Making Silicone Moulds and Casting in Resin

Introduction

When I was building my 1/48 Mig-29A I used one of the front wheel door parts as a mask while I sprayed the camo.  I (wrongly) assumed that there was a replacement in the Aires wheel well set I installed and to make the part fit I altered it.  This made it useless for its intended purpose.  I did have a the Eduard 1/48 Mig-29UB which has the same part so I could have used that, but that would render that kit useless.  So, I decided to cast a replacement part from resin.  As I was going to do this I thought it might be a good idea to make this tutorial to show how easy it is to do.

Making the Mould

What you need

In order to make the mould you're going to need the following materials: Silicone Rubber, Catalyst, a clean mixing cup and a flat sided spatula (I used the handle of a disposable knife).

You're also going to need some latex or nitrile gloves to keep this stuff off your hands as it is really sticky and according to the directions it can be hazardous.  I have shares in this company so I recommend the brand :-)

Preparing the Master

The part in question (the master) was given a cleanup and was temporarily cemented to some plasticard.  This was then glues to a resin block with super glue.  There is a small hole in one end and since this would create problems getting it out of the mould it was filled with a small amount of PVA.

A suitable container for the mould was found.  In this case it happens to be a blister pack from a resin update set.  The master was stuck to the bottom of this using some plasticine.  You can also see that I have taken the opportunity to cast another part at the same time.

Pouring the Mould

I measured the length, width and depth of the container that I was using as the mould.  It was 6cm x 3.8cm x 2cm.  This give a volume of near enough to 40ml.  You can convert this to a weight of required silicone but since this is close to 1g per cubic centimeter I chose to work with the volume instead.

I measured out 40ml of water and poured it into my mixing cup. Using a permanent marker I marked where the water came up to.

The water was then discarded and the mixing cup dried thoroughly.

The silicone rubber was then poured into the mixing cup up to the mark.  You can see I overshot a little as this stuff is really thick to pour.

For the amount of silicone rubber I was mixing I added 1.2ml of catalyst to the raw silicone.  I then mixed it with the handle of the knife.  You should try not to get air into the mix but it is really difficult not to.  Professionals would put the mixture into a vacuum chamber to de-gas the silicone after it's mixed but I don't have that luxury.  Also make sure that you scrape the sides and bottom of the pot while you're mixing it.

Once it was thoroughly mixed the rubber was then poured slowly into the mould.  Start from one corner and let the rubber flow slowly around the master.  This will minimise any chance of getting air bubbles.   Again, professionals would do a second de-gassing at this stage and again I didn't.  Once it is full set it aside for 24 hours to cure.

After it has cured you can remove the hardened silicone rubber from the container...

...and then remove the masters.

Casting in Resin

What you will Need

To do this part you will need.  Part A and Part B resin, latex or nitrile gloves, a container to mix in, something to mix with and either two measuring beakers or, as I am using, disposable pipettes with measurements on the side...and of course your silicone rubber mould.

Put on the disposable gloves and measure out equal quantities by volume of part A and Part B resin.  Add these to the mixing cup and stir thoroughly.

Once mixed pour the resin into the mould.  In my case I used a third pipette to transfer the resin to the mould.  Experiment with what works best for you.  The trick is to get the resin into all parts of the mould without getting any air bubbles.

As the resin sets it will turn white.  Leave it for 20-30 minutes before removing it from the mould.

Success.  Perfect copies of the originals.

Be prepared for some failures though.

I hope that you have found this useful.

Hobby Boss 1/48 Ta-152 C-0 - Part 2

Back to part 1.

Somewhere to Sit

Like most model aircraft, construction starts with the cockpit.  Since I'm using the Eduard detail set some of the plastic bits won't be used.  I started by removing the bits that were going to be used from the sprue.  These were test fitted into the fuselage before gluing selected pieces.

The cockpit sidewalls are photoetch.  These have a lip on them at the bottom which required careful folding.  I don't know how I would have done this if I did not have the right tool for the job.

The rudder bar and the control column have been offset a bit.  Since the kit has poseable control surfaces I'll place the ailerons and rudder to match.  I'll have to remember to pose the tail wheel too or it might look a bit odd.  Detail as been removed from the side consoles.  This will be replaced with photoetch once the cockpit has been painted.

The photoetch rudder pedals from the kit were added to the rudder bar.  I was going to use the Eduard replacements for this but one of them flew off into space as I cut it from the frame.  I should have known better than to cut it unsecured.  Of course after hunting around for it on the floor for about 20 minutes and then deciding to use the kit rudder pedals, I found it right next to the sprue it was cut from after I had done all the painting.

Looking at the layout of the cockpit it is apparent that Luftwaffe pilots had unfeasibly long legs in order to reach the rudder pedals.

The cockpit was given a coat of paint.  Luftwaffe cockpits of this era were painted in RLM 66 Black-Grey.  The closest colour I have to this is Vallejo 71.055.  The cockpit was drybrushed in a lighter shade of grey and then in lightly Citadel Chainmail.  Scratches were done with a prismacolor silver pencil.  I also sprayed the engine bay and the area around the tail wheel.  These were in Vallejo  71.044 which is a good match to RLM 02 grey.

The cockpit was given a gloss coat and a few placards were placed using the Airscale WW2 Luftwaffe Placards set.

Another gloss coat and then the Eduard photoetch side panels were applied and the whole thing was given a wash with Lamp Black oil paint and Raw Umber for the leather on the seat.  Applying the oil wash over the photoetched parts helps blend the colour in.  The Eduard photoetch has a distinct blueish hue and the oils know that back a bit.

Assembling the instrument panel was fiddly.  One of the tiny parts did fling off into space when I picked it up in the tweezers.  It's hardly noticeable though...unless you notice it that is.

I also assembled the lap belts for the seat.  I have not folded them onto the seat at this stage so the seat looks like its trying to grab a victim in some b-grade horror movie.  "Leeetle 1/48 scale pilot you must sssit on me so I can eeeat you!"

The cockpit parts were given a coat of matt varnish and Crystal Clear was put into the instrument dials to simulate the glass.  Finally the tub was installed into the fuselage.

Next time I'll work of the engine and the tail wheel and hopefully get the fuselage sides together.

On to part 3

Academy 1/48 Mig-29A - Part 12

Back to part 11

Rise Up

Alrighty then.  Time to get this baby onto it legs.

The landing gear and the inside of the gear doors were all given a coat of Tamiya XF-66.  Details on the legs were picked out with citadel boltgun.  The wheels themselves are Gunze H77 and Tamiya X-05 Green.  The red mark on the tyre and rim is the tyre slip indicator.

At last I can get the gear in into the aircraft.  They're only a push fit at the moment but it's really starting to look the part.

Finally the gear was cemented into the wheel bays.  However I do have a confession to make.  The strut in front of the nose gear is pinched from the Eduard Mig-29UB because I wrecked the one that came with this kit.  I used is as a mask for the front wheel well and to make it fit it required...well...surgery.  I'll have to get a replacement made as the part in the photo below is only there to make sure the nose gear is placed correctly.

Once the gear was fit I attached the gear doors.  These were very fiddly and some of the small resin parts broke requiring me to fix them as I worked.

Time in the Office

I also worked on the ejection seat and finally got it glued into the cockpit.  The Aires photoetched harness was tricky to work with but they came out alright in the end.

The office now looks busy - like the real thing.

I used some white Vallejo pigment inside the engines to replicate the white dusty soot often seen inside the business end of fighter jet engines.

Next time I'll finish the weapons and assemble the airbrakes.  Then there's just final detailing and we're done.

Academy 1/48 Mig-29A - Part 11

Back to part 10.

A Different Combat Mission

OK I'm going to have a bit of a rant.  The HungAeroDecals stencils I used on this aircraft were appalling.  In some cases the printing did not sit squarely on top of the carrier film so several of them just fell apart once they got wet.  Like, the Aztec decals that I also used on this build, there did not seem to be much adhesive on them.  Further, they were often mislabeled in the instructions making it very confusing as to which decal goes where or what way up it went.  I left some of them off completely for these reasons and some of them that are on may not be correct to an expert on the plane.  Many of these decals had me battle with silvering by using Micro set, Micro sol and Mr Mark Softer (that name always makes me smile).  

Anyway, with the exception of some cockpit, leading gear and weapons decals they're now on and, despite the amount of time it took me to apply them, I think they look pretty good.

They're still a bit bright but weathering will tone them down a fair bit.  They're also in Russian but I mentioned that in an earlier post.  These photos were taken after sealing the decals in with another gloss coat.

The Devil's in the Details

While I was working on the decals I also worked on the additional bits that will eventually be added to the aircraft. Here they have all been primed with Alclad II grey primer.  On the right there's also some bits for a 1/48 Saab Draken that I am working on at the same time.

I decided that I was not happy with the way the burner cans looked so I resprayed them too.

I also made some progress on the AA-10C missiles

Weather Forecast

Some people seeing this for the first time might think I'm crazy painting this crap all over a nice looking model Mig-29.  This is Flory Models Dark Dirt wash.  The idea is that is gets into the panel lines and makes the plane look like it's been used and is a bit dirty.

Once the wash was dry the process of removing it starts.  This is done with a moist kitchen towel and cotton buds.  On the lower part of the photo you can see where the wash is trapped inside the panel lines and give the impression that the plane is being used.

Now the panel lines can be seen clearly and the plane just looks a bit dirtier.  Once all of the wash was removed I gave the model it's first coat of flat varnish.  It's starting to look like the real thing now...except for the fact that it's small enough to sit on my dining table.

This was left a good couple of hours for the flat coat to dry and then weathering with pigments started.  Dirt was added around where maintenance crew are likely to walk and streaks were added around the engines.  A final flat coat and the canopy masks were removed.  The stabilators were also glued in place.  The burners and main canopy are a loose fit at this stage.  They'll be glued closer to  the end.

That's where I'm going to leave it for this update.  Next time I'll be working on the weapons and landing gear.  Hopefully I'll get this thing onto it's legs.

If you're following this and like what you're seeing leave a comment.

On to part 12.

Hobby Boss 1/48 Ta-152 C-0 - Part 1

Ok, so my mind is moving on to a new build.  I'm still going to finish the Mig-29A (there's so many decals to place on it) but I thought I'd give you a taster for what's next.  Unfortunately (for some), building these kits does not make the collection in my cupboard any smaller.  While there's two being worked on, over the past couple of weeks I acquired another two to replace them.  Well not really replace them...I just saw some other cool aircraft which I wanted.

I do wonder where I would display them if I built them all...there's 32 unbuilt planes hiding in my study cupboard at the moment.  Sure, that's not many when compared to some collectors that I know, but I'm guessing that it's 32 more than most people have.  My wife complains that they're dust traps but what would she know?  I just think they're cool...in the same way that Dr Who made bow ties cool.

Introduction

The Ta-152 is the ultimate variant of the Focke-Wulf FW-190, a fighter that saw action in great numbers during WWII.  The Ta-152 was produced in small numbers over three main variants right at the end of the war.  The Ta-152H was a high altitude interceptor, the Ta-152C was a medium altitude fighter and ground attack aircraft and the Ta-152E was a reconnaissance fighter.  The Ta-152H has the somewhat redundant claim to fame as being one of the fastest piston engined fighters of the war.  While other versions were in the early stages of production the Ta-152H is the only version of this fighter to have seen action.

I'll be building the Ta-152 C-0, a pre-production aircraft and one of three aircraft of that designation that were built.  I'm doing this build as part of a Special Interest Group (SIG) build on a forum that I belong to.

The Kit

The Hobby Boss 1/48 Ta-152 C-0 kit is a fairly recent release hitting the shelves of hobby shops in 2011.  The main components of the kit are molded in light grey plastic with finely engraved panel lines. 

A nice touch is having separate flaps and ailerons on the wing.

Detail extends to the rear part of the DB603E engine, which will be visible from the opened wheel well.  Interestingly for some reason Hobby Boss chose to mold the exhausts in an upper and lower half.  This might make them easier to hollow out.  I did read in a review of this kit that you could use extra glue and have it squeeze out of the join to replicate the weld seam on the exhausts - maybe?  The radiator is wrong btw.

There are two versions of the cowl.  The one with the larger hump on it is for the C-1 production model which was going to have a DB603LA engine.

I don't like the look of that propeller but having a separate rudder is nice.  The fabric effect is nicely subdued.  The MK108 cannons look nice too.  Unfortunately you won't see much of them as they're buried in the wing behind the main spar.

The clear parts are beautifully clear with very little distortion.

The decals are well done and there's even a bit of photoetched brass for seat belts, aerials and the rear of the cockpit.

There are two marking options in the kit.  One of these is for the pre-production/prototype machine CI+XM, and the other, "Green 13" from JG301 is fictitious.  I'll be using the CI+XM markings.

It is an accepted fact that, with a few of exceptions, the Luftwaffe colours used on late war fighters are notoriously hard to have certainty over.  Even if you know the RLM colours used, matching the shade is still open to interpretation.  That said, I cannot help but think that the colour callouts in the instructions are not quite correct.  Images of the actual aircraft show there is a demarkation of colours on the cowl just behind the radiator flaps and again halfway along gun cover just forward of the cockpit.  The amount of contrast in these colours is not enough to suggest the two late war greens RLM 82 Light Green and RLM 83 Dark Green as shown in the colour callout of the kit.  My references (see further down) suggest that the colours are RLM 75 Grey-Violet and RLM 83 Dark Green and I think they're probably correct.  Interestingly kit does suggest these colours on the upper surfaces of the wings, however a well known image of the aircraft shows that the pattern Hobby Boss have suggested is close, but not quite correct.  Especially on the left wing.  I am also not sure that the unpainted aluminium area on the undersides extends so far back on the fuselage.

So, colours decided, there are a couple of issues with the kit itself which a true Luftwaffe Experten would not miss.

Firstly, the propeller blades are the wrong shape.  They should have more of a paddle shape to them with a characteristic 'kink' on the leading and trailing edges.  Similarly the spinner has a large hole in the tip commonly seen on Fw-190D and Ta-152 prototypes.

Instead the kit part has a much more gentle curve to the profile of the blades and the spinner tapers too much and has a small hole for the cannon barrel.

Secondly, the radiator used on the kit is not correct.  For some reason Hobby Boss have used the radiator arrangement from a Fw-190 D-9 - an aircraft with a different engine.

The real aircraft had a very different radiator arrangement.

So, for a correct Ta-152 C-0 the entire radiator and propeller assembly has to be replaced.  This leads us onto the extras I plan to add to this build.

Aftermarket Extras

In order to correct the propeller and radiator I'm going to use the Quickboost cowl correction and propeller correction.

Looking at the photograph though it appears that the spinner will still need some work or it too will need replacing.  I do have the spinner from the Engines & Things Fw-190 D-11 conversion kit which I may use instead as it looks like it's the right shape.

To add some general improvements to the already good detail on the kit I'll also be using the Eduard detail set and some replacement wheels from True Details.

Reference Material

It's always good to have some reference material on hand when building an aircraft.  I have quite a number of books on Luftwaffe aircraft some of which are pertinent to this build.

Both of these books contain quite a bit on the Ta-152C and, in particular, the specific aircraft I am building.  The book by Thomas Hitchcock is a limited edition that has been signed by Willie Reschke, one of the pilots that flew the Ta-152.  It cost me a packet at the time but I do like it.

The other reference book that will come in handy is Luftwaffe Camouflage and Markings 1933-1945 Vol. II.  This book has two colour charts with colour chips that have been made to exactly the same recipe as the original paints.  They give a very clear idea as to what the actual colours looked like.  Unfortunately my photography is not up to making them look right in the image.

So, that's where we'll leave it at the moment.  I still have a Mig-29A to finish so I won't really get too far into this kit until that one is finished.