epoxies?

[petn7]

i know not to use the 5 min cure epoxy, but i couldn't find the 2 hour+ epoxies. i did find 30 and 45 minute epoxies, so will those work? i mean, Great Planes at Tower Hobbies has "Pro Epoxy45-minute formula" that i would like to use. is it 45 minutes SET time and maybe 2-3 hours CURE time? i'm confused...i'm not seeing anything that has more than 45 minutes...:rolleyes:

[Tachikaze]

Why can you not use the 5-minute epoxy?
My Ace True value has a 2 hour that is made by thesame company that makes the 5-minute that I use. Will check this weekend and get the name.

[Umi_Ryuzuki]

Because you will never get the piece covered, and the fiberglass worked in, in five minutes. :D

We get a lot of our lay up resins at Tap Plastics.
Depending on where you live, they may be local to you.

http://www.tapplastics.com/

[petn7]

because 5 min epoxy is not waterproof...

[Umi_Ryuzuki]

Originally posted by petn7
because 5 min epoxy is not waterproof...


Wow, really?

Hmmm. I wonder why my prop shafts have never fallen out of my boats?:confused:

I cut a long hole in the hulls, and then tape the drive shafts into place. The tape conforms to the out side of the hull. Once they are in the right position I have always used five minute epoxy to lock them into place. In fact most of our club does this.

My destroyer is 15 years old now, and the light cruiser is 13 ears old, and the shafts have never budged in all those years. And we sink our boats,...

[Umi_Ryuzuki]

Here is a shot of some propeller shafts being positioned prior to a five minute epoxy pour.

You can see there's enough space, that if the epoxy was water soluable, I would definitely experience some major problems if the epoxy dissolved when it got wet.

[petn7]

go here: http://www.thordesign.com/permit/kit_permit_4.html

http://66.241.230.141/ikonboard.cgi?;act=ST;f=21;t=24;hl=epoxy

http://66.241.230.141/ikonboard.cgi?;act=ST;f=4;t=250;hl=epoxy


read what they say and maybe u'll understand my confusion...:confused:

[Umi_Ryuzuki]

Hmmm,

Must be a submariner thing,...

Let me check with a couple of my locals, and get back to you.
The only thing I can imagine, is that the quick cures will trap more air bubbles in it and therefore have less strength, or be more permiable. The other difficulty like I stated before, is that it cures so quick, that there is not time to work it. So you can't run a bead all the way around a hull before the starting point has begun to cure. Another weak joint.

Thanks for the Links. I haven't seen the new BBS for Subcomittee. I like the new format. Much better than the old style they had been using.

Also, you should be able to find those little bottles of epoxy from Micro Mark. You can probably find them on line.

[Tachikaze]

The epoxies are not fully water proof. The two hour epoxy is not fully water proof. It is more water resistant than the 5 minute though.
What is more important is the interface between the two pieces that you wish to epoxy. The 5 minute epoxy is good for joints that require some movement because it is flexible, it is more flexible than the 2 hour epoxy. In the photo of the drive line that Umi displayed it works very well because of the vibration that we get on the drive shafts. ( yes I know that the drive should be balanced, but you put a ship in combat and see how often you run up on something when fleeing from the evil allied pig dogs).
The epoxy in my case has never really softened and allowed water through, but if the interface between the two pieces, in the case of the photo, the brass stuffing tube and the fiberglassed hull is not roughened up, then I get some water if from underneath the epoxy. I just wait until the boat dries out, peel back a little of the epoxy, rough up the edges a little and refill. Works for anothet season or two.
Even when you see what happens in the photos of the sinking Italian destroyer we have had very little trouble with the epoxy coming loose or softening to a point where we can not fight.

[Umi_Ryuzuki]

Bottom lineis,

That hobby epoxy is not 100% resin, and it has trouble bonding to polyester resin. Hence the roughing up between surfaces.

Since the hobby epoxies contain a filler, it is the filler that allows the water to penetrate, and "soften" the epoxy.
I was basically informed, that most hobby epoxys are susceptable to this "softening".

I guess the amount of time our hulls are under water compared to submarines is what makes most of the difference my application.

So best to purchase an epoxy meant for marine use.

[petn7]

yeah; they say longer the cure time, the better. i got some like 45 min set, 8 hour handle, and 24 hour cure, epoxy from tower hobbies; hopefully it will work

[ThorDesign]

zzz