Clear Coat- Not Enough Hardener?

General Discussion. Make yourself at home...read, ask and answer!



Non-Lurker
Posts: 3
Joined: Mon Jul 16, 2018 2:28 pm
Location: New Hampshire
Country:
USA
PostPosted: Tue Jul 17, 2018 10:12 pm
I repainted my bumper last Tuesday and i can still dig my nail into it and peel it and the base coat off (primer still has good adhesion)

This was my first time ever spraying with an HVLP gun, it was sprayed in 70-75 degree heat with around 35% humidty.

BC instructions recommended 15 mins between the final coat and clear coat i gave about 20

CC Instructions recommended 2-wet coats with 5 mins between, i sprayed 4 although i got a distracted talking to someone and ended up giving only around 1 minute between the 3rd and 4th coat :roll:

the humidity since Wednesday has been over 70% and its been around the 75-85 temp range

So did i not add enough hardener? too much humidity? not enough time between coats or a combo of all 3?

Products used:
Finish1 2K Primer 4:1 ratio
Finish1 2K Clear 4:1 ratio
ATU acrylic-lacquer basecoat (pre-mixed)
Attachments
IMG_1554.jpg
Assembled
IMG_1500.jpg
Primer
IMG_1510.jpg
Basecoat
IMG_1520.jpg
Clear coat

User avatar

Top Contributor
Posts: 3957
Joined: Wed Sep 07, 2005 9:59 am
Location: Louisville, KY
Country:
USA
PostPosted: Wed Jul 18, 2018 4:02 pm
You probably didn't use enough activator.
Humidity will actually speed up the activation process.
I paint when it's raining all the time, I prefer to because I get cleaner
results. It always sets up just fine.
Humidity is not a problem with urethanes like it was with
the lacquers that we use to use.
JC.

(It's not custom painting-it's custom sanding)



Non-Lurker
Posts: 3
Joined: Mon Jul 16, 2018 2:28 pm
Location: New Hampshire
Country:
USA
PostPosted: Wed Jul 18, 2018 5:27 pm
JCCLARK wrote:You probably didn't use enough activator.
Humidity will actually speed up the activation process.
I paint when it's raining all the time, I prefer to because I get cleaner
results. It always sets up just fine.
Humidity is not a problem with urethanes like it was with
the lacquers that we use to use.


Heh thats what i was afraid of, knew something had to go wrong since i managed to get no runs or spray-related issues on my first ever try with an hvlp gun :roll:

Would i be able to sand down the clear with 320/400/600 grit paper and re-clear or would i need to bring it back down to primer?

User avatar

Top Contributor
Posts: 3957
Joined: Wed Sep 07, 2005 9:59 am
Location: Louisville, KY
Country:
USA
PostPosted: Thu Jul 19, 2018 10:58 am
If it's hard enough to sand easily, then it should be hard enough to
sand lightly and reclear.
But for just a bumper I'd opt to sand most of the clear off, rebase and reclear
to be safe.
And add a little activator to your base too. (about 1oz per qt of mixed base)
that will help adhesion.
JC.

(It's not custom painting-it's custom sanding)



Non-Lurker
Posts: 3
Joined: Mon Jul 16, 2018 2:28 pm
Location: New Hampshire
Country:
USA
PostPosted: Thu Jul 19, 2018 11:25 am
JCCLARK wrote:If it's hard enough to sand easily, then it should be hard enough to
sand lightly and reclear.
But for just a bumper I'd opt to sand most of the clear off, rebase and reclear
to be safe.
And add a little activator to your base too. (about 1oz per qt of mixed base)
that will help adhesion.


Appreciate the help, im gonna try just sanding it light and re-clearing as the truck is on daily-driver duty and i cant afford to have it down for more than a day.

Return to Body and Paint

Who is online

Users browsing this forum: amsetikas, Google [Bot] and 150 guests