Superb work again Robin, love the wicker work too - this is looking like the dio's you see in the museums now
Steve

Hi again! Many thanks to Adrie, Alan, Derek, Martyn and Stevie! Since the last posting I have completed the first section of wicker, it's still 'freestanding' until the ground work behind it has been coloured but all the painting has been done on the panel and I'm really pleased with it. I'm still trying to decide whether to post up the completion of that panel as a part of the instalment that covers that far corner of the base work or to put it up as a 'fill in' or extra piece. Time will tell!
Derek, this week's is just for you!

Part Twenty Five:

“Any old Iron!”

As mentioned previously, in this instalment we come to the other scratch built trench lining: Corrugated Iron sheeting or “Wriggly Tin” as it has come to be known! The raw material for this little exercise comes courtesy of my mum, namely, her finished / out of date eye ointment, or more precisely, the empty tubes of the same!
Although the base material remained the same, I tried various means of turning it into the finished article before I settled on the method shown here. I will outline the earlier method when I get to that part of the procedure in order to point out a ‘near mistake’ to avoid committing if you want to give this a go yourselves.
Where as last week’s tutorial on the wicker work was mainly useful for those creating models from the Great War and earlier, this one is suitable for dioramas from the early 20th Century to the present day (WW2 Lancaster Airfields included!!)
Photo 1 illustrates the tube of corrugated iron in its raw state! This is a tube of ‘Lacri-Lube’ eye ointment used to treat dry eye conditions. The first task is to get as much of what ever remains inside the tube out, firstly by just squeezing the tube out through the integral nozzle and then by slicing off that nozzle end and rolling the tube flat to squeeze out the last drops as in Photo 2.
Note also that the opposite end of the tube has also been rolled back from the crimping which seals the end. The rolling flat was accomplished using my old rubber roller from my artistic screen printing days, it is about six inches across with a metal frame and wooden handle. If you have such a thing great! If not, the larger type aluminium knife handle (the round cylinder kind with a chuck in the end) would do the job just as well, or even just a wooden dowel.
With all the sticky gel removed as far as possible, the next job is to slice off a thin strip down one side of the flattened tube together with a similar strip off the bottom end (down to about the end of that black rectangle printed on the bottom). With those two strips cut off you can now open up the tube to reveal the inside as in Photo 3.
With the tube now opened up, it was taken to the sink and given a good scrubbing with an old toothbrush loaded with a drop of washing up liquid to remove the last vestiges of the gel. This is pretty easy to do as the gel, being specifically formulated for the eye is water soluble, (just as well really!)
Once the tube is thoroughly cleaned and dried it was again rolled out flat with the roller to give the rectangle of malleable metal as seen in Photo 4. As I’ve said many times in my Victory diary, I really miss those days when all the toothpaste tubes were made of soft metal instead of today’s ‘pretty useless for modelling’ plastic!
The next stage is the most laborious and messy part of the whole process – removing the paint from one side of the metal. I have achieved this by sanding, sanding and then sanding some more! I must try and get a bottle of paint stripper and see if that will work on this material, I’d much rather make up a few sheets and leave them soaking overnight than keep doing it this way! In actual fact, it’s probably not a definite requirement anyway, I do paint both sides but I think having a bare metal starting point makes the finished article look more authentic as any scratches or flaws will reveal the metal finish as it would in the original, plus, the acrylic paint doesn’t like sticking to that gloss finish too much either. With all the paint removed, we’re left with a sheet like that in Photo 5.
Now this is where the methods changed. In my original test sheet, I used a blunt ended carving tool with a steel rule to scribe the channels into the sheet. This worked fairly well apart from trying to keep the channels running parallel, the steel rule kept trying to spin off target! (Plus it's very easy to press too hard and tear through the sheet!) In fact, I actually preferred the finished trial sheet to the eventual winner in the Miss 1917 Wriggly Tin competition, the corrugations were narrower and looked, well, more authentic. Fortunately, my pictorial research brought me to a different conclusion. You see, like most of you, I’ve grown up in the era of DIY superstores and translucent corrugated roofing sheets. The reason the first attempt at the wriggly tin looked better to my eyes was because what I had made was a sheet of modern corrugated iron! Checking the old photographs again and again revealed that back then, the corrugations were much wider and deeper. You can still get a very similar thing today, in a synthetic material for stable and shed roofs, but much of today’s sheets come in a tighter, shallower profile. So what I needed was a ‘clunkier’ looking ‘old’ style sheet.
Enter that mystery object from a couple of week’s ago! AND I noticed nobody tried to guess what it was!! Actually I made it more difficult by deliberately reversing one of the two halves! This is my MkI corrugated press jig, (Photo 6) composed of two flat strips of brass with a series of 1mm brass rods soldered across each one. When placed together, the lines of rods on one flat fit into the gaps between the rods on the other flat – see where this is going?
The flattened, paint-stripped sheet is placed between the two brass jigs and the sandwich is carefully slid in between the jaws of my bench drill vice, keeping the metal sheet straight as the jig is slid down to the top edge of the vice. Once in position, the bench vice is tightened up and the two halves of the jig force the sheet between the rods, much as the steam presses would have formed the original full sized sheets back in 1917, (Photo 7).
With the vice jaws tightened up fully, they were released back and the resulting corrugated sheeting was cut off the remaining flat sheet which was then slid back down the jig and the whole procedure repeated. In Photo 8 you can see two of the newly pressed sheets looking like a pair of freshly galvanised bits of corrugated iron. Unlike the earlier hand scribed method, the beauty of this process is that each sheet is a copy of the last, so they will easily overlap each other when they are employed in the diorama, whether as roofing or trench linings.
The first stage in turning these pristine sheets into the more ‘weather-beaten’ variety was to undercoat them in the same Citadel Celestra Grey Base as I’ve used on just about every other bit of undercoating on this build (as well as the Bunker Concrete Grey as well!). The sheets, all four of them from the one tube, were all painted on both sides and left to dry. They were then given a wash to emphasize the shadows and general ‘grubbiness’ of the sheets. I was in two minds here, whether to do them in Citadel Shadow Black Ink or Citadel Skaven Brown Ink so I did one in each only to discover that the best looking effect was a mix of both the inks together. You can see the result in Photo 9. The reason there are two of each is because I actually forgot to take a photo of the sheets in their grey undercoats! All the sheets have been given a wash of ink, the two grey ones are simply upside down!
Once the ink wash was dry, the final step was to give a slightly rusty look and this was achieved with the Humbrol Rust Wash, an enamel based wash which was further diluted with white spirit to tone it down a little. The little ‘spots’ of darker rust were obtained by using the inner cap top off the rust wash bottle where some thicker pigments had semi dried out. The final effect is illustrated in Photo 10.
The last two Photos, 11 and 12, illustrate the two ways in which these sheets will be incorporated into the diorama. In the case of the bunker, only the edges of the roof will be covered in the sheeting. Just in from the edge will be a line of sandbags, with a mound of earth on top of them so the front and back edges of the roof will only need short sections of cut down sheeting. The rear edge will have some additional work on those sheets as an 18pdr shell crater sits just behind the bunker so the sheeting will exhibit some ‘wear and tear’ OK! Shredded then!
The bottom photo shows the same sheets in their ‘horizontal’ role as trench linings. This is one of the two removable sections of trench which I can work on off the main base, I didn’t want to stick too many bits of wood in there, as this section is actually supposed to be wicker lined! But you can get the general idea.
I have to say, my ‘cost cutting’ exercises do sometimes go better than I had hoped and this, I’m really chuffed to admit, is one of them! The corrugated sheets have turned out really well, and apart from the brass to construct the jig (which I already had anyway) don’t cost a penny to make. One last idea though, if you don’t have a source of free medicine tubes like me, I would think that this method would work just as well with the type of disposable flan or pie base as sold in supermarkets. They are simply a thicker form of aluminium foil and should be just as ‘mouldable’ as the tube material.
In next week’s instalment, I’ll try and get the mould for casting the tank track ‘spuds’ put together (I’ve just got this ‘thing’ about mixing epoxy substances together, horrible messy stuff!)

Until then, Happy building to you All!


Robin

WOW stunning simply stunning lovely work Robin Rgd Martyn

Many thanks to Alan, Martyn and Derek, and as for not expecting anything else - you had to say it didn't you!!

Part Twenty Six: Casting the Spuds (Or NOT as the case may be!)


Come to the cookhouse door, boys, sniff the lovely stew.
Who is it says the colonel gets better grub than you?
Any complaints this morning? Do we complain? Not we.
What's the matter with lumps of onion floating around the tea?

Another verse from “Oh What a Lovely War”

Well, they say pride comes before a fall! I was so pleased with the way the corrugated sheets turned out last time, here’s my reward!
This instalment was supposed to be about how I was going to cast the little track extensions called ‘Grousers’ or ‘Spuds’ which were fitted to the MkIV’s by the time of Messines. Unfortunately, due to a slight er, error on my part, the exercise had been an almost complete disaster. Still, in this hobby we learn as much from our failures as from our successes so I think I’ll still post it up and hopefully, next week I’ll put it right!
Everything began quite well, I’d already made up a set of five spuds in plasticard and glued them onto a length of plastic to form a sprue as you can see in Photo 3. To form the casting mould I was going to use one of the Perspex ‘boxes' I’d made up a couple of years ago to cast the Brandywine figures in, and with the length of the sprue it gave me enough spare room to fit a single figure as well. What I need is a type of ‘Generic German’, no particular pose but easy enough to convert into a variety of new poses later on. Out of the packs of Revell WW1 German Infantry and HaT WW1 German Heavy Weapons, the best one I could find was a figure holding a pair of Lewis Gun Ammo drums. Lewis Gun? That’s right, apparently the Germans loved the Lewis and used captured guns whenever they could get them. The heavy weapons set includes a figure firing a Lewis from the hip with his assistant carrying a pair of spare drums as shown in Photo 1. (Still with some of the sprue attached!) In Photo 2, the same figure has had the drums removed and tidied up. As you can see, he is now just a basic figure awaiting ‘corrective surgery’!
Both the figure and the spud sprue were glued onto a piece of Plastruct square girder ready for the mould making. The piece of wood behind is to form a reservoir for the white metal, more on that later.
In Photo 5 we see the actual mould making material. This is the large 1kg tin of Hobby Time RTV/HB Silicon Rubber, a two part epoxy rubber available from the Hobby’s catalogue or website. The RTV (as I found out on Youtube) means Room Temperature Vulcanisation, ie, a chemical process which hardens the rubber rather than the heat process as in car tyre production. I’ve made nearly ten moulds with this tin and there’s enough still in there for two or three more (I think). I have actually sent off now for another tin in order to start casting the figures for this diorama. The only problem I’ve got with this one is that when the blue paper label was stuck around the tin it overlapped the section with the instructions in English so the first three or so words in each line are missing! (Well, it IS made in Germany, crafty blighters!) In order to mix the rubber and catalyst (hardener) together, it has to be added at the rate of 2 – 4%, that’s fine, except that the rubber comes in grams and the catalyst comes in millilitres! Now I’m used to working in inches and millimetres at the same time (sometimes with unexpected results!) but gms and mls?
OK I thought, having ‘misplaced’ the original instruction sheet that came with the tin I decided to be too clever for my own good. In Photos 6 and 7 you can see the rubber and catalyst being measured out. (For God’s sake don’t tell Mum I’m using her bestist new digital scales. Or for that matter that I’m doing this on the worktop either!!) I measured out exactly 100gm of the rubber and then, logically speaking, I should need between 2 and 4gm of catalyst. Yeah right! By the time I got to 3gms I was already thinking ‘I’m sure I never used this much before!’ I stopped on 3gms and added it into the rubber, stirring away nicely. The correct measure will give you about five minutes to mix and pour the compound into the mould, I began to feel it going stiff after thirty seconds! I scraped the rapidly thickening rubber into the box as fast as I could and managed to push the components down into the surface. It wasn’t what I would call ‘ideal’! Instead of the correct flat surface with the items half submerged, it was very lumpy with the originals not laying very flat. (Photo 8) I was able to slice away most of the raised portions and decided to persevere and try the second half the following day. This time I measured out 80gms of rubber and just added the catalyst to a little bottle until it looked more like the amounts I’d used before. Again I might have used the full 4% as it began to show signs of thickening after a minute or two but at least I was able to pour it into the mould as seen in Photo 9. The big blob on the right was just the result of me trying not to drip the mixing stick over my bench and almost pouring the rubber outside the box in the process!
In Photo 10, you can see the ‘waste not, want not’ recovery process. This stuff will drip like treacle for hours! The plastic measuring cup which I used to dibble out the rubber into the mixing bowl as seen in Photo 6 (an old Tescos fruit salad container), is seen gripped in the ‘Helping Hands’ gizmo as it drips back into the tin. I put the tin top on some hours later and still found a couple of drips on it the following morning!
In Photo 11 you can see the two halves of the mould. I still wasn’t overly optimistic about it working but decided to give it a try anyway. As I expected, the first half just wasn’t accurate enough to give good results. I tried adding channels cut into the rubber to help the flow of the liquid white metal (I’ll show the super little melting pot I bought a couple of years ago next time) but I just couldn’t get the spuds to cast properly. I think the main problem (as well as the inferior first mould) is that I made the spuds in their finished state, which doesn’t really provide a big enough entry hole for the metal to run into. I’m going to have another go at it and make the spuds in a more ‘basic’ fashion, probably only three at a time, and with larger sprues to help the casting process. It means having to finish them off in the metal form (if it works that is) but it’s worth trying to figure out if only for some future project!
As I said at the beginning, this was almost a complete disaster but the final Photo 12 shows that I did get something useful out of it. Again, due to that less than perfect mould the quality could be cleaner (and I’m going to re-do this figure in the new mould as well) but it’s still ‘usable’. The figure on the right is how it comes out of the mould with a couple of unwanted additions (air bubbles and bad fit on the two halves probably) but with a little basic cleaning up, paring away the excess metal and some careful diamond dust filing, a ‘not too bad’ figure can still be achieved. Out of the eight or so castings, I had about three ‘good’uns’, the others had either missing hands or a missing left leg (the right hand figure has the beginning of an air bubble just above his left foot!) But the great thing about home casting in white metal is there is NO wastage! Any defectives simply go back in the melting pot (quite literally!) and have another go.
So apologies to Stevie, as long as my new tin arrives soon I’ll have another go before next week and hopefully get it right this time!

See you all then!

Robin

Lovely work with the castings Robin, you make it look so easy..... Keep the posts coming, can't wait to see the finished results on this dio....

Regards

Alan

Hi again to All!

Part Twenty Seven: More Spuds!

There’s something about casting spuds in white metal that apparently the Gods of Modelling don’t like! I was hoping to show the shiny new additions in this instalment but unfortunately, not quite yet!
The delay is two fold, partly, after the new pot of rubber arrived from Hobby’s and I read the full instructions I realised that you are supposed to give the newly made moulds four to five days to completely cure, that in itself would have pushed the actual metal casting back to the weekend as I only poured the second half of the mould last night. The second reason was that I made a monumentally ‘plonker’ style mistake during that pouring, more on that in a mo’.
Anyway, in Photo 1 we have the old and new styles of the plastic spud originals. In designing the second variant I have literally turned it on its head! The left hand Mk I was designed basically as a finished plastic component, if I was simply making them all in plasticard, this is how they would look (and it might yet come to that!!). The grey arrows represent the direction from which the molten white metal was or will be poured into the mould. In the case of the Mk I this was down the narrow ‘arm’ of the spud where it was then supposed to fill up the spade end. This didn’t work because I suspect that the entry point was simply too narrow to allow the metal down inside before it cooled and solidified. Cutting a further channel in the rubber down to the lower ‘reservoir’ to aid the flow rate only allowed the metal to run straight down the arm, again by-passing the spade completely.
As you can see in the right hand Mk II, the new mould is much chunkier and the flow direction has been reversed and substantially increased. By having the metal flowing down the stepped channel it should be able to fill in the spade before flowing on down the arm. (Good in theory anyway!)
In Photo 2 we have the three completed spuds on their new channels whilst in Photo 3 they are seen again glued to the wooden block that will form the pouring channel with plastic sprues glued to the arms, which will lead down to the flow reservoir. All that now remained was to make up the first half of the mould.
Photo 4 illustrates that process under way. The mould box has been adapted slightly, moving one of the ends in to create a smaller mould as I’m going to just try this one for the spuds this time (and just as well I did as you’ll see!) This one will take two halves of 50g of rubber, not the 100g as before. The ‘proper’ instructions for the rubber says to add 2-4% catalyst (at least I had that right last time) and it also says that the catalyst is measured out at 40 drops to one gram so a mould of 100g for example would need 80 drops to give the 2%. My 50g mould would therefore require 40 drops. Forty drops were duly measured out and mixed in to the rubber. The instructions also say that the pot life (time until the rubber begins to cure)is five minutes. That being the case, I wondered why my pot was starting to congeal after just one minute! It might be the temperature up in the attic (it’s a warm spell down here again!) or it might conceivably be my old pot of rubber is too old, its supposed to have a shelf life of “at least 12 months” and mine must be over two years old by now! Anyhow, I managed to get the stuff out of the mixing pot and into the box and quickly press the spuds and the reservoir block down into the rapidly hardening mixture. Not very neat but it would do.
After that, everything went down hill rapidly! As well as the tin of rubber, I also bought a bottle of releasing agent, basically a high quality Vaseline type cream which is smeared over the first half of the mould to prevent the second half from bonding to it, and also a tub of casting talcum. This is designed to be brushed over the open parts of the hollow mould before the metal is poured. The powder contains lycopodium (whatever the hell that is) which increases the flow rate of the metal allowing it to flow into every little detail on the mould.
For the second half I reduced the 40 drops to 30, even so I still found the mixture beginning to cure far short of the stated five minutes and it was a rush to get the stuff into the mould box in time again. I just managed it although the pouring channel did have a gap up one end. With the second half in place I put the mould to one side and got on with one of the many other tasks which are now running side by side on this model. After a few minutes I checked on the mould and the rubber was virtually set. Turning back to the workbench my eyes fastened on the jar of releasing agent – the still unopened releasing agent! What a complete Plonker! In my haste to finish the mould I’d completely forgotten to smear the cream over the first half of the rubber! I probably had a beautiful mould in there, whether it would ever see the light of day again was another matter!
There was no point in waiting until the following day, the longer the rubber cured, the stronger it would be stuck together so I attempted (without much hope of success) to prise the two halves apart. The result can be seen in Photo 5. As it happened, it did eventually come apart, not perfectly as you can see and with the aid of some careful razor bladeing but all may not be lost! The lumpy part in the centre of the mould is where the two halves did not separate cleanly and in fact the second half has torn itself here which has partially buried the arm sections of the spuds but with a single razor slice along the dotted lines and a little flexing of the rubber block the entire hollow mould is accessible. I’m hoping with the application of the talcum into the gaps the mould can still be usable. I’ll now have to wait until the weekend to give it a try (to fully cure) and if successful, I’ll post the result early next week. If it doesn’t work, all three plastic spuds survived intact to try again! (This time with the new pot of rubber!)
So that’s where the moulding epic stands at present, as I mentioned, other parts are now running in tandem, with the wicker work almost there, some wooden plank walls coming together, more corrugated iron on the way and, most time consuming of all, the internal structure of the cut away MkIVs getting measured, designed and constructed (it took me an entire evening to construct one side of the radiator system! Mind you, it looks good!)
The next instalment then will either be the successful field of spuds or one of the many other ‘ready to print’ topics lining up for posting!

Until then, happy building to you all!


Robin.

Thanks Stevie! The Saga continues!

Spud Update…

This is just a quickie to update the progress on the spud moulding front! The mould I constructed last week ‘sort of’ worked. If you remember, I wasn’t too happy with the mould, suffering as it did from ‘premature curing’ syndrome but I thought I’d give it a try anyway.
The very first casting did in fact produce a single spud out of the three, which I was very happy with. If it meant casting just one at a time I could live with that, but, try as I might I just couldn’t get the damned mould to produce any more! I tried upping the temperature of the metal to make it runnier, tried adding more of the special talcum to the inside but no joy so now here’s the third and final attempt before I accept having to make them all by hand!
In Photo 1 you can see that I’m now hedging all my bets with a trio of different spud designs. The one on the left is the original version (well it worked once dinnit!). The middle one is the same as before but with an extra width of spine, which passes right down the full length at the back. This essentially doubles the thickness of the arm section which should help the molten metal to pass down through the mould. If this works, I’ll have to slice off the extra white metal in the spine to return the moulding to the correct thickness but this is still much less work than making each one up from plasticard. The last one on the right is going the other way. I’ve glued a flat plate of plastic onto the edge of the spade part and built the central spine onto that. Again, if this works out, I’ll have to trim the extra flat part back to the dimensions of the original spud, but that’s no big job either and any trimmings go right back into the melting pot again so no wastage at all.
And now onto the mould (MkIII). For this one I opened up the brand new tin of rubber and taking no chances, again measured out the 50gm and added the reduced 30 drops of catalyst. What a difference! I got my full five minutes of pot life all right, I was able to pour the syrupy mixture into the mould box where it took up the perfectly flat surface into which I was able to gently sink the spuds, attached to their wooden block together with the flow reservoir block and a smaller wooden block to form one locating peg for the second half. All this can be seen in Photo 2.
Then the worrying began! As I said, I got my five minute pot life. I also got my one hour pot life and by evening time I’d had my two hour pot life as well! Since the prescribed dose of catalyst was 40 drops I was beginning to think I’d seriously under done the catalyst and the flaming stuff was going to remain a soft gloopy mess forever! Fortunately, (a huge sigh of relief) after leaving the stuff alone until early afternoon today I found the remnant in the mixing pot had turned into a solid skin and the mould itself had gone hard too. I had hoped that being a chemical reaction, the catalyst would eventually work which it appears to have done. This leads me to think that all the previous problems were in fact down to the old tin of rubber having exceeded its shelf life (plus the summer temperatures which didn’t help).
I’m now going to give the first half another twenty four hours to completely cure and then do the upper half (WITH the releasing agent this time!) and then give it another shot. Hopefully third time lucky!
Just to show what I’m actually trying to achieve, Photo 3 illustrates the one and only ‘good spud’ sitting on the tracks of the first MkIV. Notice the sixth link in front and behind the spud has had the rivets filed away. This is to help the (eventual) spuds to sit flat on the track and will be repeated all around the track length.
That’s it then for this update, it’ll be nearly the weekend again before I can attempt casting, so midweek I’ll be putting up the next ‘proper’ instalment which will be the continuation of the Wicker tutorial and how to turn your melted plastic into wood. Now where’s me wand gone!

Bye till then.

Robin

Hi Robin, perseverance is a wonderful trait and you obviously have it in abundance..... Excellent work to achieve the desired results no matter how many attempts it took..... Your work is an inspiration to me..... .. Very well done...

Regards

Alan

Brilliant work again Robin

Steve