Nitro paint checking

[MyNameisChris]

Hi!
I have put together my partsmaster, which i painted in seafoam green over sunburst. The lacquer is quite thin and is supposed to be worn off over time so the sunburst comes through. The green is nitro-paint, while the sunburst is poly from the producer.
Today I tried to so some checking on the paint and it did nothing at all. I tried the hairdryer/air duster method. Does this mean my paint is not actually nitrocellulose?
I bought it at a local paint store, that mixed it up and said it was real nitro.
In order to get some checking, could I buy a clear nitrocellulose lacquer, that should be real nitro, or at least made for painting guitars, give it a few coats and then get it to check/crack up?

Thanks in advance for all helpful answers!

[CROSS_guitars]

I'm no expert on this but I think it's to do with the temperature.
Maybe pop it in the fridge for a few days.

[jvin248]

.

+1 put the body in/out of the freezer and full-sun. The heat gun/cold-spray can do it too.

You may be trying too soon after spraying. Nitro doesn't get 'hard' for a few weeks to a couple of months. Until then it's quite pliable and will resist cracking. You need to let it finish curing for quite some time. Use your fingernail on overspray in the cavities to see if it still seems 'gummy' and then hang it so it can cure further.

.

[MrJagsquire]

It might need to dry and harden a bit more, but also some nitro have plastisers in them which are to prevent cracking. Depends on what brand/type you've used; maybe post back with those details and someone else might be able to confirm. I'm UK based, so not familiar with the brands where you are, but I'm hoping to do some light ageing on a nitro finish myself later this year: I've sprayed some test pieces to play with in the meantime before I go near my Jaguar.

[MyNameisChris]

Thanks for the replies.

It dried it for about five weeks before i sanded and buffed it. Then some more before assembling and another few weeks before i tried some checking. It seems hard and dry, so maybe the nitro indeed has some plastic in it. Ill have to call the shop.

Has anyone tried to check/crack clear coat? Im wondering if i get some ‘better’ nitro clear lacquer, add a few layers, sand, buff and then try checking again if that’ll work.

[Lost In Autumn]

you're going to have mixed results- the poly underneath is less prone to checking; checking is largely the result of the paint and wood expanding and contracting at different rates. If the poly remains stable, it's not likely to check.

[Lost In Autumn]

Thanks for the replies.

It dried it for about five weeks before i sanded and buffed it. Then some more before assembling and another few weeks before i tried some checking. It seems hard and dry, so maybe the nitro indeed has some plastic in it. Ill have to call the shop.

Has anyone tried to check/crack clear coat? Im wondering if i get some ‘better’ nitro clear lacquer, add a few layers, sand, buff and then try checking again if that’ll work.

from personal experience, I would not recommend mixing brands of lacquer.