Priming with Gesso

[vcina]

So I recently got turned onto priming figures with Gesso.  I posted an short post on my blog about using it.
http://operationwargaming.blogspot.com/2014/11/gesso-as-primer.html

[blackstone]

How strong is the bond between the gesso and the metal. If you lightly draw your thumbnail against the gesso does it come off? I only ask because I can't see this being in any way as strong as a brush on oil based enamel primer ( which in turn is no way as robust as a spray primer).

I agree that a grey prime acts as a great witness coat btw. Really brings out the detail!

[Mr. Peabody]

Quality gesso forms a strong acrylic skin with good 'tooth' for taking paint.

Is it the single strongest bond possible for priming minis? Maybe not. However, a thumbnail drawn lightly against the gesso does not take it off.

It does provide one of the nicest foundations to paint upon that I have encountered. It can brushed on or diluted with water and sprayed with an airbrush to achieve equally good results making this a convenient and economical choice for priming minis that can be used indoors and at any time.

I have been using gesso for years to prime 1/72 scale metal and plastic minis (soft as well as hard plastic) and for 28mm metals with no chipping, flaking or loss of paint. I'm totally sold.

A single tub of the Holbein V-7 Grey Gesso has lasted me years, and it stores very well. I like the V-7 (lighter) grey but Holbein makes the traditional black and white gesso as well. Holbein coloured gessos now come in a squeezy-bag format.

[vcina]

Just quickly dragging my finger nail across the one of the figures didn't scratch off any of the primer.  Of course I always use a flat varnish after I'm done painting so I'm not too worried about the primer releasing from the figure.

[frogimus]

From my experience, gesso is much stronger after curing. I did a test model for an article I wrote a few years back.  I dug it out about a year later to actually paint it and the gesso was like a rock. To bad it won't go thru my airbrush.

[blackstone]

Interesting. I bought some gesso year ago specifically for priming some 1/72 soft plastic figures ( revell germans if I remember) since no other primer would bond to the plastic. The results were terrible with the gesso just peeling off. In the blog post this property was stated as a bonus since the gesso just peeled of the palette so I was wondering why it wouldn't just peel off the miniature.
Btw the northwest of england has similar weather to you so I'm always on the lookout good indoor priming options!

[vcina]

Did you wash the figures first to get rid of the mold release agent?  That might be the reason.  I have some plastic Perry Miniatures that are in the que to get primed and I'm going to use the Gesso so I will let you know.

[blackstone]

Yeah I'm a stickler for degreasing minis before priming. I tried everything to get paint to stick to 1/72 plastics, expensive aerosol plastic primer (useless), the pva method, (worse), even shaking the figures in a jar full of sand to rough the surface of the plastic up and provide a key of the primer haha.

After the bad experience with the plastics I never considered using gesso on metal but shall give it another try!

[frogimus]

Gesso has a high shrink rate and will pull voids if painted too thin.

I believe this shrink rate actually helps with miniatures because it creates a tight film. It may not stick to the mini but it bonds to itself so well it doesn't nick and flake like some primers. It also shrinks into the details.

BTW, some soft plastics have very low surface energy and require flame, plasma, or electric arc treatment to make it wettable in an industrial setting.

[Mr. Peabody]

Oh lord, I just googled very low surface energy... Help.


 

[frogimus]

Oh lord, I just googled very low surface energy... Help.


 

Lol! Try surface treatment of plastics

[tomrommel1]

I use Gesso for years now and it works just fine never had it peal off but sometimes you have to retouch a few spaces were the gesso pulled holes because of the shrinkage. It dries quite quickly also
so very recommended

[snitcythedog]

After reading this I will have to try the gesso since I have some on the shelf. 

Yeah I'm a stickler for degreasing minis before priming. I tried everything to get paint to stick to 1/72 plastics, expensive aerosol plastic primer (useless), the pva method, (worse), even shaking the figures in a jar full of sand to rough the surface of the plastic up and provide a key of the primer haha.
After the bad experience with the plastics I never considered using gesso on metal but shall give it another try!

A fix for your priming plastics issue is to use a spray paint made for plastics.  In the US it is Krylon plastics.  I have seen similar in the UK.  The paint has a light solvent in it so it literally bonds with the model. 
Snitchy sends.

[abelp01]

I'm using Gesso for about 90% of my priming due to the high humidity here in Central Florida. I thin it slightly and use an airbrush to apply, really works out well!

[syrinx0]

I use gesso if I can't spray and only have a figure or two to prime.  If I have more I break out the airbrush and Vallejo spray primer.  The gesso takes longer to cure but I have never had a problem with it.