Shelf life

D

DATEC

Member
The question I have is what would the usable shelf life be on Epoxy and the hardner be once it has been opened. I have been using everything SPI through out my entire project and mixed some Grey Epoxy (1/2 qt Epoxy, 1/2qt Hardner) for the bottom of the truck cab I'm doing. I had some hardner left over from a previous mix and desided to use it up. It was about a couple weeks old it had been opened and cap was tight but the color had turned a brown tint. I know from using this in the earlier days that it would turn color upon aging but thought that a couple weeks was alittle too soon but I figured I would ask, What would the usable shelf life be before a problem happens? What would the problem be? Not getting hard or just color shift? I figured it was because it had been exposed to the air when I broke the seal but I would have thought the cap being tight should have protected it longer.

I used it anyhow and didn't notice any color shift (I wouldn't have cared if it did it's the underside of a truck cab) and it acted just like it should and kicked off like it should. I sprayed the entire sprayable quart on the underside of a standared cab truck flooding what I could with a 1.8tip gun 3coats applied.

I have (on a previous freebie job) used some left over old epoxy with old hardner (over 3 years old) and even though the color of the hardner had changed I have seen no issues with it and the job still looks great to this day and it has been over 3yrs since I had done it.


Dave
 
I don't know what is "acceptable" but I can tell you I have used products over a year old after opening more than once. I am careful to keep the lids on cans as soon as I am done pouring and making sure everything is sealed properly when storing. I keep things in a metal cabinet where they won't freeze during the winter.
Activator is the most susceptible to going "bad" after opening. Yet I can say my experience so far with SPI is that I have never had anything go bad.
 
I bought a gallon of epoxy (split into four quarts) and a gallon of activator in October 2009. Mixed the first batch that month and activator cap was off just long enough to pour out one pint. I've opened the can a couple of times over the past five years and mixed up the most recent batch two months ago. It went on just fine, hardened and was sandable 12 hours after I applied it. After opening the can this time I did give the open can a shot of Bloxygen. As insurance I bought three quarts of fresh activator just in case the five-year-old activator fails.
 
That's what I thought but figured I would ask anyhow.

Another question. I just went out to check it and while dry to the touch just like it should be, it has a shine like I used straight enamel :confused:. I'm guessing that it is because I sprayed it upside down (I don't have a rotisserie) on the heavy side and mabey that caused the resins to come more to the surface then if it was laying flat even the veritcal inner rockers have the same shine. Is ths usual for SPI's grey Epoxy? I don't mind the shine it has it kinda looks good that way. I prepped the mix as I always do, shook Epoxy by hand a couple min., opened Epoxy and mixed with stick 5min till no lumps, measured the Epoxy and hardner in seperate can, mixed again with stick 5min, let sit 30min, mixed again, strained while filling gun and sprayed. That's my way of doing it and it ayways works for me.

I know the Black and Red Epoxy the next day went flat but this Grey I sprayed yesterday morning surely has a shine to it. The temp was in the shop around 68-70deg's with heater going and stayed at least that for the rest of the day but temps did go down into the 30's outside last night. I guess it may flatten out but I kinda hope not I kinda like it it looks like paint not primer.

truck.jpg

truck2.jpg

truck3.jpg

truck4.jpg

Pics taken after 33hrs dry time.


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A little tip for those at home who don't have a bake lamp to get the metal to a warmer temp. You can use a cheep 500W halogen work light or spring for the twin bulb version. The single can be had for $10 and they put out some heat not to mention light and can aid in getting the metal temp up on the cheep.

I also have a 24" FanTech exhaust fan ( http://www.ebay.com/itm/New-Fantech...291?pt=LH_DefaultDomain_0&hash=item43c972a7bb ) mounted in one window and it is speed adjustable from a creepy crawl to full blast by a 5amp fan speed control. The motor is totally inclosed and has aluminum blades. While not rated explosion proof I don't feel the there is a really high risk for home use, if I was using it in a comm. enviroment then it would be rated for explosion like the ones at work.

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I have never sprayed the grey, but the red and black will have a shine to it if you lay it down wet. Pics look great. I have been using those lamps for my epoxy as well.
 
They'll all have a shine depending on how it is sprayed, substrate, how many coats. Part B will darken as it ages but doesn't affect the performance from what I've seen. If you're ever worried about the shelf life on a 2K product and want to make sure it's ok-just mix up an ounce and spray a small test panel to verify it cures ok.
 
Thanks guys for the replys. I didn't feel there was going to be anything bad happening with the product just wanted to make sure. Next will be the outside firewall and inside of the cab with Black Epoxy. The cab is completely taken apart and will be painted black once the very minor dents are repaired. I want to never worry about rust again and the is the reason I am going to the extreme with soo much epoxy. I figure if I coat every square ince and flood the seams and heavy on the edges with Epoxy there should be no rust for a very long time, hopefully.

I will post pics as things progress.
 
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