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Epoxy Mastic Paint - Curing Time?
scootz - 10/9/13 at 12:34 PM

Does anyone know roughly how long you should expect epoxy mastic paint to set hard?

I finished the first coat about 6pm yesterday and it's still pretty soft now (20 hours later).

jps - 10/9/13 at 01:07 PM

quote:
Originally posted by scootz
Does anyone know roughly how long you should expect epoxy mastic paint to set hard?

I finished the first coat about 6pm yesterday and it's still pretty soft now (20 hours later).


Out of interest - what's the temperature like where you've left it? (chassis I assume?)

scootz - 10/9/13 at 01:35 PM

Unheated garage... maybe averaging 10 degrees in there from when I painted.

davidimurray - 10/9/13 at 01:36 PM

Mine went hard within about 24 hours, but it didn't go proper hard (chip resistant) for about 3 months!!

scootz - 10/9/13 at 01:47 PM

Ah! This is going to take me about a week to put on a few coats then!

TBH, I wasn't too fussed about it still being soft when I went out today as there are some areas that needed rubbing down before the next coat (it's the inside of a Quantum chassis, so it's flat panels and all on show).

Benzine - 10/9/13 at 01:49 PM

Brushed/rollered or sprayed? I found with spraying lots of thin coats it's very fast to cure, but with brushing I ended up with thicker coats which took longer. Tacky within an hour usually, and I'd feel okay handling them after about 24 hours, that was in summer.

scootz - 10/9/13 at 01:50 PM

Combination of brush for the corners and roller for the flats...

scootz - 11/9/13 at 09:01 AM

Hmmmm... still soft. Can scratch through to the metal by running my fingernail (pretty lightly) across it!

iank - 11/9/13 at 09:11 AM

Curing time (and conditions) should be on the datasheet (usually downloadable from the manufacturer).
Did it have a separate hardener to add?

coozer - 11/9/13 at 09:26 AM

Data sheet on mine was 8 hours for touch dry and 7 days to fully cure.

Peteff - 11/9/13 at 11:23 AM

Did it have any hardener with it ? I see iank asked the same, if it hasn't got a separate hardener 10° sounds a bit cool for paint, try running the hot air gun over it to start it curing.

[Edited on 11/9/13 by Peteff]

scootz - 11/9/13 at 02:58 PM

Cheers fellas... it was a 1:1 mix with hardener (and about 5% thinner).

scootz - 17/9/13 at 03:35 PM

Still able to score through to the metal with my fingernail.

I'm thinking I'm going to have to remove it, and then start again with an etch primer. It's going to take me forever to sand it all back...