Piper Cherokee 140 conversion from an Airfix Piper Arrow - Detailing

[Cheshiretaurus]

Talk about raising the bar!

That Chippy of yours certainly did that!

[kev67]

Perdu, Kev thanks for the comments

The PE is done with stuff available on ebay.

Artwork is printed on inkjet OHP film, Dry film etch resist is applied with a laminator & exposed between 2 sheets of tesco 50p photo frame glass clamped together, using a UV lamp intended for curing gel nail varnish, then developed with sodium hydroxide (caustic soda), etching is done with sodium persulphate. resist is then remove by soaking in acetone. To get where I have has been the result of many attempts that failed at various stages. But I think I now have a winning formula of techniques, timings and solution strengths etc. So when I can I'll get some pictures together and write a post for it.

Mark

Also if you could please put some links to where you found some of the stuff to do photo etch

[Cheshiretaurus]

No prob

to get things started

Brass http://www.ebay.co.uk/itm/Albion-Alloys-BRASS-SHEET-0-12mm-x-100mm-x-250MM-SM1-/400241801136?pt=UK_Toys_Wargames_RL&hash=item5d304537b0

Dry film http://www.ebay.co.uk/itm/10x-A5-Negative-Dry-Film-Photoresist-Sheets-for-DIY-PCB-Circuit-Prototype-/140969962092?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item20d276ea6c

OHP film http://www.ebay.co.uk/itm/5-sheets-A4-Inkjet-Acetate-Transparencies-OHP-Film-/190709671370?pt=UK_Computing_Printer_Paper_Accessories_ET&hash=item2c672ea5ca

UV Light

http://www.ebay.co.uk/itm/36-Watt-UV-Gel-Nail-Lamp-Light-Shellac-Gelish-Timer-36W-/350843766315?pt=UK_Health_Beauty_Nails_Manicure_Pedicure_CA&hash=item51afeb062b

Sodium hydroxide, caustic soda cleaning product section of ASDA Tesco etc

Etchant

Couldnt find the Sodium persulphate I used doesnt seem to be listed, this should do instead though!, http://www.ebay.co.uk/itm/500gm-Potassum-Persulphate-99-PCB-etch-etchant-/161014734561?pt=UK_BOI_Medical_Lab_Equipment_Lab_Supplies_ET&hash=item257d39dee1 Ferric chloride should also do the trick but is very messy.

[woody37]

I keep learning

[Cheshiretaurus]

Back from work a day earlier than expected....Sometimes patience isn't a virtue, I'll call it a practice. 1st cast, logo is actually dry brushed with silver bit more practice & cleaning up will be required. Just a very rough draft. Hope I dont do the real one this badly.

[noelh]

Fascinating, inspiring. I was technically a part owner of a Cherokee 140 at one stage but never got to fly it for one reason or another. But I did fly the PA-28R, retractable version of the Cherokee Arrow. This article has got me thinking. I think I have an Airfix Cherokee in my stash somewhere. Dangerous thoughts!

One aircraft I'd love to see modelled is the Gippsland GA8 Airvan. I doubt that will ever happen unless I scratchbuild. I've nearly a thousand hours in the things. Just my luck to fly something obscure.

Now where's that Cherokee?

[wellsprop]

I love this! Im learning on Pa-28 warriors and theres a lack of representation of the Piper and Cessna airframes :/

Ben.

[Cheshiretaurus]

How to make PE is in modelling tips chaps.

http://www.britmodeller.com/forums/index.php?/topic/234944044-making-photo-etched-parts-at-home/

[Cheshiretaurus]

One aircraft I'd love to see modelled is the Gippsland GA8 Airvan. I doubt that will ever happen unless I scratchbuild. I've nearly a thousand hours in the things. Just my luck to fly something obscure.

The Airvan looks a simple shape to scratch build might be worth a go.

1000 hours, was you meat bombing in it?

[Cheshiretaurus]

Bit more progress :- Have used the templates to re-shape the windows

As you can see some areas need more plastic behind them in the frames and some filing away of other bits plastic. the areas that need building up were lined with plastic strip and left overnight.

The templates refitted and then I set to work with the needle files. The pillar between the left windows is a 1x1mm strip. I intend to fill the side windows with clear resin later. I've ditched the plan to embed a PE frame of the DV window in the resin in favour of scribing the DV window on the resin once its hardened. I included cut out on the bottom of the left template for this.

Hopefully they should look ok on the finished model from the masking tape defining the shape of the window. The pillers on the right on the PA28 are wider as they have to accommodate the door frame, Have designed a scribing template for etching to do the door next and the rest of the panel lines to scrible back in

I've shown the original Airfix parts for comparison of the different windows between the Arrow and the Cherokee.

Edited August 9, 2013 by Cheshiretaurus

[milktrip]

Really enjoying this and thanks for posting the home made PE demonstration.

[Cheshiretaurus]

Really enjoying this and thanks for posting the home made PE demonstration.

Very welcome milktrip, found it very useful for making custom tools & templates as well as parts. Hoping to see some others make some home brew PE on here soon.

[Cheshiretaurus]

Bit of progress over the weekend, I'm making RTV moulds to make a resin copy of the masters for vacuforming the windscreen and spats the intention is make female mould for them so going to cast copies of the masters to prevent trashing the real master in the process. The RTV has been setting for nearly 48 hours and is still not fully set, I'm suspecting I didn't put enough catalyst in as I forgot to tare the scale before pouring the RTV into the mixing beaker and had to guess. Anyone know the specific gravity of RTV? Hopefully it should eventually set but It was still tacky when I left for work at 4AM this morning.

Ive made a decal sheet for the instrument panel from clear stock to go on the reverse of the panel so have printed it mirror image

I've also had a few trial runs on making the resin filled side windows on the fuselage of another arrow kit, I taped a piece of this acetate to the outside and filled from the inside, few for practice sessions to go I think

Wings are nearly done, spent Sunday scribing them filling sanding re-scribing. was getting very deep and wide rough scribe lines on areas that had filler e.g. undercarriage bays so those lines were filled back with thin CA and re-scribed with good results. A coat of Halfords rattle can plastic primer was then applied. still more work needed under the wings and walkway this evening.

Thanks for looking

Mark

[Cheshiretaurus]

Little more out of the way, RTV is still not fully set from Saturday but its getting there I'll give it a few more days! not sure what went wrong with it.

Been scribing the fuselage today, have a lot to learn about this scribing lark, but found some good tips on BM, thought the simple shape fuselage of the Cherokee would make it a bit easier....nope, but learnt a few things though, tried using electrical tape as to get the lines on the top of the fuselage, seemed to work ok . Still have a long way to go if I ever going match Fritags superb scribing on his chipmunk.

Lots of clean ups to do here and there still but will do them as I go along with rest of the assembly.

I've painted the upper inside cabin white and window frames in preparation for casing the resin windows hopefully in a few days.

Just a few pics, blue-tacked together with the test nose.

Mark

[(ex)Sgtrafman]

Hey mark

Being able to rescribe is one of those things that you can either do or you can't and I fall in the cant category....however you seem to have the knack, it's looking good so far!

Great thread and skills.

Yours aye

Iain

[Fritag]

Really enjoying this and thanks for posting the home made PE demonstration.

Ditto.

Wings are nearly done, spent Sunday scribing them filling sanding re-scribing. was getting very deep and wide rough scribe lines on areas that had filler e.g. undercarriage bays so those lines were filled back with thin CA and re-scribed with good results.

Been scribing the fuselage today, have a lot to learn about this scribing lark, but found some good tips on BM, thought the simple shape fuselage of the Cherokee would make it a bit easier....nope, but learnt a few things though, tried using electrical tape as to get the lines on the top of the fuselage, seemed to work ok . Still have a long way to go...

Scribing: bit daunting - very frustrating - almost certain to get cocked up and need redoing in several places - but ultimately kind of satisfying. Don't you think?

As a man who's had a bash and suffered the same frustrations of trying to scribe over filler and around tight curves I can only admire your efforts Mark.

I reckon you just have to have a selection of guides (I currently reckon a triple thickness of insulating tape cut to a nice straight edge is a good answer to curved surfaces/curved lines), a selection of scribers, a selection of fillers for when it inevitably goes wrong and a few short sessions - followed by a few long beers....Oh and enough self control not to chuck the thing against a wall when it goes wrong...

Definately a 'must read' thread.

[Cheshiretaurus]

Fritag,

Definitely frustrating yet satisfying, The insulating tape trick I think is certainly the way to go for complex curves. Beer & short sessions are a must!

Edited August 14, 2013 by Cheshiretaurus

[Cheshiretaurus]

Spent last couple of hours making the scribing template for the door from 0.002" brass, think the result was worthwhile, hinges I'm going to make from something very thin I think and then CA them on.

[noelh]

The Airvan looks a simple shape to scratch build might be worth a go.

1000 hours, was you meat bombing in it?

It is to be fair and I found a set of plans for a flying model online. It's pretty boxy. But it would be pushing my limits as a scratchbuilder. I would have impeccable references though. Maybe you'd like to consider it for you next project????? You can make one for me too.

Yes indeed I do drop people out of planes for a living. Most of them survive.

Continuing to enjoy your build.

Edited August 14, 2013 by noelh

[Cheshiretaurus]

Been working on the interior today, mixed a better match to the red toned down with brown n blue, Tamiya tape seat belts re fitted. Made some seat pockets items from plastic card shapes (usual light aircraft stuff, tech log, first aid kit and fire extinguisher) CA'd to thin backing sheet then masking tape CA'd over the top, when the paint is dry I'll cut them out and stick them to the back of the front seats. Added a little detail to the side walls, once this is dry I think I'm ready to cast the resin windows.

Quick summery of today's work

Went to Barton a few weeks ago to have look at the real G-PAWL. Apologies for the quality, taken with the phone on a very sunny day lots with of reflections and a greasy fingerprint over the lens.

Edited August 20, 2013 by Cheshiretaurus

[Cheshiretaurus]

Made a start on the side windows filling them with clear resin, I’m on my second attempt as I removed the acetate former from the window too early and left ridges on the surface from it. I tried to polish it out but made an even bigger mess as the resin was not hard enough even after few days. I’ve removed them and started again. However on the plus side I have learnt how to make realistic looking broken windows while removing the old ones. I’m away with work again overnight so that gives them plenty of time to set before I remove the acetate this time.

Finally my RTV mould for the spats and windscreen set, took 5 days! Defiantly didn’t put enough catalyst in as they are not as deeper pink as previous ones I have made. All in all, a bad week for casting I think.

I’ve made casts from them now and these have become the basis for making the female vacuum forming moulds. I CA’ed the casts to a plastic card backing along with another cast cut out for a second set of main wheel spats then started spraying PVA mould release in a very light layer at a time and leaving it for 10 to 15 mins between layers, I think they got 5 or 6 maybe 7 layers in total this forms a barrier only a few microns thick. The mould release needs to be dusted on lightly at first as it tends to bead and form blobs if too much goes on at once. After a few layers the tendency to bead reduces . Don’t use your expensive airbrush for this, I used a cheap £7 mini spray gun from ebay. I had also made a couple of wooden frames to fit round the cast from 12x4mm batons and glued together with white PVA glue.

Sewing pins were gently tapped in at strategic points for the air evacuation points on the mould. The frames were fitted and dammed with plasticine. A mix of 50% aluminium powder and 50% resin was then prepared, this becomes a thick mud so a little acetone was added to thin it into a pourable mix. This was then poured into the frames leaving an air chamber above the resin, given 15 mins to gel then the pins were removed.

I gave them about an hour to set then gently prised the plasticard along with the cast masters away, took a little force at times but they both cleanly released, leaving a negative impression of my parts for a female mould. I’ll leave them for a couple of days to set hard before I try to make use of them. In the mean time I have bought a new vacuum cleaner, not sure if the wife picked up on the fact there was no grumbling when it came to getting her a new one! However I need to make an adaptor as the new one doesn’t fit my vacuum tool with the nozzle being the wrong size.

Edited August 19, 2013 by Cheshiretaurus

[CarLos]

Very interesting!

I did something similar for small pieces but I used acupuncture needles instead of pins and plaster for the female molds (the kind of plaster with resin mixed, but I think that normal plaster would do) . It works well for just a few moldings.

[Cheshiretaurus]

Very interesting!

I did something similar for small pieces but I used acupuncture needles instead of pins and plaster for the female molds (the kind of plaster with resin mixed, but I think that normal plaster would do) . It works well for just a few moldings.

Going to try that, just ordered a box of 100 0.25mm needles for next time i make a mould, thanks

[Cheshiretaurus]

Right, done some hoovering, the fun kind. Taped the moulds to my vacuum tool and sealed up all other gaps.

Toaster at the ready and go.

Just really test and practice pieces at moment, spats are formed from 0.5mm card and seemed to come out ok but I think next time I make a vacuum mould I'll make smaller air holes, the pip marks left are quite pronounced but these can be sanded so ill stick with this mould and try using 0.75mm card, (1mm card will be too thick and wont leave room for wheels). I've now run out of 0.5mm card so need to order some more today along with some 0.75mm and have another go.

As for the windscreen, Ive made a few from 0.5mm PET-G, I'll regard it as a partial success as last time I tried to mould a canopy it just stuck to the resin mould leaving marks on the canopy, I had used less aluminium powder to make that mould but this time I used more I think I've solved that bit. I'm going to make a new master & mould for the windsreen as this one has too many imperfections and no defining line for the edge of the screen making it hard to see where to cut it.

Altogether a partial success as I learnt a fair bit more about vacuum forming from it.

Edited August 21, 2013 by Cheshiretaurus

[perdu]

I love the vacforming dies, it's something I wish I'd tried when I did my Sherpa sponsons, even though it worked that time for me

All along the work you are doing I'm finding immense pleasure and value from seeing how you tackle these tasks

I really do have to sieze the moulding nettle and have a go at resin and etch

thanks for showing me how