Painting a new bust for Steve Leadley of a Russian Crimea Private. Used GW acrylics for the base coat and spent yesterday evening painting the head, hair,collar and hat in oils-really pleased with the result!
Put it in my light box this morning to flatten the oils and to my horror the acrylic base coat on the great coat had bubbled............result strip the whole thing and start again-never had to do this before...are GW acrylics the problem. They are quite thick and opaque which is why I use them instead of 2-3 coats of enamel as a base.
I've resigned myself to dumping all of my acrylic paint and sticking to enamels and oils.
Anyone any experience of Model Master Enamels, I like the idea of the screw bottle rather than the humbrol lidded tins.

Keith

Was this base coat brushed or sprayed on Keith? Resin or metal bust ? I can honestly say that I always use GW 'skull' white (aerosol) and have not had any problems. However, I do not force dry my oils as this can prevent them bonding to the base coat properly.

Cheers

Ron

Yikes! I've not heard of acrylics blistering like that!

How long did the acrylics dry before putting them under heat ?

Hi Ron, The bust is Resin spray can primed with Tamiya Fine Surface Primer-I then brushed 3 base coats of GW acrylic Foundation colour on the great coat-It is a khaki colour and needed 3 coats to give a smooth coverage.
I have to say I have used this technique many times without this happening,
1) Was the box too hot and caused a reaction in the resin?
2) The base coat was put on 48 hours ago so should have been dry
3) The melting occured mainly on the edges. E.G The neck, where the arm and body meet, along the edges of the cross belts and under the epaulettes also around the piping on the hat....curious?
I'm beginning to think it has something to do with the resin?
Keith

One further question Ron how do you remove the sheen from your oils? Dullcote?

Keith

HI Keith

Have you thought of undercoating with an air brush,
you will get a very even coat from humbrols without any shine which can happen when brush applied.

I always feel that force drying anything can have adverse affects and unless you are working to deadlines best left to dry naturaly,oils have a sheen ,part of the beauty.
If you apply sparingly and get most back off apart from a fine slick ,they will dull very .
Just a thought!

Ronnie

Hi Carl.....at my age there's no time left to practice

Hi Ron, I think I will settle for the sheen in future, I do like the finish and find acrylics dull and uninteresting unless exceedingly well painted-they also present difficulty in larger scales with very visible transitions-having said that some people produce stunning results. I do occasionally air brush on larger areas but primer is usually a spray can of Halfords, Tamiya or Skull White from GW.
I did have a comment today that the problem may have been something left in the resin which tried to escape as the bust expanded and cracked the paint.
Re-primed it tonight so start again tomorrow.

Keith,
It could be that some liquid was forced out of the resin by the heat. Causing the paint to blister??????
Just a thought as I know that some resins when hard still give off sticky moisture.
Cheers
John

Hi Keith, usually you will only get a sheen if you apply oils too thickly. I will only apply a dull coat to seal pastels/powders that i have used after the oils have dried. If you look at the celt I posted recently on v bench you will see that the oils are naturally flat because they were applied in very thin layers. Reading through the previous posts, I note that you applied Tamiya primer and overlaid GW. This is where I think the problem lies. I stopped using Tamiya as it seemed to vary from can to can, and went over to GW 'Skull' White in aerosol. It seems to work best with Vallejo acrylics for me. Hope the above is of use to you.

Regards

Ron

Hi Guys, It was Tommi who suggested that this may have been the problem so I think collectively we have the answer. I've used the same paints and technique many times before without this happening.
Thanks for all of your responses-have to fish my acrylics out of the dustbin now

Keith

Hi Ron, I use the Tamiya fine surface primer usually-I've re-primed this time in Skull White. Thanks for your response I'll have to adjust my Oils technique to avoid the drying box as well.

Keith

Thanks for that link Carl it has answered another question-Steve came to see progress last night and I remarked to him that in spite of primer and 3 coats of acrylic an area on the back of the neck had started to gloss....I think it was already leeching.......Looks like a bad mix, only 2 or 3 have been cast so far so it shouldn't be a problem to get them redone......thanks for your help

Keith

Hi Keith,

This stood out to me. If you applied one thick coat of GW acrylics, then yes, they probably will blister as they would not be able to cure properly. There needs to be 2-3 coats of acrylic just like there would be with enamel paint.

If I'm mis-reading this, I apologize but like I said, this sentence stood out to me as a potential cause of the problem.

Cheers,
Karrie

PS - Woops! just read your other post! If it's a bad resin and leeching chemicals, you're stuck!

We get these in the model horse hobby all the time. Can you return the piece to the manufacturer? If it's a small area, it's possible to cut the piece out and repair the gap with apoxie but you never know when something else will go bad. It could happen in a day or two or in a year or two. With an unstable resin mix, the manufacturer should replace it.

Good luck!

I don't know much but I do know that GW paint is latex based, I also know that if you apply acrylics to thick they seal them selfvs, that's what causes that plastic look sometimes. So I think the GW paint may have been applied to thick and not left to dry completely trapping moisture, (BTW) did you use GW foundation paint they cover great but dry uneven. Bubbles form because air cannot escape so the air was formed by moisture from humidity and or small amounts of water trapped between the primer and the top layer of paint. So apply several thin coats making sure there dry befor applying oils. Just a thought may be put the fig in the crock pot for a few to make sure the acrylic is completely dry before applying oils. Just Saying.

Model master enamel is OK their acrylics bubble without heat. I like Humbrol better but hard for me to get in San Diego.

Pete

Hi Carrie and Pete, thanks for your comments. It may have come down to a bad batch of Acrylic but yes I did use foundation paint which as you say is opaque and thick. May have been a combination of the two factors. I've stripped the piece re-primed and used Model Master Enamels as a base coat. That was a week ago and so far it seems to be OK-of course the problem may have been cured, excuse the pun! in the light box as the resin was forceably dried out. We have decided to recast the piece to ensure that it doesn't happen again. Thankfully there were only 2 or 3 castings made originally so scrapping them isn't a problem....thanks for your comments....Keith