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A pair of Airfix Hawks in 1/72. Finished.


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The Plasticine I bought last year for use in silicone mould-making is nothing like that which I remember as a wain. Unless my memory is totally shot, it certainly smells nothing like the stuff we had at Primary School (although that was over 40 years ago! :o ). It also seems somewhat more 'cheesey' in feel - I remember the old stuff being more like 'Blu-Tack' in consitency

Anyhoo, if you are worried about Platicine lacking the capability to reproduce fine detail, or undercuts, on press moulds you might try 'Play-Doh'. Many years ago I used to use it for creating ground features for my 54mm Napoleonic figurines.

It can be moulded and modelled just like Plasticene, but if you leave it out of its container for a couple of hours it sets in air and goes hard.

http://playdoh.hasbro.com/en-gb/product/play-doh-favorite-colors-4-pack:9383B47D-6D40-1014-8BF0-9EFBF894F9D4

You can find it in Toy Shops as well as in places like Argos and ASDA.

Any chance of some pictures of those Napolionic figures.My late father used to make and paint those back in the 80's.would love to see them.

Neil

Edited by fatalbert
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It can be moulded and modelled just like Plasticene, but if you leave it out of its container for a couple of hours it sets in air and goes hard.

http://playdoh.hasbro.com/en-gb/product/play-doh-favorite-colors-4-pack:9383B47D-6D40-1014-8BF0-9EFBF894F9D4

You can find it in Toy Shops as well as in places like Argos and ASDA.

That's exactly what I have. Like 30 or 40 assorted size and color pots of it ...

Ciao

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I too read that line as

"making moulds of a couple of other bust and boobs at the same time"

I thought to myself "He'll be getting a clip 'round the 'earhole from his Mrs if he's not careful saying things like that too"

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I dunno...

A chap types "bits and bobs"

The clearly slightly lewd Apple autocorrect makes it "bust and bobs"

And the clearly even lewder BM community auto correct makes it "bust and boobs"

I ask you....... :)

This is the result of my little casting session last night:

BF151705-1AE0-4C2C-A659-4DF944189410_zps

From left to right: 1. The airbrake aerodynamic fairings 2. aileron aerodynamic fairings 3. nose wheel yoke and 4. nose wheel.

The master of the nose wheel yoke I fabricated sometime ago:

BCF39C35-467A-4B56-A918-58DB73FC595A_zps

For the aerodynamic fairings I made silicone rubber moulds of the moulded in detail on the new tool Revell Hawk :whistle: And the nose wheel is also from the Revell Hawk as it nicely represents the bolts in the wheel hub - rather more neatly than did my scratch built effort from several months back. And I put a lot of effort into that nose wheel as well :(............. Still - no point in being sentimental about it :)

Edited by Fritag
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S'not that impressive :)

What I should have said was that i fabricated it out of the original Airfix nose leg (middle one in this piccie) - by cutting out the nose wheel, opening up the yoke, refining the shape and adding some details from strip. See how horribly over size the Airfix offering was?:

49cf9940-557c-4ae2-bc97-4410fe27c86e_zps

Re reading my post - it did sort of sound and look like I was implying I'd carved it from scratch.... :)

Sorry.....

Edited by Fritag
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Well, the casting session has certainly produced some remarkable bits and bobs :D

Sorry if I keep bothering with these questions, but this casting thing is quite intriguing: how do you remove the resin bits from the silicone mold? You just pop them off or is it the mold cut and joined along some line?

TIA

Ciao

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Giorgio,

With small parts like wheels what I do is bond the master to a 'sprue' (usually a thick strip of plastikard) and then make a one piece mould. It is relatively easy then to just pop the master (and the castings) out of the mould. The 'sprue' makes it easy to grasp the component during mould release but, more importantly, acts as a 'sink' or reservoir that assists in removing any air bubbles.

With large components such as, for eg a fin/rudder, I make a 2 piece mould. Here you press the master into some plasticine and make up a half mould in silicone (you put some 'keys' into the plasticine such that the mould will have joining 'lugs'). Once set you paint the first half mould with release agent and make the second half mould on the first half. Obviously you have to build in feedways for the casting medium and exit holes for the air to come out when casting. Once that's done you pop the master out, paint the mould joining surfaces with a sealant such as vaseline (petroleum jelly) to seal the mould halves together and you are good to go.

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Debs, thank you very much for the detailed explanation :thumbsup: :thumbsup:

The two halves mould seems fairly complex for me, or at least would involve a lot of trail and error. I think I'll have a go at small pieces with the first technique you described, first. :hobbyhorse::pilot:

Ciao

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For making a 2 part mould see:

https://www.sylmasta.com/acatalog/Instructions-for-Mould-Making---Casting-1.html

For a single part mould what I do is make a 'frame' out of lego or similar. Press blu-tack or plasticine into the base of the mould to give a smooth base. Place the master on top of the plasticine (if it has a good 'sprue' you can push it into the plasticine slightly so as to hold it firm). Then fill the 'frame' around the master with RTV silicone. In order to de-aerate the silicone pour it slowly from a height of at least 1/2m. As the silicone sets it will further de-areate - bubbles will come to the surface.

This is a bit long winded but should serve to explain what I mean:

Sorry for the Thread Drift Steve!

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I dunno...

A chap types "bits and bobs"

The clearly slightly lewd Apple autocorrect makes it "bust and bobs"

And the clearly even lewder BM community auto correct makes it "bust and boobs"

I ask you....... :)

It wern't me honest M'Lud(one day maybe eh )it was that naughty Ascoteer :bouncy: ,she's a rum'un that one :whistle: :whistle:

That undercart looks great,I reckon one could do a roaring trade around these parts with those busts and boobs Steeevey.

Edited by Miggers
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Sorry for the Thread Drift Steve!

Apologies not required Debs - very useful and much appreciated input :)

Giorgio - Debs is further along with this resin casting malarkey than I am.

I have always been casting small parts - albeit often complicated shapes - and I have always been able to use a single part mould.

There are differing RTV compounds ( so I understand) but the 'standard' one I use is certainly flexible enough to be able to pull out the master and resin cast even with substantial undercuts.

I agree with Debs that it is important to mould in a substantial sink or reservoir at the pouring end of the mould to help deal with air bubbles in the pouring resin. The RTV mould will need a lot of squeezing and stretching to expel unwanted tiny air bubbles from the corners - and a reservoir of resin allows space for the bubbles to rise clear of the mould and for resin to replace the air bubbles. I usually create this with plasticine shaped around the master's attachment lug.

Back to the Hawks - and I'm afraid yet more airbrakery - but nearly the end!!!!!

Lined the sides of the bays with 0.1mm card - just to ensure a crisp edge:

420A1BB6-1C0C-47BC-9368-B9144264EA6A_zps

Carefully sanded down yesterday's resin casts of the aerodynamic fairing and marked out where to stick em on the airbrakes:

A3D31AFB-EECF-45BF-B7ED-4834A24C017A_zps

Had a brainwave about how to ensure they got stuck where I intended them to be. Drilled some holes in the airbrake and used strips of tamiya tape to hold the fairings central:

A0320FD8-89FF-4C0F-9B98-E6778411D57D_zps

04AF029E-DB68-4843-8BF3-E0F0E08D8914_zps

And applied some thin cyano to the back of the airbrakes so that capillary action drew it down the holes and between the fairings and the airbrake.

Et voila:

CAFA6DEA-0509-4C90-89CE-E61BF3310121_zps

I like doing stupid little stuff like this......

Stops me having to do big difficult stuff.....

Edited by Fritag
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Debs, thank you very much, those links are very instructive! :thumbsup:

Steve, I couldn't see any stupid thing here :coolio: Great job all round on the airbrakes, and brilliant idea about how to glue their fairings on :clap: I'd have probably only used tape and some Tamiya Green Cap on the edges, they would have moved before settling, etc ... :banghead::chair:

Ciao

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it was that naughty Ascoteer :bouncy: ,she's a rum'un that one :whistle: :whistle:

True, the story of my life, aways been a bad egg me... ;)

She's terrible that Debs, she drinks, she smokes (Author's Note: Not anymore I don't), she wears all the wrong clothes, and have you seen her spikey hair and those safety pin earrings? She listens to that Punk Music and... she leads boys astray! :o Mark my words nothing good will come of her...

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I like your stupid little stuff Steve cos it all adds up to sensible big stuff at the end of the day. Nice techniques on display. Flash back to the one dimensional kit offering to your improvements. What a contrast. Good casting advice from Ascoteer too.

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True, the story of my life, aways been a bad egg me... ;)

She's terrible that Debs, she drinks, she smokes (Author's Note: Not anymore I don't), she wears all the wrong clothes, and have you seen her spikey hair and those safety pin earrings? She listens to that Punk Music and... she leads boys astray! :o Mark my words nothing good will come of her...

Ah that'll be the future Air Vice Marshall (Air Training Corps- East Angular Wing) DE then?

What a gal ;)

Leads boys astray? Hmm I bet the girls go just as willingly Debs

Steve, you know we haven't seen you having trouble with any jobs, big or teeensyweensy

You just sit there and artistically engineer the answer we all stash away in our memory bank

[note to Miggers... I said MEMory bank] :)

Anyway

I suggest you ditch these two and get on with Jagmagic pretty soon

he he - only kidding

Jags can wait

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"Not sure..."

Stumped, no doubt not for long :)

(I would add in me own defence milud, that all the ATC Sqns I've seen lately are very well mixed ratios lads and lasses. We never 'ad no girls when I was wearing scrubby blue battledress and studded collar uniform shirts) :(

Edited by perdu
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(I would add in me own defence milud, that all the ATC Sqns I've seen lately are very well mixed ratios lads and lasses. We never 'ad no girls when I was wearing scrubby blue battledress and studded collar uniform shirts) :(

Battledress?? Now you're dating yourself...and me, for knowing it. Never did like that scratchy stuff, woolly pullies were MUCH better.....

Ian

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How about some masking and painting? :whistle::devil::D

I wish :)

Could be working on the ejection seats. Remember that I made up and cast some early mk 10 seats back near the beginning of the build? Well they need painting and detailing....

Or it could be some work on the surface detail. I need to cut a slot at the base of the rudder - there's a noticeable gap between the bottom of the rudder and the fuselage on hawk photo's - and I need to decided whether to cut out the wind tip lights and replace with some clear sprue - although I'm thinking maybe not as the wingtip light covers are such a dark green and red colour that I think I might do what I did with my JP3 and apply Tamiya clear colours over a black base coulour rather than over clear sprue - and I've got scribing to do and.....and....

And I've got the undercarriages to do

And the canopies to mould and detail.

And....

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Alright, alright, I got the sense of it :). We'll just wait for your next brilliant piece of micro-engineering :popcorn: (while the sprues of my next two builds are drying after a bath in warm soapy water :winkgrin: )

Ciao

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