Mr Polobeer,
UBoatBuilder gave me the following tips a while ago when i enquired about weathering, he has done a fantastic job with some of his subs and when i get around to finishing a model i will have ago. Try this:
Hi Simon,
ill try to keep it short and simple.
GRIME
first you have to build up the "grimey" look. I used humbrol No.1 through an airbrush, just spraying a relatively light mist over an areabut dont let it dry to much, take a cotton bud (you may have to find something else for such a large scale) dip it in some thinners (enamel) and use it to spread the paint and get it watery (horizontal strokes) then do the same again but with light vertical strokes (direction water will run off of the surface) when dry this will make the surface look like it has had water running down it from splashes etc. and gives it that grimey streaky look and if you have panel lines and rivets the paint will collect in these more than the on the flat surface (check out the sub photos again and look at the conning tower and the front end and you should be able to see what i mean. check out my original post aswell, revell type 7 pics ) do small areas at a time. it keeps it random looking and also you dont want one part to dry whilst doing another 'cos it wont spread properly.
It probably wont look dirty enough with the first cote so let it dry for about a day and do it again and keep doing it till your happy with it. once your happy with it take the airbrush and just give it a light spray over this will darken any left over "clean" bits and gives the illusion of ground in dirt with the streaky bits if you know what i mean.
For where dirt collects very heavily for example on the sub flowing out of holes and on the panel line on the trim tanks and lower hull just airbrush as normal. Also pay close attention to the bottom edge of the superstructure as dirt will collect at the here both from it running down the surface and being splashed from people running around on deck (again check the subs) i used the cotton bud technique but heavier than on the hull to really drag alot of the paint to the bottom, then just airbrush normally on the edge.
RUST
For rust i used windsor and newton artists oil colours, the range is called winton oil colours, and the colours are raw sienna (light rust), and burnt umber (dark rust) these are thinned with white spirit, and are brush painted they wont go through an airbrush.
First use raw sienna and simply paint on where and in the shape you want, typically it starts fat and slims to a point. try to do it in one stroke decreasing the pressure as you go to give the point and you can always fatten it out at the top after the point is the main bit to get right. however make sure that this will be fatter than the dark rust your about to put over it (the key is to look ahead of what your doing). let this dry but not completely take a cotton bud and lightly smudge it particularly at the edges, it may not look like much at first but this will give the rust that "bleeding" look.
Now take the burnt umber and do the same as you did just now but try to get it in the centre of the light rust, basically it just needs to be thinner and shorter, let this dry but for slightly longer than the light rust because you dont want it smudged as much you just want to take the harsh edge off of it. In smaller areas i used the light rust on its own just to give some variation. Also for very rusty areas i didnt smudge the dark rust at all (at the front, on the edge of the deck) i tink this makes it look like the rust is really eating into the metal.
SMALL DETAILS
almost finished,
for grime build around small things like hatches, deck guns i used oil colours again, same ones the colour is paynes grey. mix some with white spirit till its almost like water put some on the brush and just touch an edge or crease (eg. around a hatch or gun sight) the paint will flow around that edge, giving a grime build up look to it if it looks to dark just dab it with a cotton bud to take off any excess, i did the whole gun like this, if the object has any flat surfaces then use the oil colour and smear it with the trusty old cotton bud, WITHOUT white spirit, as the paint already has it and using more will just take the paint off.
a few words of warning i noticed the boat has been on the water so it is probably varnished with a gloss or satin cote, you may want to spray over this with a matt cote to help the paint stick (our subs are matt) you will have to seal in the oil colours anyway because they arent at all durable and will rub off with alot of touching, picking up etc. so you will be able to put the old varnish back on.
I CANNOT 100% GUARANTEE THAT THIS METHOD WILL WORK AS THIS METHOD HAS BEEN USED ON A MODEL THAT IS TINY IN COMPARISON TO YOURS, BUT IF NOTHING ELSE IS AT LEAST I SUPPOSE A STEP IN THE RIGHT DIRECTION
also i think experimenting on maybe a small cheap kit or another boat you dont really care about (though thats probably unlikely). I used my sub as the experiment and it happened to come out right. (I have never weathered anything before the sub). But whilst experimenting you will develop your own method of doing as mine is by no means the only way and for all i know it could be the hardest and longest way to do it , its each to his own.
I hope this is clear and easy enough to understand, i know its a bit long, sorry, but at least you'll have something to read when there's nothing on TV.
any probs or advise along the way of course its ok to ask, just send me pm, or start add it to your build thread so we can all see how your getting on.
happy reading, let me know if this is all ok for you, AND DONT BE DAUNTED BY IT, HAVE A GO! LIKE ME YOU MIGHT SURPRISE YOURSELF
Grant