W/based polyurathayne on purple paint! :mad:

[Waldo]

G'day,

I'm smack in the middle of painting toy trains (water based paint) and the bits I've painted purple as soon as the water based p/thayne hits it, it either goes cloudy like I've over painted or it bubbles.

It only happens to the purple painted bits - no other colour reacts like this and they all get painted with the paint and polyurathayne.

I know in printing blue is a rotten olour for commercial printers in regards to drying, scuffing etc. Can anyone enlighten me on the purple? I could not use it and probably won't use it again.

I'm not overpainting and the coat of p/thayne hasn't got bubbles in the tin etc. been doing this for years now. Buugered if I know what's going on. :confused:

[Skew ChiDAMN!!]

Sounds like there's a chem reaction going on. I've had similar problems iwth some colours of printers' ink when I'm staining finishes.

One method that may help, if you're spraying the poly, is to give the purple paint a quick couple of coats with hair-spray first. 'Tis a trick that has saved my butt a few times. I'm not too sure whether it'd work when applying by brush though. Probably not.

You might want to think about trying a different finish on an offcut painted purple. It may be additives in the finish you're using... or in a worse case scenario switch to a non-waterbased one.

[Waldo]

G'day Skew ChiDAMN!,

I'll give the hair spray a go. I'm painting the poly on, but what have I got to lose? If it doesn't work I'll just sand the stuff back and repaint a different colour.

I suspect the same, that it is a chemical reaction.

Thanks for the tip.

[echnidna]

You could try a coat of white shellac before the poly.