West System 105 application under 60F question

[Hoosierdoc]

I really need to cover a few holes in my deck from prior hardware before winter really sets in. I doubt i’ll See another 60F day and I don’t have access to a garage.

Can I put a heater in the boat to raise cabin temp and then take a bucket to the deck above the repair to try to keep it warm?

Or should I just use silicone or something else in the holes for the time being and do it right when warm?

[john61ct]

Definitely no sillycone

[John_Trusty]

Why not call West Systems / Gougeon Bro. and ask advice? They've got great technical service, and I'm certain they've answered that question before. https://www.westsystem.com/

[Hoosierdoc]

Originally Posted by john61ct

Definitely no sillycone

I realize it’s not a permanent fix but either I formally repair when it’a Too cold or i do a temp fix to keep water out. Why would silicone not keep water out of a hole over winter? Seems easily removable when time to do it right.

[Hoosierdoc]

Originally Posted by John_Trusty

Why not call West Systems / Gougeon Bro. and ask advice? They've got great technical service, and I'm certain they've answered that question before. https://www.westsystem.com/

Sometimes the easily solution is hard to see. Thanks

Quick answer: 206 hardener is 60F minimum, 205 is good to 40F

But as long as surface material is 60F+ you’re good to go.

[john61ct]

Originally Posted by Hoosierdoc

Why would silicone not keep water out of a hole over winter? Seems easily removable when time to do it right.

Only acceptable use for silicone is glazing acrylic (Plexiglas) or polycarbonate (Lexan) portlights, use Dow 795.

For other surfaces, there are dozens of better sealants to use, especially butyl rubber, also

Sikaflex 291
3M 4200
lower adhesion, LifeCaulk & 3M 101

Nothing will ever adhere to silicone, nor to any film remaining after trying to scrape it off. Not even more silicone.

It is never "easily" removable, need to mechanically remove layers of whatever surfaces it touched,

Grinding, sanding, solvent? off all traces **completely**, no remnants

[foufou]

A hair dryer under a cardboard box will do the trick. Ore a heater under a bigger box. I've done this many times use a thermometer if you want to keep it in a reasonable temperature range. Up to 120F is ok

[Locquatious]

The epoxy/amine cure will proceed but it will be slowed by temperature. In general for every 10°C increase in temperature, the reaction rate will double.

But another factor comes in to play during cure. As the cure proceeds, the viscosity of the curing epoxy rises, this slows the cure rate. As some point called the glass transition temperature (Tg) the cure will stop. At low temperatures, the Tg will be lower and often about the same as or slightly lower than the cure temperature. If you provide heat, the reaction will proceed again and the epoxy will cure to a higher Tg. You can continue to raise the cure temperature till you reach the maximum Tg of the polymer. Raising the temperature above the Tg may still allow the cure to proceed, but the Tg will not go higher.

A problem with a low cure temperature (low Tg) material is that water and other solvents can penetrate the matrix and harm future cure and cure strengths. This may take time or be faster in condensing conditions such as transitions from day to night.

It is best to warm surfaces first before adding the epoxy mix and then as the cure progresses, keep adding heat to achieve a more complete cure.

[Delfin]

Originally Posted by Hoosierdoc

Sometimes the easily solution is hard to see. Thanks

Quick answer: 206 hardener is 60F minimum, 205 is good to 40F

But as long as surface material is 60F+ you’re good to go.

If you mix what you've got inside from containers kept inside and are themselves room temperature, wait until the mix begins to kick and you can apply it in very cold weather and it will be just fine.

[donradcliffe]

If it hasn't kicked hard by 4 pm, I get out the heaters. Hair dryer works well, or heat gun, or 150 watt spotlight, but be careful not to get it too hot.

[Jetx]

West's G/flex epoxy also cures at temps as low as 40F.

[Lepke]

My experience on decks below 50°F curing West or any epoxy is a problem, but heating until solid will work. When it cures and gets down to about 40° before the epoxy is solid, the epoxy cures cloudy. I don't know if it affects strength or bonding.

I heat the compartment below and use an infrared heat lamp on the area to epoxy. Usually blocked off with sheeting to retain the heat and block any wind. Heat lamps they sell in feed stores for chickens work fine. Later the heat lamp is a good winter heat source in a stored boat.

[roverhi]

Spent a couple hours with a heat gun warming an epoxy patch on the hull. Not stimulating use of my time but it worked to get the epoxy to set up.

[jharding]

Heat area best you can, I also put my epoxy and hardner in a bucket with hot water for a half hour before mixing. I have had good luck in 50 degree temp doing this

[thinwater]

So long as you can keep the substrate warm through the cure period, 105/205 is fine for small jobs in cool temperatures. Take the time to warm the hull and plan on staying around for a while.


Do NOT pre-warm the epoxy above room temperature before mixing. It will exotherm and go off in a hurry. In fact, in the summer I intentionally cool the products to extend pot life.