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Skybirds 86 Percival Prentice in 1/72nd Scale.Finished.


Alex Gordon
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Crumbs Chums!

We're limbering up already!

I'm going to have a go at this one

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The plastic looks like this

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The white metal looks like this

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The decal sheet I'm not too sure about but will find out sooner or later

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And,the greater cause for concern,I present to you dear reader one of the worst photos of a badly yellowed vacform canopy that you are likely to see this day and age.More of this anon.

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Roll on the 4th,this could be interesting.

Edited by Alex Gordon
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G'day Chums,

Tom,a challenge she certainly will be.

Enzo,you're not wrong.

Rodders,I haven't decided how to tackle the canopy yet but what I come up with I will try to explain in detail because I think that the yellowing will affect all kits of this.

Deacon,enjoy the ride.

E.E.,I don't think that there were that many of these made in the first place.

Managed to make a start on this little beastie today.For a change to the normal routine of construction I decided to start with the wings.Each wing consists of the upper and larger lower surfaces.

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As supplied there is a fairish step at the join so a little light fettling to remove this was in order.

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This was also a way of divining the consistency of the plastic,which was found to be some of the hardest I've ever encountered in a kit.

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This done I moved on to the fuselage and offered up the two halves.

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The mating faces looked like they were going to go together with no fuss so I gave each edge a quick once over with the sanding block to make sure that there were no errant lumps and then set about glueing them together.My usual method of taping the halves together with insulating tape took a few moments longer than normal due to the lack of locating pins,but once done held it all together a treat.My glue of choice was Polyweld liquid glue which is very hot stuff and worked absolutely splendidly well on this plastic.

While that was setting I thought I'd have a play with the white metal components.First off the cowling.

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Two parts,the larger one being the upper portion and having a very prominent part line on both sides and around the front.

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A spot of scraping,filing and sanding led to this being taken away and an attempt to burnish out the sanding marks got me to the point of priming.

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The various intakes and the exhaust were all opened up or hollowed out,the two components dry fitted and then superglued together and then set aside.

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The cockpit components are all made from white metal and the castings were all very clean and crisp with no flash or part lines to clean up.

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These were separated out into the bits that were going to be painted black and the bits that were going to be green.The control columns,trim wheels and throttle and mixture controls were all superglued into their respective locations and then a coat of Humbrol Matt Black was sprayed onto the resultant subassemblies.

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By this time (about 3 hours into this build) the fuselage had set well enough to take the tape off and give the joints a tickle up with the sanding block.

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I then turned my attention to the tail surfaces.These had a few little niggles to sand off,but nothing major,and the slot for the fin locating lug needed to be opened up.

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This was a matter of a couple of minutes with the Dremelesque (it's not a Dremel) with a suitable burr fitted.

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I thought I'd busy up the cockpit aperture a bit,so I cut some masking tape into thin strips and double layered them into something resembling structure.

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A few slivers and squares of plastic card were made to look like map pockets and boxes and all was placed to roughly resemble the diagram in the photo of the instruction sheet that I found last week.

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A coat of matt black and a little highlighting will make it look believable.
The canopy will be the next part of the job,I would like to sort it out and fettle it before I do any more inside so that I don't cover everything in dust.

And after all that I still don't have the faintest idea where this bit goes.

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More soon chums,thanks for looking.

Edited by Alex Gordon
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I built the Skybirds Scimitar many years ago and similarly found the plastic incredibly tough! Wish I had bought one of these at the time, but will content myself that you will do a far better job than I ever could!

Tim

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  • 3 weeks later...

Hello again Chums,

Jessica,that thought occurred to me too,but most of the rest of the metal parts sit behind the mainlegs so nosediving shouldn't be a problem.I will temp it all together first though to double check.

Tom,I'd hardly say it's a masterclass,there's really not that much to it to be honest.

Rodders,cheers for that.

Cliff,I haven't finished yet,much can go wrong.There's a bit more polishing to to on the nose section yet.

Jonners,it certainly looks cockpitesque but quite where it lives is still a mystery.

Feifeitim,I'll try not to disappoint.

Giorgio,It's certainly interesting but it's not a daunting prospect.

Steve,yes please.A few piccies would be very helpful.Would it be worth doing a walkaround set and posting them up in the walkaround section elsewhere on this site?

Deacon,thanks for looking in.

Right down to business.The thing that has been holding the job up is the canopy.I need to make a new one.A couple of weeks ago I made a vacforming box.Today I made the clamp to hold the plastic sheet.I found some clear sheet about 3 weeks ago.Tomorow I'm going to have ny first go at vacforming.

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At last there is a hope of progress.Wish me luck.

More soon chums.

Edited by Alex Gordon
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G'day Chums,

Max,what you are about to see is my method.I've never tried this before so it may all fall apart round my ears but we'll give it a go anyway.

First things first a mould needs to be made.Plaster of Paris seemed like a simple enough route so a quick visit to Mr Goodwins fine establishment provided me with a kilo of very fine white powder in a vacuum sealed bag.

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Anywhere else I would look a little doubtfully at this.Anyway,I stirred up a mix in a lid off a rattlecan and poured this into the old canopy,sat the whole lot on the upside down lid of a Ferrero Rocher box and then ran the dremelesque against the side of it to try to get rid of any air bubbles.

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This was left to stand for 24 hours.The Plaster of Paris actually took about 30 minutes to go off but I thought I'd give it a chance.This morning I very gently turned the casting out and this is what we've got.

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There are a few tiny pinholes but I'm going to give it a go as it is.

More soon chums.

Edited by Alex Gordon
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G'day Chums,

Max,what you are about to see is my method.I've never tried this before so it may all fall apart round my ears but we'll give it a go anyway.

First things first a mould needs to be made.Plaster of Paris seemed like a simple enough route so a quick visit to Mr Goodwins fine establishment provided me with a kilo of very fine white powder in a vacuum sealed bag.

Skybirds86Prentice27_zpseda42532.jpg

Anywhere else I would look a little doubtfully at this.Anyway,I stirred up a mix in a lid off a rattlecan and poured this into the old canopy,sat the whole lot on the upside down lid of a Ferrero Rocher box and then ran the dremelesque against the side of it to try to get rid of any air bubbles.

Skybirds86Prentice28_zps8aff1a7e.jpg

This was left to stand for 24 hours.The Plaster of Paris actually took about 30 minutes to go off but I thought I'd give it a chance.This morning I very gently turned the casting out and this is what we've got.

Skybirds86Prentice29_zps6d33797b.jpg

There are a few tiny pinholes but I'm going to give it a go as it is.

More soon chums.

Excellent! :thumbsup: I'm following this with great interest - since I have the same kit (plus a few old Rareplanes) with yellowed canopies...

I had already bought the plaster of Paris but haven't gotten around to perform the deed ;)

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Here we go again Chums.

I've just spent the last hour on the learning curve.

Having clamped my rectangle of clear sheet into the frame and plumbed up the hoover I then discovered that there was no fuse in the plug on the toaster.A frantic search unearthed a suitable 13 amp beastie and so set to work again.Holding the frame about 6 inches above the toaster got the plastic sort of warm so I gave it a go.Not warm enough so didn't pull down enough.Also I realised that I had forgotten to place masking tape around the outer edges of the box so as to concentrate the suction nearer the middle.Attempt number two saw me holding the frame a little nearer the top of the toaster and finding out the hard way just how much heat is involved in this caper.Still not warm enough.

Attempt number 3 involved holding the frame about one inch above the toaster which heated the plastic rapidly and to a much happier temparature.With a satisfyingly increased pitch in the whine of the hoover I realised that this was the one.

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In the interests of no-one hurting themselves while performing this procedure I would suggest adding a handle of some sort to the frame so that you don't cause yourself some fearful burning all the skin off your fingers type injury.There is a lot of heat involved here.

I used the same piece of plastic throughout this job.Handy that.

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The plastic didn't draw all the way to the bottom edge of the mould,still not hot enough,but the bottom edge of the transparency is cut off the finished item anyway so it's not too critical.

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On turning out the mould I was surprised to find how much moisture had developed inside.

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There are a few little dust spots in a few places.I'm going to have a look and a bit of a think as to whether or not to make another one or be happy with this one.

I also made a couple of attempts on a previously made mould using a small blowtorch.These didn't work because of not enough heat spread widely enough at the same time. the big burn mark is what happens when you try to post heat while on the box 'cos the plastic didn't quite go far enough.

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Moggy,Max and anyone else,if you want any more piccies or have any questions please feel free to ask,just don't get hurt for lack of information.

I'm going to call it lunchtime now,catch up later.

Edited by Alex Gordon
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Great stuff Alex. You've discovered, as I did with my plunge moulded turret, that the temperature of the melted plastic is critical - enough but not too much. I've seen ovens used before for vacuforming, either directly in the oven or over the hot plate. Fascinating stuff, it certainly looks pretty professional!
Max

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Hmm. I built a Dujin resin kit of the Prentice some years ago. I still have a spare canopy but... yes you guessed it, its turned yellow. I'll try a do a photo or two of it to give some inspiration if nothing else.

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Hmm, I have all the Skybirds spares and all of the metal moulds, some plastic parts and canopy moulds for the Prentice and the Masters for the rest of the range sitting in my second workshop. I recovered these recently, when following Mike's recent death I helped to clear his workshop I do have a box of canopies but these are all brown. I do have the master production mould. I have boxes of my canopies some 30 years old and they are as clear as water. Mike made his own canopies for the Prentice. There is just no clear reason for canopy deterioration and it's nothing to do with UV. I suspect it's a Cloride reaction. I have had very few canopies ever go brown despite age. One thing is for certain is that the packaging materials used were only meant for a short shelf life and aircraft modellers are keeping them for much longer than ever the plastic chemist envisaged.

John

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