One Eighteenth of a Canberra B.2

[Scott Edwards 2]

Well, despite my best efforts, I have ended up with surfaces to paint that are as smooth as Tutankhamen's genitals. My cure is Upol High 5 Filler Primer from Halfords. Not cheap, but by 'eck it works. I've used all sorts of paint on top of it and never had a problem. Halfords do a cheaper Filler Primer, but it's hard as nails and doesn't fill anything like as well.

[Engine Doctor]

You should be able to buy the same /similar product from a car paint factors for far less .or this perhaps from Amazon

https://www.amazon.co.uk/Autotek-AT000FP500-500ml-Filler-Primer/dp/B004ZJIM8O . There may be others on E-bay

They are all very similar but very heavy . They will also dry sand when fully dry without clogging the paper .

What dope are you using to fix the tissue ? It would be interesting to know what to avoid if it clogs when sanding.

Great looking build , very neat .

E.D.

[Andy Blackburn]

Onetenor wrote:

> Wet'n'dry used wet with a drop of washing up liquid in the water will stop the clogging

Sadly, I think you're right - I'd hoped that I could dispense with all the wet sanding which was partly why I thought I'd try tissue and dope rather than glass & epoxy.

Engine Doctor wrote:

>What dope are you using to fix the tissue ? It would be interesting to know what to avoid if it clogs when sanding.

I think the fact that it's non-shrinking (plasticizer added) dope is more important than the make (H.M.G. from The Balsa Cabin); I think any plasticized dope is probably going to dry slightly softer; I can't use ordinary dope (or acrylic varnish) because it shrinks far too much, even thinned.

It's now had the last coat of home-made sanding sealer (non-shrinking dope and talcum powder) so I'm going to let it dry out for several days, then I'll have a go at it with wet & dry, used wet; if that doesn't produce a surface that's good enough for paint, I'll think about using primer.

BTW, what I have (re) discovered is that because dope starts drying within a second or two, it goes on much, much smoother with the correct brush; I started off using a 3/4" flattie which wasn't working particularly well, but found on old (cheap) mop brush in a drawer; the mop works much better with dope, even if it does shed hairs everywhere.

[Andy Blackburn]

Everything has now been wet-sanded; and at first sight it looks OK; however, if you look very carefully:

...the small patchy shiny bits are tiny hollows in the matt sanded surface; given that the paint is satin/semi-gloss, I don't think I can get away with that. I'm going to have to prime it and sand again, I think.

The shocking news, in passing, is that I has always understood that a tissue/dope finish is lighter than glass/epoxy; that might be the case if it's a single thinned coat, but after 2 coats of 50/50 sanding sealer, tissue, 2 coats of 50/50 non-shrinking dope and 2 more coats of 50/50 non-shrinking dope + talc (home-made sanding sealer), the total weight gain works out at about 170g/square metre.

This compares with only about 150g/square metre for 0.6 oz glass & epoxy.

[Scott Edwards 2]

170g/sm ! Golly, that is surprising. I've got tissue & acrylic varnish down to about 60g/sm, but that's minimal, more coats would give a better finish. I then use lots of Upol Filler Primer to hide all of my sins. With hindsight, still using tissue & dope, would you have done anything differently ?

[Andy Blackburn]

> With hindsight, still using tissue & dope, would you have done anything differently ?

You mean, other than using glass & epoxy cos it's lighter and less work? Maybe use a single coat of home-made non-shrinking sanding sealer at the start rather than two coats of commercial sanding sealer. But I don't see there's much else you could do, really...

For me, glass & acrylic varnish (about 8 coats) usually ends up about the same weight as glass & epoxy.

[Andy Blackburn]

Sorry about the lack of posts at such a crucial stage, but not much has been happening. Well actually, stuff has been happening but there's not been much visible effect; this sort of thing has been going on:

...and then the weather turned so I had to negotiate with SWMBO to get permission to do this:

...and of course once the principle had been established, it was only a short conceptual step to assume that it would be OK to wet-send primer over the bath. I haven't got any photos of this (far too busy getting everything done before She came up to see what was going on) but I'm happy to pass on the following safety information in case anyone else wishes to take a similar risk:

1. Splashes of grey primer will come off tiles and grout without any difficulty, but don't then wipe down the silicone sealant with the same cloth because it will go grey and I haven't found out how to get it off yet.
2. There will probably be tiny grains of abrasive that come off where the wet & dry has been tightly folded and will fall into the bath. I strongly advise you to ensure that none of this remains in the bath when you tidy up afterwards...

So, here's where we're at:

To my - admittedly somewhat biased - eyes, it's starting to look quite Canberra-esque, although there's quite a bit more primer left on the surface than I'd expect with glass and epoxy. And I suppose I should admit that after I'd been wet-sanding for 20 minutes or so I was beginning to wish that I'd gone for a filmed finish, in spite of the slightly fragile and ding-able surface.

In this state it weighs 28.5 oz, which is quite good; if we allow 8 oz for radio, battery, switch and other sundry essentials and - wild guess here - about 2 oz for paint, that's a possible finished weight of 38.5 oz. So even if it needs some nose ballast and ends up nearer 40 oz, that's about 13.5 oz/sq ft, which is really quite nice for something that has nearly 3 sq ft of wing.

With a bit of luck, Scotty's spray booth will be available on Wednesday for the top surfaces to be sprayed with Humbrol enamel Medium Sea Grey. Hope I've got enough tinlets...

Normally I don't bother with cockpit detail as you can't see it in flight, and in any case this is a slope model so it's going to be subjected to a bit of rough and tumble. However, I got this chap from Real Model Pilots yesterday:

which is the correct seat and is at the correct scale, so I felt that at least some degree of extra detail in the cockpit area would be required to stop it looking out of place. I managed to find a diagram of the Canberra B.2 instrument panel and produced this impressionist rendition using TurboCAD and PaintShop Pro:

It won't win any prizes but it's only visible if you squint a bit through the canopy, so it's probably good enough.

 

Edited By Andy Blackburn on 06/11/2016 12:44:35

Edited By Andy Blackburn on 06/11/2016 12:53:19

[Scott Edwards 2]

Spray booth most definitely available on Wednesday, with complimentary tea and ginger nuts too !

Is it just me, or does your pilot remind anyone else of Ghostbusters ?

[Andy Blackburn]

So, top surfaces are sprayed using Humbrol enamel Medium Sea Grey (no photos yet, every time I remember to take some the light has gone - I'll do it next week), the painted surface needs rubbing down with very fine wire wool because the finish is a bit dusty - paint not quite thin enough. It needed 3 coats to cover, and 5 tinlets of satin enamel; I suspect that the (coal black) lower surfaces might need a bit less.

And after a trip down memory lane when I dug out all my old acrylic paints (20 years old, some of them), and some careful study of Internet videos showing how to paint faces, the pilot is as done as he's going to be:

This may not be my best work but it'll have to do; the left side of the face was OK but as I'm right-handed, the right hand side was quite tricky and required two or three attempts. The amount of highlighting you can do is limited because at this scale the 3D print layers are visible and you don't want to unintentionally highlight the non-scale detail.

The pilot needs to dry properly for a few days, then he/it (?) can be installed in the cockpit and the transparencies attached and faired in. The only other thing to do before masking is to install the hatch magnets; should be able to visit my friendly local spray booth the week after next.

Edited By Andy Blackburn on 20/11/2016 15:58:29

[MAD Dave]

Ummmm, super looking chap, but, in the days of Canberra were overalls not blue and bone-domes white?

[Andy Blackburn]

Well, yes...

I really wanted to do a white bone dome, but as you can see from one of the previous pictures, the pilot is quite small and the 3-D print layers are quite visible, particularly on the helmet. To do a gloss white bone dome would have required quite a lot of extra priming/filling and sanding.

To make the print layers less visible, I took an executive decision to go with a matt dark green helmet, which then required the pilot to have more modern-looking clothing to look correct and if challenged, I was going to claim that the pilot was wearing modern attire because it was a restored aircraft.

Or I was going to bluff. No chance of getting away with that now, of course

Edited By Andy Blackburn on 21/11/2016 19:34:04

[Andy Blackburn]

Managed to get some pictures of the sprayed top surfaces, in between the showers:

The paint is Humbrol Medium Sea Grey Enamel (satin, as they do't do matt in that colour) and it's dried quite well - there are a few blemishes which are easily fixable, but the surface is otherwise very good and it looks as though it'll take some panel lines with a 4B pencil.

There is of course another wing, but it's just a mirror image of this one...

Finally, I nearly had another epoxy fiasco today when gluing the hatch magnets (4 pairs of 6mm x 2mm magnets from Maplins); the first attempt was using some 20 minute epoxy that was meant to fill the gap between some over-sized pockets for the magnets but a) I didn't put enough in, and b) it looked like it wasn't going to set properly...

So I had to dig everything out again and then sit there with a hair dryer on low to try and accelerate the setting process, without setting fire to anything or melting anything important; luckily it did eventually start to go off and after a couple of hours, all seemed to be well so I re-did everything with normal 5 minute epoxy and a bit of filler to make sure it stayed in place:

I think what probably happened was that the hardener for the 20 minute epoxy is quite a bit more runny than the resin, so although the hardener bead had the same length as the resin, it just wasn't the same diameter so the mix was wrong. Think I was lucky to get away with that one.

[Scott Edwards 2]

On more than one occasion I've mixed up my 5min epoxy bottles with the 2hr ones. That creates some "interesting" joints.

Out of interest, do you seal the control surface hinge line ? I generally do, but often wonder if it's actually necessary.

[Andy Blackburn]

> Out of interest, do you seal the control surface hinge line ? I generally do, but often wonder if it's actually necessary.

Not unless I've made a complete pig's ear of the job and the gap is wide enough to fit a ham sandwich in. Having scoffed at the idea, I suppose I should admit that I own one PSS model that had to have the aileron hinge gap sealed because it was huge...

Edited By Andy Blackburn on 27/11/2016 16:48:34

[Andy Blackburn]

Have I been putting this off? Well, yes, I have, as a matter of fact...

1. Canopy glue, lots of tape & crossed fingers:

2. Tape off, minor clean-up:

3. This is attempt number 2; had to use 2mm Tamiya masking tape for curves, and discovered that it's not easy to cut concentric circles that are just a little bit too small for an Olfa circle cutter:

4. But after lots and lots of bad language and a visit to the Scott Edwards Spray Emporium (tea and ginger nuts included in the standard service package), we have:

- bit of touch-up required, but if the tape comes off OK it should be good enough.

Edited By Andy Blackburn on 01/12/2016 18:11:08

[Andy Blackburn]

Few photos of the transparencies, in between sherry trifle and turkey...

Canopy area is more-or-less done, if you look carefully there's a brush-painted layer of Satin Cote just around the canopy:

I did take a couple of pics from the front but the lighting was wrong and all it showed was a reflection of the iPhone and hand in the canopy....

The nose transparency is attached with a thin bead of 20 minute epoxy mixed (very carefully after the last fiasco) on a bit of cardboard that's been painted black, so that it tends to pick up some of the paint and looks a bit less obtrusive, then there's a tiny amount of odourless cyano around the join. It needs masking and then filling/sanding, then we're good to go with the lower surface black, planned for the middle of January.

Panel lines will be 4B/6B pencil with a few dots from a silver rollerball pen here and there, and I think I'm going to go with Solartrim for the roundels and letters.

[Andy Blackburn]

Took another picture of the canopy:

- not perfect but not too bad, might be able to clean up the area around the DV panel. I think film or trim is probably easier for canopy framing.

[Andy Blackburn]

The final visit to Scotty's Spray Emporium to do the black bits is planned for Wednesday, I've been putting the nose transparency masking off but couldn't procrastinate any longer:

- as it happens, the masking took about three goes to get roughly right, but it was all done in about 40 minutes. With hindsight, I don't know what all the fuss was about...

[Andy Blackburn]

So, spraying is done :

Quite pleased with it, actually - in the end it used 4 1/2 tinlets of satin Medium Sea Gray and roughly 3-4 tinlets of satin black - it's difficult to to sure because I'm afraid I spilled quite a bit of the black over Scotty's modelling room floor...

There are a few imperfections but in time-honoured fashion they'll be converted to paint chips where possible, nobody will suspect a thing. It's had a scrub of fine wire wool to get rid of the spray dust and needs radio gear installing, framing for the bomb-aimer's clear vision panel, black crew windows behind the canopy, panel lines - I'm thinking 4B pencil with a few strategically-placed bits of silver, although a harder pencil might be better - satin varnish, intake & efflux painting, starter fairings painted and installed, decals, balance and ... well, that'll be it.

It's a bit light, though - what you see here is 30 1/2 oz, which after all the bits are added (say 1/2 lb) will still be a tad less than 14 oz/sq ft.

Edited By Andy Blackburn on 08/02/2017 15:36:10

[Andy Meade]

I'd say that was pretty close to perfect, Andy! Lovely job

[Phil Cooke]

Looks very nice indeed Andy, super job!

[Bob Jennings 1]

Nice one, love that!

[Peter Garsden]

Been following this closely. Great job, in nothing more than I would expect perfection to be. Hope to see you and the plane at a PSS event this year - plenty to choose from?

[Andy Blackburn]

Thanks, chaps!

> Hope to see you and the plane at a PSS event this year - plenty to choose from?

Hi Peter - yes, that's the plan, wether permitting, of course...

Things are still happening on the Canberra, have just about got to the point where I can't put off drawing the panel lines any longer; I think I can probably finish installing the Rx, do a bit of soldering, and then I'm going to have to do the panelling. I don't like panelling. There, I've admitted it...

Photos next week.

Edited By Andy Blackburn on 26/02/2017 10:07:13

[maurice northcott]

Lovely model Andy - Very well done. Canberra is one of my favourites being one of those aircraft flying in numbers when I was a sprog....you have done it proud.