HI All
Whats the difference between an undercoat and the next coat applied?
Whats the difference between undercoat and any other coat?
Can I use gloss as an undercoat?

Instead of using "klear" or similar floor shine .Can I use a matt varnish? Will it have the same effect .Why?well instead of buying floor polish ill stock up on vallejo matt varnish and use that instead.Why ?Cant find any Klear.

An undercoat is usually a highly pigmented Flat paint, used to give a grip/key for other coats to stick to, and to highlight any imperfections in the finish of the model, seam lines etc!! I use Halfords auto primer - in either grey, white or red dependent on the subject. Spray from a distance and then a rub with wire wool to get a nice smooth finish.




Undercoat is not a finish paint!




Not if you want other paint to stick on top of it!!!




Klear and matt varnish have two different uses. Klear is used to give a gloss finish for applying decals and washes, Matt varnish does exactly that, gives a matt finish.

Decals will look awful over a matt finish, they silver horribly

Look out for Klear, to the best of my knowledge i didn't quite buy all the stocks from Wilkinsons or Morrisons in the south east.

Hope this helps

Andy

Andy

Thanks very much for clarifying, brill

Wow! Lotsa questions...

An undercoat (or base coat, or primer coat) does two things. It gives the model a uniform colour over which to paint since different colours from different materials will affect the tone of the finished paint. This can be important if you want to paint a light colour like yellow, which goes better over a white undercoat than say a black one.

The second thing an undercoat does is grip the model better than ordinary paint. Of course, this assumes your undercoat is a good quality primer designed to grip. A good primer is especially important on metal parts.

Most primers are matt, as top coats of paint don't stick as well over gloss paints.

As for Klear, you could substitute gloss & matt varnishes. The only thing Klear does better is protect the underlying paint if you wash & weather with oils & turps. (I use Micro Gloss before decals, and then Pollyscale Flat Finish acrylic myself, but I don't use oils...)

However, search the site and you'll find lots of threads about these topics...

Hope this helps,

Tom

Thanks for your replies
However, as I understand it Halfords primer or similiar in a can is cellulose based.

What makes a good primer .
Is a primer a different kind of paint .

There are folk who use Halfords primer, but I find it goes on a bit thick for my liking. As I don't use too much metal in my builds I get away with Chaos Black spray from Games Workshop as my primer for armour. I use their Skull White spray for figures.

If you are worried about paint rubbing off of metal grabs etc you could invest in an acid-etch primer instead - these slightly etch metal and plastic to give good grip, and are best tracked down via the model train fraternity as they build lots of brass loco kits. However, I haven't felt the need myself - my models don't get handled all that much once painted.

Hope this helps,

Tom

If sprayed on thinly, cellulose or lacquer based paints and primers are generally not dangerous to use on styrene (when in doubt, spray some on some scrap plastic first, to assess the results before risking your model).
If you brush them on, though, you will craze the surface of the plastic and actually melt fine details, ruining the model.

Hi

I have a spray can of Halfords Primer - White, purchased about a year ago. Unless they've changed the composition, and in these days of "eco/green awareness" I doubt it, the label reads "The advanced acrylic based formulation of Halfords Primer is compatible with virtually all types of automotive paint , including cellulose finishes." So no, it's not cellulose based but acrylic.

As regards alternatives, Games Workshop Chaos Black or Skull White again in spray cans for priming. On the subject of worrying about this not adhering to metal as Tom mentions, many of Games Workshop figures are white metal so the primer was created for their figure range therefore adhesion to metal shouldn't be a problem.

Another alternative in a spray can is Tamiya's primers. I've not used these but they do a "Fine" version as well as straight primer, in grey and white. The only downside is they are expensive compared to Games Workshop. Cans are about the same price but contents are much less.

If you want to go really cheap try places like Poundland etc, they do spray cans but I'd try them out on scrap models first to check coverage and adhesion.

Regardless of what primer you use it's only as good as the surface preperation you do beforehand. If the kit is covered in oily deposits, greasy finger marks then you are not going to get a good start. Clean the model well and let it dry off completely before application of primer.

Alan

Thanks for the replies guys
and a recap
A primer is an individual paint with characteristics and properties that are distincly different from any other paint.
Better results are obtained if used correctly therefore ordinary paint is not a good primer as above.
Modern spay cans can be acrylic (best to check)
Klear does a better job than matt varnish