As for bubbles in your surface. Paint a thin coat of epoxy into the mold first. Let it sit a few minutes. Then use your heat gun to slightly warm it. You will be able to see the bubbles popping. Then put in your first layer of glass, something fine. Rub it out well with your fingers.

Good luck.

Lee

[soholingo]

Excellent INFO!!!! Thanks

[lestingoy]

One more caution. You will likely want to heat the mold after the layup to speed to the "open the new christmas present" phase of the process. Don't. More often than not, the mold will get too hot, the parting substance can't work and you will get one big crunchy mess.

If you must heat the mold, use only indirect heat, point the light bulb away from the mold, etc. Never allow temps to exceed about 120.

Lee