RE: Epoxy primer for paint

[tartan30cirrus]

All,

As a follow up to my "Epoxy primer for non skid" query, I have a couple Q's that may be of interest to others doing the inevitable low temp epoxy/paint work of the season.

1) I plan to put some thickened epoxy on my deck to fair out the skid/nonskid interface. I have a heater or two that I could use...I am concerned about the low temps (30s @night), but how much should I push it. I came close to failure last time when the temps fell into the low 40s and the epoxy nearly failed...but this time I have a tarp and a couple heaters. One thought I had was to get a surface thermometer to watch the boat temp. Other ideas would be great and techniques for low temp work welcomed.

Cheers,
Clint
Tartan 30 dude

[Figment]

I've had success with warming the skin of the boat by warming the interior. An electric radiator I have gets the cabin to 75 degrees or so, which after a few hours will hold the outside skin temperature above 40, though the air temp may be in the twenties.

Obviously, this won't work on a windy day, though.

[heartofgold]

During the coldest days down here, if I felt I had to epoxy, I would begin by warming the resin and hardner by setting the cans on a radiator heater. I would mix the epoxy in the heated room (and wet out glass, if used), and I would take that out to the boat. I would have run heaters in the boat to warm the surface, and finally, I would hit the area with a heat gun, until it began to cure.

We use primarily WS epoxy at the yard, and the 205 hardner is listed as addequate to 40 degrees. When working below this threshold, it was sufficient to apply the heat gun only until the material kicked; the heater inside the boat generally kept the surface warm enough to finish the process.

Only once this winter did this process not work, a particularly windy day with the overnight temperature dipping into the mid 20s. The following day, once exposed to the sun and warmer temperatures, it finally cured.

[argonavis]

Hey all - just thought I would pass on something that I found extremely helpful. I have found an epoxy product from Progressive Epoxy in New Hampshire called LTC 38(Low Temperature Cure 38). It is great stuff and really does cure in colder conditions. I build surfboards, as well as work on my 1965 Cheoy Lee, and bought this stuff so that I could extend my building season and have been very pleased. It dries very clear with little to no tint and is very easy to work with. It is also very tough stuff. I originally found Progressive b/c I was looking for an alternative to WS. I know they are the standard, but I have had some bad luck with their products and needed a change. BTW - the fumes with Progressive are significantly reduced as well.
Good luck

[A30_John]

I came close to failure last time when the temps fell into the low 40s and the epoxy nearly failed...but this time I have a tarp and a couple heaters. One thought I had was to get a surface thermometer to watch the boat temp.

Clint, how do you know your epoxy nearly failed? Temps in the low 40s don't seem outrageous to me. It takes a lot longer for epoxy to cure at that temperature, but eventually it will cure. Most epoxy manufacturers have information available about full cure times at different temperatures.

FYI, I've been working all winter at temperatures in the 40s and low 50s and haven't had any failures yet.

Note: if I'm working to a schedule, I sometimes speed up the cure by covering my work with a tarp and use the electric heater as you describe. Again, just follow the manufacturer's documentation.

[Tim]

Also, don't forget the utility of a simple heat/work lamp. These produce lots of heat and will easily accellerate any cure time.

[tartan30cirrus]

Today I sanded the nearly uncured epoxy....most of it sanded to a powder indicating that it cured, but 20-25% was not cured 100% evidenced by curlies coming off when i sanded...like eraser residue from a pencil...well the more I sanded the better it seemed so I epoxied over it...I don't expect problems...but always expect the unexpected.

Had the boat in the 60s and the surface temperature maybe high 50s or higher...the stuff cured beautifully...I was using FAST hardener and was actually thinking it might be to warm for it...but I need to get paint (nonskid) on the epoxy next week. Incidentally, i have heard that you should wait 2 weeks to put a polyu. on cured epoxy???

Heat was supplied with one little black ceramic electric heater from Maine Hardware (Ace) and it kicks but...I've been working in the boat the last week in a t shirt late into the night.
Cheers,
Clint
Tartan 30 #388 Cirrus