Drilling & Pinning miniatures

2005-3-29

Drilling & pinning miniatures…

I guess almost everyone who collects metal miniatures will at some point struggle with multi-part models that have a less than perfect fit between the pieces, or have broken miniature in need of repair.

A common method for increasing the strength of multi-part miniatures is to 'pin' joints, rather than relying on the strength of glue. Having made that statement I must add that the right glue can be stronger than the metal itself. The problem of weakness lies in the very small areas that are difficult to prepare, poor fit of the surfaces and contamination which all contribute to poor adhesion.


Way back when I first started collecting miniatures, I assembled a large Games Workshop model with two-pack 'Araldite 2002' (an industrial strength version in 500g tubes) that my Dad got me from work. It was messy, awkward and slow - having to support the pieces temporarily with plasticine for each joint, but it gave possibly the strongest joint ever! The figure was dropped from a height of 5 feet and only suffered a bent extremity and chipped paint. The join is supremely strong because the glue filled the gaps as well as bonding the surface. However, many people would rather avoid the drawbacks of epoxy, preferring to use cyanoacrylate 'superglue' of one sort or another.
Ahem. I digress...

Pinning models isn't anything new, and with the internet facilitating numerous tutorial sites and 'how-to' discussions you may be wondering why I'm going to add to the pile…


Well there are two reasons, one because I can, and more seriously I have never been satisfied with the traditional method:


        "Drill a hole, put a short pin in with red paint on it, press the pieces together to leave a mark
        and drill a second hole in the opposing piece before cutting and gluing an appropriate length pin
        into the joint."


I used this technique many years ago on an Eldar Avatar from GW without success. I ended up drilling a much larger hole and stuffing it with milliput because I got it slightly out of position and the arm fit was wrong. During this process I happened to push the pin into almost cured milliput to get it in the right position, then removed it until the putty was set. Once the putty was completely hard the arm was attached successfully in the correct position using superglue. This developed into the techniques described in the following case study, which I found very successful for assembling 54mm Inquisitor figures some time ago.

A common feature of these larger figures is the 'hollow' insides, basically the casting process limits how thick a section can be. So, to create the large bodies they are made from a 'shell' of cast pieces. The fit of these pieces can be poor because of distortion, so they are generally aimed at experienced modellers. I take pride that my own models are very well put together, as the above example testifies…


Case study - Rackham Centurus clone.

Ideally I would have liked to demonstrate this with the 'Preacher Joseph' model from the GW Specialist Games Inquisitor range I did recently but it's complete and can't find a cheap one to do a walk through with taking photographs.

So, we're left with a couple of clones…

I recently bought the mail order only edition of Rackham's new Centurus Clones. The pictures on the Rackham web-store look fantastic! Big, brutal and mean warriors of the Dirz Empire - I couldn't wait for them to arrive. Imagine if you will then my utter dismay when I opened the clam-shell…

As can be seen in the picture, both sets of arms were badly miscast, one missing a finger, the other snapped at a 'misrun'. I didn't buy them direct from Rackham myself, so no simple solution for an exchange, or so I thought.

The simple bit - drilling holes in the right place.

Now simply the only way to repair these is pinning and reconstruction. Such small sections as the finger blade and halberd shaft need to be drilled very accurately if the drilled hole isn't to weaken them even more.

First up was the missing blade of the finger - this I intended to simple re-sculpt in super fine epoxy putty, one that can be filed and sanded to a crisp edge without becoming weak. However, to do this I needed an armature to work over. I intended to use 0.5mm brass rod, fitted into a slightly oversized hole drilled down the to base of the blade. The larger hole allows for plenty of glue and also lets air out from behind the glue and rod as it is inserted.

To drill an accurate hole the end of the broken blade was filed flat before creating a centre-mark for the drill by twisting the point of a scalpel blade. This prevents the drill from wandering by giving a dimple for the tip of the drill to sit in. This makes the drilling much easier because the drill can't move out of position.

With the tip of the drill unable to wander, one only needs to concentrate on drilling along the axis of the fine component. Stopping periodically to turn the piece around to inspect the direction of the drill ensures that it isn't going to break out of the side. Drill as deep as possible to give plenty of surface area within the hole for glue to bond between the pin and figure component.

Initially the thin brass rod of the armature is left longer than the final length needs to be. This makes it easier to handle and position, plus there's the added safety of it never being too short after the curve is made. Once the glue has fully cured the wire is gently bent to the shape the blade is going to be formed and then trimmed to the finished length.

The finished armature is lightly sanded with emery cloth to roughen it and provide a good 'key' to bond the epoxy putty. The actual putty used was superfine milliput, which is easy to file, carve and sand to the shape of the blade. Obviously to do this the final shape isn't produced in the 'wet' putty. A sausage of putty was applied over the armature and left to cure until it was almost set, then rough carving produced an 'oversized' blade.

The completed reconstruction after filing and carving to shape to match the blades of the opposite hand. The final shape was produced purely by subtraction, no fresh putty added since that could leave weakness between layers.

The halberd shaft was slightly more complicated to fix because the spacing of the hands is critical for the upper one to match up with the other arm. Firstly the two broken pieces were dry fitted together and the distance between the two 'bumps' measured. This gets the correct dimension so the broken ends could then be tidied up by filing flat for drilling. A long pin inserted and fixed in one half could then be trimmed to get the correct spacing between the two reference points. Lastly, the second half is glued in place, the gap filled with putty and filed to make a seamless transition for the repair.


Hmm, slightly digressed again, but illustrates the how, if a bit long-winded, and gives a couple of examples where accuracy is essential to success.


The 'where' to drill & why...

Ok, so now on to the real substance of why I decided to write this little article ( which is rapidly expanding ).
The thing that makes this different, the fundamental principle of the technique is this: not trying to match pieces and pinned holes up from the inside...

This alternative method to the 'traditional' view is to drill completely through one piece into another from the outside. At the same time, any space between the component parts on the inside is completely filled.

Going back to the reason I came up with in the first place - getting an accurate, strong join between parts of a miniature. To illustrate the principle, I'll be taking a look at the other Centurus Clone in the set. After a bit of cleaning up, the arms sit quite well onto the shoulder locations around the edges but there is a void in the middle.

So, this is how I tackle these types of figures. The pieces have been cleaned up of flash and mould lines and filed to be a close a fit around the edges. A blob of wet milliput is gently pressed onto one surface and the other part fo the model then firmly pushed into place. The fresh putty is soft enough to fill the gap and be extruded out around the edges.

'Wet' milliput is just freshly mixed with a dab of water on my fingers. The tiny amount of water makes it even more sticky.

Where the excess putty is squeezed out of the gap it can simply be removed with a scalpel and then smoothed using sculpting tools. I found a 'clay shaper' ideal for blending putty around the joint.

The model was rested on the bit of sponge from the packet so that the arm remained in place until the putty had completely set.

The actual drilling is fairly straight forward, all I had to do was pick a bit of detail in the model that could be re-sculpted easily afterwards. Conveniently, in this case there was a dimple in the detail of the sculpture of the armour - even better!
Since the pieces are already perfectly fitted together, all the guess work and fiddling about of the 'usual' pinning technique is completely avoided.

I split the shoulder apart again to show how the hole line up and that the gap in the model assembly is nicely filled by the putty. Sometimes it may be easier to paint sections of a model before gluing it all together and such a closely fitting joint will only need the smallest drop of glue afterwards.

This shot shows how easy the pieces go together. The pin can be marked off and cut to the correct length and the outer hole in the model filled up and blended with the sculpture.

Next I had to get the fit of the other arm correct so that the hand on the halberd met the arm. No matter how hard I tried, I could not get a good position of the arm holding the halberd so a bit more work was needed.

Close examination gave me a simple option - to rotate the wrist slightly. Following the same principle as 'easy pinning', a bit of planning makes life much easier...

This time I drilled up the forearm before doing any cutting. The reason for doing this is to get a hole to put a pin through that will line up without any hassle. Being careful to drill along the axis I intended to rotate the wrist around I then chopped the hand off perpendicular to this axis. A 0.5mm circular blade gave a very neat cut that is very easy to reposition and remake the gap in putty.

Well that's about it. One last picture of the completed assembly with the wrist corrected and all I need to do is plug the hole in the knuckles before undercoating the figurine.