Black Epoxy settling in the gun

Brad J.

Oldtimer
Why does the black epoxy settle so much more than it used to? Been using it for almost 15 years now and since around covid time it seems like it settles fast. I used to mix and spray 3 coats morning, noon, end of day leaving it in the gun between coats with nothing more than shaking the gun before I shoot. Now it settles so much that I have to clean the gun if it sits more than a couple hours hours as the pigments gum it up. I'm used to it now, but I sprayed some grey yesterday and it was like the black used to be. I'm curious if anyone else notices this?
 
I'm sorry I missed this post! I'm afraid that I can't be any help, since I always pour my epoxy back into a cup between coats, mostly to see how much I used and make sure there is enough for what I want to do. I think some small changes get made here and there to the formula but it isn't ever anything big enough to need a TDS change or anything. I hadn't noticed anything about the black at all, it's always been the easier of the two, white is usually my "problem child," since it doesn't cover as well and is therefore easier to over-apply. I wonder if anyone else has noticed anything?
 
For me, the black seems to settle and cure faster. It is not sprayable anymore longer than 24 hrs, after poured into a cup with lid. Hot weather always made it settle sooner, but has definitely changed. Normal temp is not usable 24-48 hrs., like it was possible, IMO.
 
Surprised you leave it in the gun. I never like to leave anything in the gun. With epoxy I'm pouring it out back into the mixing cup after each coat. Especially if I'm waiting an hour or so between coats. That and rinsing the gun.

As for the original question, I've been using SPI epoxy since about 2015. Not as long as some of the guys here but long enough to notice variations in the different batches over the years. Some years ago it would settle much like you describe, then at some point it was much less prone to that. Latest batch I've used it seems about normal. Not excessive. I've noticed as TexasKing mentioned though that it doesn't really stay sprayable as long as it did 7 or 8 years ago.

Barry would be the one who could answer this definitively but he isn't on here much anymore. When I talk to him again I'll try and remember to ask him about it.
 
Yes the black is a little prone to clump up after 30 mins or so when setting but stirs right up. So after induction 30 to 1 hour I mix or stir it very well kinda a good thing.I don't let it sit in my gun at all. So I do notice a little differnce in the last few batchs of black.
 
I confess that I do not let it induce for more than 15 minutes, usually less than 2 minutes. Just mix it very well and pour through a screened funnel into the cup. Been doing it this way for years now and never had any issues

Backyard hack disclaimer inserted here!
 
Black does appear to settle far faster than the grey or white that I use regularly. Even when I let the black induce for 30 min I will come back to give it a quick stir and its clumped up pretty bad.
 
I think the OP said he left it in the gun for several hours.:)
Heck yes. Used to sit in the gun all day. Just shake and go. I would stir if only used every 4 hours or so, but it was never settled. Used some this week and it will settle out in a half hour. If it sits overnight, it damn near tears the pps cups to get it stirred back up. Never did this years ago. I noticed around covid time. It's a pain compared to the old stuff, but it's worth it. I feel it sprays a little different, harder to keep consistent. Sprayed a lot of it over the years in my trusty Iwata LPH440 so nothing has changed on my end.
 
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