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Chris McG F-86 Sabre Dog build blog

my first attempt to a soaring bird for the PSSA MB 2020?

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Eric Robson21/11/2020 21:12:09
568 forum posts
129 photos

Hi Chris, I should have realised you were not gluing to a surface therefore thin card may have been a better choice. The important thing with card is the grain , curve it one way and its fine the other way it creases and looks awful. I use card to make the wing fillets on some of my electric models as there is no problems with fuel contamination. I drew this Magister up and built it about 15 yrs. ago the fillets were made from cereal packets and they are still good just one former at the rear.

In the 1970's and 80's IC. engines with rear exhausts and tuned pipes were popular Ideal for the dog as the exhaust could go through the fuselage and not stick out the side which spoils most scale planes with IC engines.

Cheers Eric.Magister

McG 696922/11/2020 19:59:43
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3529 forum posts
1338 photos

Hi Eric,

The brown paper I used was in fact about twice as thick as the normal packaging one.

But even with the second layer, it didn't want to do the job. sad

I thought about using thicker cardboard as a test now. A bit weird that you mention 'cereal packets' as it is exactly the kind of stuff I had in mind for the following try. smiley I'll keep in mind your tip regarding the grain direction.

Test results coming soon, I guess.

Cheers & stay alert

Chris

McG 696923/11/2020 20:07:46
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3529 forum posts
1338 photos

Hi again,

Just a couple of short sessions lately, but I thought it would bring a bit of ‘colour’ in La Grotte. smiley

1695_ailerons_painting_900.jpg

The ailerons received their vermillion red paint and are finalized now on both sides.

The elevators had their first coat of yellow.

The bottom side is going to receive some red and black to become the Belgian tricolour and will be full vermillion at the top. If you remember the Hunters of the Red Devils, this deco will in some aspects be quite in the same line.

1700_elevators_painting_900.jpg

Happy with the small progress as it gives a motivation boost as well… cool

Hakuna matata & stay safe

Chris

BRU - BE / CTR Colour Control

Phil Cooke23/11/2020 20:25:49
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2727 forum posts
1915 photos

Hey looking good! Lovely to get some colour on it!! Great stuff!

McG 696924/11/2020 18:13:37
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3529 forum posts
1338 photos

Thank you for jumping in and for your kind comment, Phil.

Due to the recent re-confinement, the shorter wet and windy days, I'm struggling a bit with my motivation and the progress of the bigger items... blush

I thought concentrating on the smaller bits would assist me with having some progress anyhow.

How about you? Is your fuse fully sanded now? Glassed? Sauced? Primed? Painted?

Let us know, please... wink

Cheers & stay careful, young man

Chris

Martian24/11/2020 18:43:43
2700 forum posts
1270 photos

Heading for a beautiful finish and love the colours

McG 696925/11/2020 11:23:00
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3529 forum posts
1338 photos

Hey Martian,

Thanks for your kind post.

I must admit that I like those colours as well. Quite chuffed with the 'warm' vermillion red and the 'sparkling' yellow. cool

I think the Belgian tricolour at the bottom of the flying surfaces will give the Dog a high vis pattern as well.

Many moons ago, when I was designing the deco schemes for race cars, I managed to use yellow a lot. Up to the point that customers joked about the fact that I probably had bought the entire Belgian stock of Traffic Yellow paint or vinyl... angel wink

chris franco r8 audi.jpg

Cheers & keep careful

Chris

McG 696926/11/2020 20:20:18
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3529 forum posts
1338 photos

Hi to all,

I first thought I wouldn’t post these pics as they are quite a bit ‘didactical’ and really not ‘esthetical’, but then if it helps just one forumite, it was worth it. cool

As you all know by now, the golden rule of glassing is to have the same weight of resin to saturate the wave of the glass cloth used. So, 25g/m² cloth means 25g of resin for the same m².

That’s fine but fairly theoretical being close to impossible to achieve. I’m afraid we (modellers) are never reaching that goal even with appropriate vacuum bagging technology and equipment.

In fact, prepreg composites and oven curing is the only answer here…

What I really don’t understand is applying a second coat of resin to fill the cloth wave. Of course, it’s very tempting and… easy. But it is bringing no extra strength at all to the lamination at the expense of a lot of extra weight. surprise

Hence my choice of only a single lamination coat and the use of… Freddy B’s Sauce to fil the glass coat wave.

1701_wingsauce_sanding02_900.jpg

I use the Sauce quite diluted for the first coat followed by a light sanding when dry (150 to 240, then 400 grit for the final second or third layer when all ‘pin holes’ are covered).

As the pics are showing, the first coat isn’t enough to fill the wave all over but it allows me to see where it needs some more.

(to be continued)

McG 696926/11/2020 20:22:27
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3529 forum posts
1338 photos

(continued)

The following close-up is really awful as it shows all the imperfections that would mostly be filled with ‘heavy’ resin if a second float resin coat is used. A second coat of Sauce is on the order here, possibly followed by a third one if needed.

1704_wingsauce_sanding01_900.jpg

The Sauce is really easy to sand and btw… sanding remains a modellers’ dream anyway… wink

Note > the above pics were greyscaled to allow a better clarity/contrast.

… but apologies for being mega-boring here…

Takuna matata & stay careful all

Chris

BRU - BE / CTR Esthetics Control

McG 696928/11/2020 20:12:11
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3529 forum posts
1338 photos

Hello all,

A few productive sessions at La Grotte went well, but not much to show really.

Another sanding duty to the wing’s Sauce, some prep work - read fine primer sanding again - to get some more Belgian colours on the elevators and some diluted PVA applied to have another go at the fin fairing.

1712_cardboard_channel_900.jpg

I used bits of a cereal box, curved over a length of PVC tubing with the correct diameter while drying, but as they are too short for the fairing, I added a small tongue to easily add a small second part at each side of the fin. No probs as they will be glassed anyway.

That is of course if the fairing test works out properly this time… angel

Thanks again to Eric R for the welcomed tips… yes

Hakuna matata & stay careful all

Chris

BRU - BE / CTR Fairing Tips Control

Eric Robson29/11/2020 10:14:10
568 forum posts
129 photos

Hi Chris, I hope it works out for you this time. Recently I have been having Tesco Malted wheats for breakfast and took one of the boxes to make the fillets for the Seafury I am building. after checking the grain direction I found the ply of the card separating, they seem to have a coating inside probably for hygene on recycled card. fortunately I had some good quality card which has done the job. Down side was I had to make them in separate pieces as I could only get the curve on the short length of the A4 card.

McG 696929/11/2020 18:49:01
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3529 forum posts
1338 photos

Hi and thanks, Eric.

I can only hope it will work out this time, but it seems OK so far.

My cereal box was of correct quality but I had to make it 'longer' as well as the right 'curling' dimension was the width of the box, hence the tongue I prepared. Fingers crossed, then... indecision

It seems that we are both slowly becoming cardboard 'gurus'... wink

Cheers & enjoy your cardboard safely

Chris

Dwain Dibley.30/11/2020 17:09:50
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1715 forum posts
1673 photos

I have used paper and card on smaller indoor models, so no reason why this should not work on a bigger scale with fatter card.

Looking forward to the results.

D.D.

McG 696930/11/2020 20:09:06
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3529 forum posts
1338 photos

Thanks for commenting, Dwain. yes

The cereal cardboard is quite thick and seems to be OK, so far.

Now I have to glue that fin in before I can progress with the fairings.

I just decided to have a small detail added to the fin before that gluing episode... surprise

Stay tuned, gents.

Cheers & keep it safe

Chris

McG 696902/12/2020 18:59:43
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3529 forum posts
1338 photos

Hi to all,

Many moons ago, when I saw Dirk and Phil cutting out their ‘dummy’ rudder to give it a more scale appearance, I decided to have a go as well.

With hindsight, I was a bit concerned about it as the Dog’s fin is 40mm taller and the rudder quite ‘narrower’. Would it still be strong enough? indecision

Still very envious of their move and having glassed the fin/rudder, I recently decided I could have an ‘in between’ by scoring the rudder instead of removing it completely.

1715_rudder_engraving_900.jpg

After a lot of precautions regarding the scale measurements, I patiently scored the glass and balsa to obtain the rudder’s shape. cool

The width of the groove is 1,5mm with the same depth, but the balsa in the channel will receive a thin coat of finishing resin with a small artist brush to get some strength back.

As this is a large feature of the Dog, I can only hope it will be more ‘scalish’ than just marker pen panel lines.

Onwards to the other side now… angel

Hakuna matata & stay prudent, gents

Chris

BRU - BE / CTR Groove Control

Phil Cooke02/12/2020 20:03:30
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2727 forum posts
1915 photos

Looking good Chris, I've not seen that scoring approach before - what did you use to generate a channel of that sort of width and depth? Did it not 'chew up' the balsa surface once you had broken the glass and resin surface?

McG 696903/12/2020 19:00:01
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3529 forum posts
1338 photos

Thanks for visiting, Phil.

TBH, I’ve never heard of that scoring method either. I only tried it as I thought it could work once the fin was glassed. If not, I could always fill up the groove again.

I started to score the rudder pencil drawing with a scalpel and ruler.

Then I used some cheap needle files from AliExpress (10pcs/different shapes/€2,8). yes

1719_needle_files.jpg

I started with one of the ‘pointed’ ones to further score the glass fiber down to the balsa.

Then I used the ‘square’ one (at the right of the pic) vertically to make the channel.

In fact, I don’t use them as a file, but only use them in one direction starting ‘scraping’ from the corner of a cut. This avoids the ‘chew up’ that you mentioned, I guess.

No magic tricks, it’s really easy to do, but it takes some patience and isn’t a fast job really. cool

The specs of the needle files read > steel, glass, stone… but I only use them with hardwood, ply or balsa to avoid ruining my investment right away… angel

Hakuna matata & stay careful all

Chris

BRU - BE / CTR Needle Files Control

Dwain Dibley.04/12/2020 10:52:48
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1715 forum posts
1673 photos

I have a set of those Chris, probably the cheapest and most useful item in my workshop Matey.

D.D.

McG 696904/12/2020 17:50:03
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3529 forum posts
1338 photos

Thanks, young man.

I can totally agree regarding the needle files, Dwain.

Probably the cheapest set of tools in La Grotte and I use them constantly when assembling/adjusting small bits.

Not a huge progress today as we decided to have some shopping to avoid the queues related to the WE.

Iris is now the proud owner of a big cyclonic vacuum cleaner nicknamed Olli, thanks to its long nose and fat body... My preferred choice was Mike, thinking that it was quite appropriate for a Dyson, but of course she remains the boss...

I still managed to have the elevators painted both sides and the fin glued to the fuse ready to start the battle with the fairings.

Cheers & keep safe all

Chris

McG 696907/12/2020 19:37:50
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3529 forum posts
1338 photos

Hello again,

I’m afraid I’ve been terribly lazy at building last WE, mainly due to the Sakhir GP, but also due to some basic household duties. I’ll just have to forgive ‘her’… angel

A bit of work painting the final red on the underside of the elevators and sanding down the build-up primer layers on the radome nose.

I’ll leave the masking tape on till tomorrow as it was far from the ideal temp outside La Grotte for painting…

1718_elevators_red_900.jpg

I'll really have to find a solution now to handle the sanding and certainly the painting of the wing and fuse... it's getting close to impossible to do it outdoors.

More to come soon…

Hakuna matata & stay careful all

Chris

BRU - BE / CTR Temp Control

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