I'm pretty much a noob at resin model kit building. I've ordered myself a number of oils from MIG Productions (502 Abteilung).
My question is: Does the model need to be sealed after using them?
1). Wash the model in lucke warm soapy water / rinse
2). Dry with paper towels
3). Trim / sand / fill any defects / bubbles as needed
4). Dry fit assembly / see no# 3
5). Spray with primer / see no# 3
6 ). Build it / have fun
I asume you are talking about varnish?
You have to ask yourself what the purpose is to seal your paints.
Some oil-paints dry in different degrees of shinyness when you thin them down with turpenoid(however fir/resinous turpentine will not have this effect).
When you alter the oil/pigment contents in your paints by removing oil from the paints,you will end up with a somewhat more leaner matt paint.
When painting layers of oilpaints over a cut down(lean) oilpaint,..the cut down layer will absorb a degree of oil from the layer on top.
To prevent this you could seal the lean paintlayer.
Usually you want the lean layer to absorb though,..this will enhance the adhering of the multiple layers and it will serve to get a uniform oilcontent in all your layers.
You have to look at the oilbinder as a necessary evil.
Oil does yellow over time,..so as less oil as possible is preferable!
You want to keep some oil in the oilpaint though to keep the pigments binded
The more oil content in your paint, the more satin shine and vise versa..so sealing could serve to get a a uniform gloss/satin/matt
A sealer could be used aswell to protect the colours from outside influences.
A sealer/varnish can make the colours richer,..more dept of colour,..this will be very noticable when using transparent/translucent colours over a lighter ground(glacis/glazing).
A gloss sealer will make your colours apear darker than they are though.
If you desire a matt/satin/gloss"oil"paint that has a strong binder,blends well, is quick drying and does not need protection from the environtment for the comming +/-10 years and is rich in dept and colour and will almost not yellow over time,..you could absorb most of the oil from your paint and mix gloss/satin//matt resinous varnish through this paint mixture to replace the oilbinder.
You will end up with a resinous/oil paint.
I think this is a far superior paint compaired to oils alone.
I typically do the oil washes and pastels as the very last step. Unless the models are going to be handled a lot, I don't find much a need to seal them unless I need to add some decals. You will also need to seal them if you are going to add more non-oil paint over them. Acrylic paint does not do well if painted over unsealed oils
I find sealing typically changes the subtle color variations and in some cases changes the overall blended look to a more stark contrast. So I try to avoid sealing for that reason. There have been many models that I feel I've ruined in a way by sealing it.
I've also seen cases where the sealant itself over time yellows, so you have to be careful which products you use
These days I will only seal things used as gaming miniatures, and even then, not always
I've been painting figures for over 30 years with oils, in the traditional 'military miniature way', which is pretty easy to do, once you get used to it. Paint the figure with all the base colors, in acrylic paint - You can use any brand you like, I like Apple Barrel and Folk Art, as they are excellent paints, and very inexpensive. The goal here is to get a good, solid covering on your figure, because the acrylic covers and gives you a nice opaque coat of paint, and allows you to have neat clean edges between colors. Then when it's completely dry, you can start blending and shading with the oils, and you don't need a thick coat to do it. I work a thin coat onto the figure starting with the flesh tones, and spread it out evenly so the surface is evenly covered. Then you can add darker shades to the shadow areas, a lighter shade to the high points, and then using the tips of a dry sable brush, blend the transitions between the shades with a light tapping motion, that just wishs the shades together. Do this a little at a time, as you can keep adding a small amount to each tone until you get it to where you like it. If the paint gets too thick, just use a dry brush to pull off the excess. I recommend leaving the oil in the paint, as that gives it its fantastic qualities, and when it's all dry, you can use what ever you want to flatten it out or gloss it. You can accelerate drying by putting the figure in a warm dry place. I like Microscale flat and satin, and for gloss, Future floor finish, shot through an air brush. The best reference guide you can get is Shep Paine's book 'How to build dioramas' as it gives you the best tutorial I've ever seen on painting and detailing figures with oils - He taught a whole lot of people how to successfully paint, including me, so check his books out! Hope this helps. Just jump right in and give it a try- Use an old figure to experiment on first.