SE5a CONSTRUCTION BEGINNING TO . . .

[Greyhead]

The full size exhausts are in 3 sections, the front, which consists of the exhaust stubs and collector, the middle section is a straight pipe and then the rear section. I’ve left the model exhausts in 2 sections, at least for now as I work on the brackets.





A coat of silver Solarlac shows up any areas that need more filling, especially where the litho plate joins the rolled paper tube. It may seem strange to go to all this trouble to get a good finish when we want to end up with a pitted “rusty” finish but it is a lot easier to get the right effect starting from a consistent surface.

[Guest]

Terrific workmanship on the tails of those exhaust pipes, they should look the business when painted up. They are a really distinctive part of the SE5A too.

[dynamite25]

Don't why i have never looked at this thread of yours Greyhead but i have just gone from the beginning to the end and i must say this is one of the best stretch built models i have ever seen,so keep up the super work Greyhead and i am looking forward to seeing the finished plane in all it's Glory.

[Greyhead]

The front exhaust brackets are very substantial units, but then they need to be, there’s a good length of exhaust pipe to support on the SE5a. I soldered them up from brass tube, squeezed in the vice to make it streamlined section, and brass sheet.





When the bracket is fitted permanently the bolts will protrude from the fuselage so that the nuts are on the outside and obviously the pinch bolt will be cut down to size.





My idea at the moment is for the exhaust complete with brackets to be attached to the engine, which is attached to the lower cowl sides, thereby making the whole unit removable. The rear brackets are a bit of a problem because they aren’t bolted on from the outside, they will have to be made as 2 parts, the arms, attached permanently to the fuselage will plug into the exhaust pipe, I hope!

[Greyhead]

The next job on the exhaust pipes is to give them an all over covering with a mixture of epoxy and micro balloons; this gives a rough pitted surface ready for painting. The layer of epoxy / micro balloons only needs to be very thin, I find it’s best to spread it with my finger, messy but effective.


When the epoxy has cured, it takes quite a while being such a thin layer, paint all over matt black. This isn’t the final colour, it’s just to make the “rust” less uniform and it also needs to be applied very sparingly, we don’t want any of the pits filled in.


A photo showing one exhaust matt black the other with its coat of “rust”, which is far more varied in colour than is evident from the photo.





On exhausts that are more than just stubs the rust usually follows a distinctive pattern so the rust is painted to reflect this, there is very little rusting in front of the exhaust stubs.

[Guest]

How do you create the rust effect on the exhaust pipes? I noticed the effect on the parnel elf was really convincing, is it just stippled on paints or do you use a rust powder of some kind?

All those details are really bringing the model to life.

[Greyhead]

Alan


The “rusty pitted” surface is created by the 5 minute epoxy / micro balloon mixture. It’s spread thinly over the entire surface, where more pitting is required leave a slightly thicker layer and keep dabbing it as it cures, I use my finger for this but that’s probably not to be recommended!


Grahame


To finish the effect use matt black, rust (Humbrol 113) and mixtures of both and dry brush until you’re happy with the result.





I find the best brush to use for this is one with short, fairly stiff hairs and to use progressively drier coats. By finishing off with a virtually completely dry brush the matt black develops a slight sheen so characteristic of exhausts.

[Greyhead]

When it came to actually making the rear brackets I decided against my original idea and made the strap hinged; I used a thin mylar strip epoxied to the inside of the strap. The brackets are attached to the fuselage by a 14BA bolt through the top flange; I don’t want to drill the longerons so the bottom flange is just held with epoxy, which will be further strengthened by covering with frayed tape.





The pinch bolt would have held the bracket together on its own but the mylar is a bit of “belt and braces” and it will also make sure that there’s no “metal to metal” contact between the bracket and the litho plate end of the exhaust pipe.

[Greyhead]

I’ve never been entirely satisfied with the original radiator grill and have been looking around for an alternative; unfortunately I’ve not found any cheap DIY type material so have had to resort to buying some etched brass.

The result is a lot more realistic, it’s not true hexagon but it is about the correct size and being so small it certainly looks right. From the right-hand picture you can judge just how small the holes are.

[ATTACH]105998.IPB[/ATTACH]


I bought the brass from EMA Model Supplies:

http://www.ema-models.co.uk/

[Guest]

Will your SE5a have those louvred slats over the radiator grills ? Those would look great in litho plate!

I've seen some models where they open and close according to throttle position too.

[Greyhead]

It’ll certainly have the radiator slats and they’ll certainly be open, no point spending all that money on etched brass and then covering it up!

Making them move would be too complex / unreliable at this scale, at least it would for me.

[Greyhead]

The tank cover side extensions are quite a complicated shape so it makes sense to use a template for cutting the litho plate but taking measurements from the model can be awkward, there always seems to be something that stops you getting the rule in the place you want!


A template is drawn as accurately as possible then scanned into the computer and several copies printed out. Cut one out first and check the fit; if it ‘s OK first time all well and good but most likely you’ll have to adjust the other templates as required, this one needed the front “tab” moving slightly forwards.





Selotape the template to the litho plate and cut out, it cuts easily with a scalpel but the blade won’t be much good for cutting balsa afterwards.


The false hinges are made as described in an earlier post.





Once glued in position the hinges show up very well and really add to the “realism factor”.

[Greyhead]

Now I’ve got the job of making 60 radiator slats!

First I made one to check the principle but measuring, cutting and bending another 59 as individual items is not really an option because the chances are that there would be noticeable variations so I’ve made a jig. It’s simply a piece of 1mm brass bent to shape with some 0.5mm steel soldered to it to produce a slot 1.5mm deep and twice the thickness of litho plate wide.

[ATTACH]105837.IPB[/ATTACH]


The litho plate was cut into 26mm wide strips, the end folded back onto its self then placed in the jig and one flap folded down forming one half of the slat.

[ATTACH]105838.IPB[/ATTACH]


The slat was cut from the strip and the process repeated until I got bored, which was after about 20, I then cut the pins to length and “tacked” them in position with a drop of cyano. The flaps were given a thin coat of epoxy, the whole lot put back into the jig and the litho plate bent around the pin.

[ATTACH]105839.IPB[/ATTACH]


Once all the slats are at this stage I will modify the jig to enable the other half of the slat to be cut consistently at 1.5mm.

EDIT: This method of producing the radiator slats has proved to be unsatisfactory; see this post.

[wonwinglo]

A typical scale models test of patience Grahame,these mundane tasks sometimes just have to be done,I just know that you will get there in the end.

[Guest]

I know the feeling with making the repetitive parts, not so much fun but well worth the end result.

I did a similar thing with My HMS Active that I built. The four Exocet containers all had ribs on them. I did the ribs on all 4 containers. 144 ribs in total...not much fun at all, but they certainly look the part now.

Keep the good work coming Grahame, I am really loving seeing it come together now.

Regards......Mark.