Model Boat Mayhem

Technical, Techniques, Hints, and Tips => Painting, Finishing and Care. => Topic started by: TomHugill on June 14, 2014, 10:10:57 am

Title: Spray paint crackling on application
Post by: TomHugill on June 14, 2014, 10:10:57 am

Any ideas why this keeps happening:

(http://i32.photobucket.com/albums/d15/team_shrewsbury/B9DA8799-3476-4763-9391-CF82CBBB24D8_zpsrsop04xk.jpg) (http://s32.photobucket.com/user/team_shrewsbury/media/B9DA8799-3476-4763-9391-CF82CBBB24D8_zpsrsop04xk.jpg.html)

Tried different spray paints, sanded it right back but no luck

Title: Re: Spray paint crackling on application
Post by: TomHugill on June 14, 2014, 10:15:24 am

I should say the grey is tamiya surface primer, but I've tried white gloss enamel too with the same effect. The original primer was enamel white primer. The item in question is ply wood bit the details are plastic and suffer the same issue

Title: Re: Spray paint crackling on application
Post by: rsm on June 14, 2014, 01:05:33 pm

Looks like your getting a reaction between the acrylic and enamel paints. I think you'll probably have to strip all the paint off very thoroughly and then re-paint.

Title: Re: Spray paint crackling on application
Post by: regiment on June 14, 2014, 01:35:16 pm

 could be dirty finger marks 

Title: Re: Spray paint crackling on application
Post by: Stavros on June 14, 2014, 04:56:04 pm

Defo a chemical reaction  due to different paints nothing else would have causd it....remedy.....strip and start again ...NO OTHER SOLUTION



Dave

Title: Re: Spray paint crackling on application
Post by: TomHugill on June 14, 2014, 04:58:54 pm

Well I managed to save it. Had to sand back the worst affected areas down to the original paint. Then slowly mist the tamiya primer in very light layers till it was sealed . Then white over the top. Seems to be ok!

Title: Re: Spray paint crackling on application
Post by: rnli12 on June 14, 2014, 05:03:51 pm

Hi,
Normally if you spray acrylic onto enamel it will crack like this (chemicals or something) but not the other way around, i've just done the same after picking up the wrong spray tin! and after years of avoiding the same mistake.
 
OOOPS
Rich

Title: Re: Spray paint crackling on application
Post by: Umi_Ryuzuki on June 14, 2014, 09:03:21 pm

If the tamiya paint is laquer or maybe some "dope" based thinner, you will get a reaction also.
However that is typically if you put the laquer over enamel, not the other way round.

As I understood it , Laquer, enamel, acrylic, in that order.  {:-{
If the undercoat is not fully cured, you could have the acrylic drying faster than the enamel underneath. As the under coat continues to dry, the top coat will crackle.

Title: Re: Spray paint crackling on application
Post by: derekwarner on June 15, 2014, 02:20:08 am

 %)...they use this effect intentionally on clay or ceramic pottery

Gold base coat...the a bone washed top coat that crackles showing the gold & provides an imitation antique look  <*<

Not my style........but have seen many examples......Derek