1/18 scale Tervamaki Engineering JT-9T autogyro

Back to the bench wrote:

Nick, you have to be one of the most creative modelers I have seen. Your use of every day materials in new and unique ways is really inspiring! Amazing photography on the builds as well. As I have mentioned in other posts I know I may never reach the skill level of builders like you, but your work inspires me try new techniques and look at new sources for modeling materials.

Back to the bench wrote:

Of course my wife and daughter may start looking at me like I am a bit strange when I go "dumpster diving" and come up excited with some scrap wire and other treasures

Using my X-acto knife, I removed the formed fuselage from the styrene sheet and test fitting on the autogyro scale model airframe. Few drops of cyanoacrylate glue applied on the right spots across the fuselage joints to make the contact secure, did some light sanding on the fresh produced thin-skinned right side fuselage to eliminate some tiny marks and as you can see at the following pictures, the nearly transparent result is more than realistic to scale and completely satisfies to me.

Do you remember the wooden picture frames I found at the local IKEA store for only 1€ each, securing the styrene plastic sheet to be vacuum formed? I kept these thin plexiglass plates, to use them as required. Continuing the cockpit construction, I had to build the rear cockpit cover, so I placed the autogyro model upside down facing a glass surface, I boxed it by placing the thin plexiglass plates around it, securing in place with modeling clay for kids. Then, I removed the scale model carefully, leaving space between these thin plexiglass plates. Wet white plaster mixture, applied into the gap, between the thin plexiglass plates to fill the area. When the first layer of thinned plaster was dry and hard enough, two or three extra layers of white plaster followed to finally build the basic cast. Keep in mind that adding salt into wet plaster mixture, reduce the plaster's hardening time and adding vinegar into wet plaster mixture, extend the plaster's hardening time.

When the plaster cast was dry and hardened after few hours, I removed the modeling clay for kids and the thin plexiglass plates. The white plaster cast got shaped into proper dimensions but cutting it with saw, filling with tiny quantities of modeling putty added to close minor scratches and pores on white plaster cast surface, dry sanded and finally sprayed overall with gloss shiny coat.

Because I was planning to use smaller wooden frame to secure the styrene plastic sheet (the piece to be vacuum formed is too small, there is no need to spend big plastic card), I had to close the outer holes on the hardboard high-density fibreboard plate. To do so, I cut a plastic bag in shape and covered as required the desired area. I pined a styrene plastic sheet on the wooden frame, insert it into the preheated electric oven as described before and as soon as I noticed that the plastic started drooping down, I removed it on the vacuum former plate, while the vacuum cleaner was already plugged & switched on. The plastic nicely formed around the plaster cast and here is how it looks like.













As long as the piece looked satisfying to me, I removed the formed plastic from the styrene sheet with a new Nr 11 surgical blade on my cutter, test fitting on the scale model and later start adding internal detail.

I was wasting my time LOL showing the missus your fantastic post and guess what she said....'Hey, hes got a local Ikea'...Geez, Women eh?

Great work Nick. Really coming together.

...Guy

Wow!!! what a gret project!!! I love to see this rare birdes... thanks for sharing your techniques and tips, very useful!

best regards

Jeremias

I placed the rear cockpit’s cover in place and secure it with just one or two drops of cyanoacrylate super glue. Then, using a small pencil, I defined the exact line that the rear cockpit cover should be cut in order to let the inside structure visible. Using the mini Dremel tool, I cut and removed the left half part, in a way to look kind artistic.

My good friend Demitris “Jagdpanther” Pravinos, who is a WWII German tanks specialist scale modeler, sent me about five hundred (!!!) cups he found and looked ideal to use them for mixing colours, modeling putty etc. Few drops of nitrocellulose lacquer thinner and just a little amount of Humbrol modeling putty, were more than enough to prepare a nice liquid mixture to apply on the rear cockpit cover surface, to ensure that little tiny scratches would disappear.

Few hours later, soft sanding and a quick airbrushing with white color to make mistakes, scratches etc become easy to spot, the rear cockpit cover was finally ready.

CHAPTER VII - Canopy construction

The Jukka Tervamäki Engineering JT-9T autogyro canopy is made by bented and cold-formed 3mm polycarbonate sheet. The backwards sliding canopy of the single seat JT-9 version, offers the possibility to taxi and fly slowly with the canopy open, a benefit in a hot climate. The trainer / tandem seating JT-9T, has a side opening one piece canopy. Of course, canopy modifications can be done, according the autogyro owner's personal needs or desires.

I used styrene plastic card to form it as shown into following pictures to give the basic shape of the canopy. Then, a layer of polyester filler applied on the styrene. The specific polyester filler I used, comes with the proper catalyst which provides a solid rock build and approximately 3 to 5 minutes time window to form it into shape. I prefer to use epoxy putty or polyester filler with fiberglass grains for special purposes, because:

• It becomes solid rock within only few minutes or seconds,
• it does not shrink and does not crack after months or years,
• you can pour to any shape that you want but you need to work fast because as soon as you mix it with catalyst cream approx 5%, you have limited time before becoming solid rock,
• you can also put additional layers of epoxy or polyester filler to build up,
• you can sand it, you can drill it, you can use any type of scale modeling glue, any type of primer or enamel / acrylic paint on it with no problem,
• can be purchased at any good crafts store into 250ml, 500ml, 1lt (comes with a tube of catalyst hardener) or bigger canisters and if you can't find it, fear not and try your local decent hardware store and finally...
• it is cheaper than dirt - estimated prices are £3 to £10 depending the canister size, the quality, if contains fiberglass grains for maximum strenght etc.

Keep in mind that the chemical reaction after mixing the polyester filler with the catalyst hardener, produces some heat that possibly effect on thin plastic parts, so test it first before try it on your scale model. I don’t think that the produced heat is more than Fahrenheit 110, but better watchout. Remember that epoxy materials are dangerous when breath or shallow and could result skin, eyes or lungs problems or even cancer when used for long period with no precaution measures. Always keep in mind, that a powerful vacuum system to suck away the epoxy dust should be used all time to keep the workbench area clean while sanding or milling epoxy or resin materials. Using an issued breathing mask and a pair of surgery latex gloves to prevent dust contact with lungs and fingers while sanding or milling epoxy, is also an important matter that you should seriously take care of! My recommendation is to also wear an overall working suit (as I do) to keep your clothes dust free while sanding epoxy. Some people might find it too much, but I wouldn't like to bring epoxy dust & grains from my work bench into living room and my beloved.

When the basic canopy shape made by styrene sheet, was fully covered by a a thin layer of polyester filler and had enough time to polymerize and get solid rock, I sand it with wet sandpaper to make the cast curved and shiny. To produce a thin-skinned canopy, the polyester part should be vacuum formed. As described into previous chapters, a transparent plastic sheet were pined on a wooden frame, preheated into electric oven and as soon as I noticed that it started drooping down, I vacuum formed it. The clear plastic nicely formed around the canopy cast following the curves & details as planed. Using an X-acto, I removed the formed canopy buble from the transparent sheet and start adding details, such as canopy's frame. Few drops of cyanoacrylate glue applied on the right spots with great caution. Remember that CA glue does fog the transparent parts and this canopy would not be an exception - that's why I placed some very tiny drops of it, just on few spots.

Nick, This build is just amazing. It makes me feel gutted to see so few responses to such stunning work. I feel like i should wear a advertising board say 'Everyone look at this build!'

Really looking forward to the next installment.

...Guy

You Greeks never do anything small, do you?

    Seriously though, fantastic work.  Simply amazing.

That does it.  I'm throwing all my kits away and becoming a monk....

Absolutely fabulous work, Nick.

Gip

Wow... where do I start? This whole build is just amazing.

Kevin

It’s sad! Obviously, voodoo curses came from the unspeakable dirty Viper snake, got real and the final varnish finishes on the model suffered what the Americans call as FUBAR - F@cked Up Beyond All Recognition.



In brief words, the color layers popped and “cracked” everywhere on the model’s surface, just before the final touch. For some mysterious reason, the color looked peeled off and an unexpected chipping (I would never succeed this by purpose) appeared! The scale modeling accidents committee is expected to investigate the possible reasons within following days, but unconfirmed sources report "pilot’s error" - OK, I made a rookie’s mistake, while using old colors or coat varnish.

Meanwhile, the following actions took place:

• Garlic cloves were hanged across the workbench to keep away evil curses, vampires and “snakes” (or those who claim themselves as “snakes”),
• The scale model were covered with a thick layer of ModelStrip product, locked tightly in a plastic bag and left overnight to let the chemical work.

CHAPTER VIII - Live After Death

When I started building the model, I did not expect to present the CHAPTER VIII under this title. Bus as all the sad & bad situations in life, it was unexpected and accompanied by great frustration because suddenly I saw months effort to dissolve in only few minutes. The old colours (or bad white spirit solvent) that I used, have led to drying crack. Unfortunately, I ignored all the warning signs such as thick grains left by the white colour in which I primed the scale model before the final painting. Having as target to make this model alive again, just like Iron Maiden Eddie’s Live After Death, I decided to try a full reset – after all, I had nothing to lose! The scale model was already FUBAR.



The following photos show the unsuccessful paint process. The problems appeared marked inside the red circles. Unfortunately, I have no photos of the model while looked completely written-off, because at that time I was not in a mood to take pictures!

ModelStrip, was the first thing came up as the most conventional solution to try paint removing. Following the instructions on the box, a generous stuff applied on the model, wrap it with airtight plastic bag to prevent drying and wait about 15 hours to let the chemical work. Opening the bag next day and checking the results, the colour (or rather the colour layers) were soft and could be removed by rubbing vigorously with an old toothbrush. Unfortunately, using the brush on some very delicate spots (even with careful use), had as result to break / or ruin a couple of plastic pieces. Moreover, the paint could not be removed through narrow points and difficult locations.



At this point and while I’ve already used all the ModelStrip material without being satisfied with the outcome, I decide to change tactics to something more unconventional, such as oven cleaner.



Following the product’s directions as always, I sprayed the model with the material, wrap it with airtight plastic bag to prevent drying and wait about 15 hours to let the chemical work. Testing results next day, the oven cleaner failed no more than ModelStrip. I noticed that the colour could be removed but only when pressure and persistent rubbing with brush and that was prohibitive for some parts of the model. Not having another solution, I approached the most unconventional method and visit a science specialist - my local grocery store!

- Hey man! I need something really strong to clean up kitchen’s oven?
- Really strong? Use this!

…and he gives me a dust covered 1lt plastic bottle found in an almost unreachable shelf. Reading the bottle’s label, I found out that it contains sodium hydroxide also known as lye (corrosive alkaline substance) or caustic soda and is a caustic metallic base. It is used in many industries, mostly as a strong chemical base with chemical type NaOH.





- Are you sure that this will work? Are you sure that this is safe to use?
- Trust me. It’s gonna clean up the kitchen’s oven like a nuclear bomb!
- How much?
- 3.50 € . Take it or leave it.

Thinking about a possible failure, I filled a plastic bowl with the milky liquid contained in the bottle and threw all the model pieces inside. As long as the autogyro model was already FUBAR, I had nothing to loose to try. I sealed the bowl with a cover and leave the sodium hydroxide to act for 20-30 minutes while the instructions sets out to wipe the sodium hydroxide chemical liquid after 10 minutes. Opening the plastic bowl’s cover, a nice surprise followed...















The truth is I was delighted! Styrene pieces simply and magically totally striped off the enamel colour layers! Absolutely success, without even apply brush cleaning! Amazing product - incredible grocer! Just because I couldn’t believe it and I wanted to make sure that the colour striped off because of the sodium hydroxide chemical (and not the previous used ModelStrip product or the kitchen oven cleaner), I decide to experiment. I threw in a bowl, already filled with the chemical, a 1/18 scale female figure that I was about to convert for a future project. The specific 1/18 scale female figure, is made by Fast Women brand and can be found by clicking HERE). The results after just 15 minutes in the sodium hydroxide chemical - Perfect! The following pictures, show the "before" and the "after".









Keep in mind that the sodium hydroxide is (and thus should be considered) a strong caustic base. This means that:

• Throughout the impregnation of the model parts into sodium hydroxide, you should take all the necessary protective measures (like mentioned in the warnings on the bottle’s label) and is certainly to use disposable surgical gloves made by latex and breathing mask with appropriate filters to protect against possible fumes.
• The colour stripped plastic parts must be rinsed with soft acid to neutralize the caustic base and produce salt and water. Dunking the colour striped parts in plastic container filled with cooking vinegar and then rinsing with plenty of lukewarm water, plastic is now safe to handle with bare hands.

Under the above "adventure" circumstances and considering that all these years dealing with the scale modeling I've tried many color striping methods (including ModelStrip, kitchen oven cleaners, blue alcohol, brake fluid, nitro laquer disolvent, etc), I think that sodium hydroxide NaOH is the best method so far, for the following reasons:

• Kitchen oven cleaners in spray canisters, can do the job, but they cost 3 - 4 € for a 300ml product in which also includes the propellant gas. On the other hand, the NaOH in liquid form is a pure substance, much less price, taking for 1lt bottle, which equals 3.3+ times more product! Using the liquid form NaOH (which you can fill a plastic bowl), you can sink several plastic pieces, same time!
• The brake fluid may be effective and remove paint, but it is not plastic friendly plastic and is likely to convert the scale model into a blob of molten plastic. It is clearly more expensive and as far it is highly toxic, flammable and hardly to manege, I will not recommended it for scale modeling use.
• Nitric acid laquer disolvent, could be a nice solution for metal figures paint striping, but it is not the best for the plastic. Just like the brake fluid, it does melt and damage plastic parts.

Hey Nick!

Ain't that a shame when it happens... But, as they say, as long as you're fightnig, you're a winner... I had my adventures with paint stripping recently and I used brake fluid for it. It isn't as powerful as NaOH, but gives good results too. With brake fluid cleaning delicate assemblies isn't so easy too, but you can strip clear and metal parts, which you reportedly cannot with NaOH.

Nice model for the second experiment, by the way. I hope the watchers ain't gonna get you for this - after all you removed underwear from a girl's model . Good luck with the autogyro, and have a nice day

Pawel

Sorry to see and hear about your paint issues. Being someone who restores cars and military equipment for a living, I can certainly feel your pain. From what I can see, it looks like you had one of two issues. The most likely answer is that one of the layers (primer, color coat, or sealer/clear coat) was old product, and had already begun to break down before using it. Another possibility is contaminants on the surface before you painted.

What did you use to prepare the surface before painting? And what kind of paint did you use?

You might want to look into an automotive surface preperation for future use. Simply Known as "DX" here in the States. It is made by PPG paints. It removes all grease, dirt, waxes, and contaminants on the painting surface before you shoot color. You also might want to pick up a tack cloth. They are excellent for getting even the tiniest speck ofdust from the surface, and remove any static buildup before painting.

Just a suggestion. Fantastic build, by the way. I am loving it.

Pawel wrote:

I had my adventures with paint stripping recently and I used brake fluid for it. It isn't as powerful as NaOH, but gives good results too. With brake fluid cleaning delicate assemblies isn't so easy too, but you can strip clear and metal parts, which you reportedly cannot with NaOH.

• It is cheap with only 3.50 € per litre,
• It is plastic friendly and does not damage or effect modeling putty inserts,
• It is easy to use, because you only need to simk the model into a bowl filled with NaOH and wait 20 to 40 minutes until it is copletely color free without even try brushing.

666Irish wrote:

What did you use to prepare the surface before painting? And what kind of paint did you use?

CHAPTER IX - Applying paint, wash & weather effects

Model parts were washed with liquid soap and warm water to disappear leaving oil traces, fingertips etc and then sprayed with light grey primer.