In this article the various methods for creating realistic weld beads are described.
There are a limited number of ways to join metal to metal and welding is one of the most common. Most military vehicles are made up of metal plates joined together either by some form of bolts and rivets, or by welding. Welding two pieces of metal leaves a characteristic ridged effect along the join line. This may be raised or level with the metal surface.
Recently issued good model kits may reproduce these weld beads very well. However, older kits tended to either leave them off or reproduce them badly. Modeller’s may therefore be left to recreate them. This may also be the case where a join on the model coincides with a weld bead on the real vehicle in which case the join line needs to be turned into a weld bead. Of course, if a modeller is doing a conversion or scratch-building then he/she will have to create any weld beads themselves.
Warning For All Methods
There are several methods available and how well each one will work depends on both the situation and the products used. For example, using liquid cement to ‘melt’ a thin strip of plasic strue will work differently with different brands of liquid cement. Also each of these methods does require some skill and practice. Therefore, we cannot emphasise enough that before embarking on any of the following processes you should practice on spare materials to check you can reproduce the desired effect before trying them out on your precious model.
Quite often the weld bead will follow a join line on the model. However, if it does not then you should clearly mark the line of the bead by some method – do not attempt to create a straight line weld bead freehand because the results will be disspointing and even a small amount of deviation of what should be a dead straight line will be obvoius.
Methods For Creating Weld Beads
1. Craft Knife
For tiny beads that do not need to be raised much above the surface of the metal, a bead can be acheived by using the craft knife with very sharp point. Lightly press and turn the point of the knife in the plastic and repeat this over and over moving along the bead line. If the result is a little too jagged then paint a little liquid cement over it with a tiny paintbrush to soften it. If the level needs to be built up, this can be done with a little Mr Surfacer.
2. Textured Epoxy Putty Line
This works best for larger raised beads. If possible, use masking tape to mask off the area where the weld bead should be placed. Leave exposed plastic only the same width that you want the bead to be. Mix some epoxy putty such as Milliput. You will only need a tiny amount so will probably have to leave this job until you need to mix some putty for another task.
Roll out the putty into a very long thin ‘sausage’ shape and lay it on the plastic. The weld pattern is then pressed into the putty using a sculpting tool, probe or even a cocktail stick depending on the exact pattern you are aiming to reproduce and the scale.
3. Stretched Sprue and Liquid Cement
A popular method of creating aerials and wires on scale models is to used stretched sprue. This is where a length of spare plastic sprue is held over a heat source such as a candle and then the two ends pulled apart to leave a very thin piece of flexible plastic.
Depending on how soft the plastic is and how fast it is pulled the stretched sprue can be thinner than piece of hair.
Such a piece of stretched sprue can reproduce a weld bead by lying it on the plastic kit and then painting liquid cement on it. Give the liquid cement a few seconds to ‘melt’ the sprue and the kit surface and then using a probe, or similar tool, the weld texture can be created in the softened plastic.
A Pyrogravure is essentially a very small soldering iron with a very fine point.
If you have one then this is probably the quickest method for creating weld beads and, in fact, it may be the main purpose that some modellers buy one in the first place. For welds that are sunken or level with the surface the weld bead texture can be created simply by pressing the hot tip into the plastic and moving along the line of the weld bead. For raised weld beads a thin plastic rod or piece of stretched sprue has to be laid down and the pyrogravure used to melt it so it melds with the surface. Care needs to be taken not to overdo the effect.
5. Waterslide Decals
Decals are usually made to be as thin as possible so that they look painted on. However, Archer Fine Transfers produce a series of decals that are the opposite. They are five times thicker than normal decals and so appear raised above the surface that they are applied to.
These decals are intended to be painted over and provide surface details to models. At least two sets in the series are devoted to simulating weld beads:
- Surface detail set No.5 Perfect Weld Beads .05, .25, .030 and .040 inches wide (AR88005)
- Surface detail set No.6 Arc Weld Beads .05, .25, .030 and .040 inches wide (AR88006)
These waterslide decals can be applied to any suitable surface and when painted over give a good impression of a weld bead. I have not tried these but reviews in modelling magazines are very favourable.