What does that mean? Its in big bold letters on the primer that I use for fiberglass (FlexiPrime, flexible bumper primer).
Thanks!
Joe

I'm thinking, well, guessing really... that it will undergo some sort of chemical reaction if exposed to light/ultraviolet.... maybe it's like the plastic stuff dentists use to make white fillings and which is rapidly hardened by exposure to a UV light source?

In EPA-speak, it contains substances which are known to cause or contribute to smog,
in presence of sunlight, Oxygen, and Nitrogen (oxides, I believe).
(At least, that's the context one always finds used when making this reference)

Literally, it appears to mean, "undergoes chemical change(s) when exposed to light".


Edit in response to seeing the above post... yeah, that makes more sense, come to think of it.
I know sunlight sure helps some things cure quicker

Until someone gives you a definite answer I'll give you my best guess. I think this term refers to the fact that the product will cure better in sunlight. Another example is automotive pin stripe tape, (3M). The adhesive on the tape reacts to UV rays and actually sets with a stronger bond if you leave the taped suface outdoors. I use it a lot on my models, and I always set them in the sun for a few hours to let the tape cure. It stays stuck and I never have a piece come loose. Anyway, that's my best guess.

OK. Thanks guys. That makes sense. Didn't even think of it. But when I was at the auto parts store I saw a Bondo product that said it dried faster in sunlight, or developed to dry in sunlight,, something like that. So basically for the primer, when the sun hits it, something happens [8D] I guess..
Joe

It means that light will cause the chemicals to react.
Keep it out of sunlight.

Then I guess its a good thing I paint at night
Thanks for the answers!
Joe

Photochemically reactive simply means that some sort of chemical reaction will take place when exposed to light.

It may be a good reaction, or it may be a bad reaction. The directions should tell you which (I.E. - Leave in bright area to cure - Or - Keep in dark area to cure - etc)

Hi Minn,
Actually it doesn't say. It just says Photochemically Reactive. Keep out of Reach of Children (all in bold letters). Either way I don't think its a problem. The helicopter is out of the sun during the day, and I paint at night. Plus the stuff dries quick. Anyway once I'm done filling, priming, and sanding, its going to be covered by a "fantastic" paint job. Below is what I'm striving for. I know its not the heli forum

I looked on the web a wee bit more today... and found this:
http://www.paintideas.com/glossary.asp?wordid=974
(On a google for: definition "photochemically reactive". There were lots of hits)

So unless the product label definitely mentions leaving it in (or out of) the sun to cure,
I'd say it's simply more of an EPA-ism than anything else.

In this context, it means that the chemicals that evaporate from it contribute to smog.

I believe you are correct. Its right above, Hazardous to Children, and it doesn't say anything about drying, in or out of the sun. So I guess I'm contributing to the smog here in Chicago [:'(] And of course the warning label is a novel.... Why it it that the stuff that works so good is so dangerous? (no need to answer that, just an out loud observation)
Thanks again to all!

Joe

I was going to make a comment about women, but then I thought I better not....

It's not good to stereotype women - you KNOW how they can get

Sounds like every woman I know!

Uh Oh,,, he's done it now [X(] I hope our female forum subscribers don't get any wind of this I won't tell if you won't.