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-   -   2 coats versus 3 coats (http://www.diychatroom.com/f4/2-coats-versus-3-coats-10862/)

joeyboy 08-20-2007 12:03 PM

2 coats versus 3 coats
 
I do 3 coats as a rule, but had a question about the difference.

I'm currently painting some gutters, and know that when installing (and just the wind blowing them, etc) there will be *some* flexing going on.

The paint's all latex (prepped with sanding, soap/water, cleaned thoroughly, dried overnight), and am wondering if going from 2 coats to 3 coats will make the paint more or less likely to flake/chip/spall/etc.

At 2 coats it looks good and uniform (I imagine because they're so thin), and I was gonna do my standard 3rd coat. But I don't think the third's gonna do much for the visual appearance, so I'm wondering if doing a 3rd will make it more durable or not.
(I guess I just want to know the difference between 2 and 3 coats, apart from the obviousness of paint used, and color uniformity :) )

slickshift 08-20-2007 02:13 PM

That depends on how thick it is
There are tools to measure this

Usually, there is no need for a third coat
It doesn't hurt, but it's usually not worth the effort/time/money

However, if the thickness (measured in "mils") of the first two coats isn't what the factory expects/recommends, a third coat may be needed/desired to make it thick enough

It's hard to say from here if it's thick enough or not

It also depends on the (exact) product as to whether or not it will "flex" enough for you and your needs
Generally, it's not an issue with the proper paint, properly applied

I usually don't get to paint new gutters, so that hasn't been an issue
Either they are in place and staying there, or removed for trim painting, and painted off the house
There's always a chance of scuffing them during re-attachment (though there's usually no cutting and forming like new ones might get)
But that's the way it goes

joeyboy 08-20-2007 10:28 PM

Quote:

Originally Posted by slickshift (Post 58607)
That depends on how thick it is
There are tools to measure this

Usually, there is no need for a third coat
It doesn't hurt, but it's usually not worth the effort/time/money

However, if the thickness (measured in "mils") of the first two coats isn't what the factory expects/recommends, a third coat may be needed/desired to make it thick enough

It's hard to say from here if it's thick enough or not

It also depends on the (exact) product as to whether or not it will "flex" enough for you and your needs
Generally, it's not an issue with the proper paint, properly applied

I usually don't get to paint new gutters, so that hasn't been an issue
Either they are in place and staying there, or removed for trim painting, and painted off the house
There's always a chance of scuffing them during re-attachment (though there's usually no cutting and forming like new ones might get)
But that's the way it goes

Ahhhh, damnit!!!!! Then I've been wasting paint!!! I've only been set in my '3 coats, all the time' mindset because of what I've read on contractor's talk forums (it may seem like I post a lot here, but I spend much more time just reading over there, and it seems the concensus there in the painting subforum is that you just always go 3 coats. I guess, as an amateur, I really want to do my best to emulate the pros, so I kind of go there a lot to get a feel for what they do, so I can do my projects in the most professional manner possible for a diy'er)

slickshift 08-21-2007 08:59 PM

I'm sure they are referring to 1 coat primer and 2 topcoats/paint
Total 3 coats
(though there mat be specific cases otherwise)

joeyboy 08-21-2007 09:04 PM

Quote:

Originally Posted by slickshift (Post 58852)
I'm sure they are referring to 1 coat primer and 2 topcoats/paint
Total 3 coats
(though there mat be specific cases otherwise)

Really? Wow, I've read so much in their forums (specifically their painting and masonry ones) and always had the impression they were referring to 3 coats of paint, not 2 paint + 1 primer.... that sucks, I've been doing 3 on everything trying to emulate the pro's :censored:

slickshift 08-21-2007 09:46 PM

It's possible, but honestly I've never run into pros that did three topcoats (paint) standard, whether in real life or on the interweb

Occasionally it comes up where three (super) thin coats is easier/better with some things in some apps for some reasons

Hey..at least you know your covered!

joeyboy 08-22-2007 09:59 AM

Haha yeah I know right?! Better to overdo it than underdo it :thumbsup:

At least I know that for the rest of my painting!! Not that it even really matters (although it does save time, which is nice) as I was a complete tard and just assumed I'd need a 5 gal of tan and a 5 gal of maroon/burgundy/red for my trim exterior stuff. I'll probably end up using 2 gals of each maximum, and that's probably an overestimate. I'm not even done with a gallon of either yet and I've triple coated my storm shutters/awnings, triple coated my regular shutters, and done 1 coat to all my gutter downspouts (which is nice, because today when I second coat them, I'll just go put them out if they look good instead of waiting another day!)

StevePM 08-22-2007 11:06 PM

One coat primer, two finish on the trim for me exterior. :thumbsup: Generally, two coats with no primer inside on already painted walls unless I'm faced with a special problem (smoke damage, etc.).

joeyboy 08-23-2007 10:04 AM

Quote:

Originally Posted by StevePM (Post 59139)
One coat primer, two finish on the trim for me exterior. :thumbsup: Generally, two coats with no primer inside on already painted walls unless I'm faced with a special problem (smoke damage, etc.).

LOL I find this hilarious (that I thought I was reading the tips of the pros and got it wrong!!)

At least I've been over doing and not under doing :yes:

Steve - you just said something that's probably gonna save me even more time and money (lol). Okay, on regular interior apps, you just do 2 coats and no primer (unless special primer circumstances)? That's good to know, as some of the only paint I still need get is my interior trim (which, as of two days ago, I would've: primed, 1 coat, 2 coat, 3 coat haha). Now, I'm doing an accent of a light gray, where they used to have a darker gray (and a blue of equal darkness) - I imagine this would still warrant a white primer? (I don't think my gray is dark enough to need a gray primer, dunno - do have both on hand thankfully).

(now the only paint I'm still really holding out on is concrete slab paint!! Still haven't found any definitive approach I'm comfortable with for re-doing all my slabs - garage, walkway, front stoop area, etc - they're all done up with green paint from many years ago, so some spots have solid thick green paint, and some are back to regular crete.... Gonna have to re-animate that thread soon lol )

blender 08-24-2007 12:43 PM

i've been getting very good results with applying 2 coats of tinted primer, and 2 coats of paint.

after priming twice with tinted primer, even the first coat of paint looks fantastic.. i apply the 2nd coat to make sure i cover everything that i might have accidentally missed the first time.

not sure if i'm over-doing it by applying 2 coats of primer, but it sure makes paint application and coverage easier and more predictable.


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