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


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15 hours ago, Fritag said:

8D1B3DDB-8791-4318-83AF-8868B5628863

 

Absolutely ace picture that Steve. Your comings are a delight to behold, and I'd forgotten how exquisite the actual IP's are on these beauties.

 

15 hours ago, Fritag said:

Next task is to see what quality of vac-formed canopies the bucks I printed off a few days ago will produce and in particular whether I’ll get problems with discolouration. 

 

As a recent convert to such work, but with just resin bucks, I'm looking forward to the next installment. Good luck!

 

Terry

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18 hours ago, Terry1954 said:

As a recent convert to such work, but with just resin bucks, I'm looking forward to the next installment.

 

Next instalment then. Vac-forming using the printed bucks.

 

Ok so, I've done a fair amount of vac-forming over cast resin bucks using PETg and had experience of the discolouration I've mentioned before, the clouding mentioned by @TheBaron and the bubbles mentioned by @hendie ('the nasties'....(no not Tony and Alan - the discolourations etc.)).

 

My hi-tech solution in the past has been to just keep trying and hope for the best....

 

Well okay.  It was slightly more sophisticated than that.  Through a process of trial and error I worked out that I could mostly avoid the nasties by heating the PETg as gently as I could and to the minimum extent consistent with forming over the buck.  It's all a bit of a judgment call and more art than science (definitely not the sort of elegant scientifically satisfying solution that would impress a man of Tony's intellectual rigour :D) but I've had success with it.

 

Trouble is I'm a bit out of practice; so on the first go I didn't quite heat the PETg enough it and it didn't fully form over the bucks.  But interestingly the failure revealed that the layers on the bucks - which frankly I'd failed to see with the mark one human eyeball - were distinct enough to imprint on the PETg!  

 

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So it was out with the micro-mesh and 10 minutes later attempt no 2 produced this:

 

C810051B-DE81-4393-9D61-2DEB60E487A1

 

 

628899E7-DB8C-43C7-B622-C3A3CF44F0C8

 

I use 0.5mm PETg as I've found in the past that with any thinner the sides of my canopies end up too thin and become hard to cut and glue (I like to be able to file/sand the base of the canopy to get the best fit) and with 1/72 scale canopies any with thicker (0.7/0.8mm) the top of the canopy ends up too thick.

 

0.5mm works according to the application of the  Goldilocks principle :D

 

My technique (such as it is :whistle:)  is to put the bucks and PETg into the Dental Vac form machine with the heating element cold or cooled down, and then turn the heating element on and let it heat up until it is just merely beginning to hint at changing colour towards red.  If I've left it until it's bright red I turn it off again and let it cool down and start again.

 

If I've caught it right I then raise the cage towards the now barely pink heating element - but never all the way up.

 

I then keep the cage it manually in place and watch the top surface of the PETg looking for it beginning to flex/ripple and subsequently sag.

 

As the heating element continues to heat up I lower the cage to take the PETg further away from the heating element.  The idea being to keep the heating as gentle as possible so as to avoid bubbles forming in the PETg and to keep the moulding temperature as low as practicable.  I err on the side of the caution.

 

I aim to get a slow controllable sag in the PETg and lower the cage and trigger the vacuum motor when the PETg has sagged to about the level of the bottom of the cage.

 

You want to avoid an uncontrollable or excessive sag :whistle: (we absolutely need @CedB back for a fnaar or two...)

 

Anyways that's my two pennyworth of faux wisdom :D

 

I'm not claiming perfect results every time mind.

 

The canopies all benefitted from a very slight polish with Autoglym super resin car polish on the inside to brighten them up (slight and polishable dulling of finish - a sort of not really clouding) - and one of the main canopies had a couple of visible small circles on the very top (maybe caused by trapped air?)- which might polish out - but which I didn't bother to try as this is just the test phase.

 

So - trimmed the base of a test canopy around the buck and tried out the jig....

 

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Accurate trimming of the front and back was what I was after.  Seemed to work.  Used a sanding stick after the razor saw.

 

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 Same deal with the windscreen jig (no photo).

 

Fingers crossed and test fit....

 

Not bad.

 

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The windscreen is deliberately a fraction under size as I want to have a go printing a frame for it; hopefully to get a really good fit with the little printed spacer at the front and the fuselage sides, and to give a surface other than the PETg to fill/sand/paint.

 

Small gap at the top of the back of the main canopy.  looks like I may have the angle at the back of the canopy buck very slightly wrong.  I'm not sure I'll bother printing a new buck/Jig though as the canopies will be posed open and the angular difference won't show.

 

I don't think it's practical to print a frame for the canopy.  Might try.  Might not.

 

It's the mid point diagonal canopy join tape that bothers me.  If I can't print it then I might print a jig to help me mask it accurately.

 

Anyways another piccie.  You can just see one of the little circles/bubbles I mentioned, on the top of the main canopy above the rear coaming.  This'd be a reject canopy if it weren't a test piece.  Windscreen's a bit smudgy from handling - but would polish up nicely.

 

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Last one.  The canopy/windcreen junction is good.  But'll never be put to the test as the canopies will be posed open.  Decent clarity with minimal polishing then spoiled a bit by mucky fingers.  Be better with a proper polish.

 

4CA246ED-1268-44E9-BD0B-F618FA8E7DDE

 

And that's were it's at now.  Promising on the vac form canopy front. 

 

TTFN.

Edited by Fritag
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32 minutes ago, Fritag said:

Promising on the vac form canopy front. 

Definitely! :clap: 

 

I bet that with a bath in Aqua Gloss, these would be usable already!


Ciao

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2 hours ago, Fritag said:

Promising on the vac form canopy front. 

 

I've seen many injection molded canopies that are nowhere near as good as that.  Nice job Steve.

I'm very impressed by the cutting/trimming jig.  Great use of the technology

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On 4/4/2022 at 2:22 AM, Fritag said:

But I’ll treasure the day that I learned there was such a thing as reptile heating mats!

Cue modified bicycle saddle.

 

"I aim to get a slow controllable sag"....

 

Don't we all sir, don't we all!

 

Bloody marvelous canopy and coamings though. Top notch!

 

Ian

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8 hours ago, Fritag said:

Promising on the vac form canopy front. 

 

I would say very promising Steve. I'd be right chuffed with that.

 

I must have got VERY lucky on my first and only multi buck vac shot for the Viking. It's often the way I guess as I'm sure when i do more of this stuff I will need to take heed of important neccessary steps and advice, and this thread has all the notes I need!

 

Do you think we are getting close to paint yet @giemme?

 

Terry

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2 hours ago, Terry1954 said:

Do you think we are getting close to paint yet @giemme?

It depends on your definition of "close to",  dear friend. I reckon  when we hit page 200 we should be pretty close to paint... :devil:

 

Ciao 

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1 hour ago, giemme said:

It depends on your definition of "close to",  dear friend. I reckon  when we hit page 200 we should be pretty close to paint... :devil:

 

Ciao 

 

Page 200 you think....🤔 hmm that feels close but perhaps a tad optimistic?

 

Terry

 

 

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10 hours ago, Terry1954 said:

 

Page 200 you think....🤔 hmm that feels close but perhaps a tad optimistic?

 

Terry

 

 

I sort of, agree.

 

I'm rather thinking these days that by that far into the MMT* our hero will discover an obscure Transylvanian pigment sorting entity/app for his iPhone which will assist him in grinding his own pigments to allow awfully accurate panel variations thus putting back any thought of actual paint getting onto model Hawk replicas.

 

 

 

 

 

 

 

 

 

 

*MMT=  Magical Mystery...

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Paint.  There has been paint.  Admittedly not for some little time...but there has been paint :blush: :whistle:

 

Yesterday was a busy day - but the advantage/problem (depends on your point of view really) of CAD is that it's only an icon click between work (PDF/Word) and play (Fusion/Chitubox) and it's easy/too easy (d.o.y.p.o.v.r.) to make the transition.  And then it's little additional effort to take a flash drive through to the garage and stick it in the Mars....

 

So a bit of tinkering was done.

 

A 1mm thick template found itself produced sliced and printed with only minimal Fritag involvement.  Created simply in Fusion by sizing a canvas (Fusion term) of some (reasonably trusted/checked against photos of the 1:1) plans to match exactly with a canvas of a plan photo of the kit nose and then sketching the plan nasal curve with a spline.

 

A sort of hi-tech version of tracing and cutting a template from the plan.  Either an improvement or an unnecessary complication again d.o.y.p.o.v.r. :D

 

Shows how much of the curve is AWOL.  Shall have to do something of a nose job even if I don't try and match the complete curvaceousness.

 

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I could design and print a new nose per @keefr22 but I'm reluctant to do so at this stage cos there's cockpit and nosebay internals in the way.  I'll probably build up the absent curves slowly with Mr Surfacer or some such prouduct.

 

I could perhaps print a wafeer theen thin slither of profile -  shaped to match the gap between the fuselage and the template in the photo and stick that to the fuselage and use it as a filling/sanding aid..... :hmmm:

 

I also couldn't resist a quick shell-extrude-slice (and somewhat longer print - but that's fire-and-forget) as a proof of concept test of a windscreen frame.   Went straight for the minimum thickness I can imagine being practicable - 0.2mm.

 

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Jig came in hady for trimming the uncured frame.

 

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You get the idea.

 

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I reckon it's a player.

 

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Not actually as fiddly as I feared.  And a little more robust than I expected. 

 

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Sorry it's not paint chaps.......

Edited by Fritag
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I had a nice little chuckle to myself reading that post.Just a few months ago you were on the fence about whether to buy a printer or not... would you use it enough etc.  Then a few weeks ago it was do you get the Mars 2 or the Mars 3, and now you're off printing jigs and bucks and frames and bomblets n stuff.

Do you think you made a sound decision or are you still a bit on the fence about the printer?  :D

 

To be fair though, I think most people go through that thought process of what will I use it for? Will I use it enough? Is it going to end up beside the waffle maker in the cupboard?  It's certainly not an insignificant investment, however, I think most folks find that they use it for much more than they first intended.  I certainly never planned on making a Wapiti from a bottle of gloop

 

Great work once again Steve, and from your last few posts it seems that you're really enjoying the challenges and rewards of the design and print process

 

 

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1 hour ago, hendie said:

Do you think you made a sound decision or are you still a bit on the fence about the printer?  :D

 

The jury is still out.  Can't you tell ;)

 

It's all your fault anyway....  And the other one in Ireland.

 

In other news - a brief burst of work avoidance behaviour produced a test fest.  L to R frames at 0.2mm (from the first batch) 0.25mm and 0.3mm.  Just to see what is the best compromise (if indeed there is a best) between robustness/usability and satisfactory look.

 

I should perhaps say that on delicate pieces like this with minimal cross section/suction effect on printing, the Mars 3 has produced no failed prints using support contact points of only 0.1mm diameter/0.2mm depth and without need for cross supports.

 

It's perhaps such small contact points that has made it practicable to print such delicate structures.  No matter how delicate a 0.2mm thin frame might be, the 0.1mm contact point is even more delicate and tends to give way first even with the Fritag ham fisted attempts at separating the print from the supports.

 

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Edited by Fritag
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Hullo! 3D printing now, Fritag! I have one of those gadgets myself. I trust you're putting them in hot water before trying to separate them?

 

Also, just as an aside, I would like to note that in the time this thread has existed, I've fathered two children, with a third on the way. Man alive do I wish I'd just spent all that effort on two 1/72 Hawks.

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More nice 3d printing there, Steve. As for the "problem" of finding it hard to resist the click from Word to CAD, you can imagine how much harder it is for people like me who work in CAD to not just load up a personal project rather than work. Not that I ever do that in work time. Not at all. Definitely wasn't me who spent 3/4 yesterday drawing up camouflage pattens instead of buildings... :whistle:

 

James

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Wow I will have to read it all again to begin an understanding, possibly.

 

Did you write that you got the image from a plan, not a drawing of your own?

 

No you can't have, I'll go and look again.

 

 

I can't even use a drawing to begin a fusion image.

 

Back to the drorring bored...

 

 

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Absolute gem !!

These canopies are spot on !!

At 1/72 at that !!

I'm amazed !! :partytime:

 

 

7 hours ago, Procopius said:

Hullo! 3D printing now, Fritag! I have one of those gadgets myself. I trust you're putting them in hot water before trying to separate them?

 

Also, just as an aside, I would like to note that in the time this thread has existed, I've fathered two children, with a third on the way. Man alive do I wish I'd just spent all that effort on two 1/72 Hawks.

Well Congratulations Mr P

And Congratulations to Mrs P too !

A protoprocopia now ??

 

Sincerely.

CC

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6 minutes ago, corsaircorp said:

Absolute gem !!

These canopies are spot on !!

At 1/72 at that !!

I'm amazed !! :partytime:

 

 

Well Congratulations Mr P

And Congratulations to Mrs P too !

A protoprocopia now ??

 

Sincerely.

CC

Even one was too many, frankly.

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11 hours ago, Procopius said:

Even one was too many, frankly.

One wasn't too bad (relatively speaking). The jump to two was quite a shock. The jump to three being as big a change as the jump to two was unexpected and comes with the problem that the kids now outnumber the parents, which causes plenty of "fun". Good luck, and congratulations* on the impending arrival & further loss of disposable income and hobby time**

 

James

 

*Or commiserations, if you feel that’s more appropriate

 

**I love my kids, I really do. Couldn't eat a whole one, mind you...

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On 05/04/2022 at 17:29, Terry1954 said:

Do you think we are getting close to paint yet @giemme?

Don't be silly Terry!

On 05/04/2022 at 20:18, giemme said:

It depends on your definition of "close to",  dear friend. I reckon  when we hit page 200 we should be pretty close to paint... :devil:

Page 200? I think we are wandering into the realms of fantasy Giemme.

 

Impressive work on the canopies and multiple posts in one week: my cup overflows!

 

Martian 👽

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On 4/6/2022 at 8:53 AM, perdu said:

I'm rather thinking these days that by that far into the MMT* our hero will discover an obscure Transylvanian pigment sorting entity/app for his iPhone which will assist him in grinding his own pigments to allow awfully accurate panel variations thus putting back any thought of actual paint getting onto model Hawk replicas.

Just spat my tea out...:cwl:

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I do think there's a rather unhealthy preoccupation with pages and paint beginning to predominate here :blush: :whistle:

 

That said I note with a certain embarrassment that during the life of this thread, not only have  @Procopius's genes had sufficient time, several times over, to ensure their continued survival, but that his boy's have had time to mature to the point of model making themselves.... :blush:

 

There also has to be a chance that this thread will continue haunt me through to retirement...

 

Fingers out then!  I have good intentions this time to continue activity through to the bitter end.  Mind you I had good intentions last time there was a burst of activity.  And the time before that...

 

Anyways.  Where was I?  Ah yes; windscreen frame test fest.  Ok so.

 

The decision was that on balance a thicker frame - 0.25 or 0.3mm - was the better option.  The benefit of the extra robustness and ease of handling outweighed the hardly visible extra over-scale effect.

 

Gluing the vac formed windscreen to the frame was rather fiddly but perfectly doable - but left a visible join at the rear which was a tad untidy.  And that triggered a process of thought I'm rather pleased with as it 'appens....

 

A quick trip back to Fusion saw the addition of a 0.2mm lip or ledge to the bottom and back of the frame.

 

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Visible (just) on this here print.  It also adds to the robustness of the frame.

 

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And now, with a modicum of subtle trimming, the vac-form windscreen clips into place in the frame and holds itself in obligingly in position ready for gluing.

 

B47BF2C6-85F9-401F-9AC4-5033D927B4C6

 

And there's no untidy join visible at the back of the windscreen - just a nice neat printed edge - which I can refine with a sanding stick to reduce the over-scale thickness (which I don't think is bad to start with).

 

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And the whole things looks pretty neat even if I say so myself:

 

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And I've now also got a sacrificial extra 0.2mm on the bottom edge of the frame to refine with a sanding stick to get as best a fit as possible and then the resin frame will hopefully give me a friendly surface to work with for any residual filling and sanding needed to get a seamless join to the fuselage (it's a pain trying to blend PETg and injection moulded plastic together seamlessly):

 

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Ok, I think that's the end of tinkering with the windscreen and frame.  I need to vac/print the 'best' editions and move on.

 

Note to self - when pre-painting the frames don't get the colour wrong - as I did with my earlier vac-form efforts and which @Terry1954 helpfully (gleefully ;)) pointed out......

 

I think I need to at least think about printing frames for the main canopy now :hmmm:

 

Oh - And as per earlier musings I've also printed off some slithers to stick either side of the nose of each Hawk to at as sanding guides for when I add Mr Surfacer (or whatever) to try and recapture the Hawks's absent curves.

 

71670E60-B8BE-41ED-9387-995149C088D6

 

 

 

Off to visit my 85 year old (and still playing golf 3 days a week) Dad for a couple of days this afternoon.  More after that.....

 

 

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