Epoxying in cold weather

[Eastward ho 24]

So I built a new compression post and I have my backing blocks for my through holes and I'm gearing up to epoxy some G10 and the gracco BBB backing blocks. I know epoxy is not recommended on below 50 degrees I was planning on using West system fast hardener and building the heated box like they say, so the epoxy will be heated up and I will also put a heat gun on to the inside of the hall to warm the substrate. Most of the stuff I read is about the viscosity being too thick in cold weather but nothing really talks about the surface of which you are epoxying to other than mentioning if it's wood it won't seep into it.however I will be epoxying Croco BBB backing blocks(which I believe or PVC) to my fiberglass Hull. I'll keep some heat on them from the inside of the boat it's pretty cold out so it won't be warming it up much. I was just gonna point a little space heater at it.'m not sure how well that will work out. And also I will be putting a G10 block epoxy on to the keel which is Led so I don't think I'll be getting that to stay hot. My question is can epoxy work on the LeadD. and bond the G10 right to the Keel if I sand it with some 80 grit? And if that is a go the next question would be how will the temperature of the Keel affect the curing I will be heating the epoxy it before I put it on. and keeping a heater on it but it is really cold the space heater doesn't do much. And the same goes for the backing blocks on to the hull. Short of building containment tents and buying all kinds of heating apparatuses what is the proper way to do this in cold weather? Can I get away with just warming the epoxy and the surface.

[GordMay]

As well as heating the structure & area (as best you can), pre-heat the parts to be bonded & the 105 epoxy resin /205 hardener/container/& pumps, & mix the epoxy (very well) in a warm area. Maintain heat until fully cured (a week or more?)
Good luck!

[Benz]

It will cure in the cold....eventually. I would caution against spot-warming too much: I once warmed a whole lotta pro-set in front of a halogen lamp to where it was warm to the touch on a 20-degree day. Pot life was nil, and as it started smoking when mixed we had to abort mission.
Keep the stuff in a warm place overnight, keep in a warm car as you drive to the boat, carry it to the boat in a cooler to insulate it, but be careful of pointing a heat gun at it. The areas to be glued to you can heat with a gun beforehand.
As far as bonding to lead, epoxy is your best bet, but if you have a bare surface, why not sink some stainless lag bolts into it? That'll really hold your pad in place.

[ggray]

I'm sure you mean an electric space heater, but for sure don't use a kerosene space heater as it would contaminate the surface.

[misfits]

Personally I'd wait for warmer weather, it's not worth the hassle.
Just saying...

[Rod B]

As you are probably going to use heat, pre-warming/heating etc, my experience suggests you should use slow hardener. Too easy to make the epoxy kick very quickly especially if you're adding a filler.

[Jammer]

There are a whole bunch of problems trying to epoxy in cold weather
- slow, uneven, unpredictable cure
- poor bond due to moisture contamination
- surface of cured epoxy affected by moisture that condenses during the course of the cure
- viscosity related problems, difficulty mixing, poor penetration, difficult to control fillet thickness

This time of year I work on projects that fit inside.

Be careful with a heat gun, the temperature is really too high for this purpose and you can easily overheat things. A hair dryer will work better, higher air flow lower temperature.

You want the surfaces being bonded as well as the epoxy to be at a reasonable temperature 60-80 F before you apply the epoxy. Once applied try to keep them there. If stuck epoxying in cold weather my usual method is to keep the surface quite warm, mix the epoxy inside, apply it to a warm surface and then it cures quickly and the heat can be shut off. Try to pick as warm a day as you can.

[donradcliffe]

West system with the fast hardener should kick overnight at 50 degrees F. I'd wait for spring.

[Martkimwat]

I've found putting the two epoxy bottles in a bucket of hand-hot water for twenty minutes before use is plenty good enough to get the epoxy runny without sending it in to exothermic cure. if you can heat the surface to be warm to the touch (which may take a while longer but will also take longer to cool down) it should be fine once it starts to go off (getting tacky) then you can lay off any surface heating and although it will take longer than normal to fully set, it should be fine. I would still use fast set hardener. Another trick I used for warming Polyester glue which needed to be kept warm to stay runny if you are gluing up all day, is to use a Brewing Heater Belt available from home brew centres or online like this, https://www.amazon.co.uk/Home-Brew-H...ds=heater+belt works a treat. Just wrap it several times round one or both bottles as required and leave for half hour.

[billknny]

Nobody posting here knows more about West System Epoxy than... West System!

Why not just read what they have to say????
https://www.westsystem.com/instructi...ature-bonding/

Several pieces of advice in the thread contradict what West System instructions say. You can take your pick about who has the best information.

[Locquatious]

The general rule of thumb is that for every 10°C increase in temperature, the chemical reaction rate will double. So if you were comparing the time to cure at 75°F (24°C) versus 40°F (4°C), it would take four times longer at 40°F.

But this is only part of the story. As epoxy cures something called the glass transition temperature increases. This is the temperature at which much of the diffusion of components essentially stops. That is, the epoxy groups in the resin will not move around (diffuse) and find the amine groups in the hardener. So if the glass transition temperature of the curing resin rises to 40°F the cure will stop. It will often pick up again if heat is applied, but the glass transition temperature will also increase, so you need to keep raising the temperature, usually to at least above the maximum glass transition temperature of the epoxy to fully cure the resin.

Just because the resin or hardener are not mixing, due to the temperature being below the glass transition temperature, it doesn't mean that moisture can't migrate into the uncured material and permanently harm the cure. And the partially cured material is also much weaker, so it will be more prone to cracking or distortion from any stresses.

Adding non-alcohol or non-water based solvents, to the epoxy mixture, during the initial mixing should allow for lower curing temperatures. For example, adding lacquer thinner or acetone would lower the glass transition temperature of the curing epoxy and help restore the mobility of curing components. But the cure will still not complete. It will likely reduce the overall strength of the final cured resin.

Adding heat with a heat gun is tricky because the epoxy cure is exothermic. That is the cure itself generates heat. So if you heat the curing resin from say 75°F to 105°F, it will four times faster just due to mobility. But the temperature and cure will be even faster due to the exotherm of the reaction. Anyone who has mixed too much epoxy in a cup has experienced this phenomena.

[coastalexplorer]

Not withstanding the ambient temperature issue, there are some substances that epoxy resin will not effectively adhere too, I think PVC that the OP mentioned is one of them?

[foufou]

I have built several boxes out of plywood or foam board and used either a hair dryer or small electric heater to get the temperature up to 60 to 70. You can duct tape the box to the surrounding structure. Nothing fancy but you can get everything up to the same temperature. A lead keel might be near impossible to warm much. I was party to building an "oven" that was 4' X 4' X 18'. It was hoisted to the ceiling over the mold when not in use. Had to put rug on the concrete slab to prevent that Sucking all the heat.

[tbodine88]

Originally Posted by misfits

Personally I'd wait for warmer weather, it's not worth the hassle.
Just saying...

I'll agree with this advice.i have a friend who built a beautiful Farrier 25. Problem is he put on the fiberglass in the winter in Texas. The boat has now fallen to pieces after just 20 years.

Caution and patience for warmer weather is advisable.

[thinwater]

Originally Posted by tbodine88

I'll agree with this advice.i have a friend who built a beautiful Farrier 25. Problem is he put on the fiberglass in the winter in Texas. The boat has now fallen to pieces after just 20 years.

Caution and patience for warmer weather is advisable.

This.

I always cringe when I see boatyards working in the winter. Some do it right, inside, but some push the limits of temperature working outside. Something to think about when you contract work over the winter.

There is no substitute for even temperature throughout the materials and through the curing period (one week). Heating the surface or the materials is NOT a solution.