Acid Etch Primer

[Pinkmouse]

Just a note of caution, I mixed up a batch of this today, the same as I've been doing for years, and discovered a problem. A minute or so after mixing, (two parts primer, two parts etch thinnner, one part cellulose thinner), it set up like a gel! Luckily I hadn't fired any through the airbrush yet, so didn't have to worry about stripping and cleaning that, but it was a bit of a pain all the same. So beware of old paint!

[bertiedog]

Sounds like enamel /cellulose reaction, the "oil base" has reacted... was the primer, or were the thinners changed, or was it all the same older batch? If new primer, the formula may have changed.

 

Some "enamel" is synthetic enamel, which is true for Phoenix and the main colours will dissolve in cellulose, but the etch primer will not, requiring the special thinners, basically very refined white spirit.

 

Have you always added the cellulose thinners to the primer in the same way and proportions?

 

Acid etch generally does go off faster than plain paint( after opening), but the process is slow and a sudden change a bit odd. All paint should really be as fresh as possible, with the exception of true cellulose paint which will re-dissolve in further thinners for many years.

 

Stephen.

[Pinkmouse]

Yes, it's very strange. The primer, thinners and cellulose were all from a batch I obtained from a custom bike repair shop, a jam jar of each in return for buying the bodyshop guy a pint in our local. The mix was exactly as he recommended, and I've been using it for about three years unaltered, and until now it's been fine. Oh well, I suppose I'll have to buy him another pint.