Basic actions; The Pommel
I find this is a very personal thing. I like a handgrip with a bit of squeeze to it. I have some very thin foam (1.0 to 2.0 mm) which I glue up and bind onto the rod between the pommel and hilt. I have a scrap glueless piece of this foam. I wind sheaths of the glued foam around the rod until it feels about right with the extra layer of scrap around it. This is normally then about right when it is finished with leather. Some form of leather is best, however fun-fur can be quite nice.
Sit down, holding the grip, with the blade over the opposite to holding hand shoulder. Take a craft knife and gentle ease the knife-blade into the foam-blade in a smooth curve, so the the knife-blade ends up running from the marked line to nearly the centre of the edge of the middle strip of foam in the sword.
For a large sword, the idea is to end up with a very slight flat edge, not a 'sharp' foam edge.
Slowly, patience is the key, draw the knife up through the foam to cut off a long triangluar section from on corner of the blade. If you have to 'saw' at it, your knife is not that sharp. The foam should 'fall' off as the knife passes. Ease the sword down from your shoulder as you draw the knife up the blade. When you get to the tip, follow it round. Repeat three more times.
Err on the side of caution, its easier to cut more foam off that cut it on!
Once the blade is edged, the hilt and pommel can be carved decoratively, as desired.
The final stage of foam-work is to sand-paper along the blade, mainly
to take the corner off the cut-face interface, and to cover up as much
of the dodgey cutting as possible.
I am a bit OTT in this respect, as I delight in donning anorak and
goggles then strapping my power tool (fnaar!) to the top of the wheelie-bin
out by the garage, spinning up my tungsten disc and grinding the blade
almost like a real sword (but pressing much more lightly!!!!)
Mix 'an amount' of glue and thinner, 50-50 ratio. This will produce a very thin version of the glue. Take a sacrifical brush and paint this mixture over the entire weapon (except, of course, for the handgrip!). Cover the entire weapon at one sitting and wait for it to go 'tacky'. Now paint a base coat of plain latex onto the glue. Leave this to dry.
This will not only act as an excellent primer but will bond the latex onto the foam and will also provide a slight 'smoothing' to the raw foam, which is most benificial.
The rest of the weapon is coated with coloured latex, which is made by adding a small amount of acrylic paint to some plain latex. The colours used will depend on what you what the final weapon to look like, but in most cases the first few coats will be black. The outer colouring of blades is a bit of a 'black art'. I quite like Citadel's Chainmail as a colour for this.
Silver is often used, Beware most metal colour paints however, as many, especially the gold/copper ones have something in which reacts with the latex in a very horrid and yeucky way. If in doubt with a paint, mix up a sample and apply it to some scrap foam.
The latex will quickly clog the brushes. I recommend you have a large set of brushes and as soon as one starts to clog, rinse it out and leave it in some water. Later on, (while watching the telly?) clear out the gunge from the brush with the back edge of a large craft knife blade.
Early latex weapons were showered in talcum powder. This effectively filled the 'pores' with talc and so acted as a 'lubricant'. It also matt-finishes and lightens the tone of the latex's colour, turning e.g. black to a sort of grey.
Although considered 'lo-tech' and even 'vulgar' these days, there is still a place for the humble talc, specifically, when you want to dull the finish, e.g. stone axe heads, old wooden shields.
For items which do not 'need' a very durable or very flexible finish, one can use varnish, but you must be careful! about which one. Some can be to rigid or even 'eat the latex'. I recommend B&Q's own brand of cheap and 'nasty' water based varnish. It looks blue during application but sets clear. It does however break up if used on 'bendy bits' (e.g. blades and mace flanges).
Many people, including commercial manufactures are using a substance refered to as Isoflex. This is the primer component of the Isoflex floor coating product range, sold in 'proper' hardware shops (not B&Q). It is EXPENSIVE, about 25 UKP for a 5 litre tin, perhaps 7.50 for a one litre tin. And it 'consumes' the brush used to apply it. And it 'goes off' quickly (24 hours?) once decanted for use (however I have found that it will stay usable for longer if put in a fridge. It may make things smell of pears...)
You may need two coats of Isoflex. It will often have a slighty yellow tinge when dry.
There are other substances being used about the place, but people like to keep their 'trade secrets'.
Differing Ingredients;
I recommend that you round off the ends of the tube in some manner, to stop them from cutting their way out through the foam. A method I have used it to heat the end of the tube in a gas-hob and press it into some suitable former. File/sand to suit.
In general the shaft is chunkier than the hand grip. Put a tube of 10mm foam around the core for a shaft that you intend to stay plain. For a shaft which you intend to give a 'wood effect' then pipe lagging is OK. And it is already round :-)
To achieve a 'wood effect', take a (hot!) soldering iron and 'carve' wavey lines into the shaft foam. Do not penetrate all the way to the core. Make the grooves quite distict, as the latex will fill a lot of it in. Knot holes here and there are quite attractive. It may not look entirely like 'real wood' but it will be genuine 'LRP wood'.
There are two basic forms of bashy end.
When you are latexing over a 'wood effect' shaft, do most of it with
black latex and use brown latex to hi-lite the outer faces only. If you
have gallons of brown to dispose of, a cheap and nasty variant is to do
it all over in brown and then use a black 'magic marker' to colour in all
the lines.