Thread: Epoxy and Working Temps.

I imagine the temperature rise is fairly gradual.

So I would start epoxying on the gently rising temperature gradient. Too fast a raise and you can get expanding air inside the ply causing bubbles.

Getting started before the warmest part of the day works well in winter with the epoxy accelerating its kickoff. Aso helps with the wet on wet. If it doesn't kick off just be patient. If mixed properly it will go off enough for the next coats.

Only the inside needs to be precoated and sanded before Assembly. Working on the flat alsoeliminatws the risk of runs in slow curing epoxy.

Good Progress!
Mik

Hi Flatdog,
When I made my GIS I did most of the epoxy stuff over the winter in my unheated studio in New York City. Winters are pretty rough, though because the building i was in adjoined another building whose tenants were less cheap than i am, I got enough warmth through the wall to keep it from ever dropping below freezing. I think the average temp from january to march was ~4C. Needless to say, this is not ideal, and I made great use of 100W light bulbs, plastic sheet, and packing blankets to get through all of the rough parts, but in my own experience, given enough time, and an eventual rise in the mercury epoxy ALWAYS cures. I was skeptical myself at first, but if you mix it well and wait, time and temp will reward you with a badass boat in the end.

Aside-

Epoxy in cold weather will crystalize like honey. The resin, not the hardner does this in some cases when it is cold, and once there are a few seed crystals started, it will keep going till it is all a solid mass. The fix is simple, and from my experience has no adverse effect on the poxy. Put the resin jug in a big cardboard box or other container with a decent amount of airspace around it. (trash can, plywood box, plastic tub, etc.) Also inside the container goes an incandescent bulb of ~60w or so in a clamp-light or similar thingy. Make sure the bulb is not touching the epoxy, or container sides and has free air circulation around it. Cover with a piece of plywood, masonite, sheetmetal, etc. NOT FABRIC OR A BLANKET WHICH COULD CATCH FIRE. (warning: dont start a fire, be smart!) Leave on for 6 to 8 hours or until the resin is crystal clear. This warms the whole affair slowly and gently and re liquifies the resin.

Cheers,
-Albert

I've had similar experiences with epoxy in cold weather - plastic sheeting and lightbulbs are a big help. One thing I always do is glue up a couple scraps with the leftover epoxy. That way I have something to test to see if the epoxy is properly cured or if it needs more time. I've found that sometimes it can feel hard to the touch but still easily come unstuck - not something you want to discover with the real pieces!

Also, the 36-48 hours of hardening time is probably until the epoxy reaches maximum strength - it may well be strong enough long before that.

Thanks for the helpful info. guys. I think that the main thing I was worried about was the epoxy not going off at all. Now I'll just plow on regardless.

Albert, for some reason I have mental pictures of you wondering through times square with GIS panels tucked under your arm . I have a big sheet of building foil here and I thought if I tent it over my panels I can throw my 400 watt work light under the end to add a little warmth. Should work. The idea with the scrap ply Andy is good security. I think I'll do it with two or three pieces to check along the way.

Thanks. Kev.

I was mentioning to my wife today that I had replies from guys who live in seriously cold places.

Howdy Kev,

Epoxy only ever fails to go off for two main reasons.

1/ Incorrect ratios - work to be precise all the time. The epoxy is tolerant of small errors one way or another.

2/ Inadequate mixing - use a regular shaped mixing container and scrape the bottom, corners and sides a few times.

This is because of experience over 10s of thousands of boats built by myself, friends and customers. It is very, very rare that there is a manufacturing error. Actually I have never seen one that prevents the epoxy from curing.

So to get those two processes right is most important.

If the epoxy doesn't go off the first thing to do is mix up a small new batch, mix it well and leave it to cure on the benchtop.

Best wishes
Michael.

Hi Flatdog,

I'm not sure we are discussing the relevant issue here. I'm not an adhesives scientist but I think the issue is not one of whether the epoxy mix ultimately goes off but one of whether it will adhere adequately to the two surfaces being joined in the process before it goes off. I suspect to some degree this depends on its viscosity when applied and this is a function of temperature at least in part? I don't know but I've used epoxy for many years for furniture making and I've never worked at those low temperatures largely because I'd go off at less than 10 to 15oC and go look for someplace else to work.

Happy shivering,

Old Pete

Originally Posted by Flatdog

Thanks for the helpful info. guys. I think that the main thing I was worried about was the epoxy not going off at all. Now I'll just plow on regardless.

Albert, for some reason I have mental pictures of you wondering through times square with GIS panels tucked under your arm . I have a big sheet of building foil here and I thought if I tent it over my panels I can throw my 400 watt work light under the end to add a little warmth. Should work. The idea with the scrap ply Andy is good security. I think I'll do it with two or three pieces to check along the way.

Thanks. Kev.

I was mentioning to my wife today that I had replies from guys who live in seriously cold places.

Originally Posted by alzuger

Hi Flatdog,
When I made my GIS...

Welcome back Al! How's about an update thread?
[/hijack]

Originally Posted by davlafont

Welcome back Al! How's about an update thread?
[/hijack]

Hi Dave,
And thanks for the warm welcome back. I'm just thawing out from my first winter in Toronto, Canada. (Though to tell the truth, this winter has been shockingly mild) I've got to go out of town at the end of the week for 10 days or so, and as soon as i return I'm hoping to kick off the sailing season. I recently picked up a trailer hitch for the new (old) car, and have to hook up the lights, and then it's the Georgian Bay or bust. My wife gave me the local charts for Christmas, so the only thing left to do is put the camera in a ziplock bag and take bets on how long till I flip. I'll be sure to fire up a new thread documenting the trouble i'm trying to get into in this beautiful country.

Cheers,
Al

Thanks for your advice and comments guys. Everything worked out fine.

Kev.

Originally Posted by davlafont

Welcome back Al! How's about an update thread?

Glad to see you back Al!

Tell us about work, where you are living. HOpe things are going swimmingly!

Or ice skatingly??

Michael