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

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.

Saw the BBMFs Lanc over Warrington yesterday too. Fantastic sound.

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.

Yes that shop is the one that is responsible for getting me back in to the hobby, I lived a about a five min walk from there on North st.

Top marks Nigel, Excellent work, love the extra detail here your perseverance has paid off. Very impressed. I see you live towards Bridge of Don, spent 18 months up there living in Inverurie.

The Airvan looks a simple shape to scratch build might be worth a go. 1000 hours, was you meat bombing in it?

Looking forward to this have that Airfix JP5 in the stash

DH Hornet

Nigel Pressing CTRL+D together will save the current URL in your browsers bookmarks.

Good point Nigel that would work, I've added that in, but it carries a bit of a chance of over exposing. Added some more stuff in too and corrected some typos

Wife has given me plastic tub that we got some candy floss from Blackpool in, so far so good, see if the smell starts to escape.

Absolutely marvellous skill, how long has this taken? , the fan blades are fantastic as is the rest of the work. Keep it it up

Thanks, looking for a suitable metal box, might have to eat a of lot biscuits!

How to make PE is in modelling tips chaps. http://www.britmodeller.com/forums/index.php?/topic/234944044-making-photo-etched-parts-at-home/

Making photo etched parts at home Many years ago I was a young apprentice in a small electronics company, one of my tasks was making printed circuit boards (PCBs) for prototypes and one off’s. Making PE parts is a very similar process, so I gave it a go. When I made PCBs the boards were pre-coated and we used ferric chloride as an etchant, I’m going to show you how to make a double sided PE using dry film resist. You will need to invest in some bits and bobs to help you along, nearly everything is on good old ebay, the rest you can get in Tesco, ASDA etc, and don’t forget to pick up some wooden or plastic stirrers from Mc Donald’s and the like. I won’t write a long list now of things you need I’ll leave that to the end and get straight to the interesting bits, You may not get success first time but keep practising, I had many fails at various stages getting this right so i'll share what I know. but first this :- Making photo etched parts uses some hazardous chemicals and as such safety steps should be taken in the form of protective clothing, gloves, goggles etc. The chemicals are corrosive to skin as well as to brass so should be immediately washed off with plenty of water if contact with skin occurs, medical attention may be required as well. By continuing to read this article you must accept that YOU are responsible for your own safety and should read all labels and safety data sheets available. Nuff said, lets get on with it. Artwork The artwork was printed on over head projector (OHP) film for inkjets this film has a rough and a smooth side. The rough side is the printing side. We are going to use negative resist film so when you create your artwork white is where you want brass and black is where it is to be etched away. You will notice the ‘sprue gates’ are only on the rear art work this is so they get etched away from one side only and become half the thickness off the surrounding brass. Start off by creating your artwork without the gates so the parts are ‘floating’ with no attachment to the surrounding frame, save this file call it ‘front’ or something now make a copy of that file and call it ‘rear’. Open the rear file into your editing software and draw the ‘gates’ in. You now have 2 files front and rear. Print your files using your printers best settings, on mine I have selected Print quality high, Use black ink only, darkness max, contrast max, high resolution paper. If your software can print alignment/crop marks, use them! If not add some crosshairs to your art work but they must be the same on both files so check for this before you create the second file. The two artworks are shown here, top is the front with the floating parts bottom is the rear with the 'sprue gates' (to be printed mirror image) Fold lines should be on the inside of the fold and twice the thickness of the brass. Printing preference page manual ajustment pop up page Because I’m from up north and a bit tight, to save on OHP film print off one of your artworks on plain paper first, now you can cut out a bit of OHP film appropriate to the size of your artwork to include the alignment marks, tape this to the paper over where it is to print and put it back through the printer, same again with the other file. Print the rear one as a mirror image and let them dry for an hour or so. I’ve tried using laser printers for the artwork but the blacks aren't as deep, I find the inkjet better. We have 2 artworks, the rear one should be turned upside onto a white surface or light box if you have one. Cut the top art work out so it just includes the alignment marks but make sure it smaller than the bottom one. Now carefully align the two together on top of each other with printed sides on the outside, this is where your alignment mark come into use, use a magnifying glass if necessary. When you are satisfied that you cannot get aligned any better put a piece of tape across one edge to form a hinge and make sure it doesn't move as you do so. We now have our art work prepared, did you make that second check that is defiantly aligned? If it has moved peel off the tape and do it again, super accuracy is required here if your PE is going to be of any use. Cut out a piece of brass just bigger than the artwork with scissors and give it a clean with Acetone, IPA or other solvent. I'm going to use a 0.005" or 0.125mm gauge sheet Applying the resist The resist is a negative resist so the bits that get exposed to UV cure and harden while the unexposed bits stay weak, the resist should be stored in the dark and away from sunlight. It should also be kept away from sunlight and bright lights while your work with it until it has been developed. Switch the laminator on. Cut out two pieces of resist just larger than the brass, the resist is in between 2 protective sheets you need to remove one before applying to the brass. Take one piece and with two bits of tape on either side of one corner pull them apart, one of the protective sheets should come away, you might find it takes a couple of goes to get this. Put your brass on something flat that will be easy to turn around as you work, a hotel room key is ideal for this, make sure there is no dust or anything and put a big blob of water on it. Take your piece of resist, find the side without the protective layer (it’s the side that feels sticky if you touch it on the edge, don’t touch the bit that’s going on the brass) and gently offer this side to the brass, when it touches the water, the water will grab it, gently lower it on and let it settle. Check there are no air bubbles trapped, if there are just lift the resist a little and gently give the bubble a little persuasion to depart. You might need a little more water before lowering the resist down again. When you’re happy that there is nothing there except a thin layer of water give the centre of the sheet a small press just to tack it into place and stop it slipping, then with a tissue or soft cloth work the water out from the centre don’t press hard just yet, if you do it will tack that bit onto the brass making it harder to remove should you find an air bubble. Once you are happy that you have ALL the water out with NO air or water bubbles trapped smooth the resist down with a bit of pressure. Take a piece of paper and fold it in half, gently lift the brass off using a scalpel blade to break the adhesion and place it in your folded paper. The paper acts as a carrier to go through the laminator if you put the brass through naked it will get bent and damaged, also as its small it might get lost in there, with all the electrical hazards you might expect with a loose bit of metal rattling inside an electrical appliance. Once though the laminator, open up the paper, the resist will be stuck to the brass except where there is air or water trapped, you did get it all out didn’t you? The overlap will also be stuck to the paper so take your scalpel and cut the brass sheet free. Do the same for the other side. Exposure You need a UV light source, ebay has some ladies gel nail curing lights for £10-15, they come with four bulbs two above and one on each side, you only want the light going straight down through the artwork onto the brass so leave the side bulbs out and put them some ware safe, these are now your spares. You need two sheets of glass, I found two cheap 4”x6” photo frames the ones that are just glass and wooden back in Tesco for 50p each kept the glass a threw the rest away. Make sure they are clean, now slip your brass between the two artworks making sure you are happy with the positioning then sandwich this between the sheets of glass and clip together with bulldog clips. A quick check that the brass is still in the right place, no foreign objects obscuring things and the handles of the clips are not in the way. -Optional- You get a slightly sharper image if you remove the protective sheets at this stage however you run the risk of the resist getting stuck to the artwork if this happens you will need to strip the resist off the brass and start again. This is why the artwork has been prepared printed side out. If you get the resist on the artwork IPA or acetone may get it off (only clean the non-printed side) but you could end up having to print a new artwork. Expose this to UV light, I have a bit of cardboard clipped to the side not being exposed, this is just to stop light spilling round to the rear so you can remain in control of how much exposure takes place. Once exposed turn over, swap the card to the other side and expose the other side. Timing, getting the timing tight is critical, too short and your resist is not suitably hardened, to long and you start to expose the bits you shouldn't, remember the artwork is actually translucent the black bits don’t block the light completely they just attenuate it. I have found 45 seconds per side seems to be the optimum timing, this will all depend on how dark your black is, how strong the light is, how close the bulb is, how old the bulb is. 45 second is for my setup yours may differ, some experimenting maybe required. Once done your brass should have the image on it with the exposed bits turning darker blue. Edit - You can use sunlight to expose but be careful as this is an unknown and variable quantity so you could end up over exposing it. Developing As I said earlier exposure to UV light hardens the resist leaving the unexposed areas soft and dissolvable in the ‘developing’ fluid. The fluid we are going to use is a sodium hydroxide solution. Sodium hydroxide is caustic soda sold as household drain cleaner. We need to make a 5% solution of this. I’m going to make 50ml of the stuff. 1ml of water weighs 1 gram so 5% of 50g is 2.5g. you need to make enough to submerge the brass in your container, find out how much you need either in volume (ml) or measure the weight of the water (g) and multiply this figure by 0.05 e.g. 50g x 0.05 = 2.5g. This is how much caustic soda you need to weigh out. Dissolve this in your measured amount of warm water. You’ve now made your developing fluid. Be careful, this is corrosive and will cause chemical burns. I warm the fluid up by leaving the it in the airing cupboard where it is 38°c, Remove the protective layers from your brass with tape on the corner, once the protection is removed avoid putting the brass flat down on any surface, if you do the unexposed bits may well stick to it and you will be back to stripping and starting again. Dunk you brass in the fluid for 2-3 min to dissolve the unexposed resist, you will see it dissolving and turning opaque or milky. Then wash the resist away under a running tap, you can assist this by gently brushing it off with an old paintbrush under the tap. Have a really good look to see if you got all the resist off look carefully as it can be difficult to see. If there is any left put it back in the solution for another minute and wash off again. Don’t leave it in for too long however as it may start to dissolve the exposed stuff too. Once your satisfied you have got it all off put it back under the UV to see if you missed anything, if you did, strip the brass with acetone (see stripping at the end) and start again. Pain in the neck I know, but you haven’t yet etched it so you can reuse the brass. Better to find out now rather than once you've etched it in my opinion. Etching To etch we are going to use an acid to erode away the brass. Sodium persulphate is an etchant used in making PCBs, other etchants are available including ferric chloride, ammonium persulphate & potassium persulphate. For sodium persuphate a 20% solution is needed so multiply your weight/volume of water require by 0.2, so for 50ml of etchant weigh out 10g of sodium persulphate. I haven’t tried other etchants yet, so other ones may need different concentrations. This is also highly corrosive and will cause chemical burns. Find a suitable non metallic container and stirrer and dissolve the etchant in the appropriate amount of water in the same way as you made the developer, and warm it up for use, for me that’s put it back in the airing cupboard again. (It may take a few minutes of stirring to fully dissolve.) Submerge the brass in the etchant, as the etchant tends to become more concentrated at the bottom give it a stir every 10 mins or so until fully etched. The pic shows pin holes starting to appear after 28mins and after 50mins it was fully etched. Keep an eye on it. I nearly over etched this one as I was writing this article at the time. Don’t forget the areas that are going to be etched from one side only will carry on being etched until it is washed off and also the etchant will start to undercut from the sides. So as soon as you are satisfied that it is fully done. Remove it from etchant and fully rinse it under a tap. The etching time will increase as the etchant becomes exhausted the more times you use it, the same will happen with your developer. Stripping Soak the PE in acetone for a few minutes to remove the resist, it should start to peel of but might need a little help. The acetone will become purple in colour and becomes a fantastic dye so watch you don’t spill it, I have a bottle I keep the used acetone in just for cleaning PE. The photo actually shows it in water and is just for illustration! If all is well you've just made your first PE, go have a beer or three to celebrate. Things you need Brass http://www.ebay.co.u...=item5d304537b0 Dry film http://www.ebay.co.uk/sch/i.html?_odkw=dry+film&_osacat=0&_trksid=p2045573.m570.l1313.TR0.TRC0.Xdry+film+photoresist&_nkw=dry+film+photoresist&_sacat=0&_from=R40 OHP film http://www.ebay.co.uk/sch/i.html?_sacat=0&_from=R40&_nkw=inkjet+ohp+film&_sop=15 UV Light http://www.ebay.co.uk/sch/i.html?_trksid=p2050601.m570.l1311.R1.TR10.TRC0.A0.Xuv+na&_nkw=uv+nail+lamp&_sacat=0&_from=R40 Sodium hydroxide, caustic soda cleaning product section of ASDA Tesco etc Glass sheets - cheap photo frame Spatula http://www.ebay.co.uk/sch/i.html?_sacat=0&_nkw=laboratory+spatula&_frs=1 Etchant Different types are available - Sodium persulphate, ferric chloride, ammonium persulphate & potassium persulphate. Couldnt find the Sodium persulphate I used doesnt seem to be listed, http://www.ebay.co.uk/sch/i.html?_odkw=pcb+etchant&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.Xetchant&_nkw=etchant&_sacat=0 Edit 28/8/13 Looks like the Sodium persulphate is listed on ebay again http://www.ebay.co.uk/sch/i.html?_trksid=p2047675.m570.l1313.TR0.TRC0.Xsodium+persulphate&_nkw=sodium+persulphate&_sacat=0&_from=R40 Containers, I used lab beakers, do a search on Borosilicate beaker Scales, search pocket scales or micro weighing scales Stirrers grab a hand full at McDonald’s Timings & quantity's Exposure 45sec per side 1ml of water weighs 1gram Developer 5% strength 2-3mins at 38°C Etchant 20%strength 45min to 1:30 at 38°C (Sodium persulphate) Single side etch To make a single side etch, still apply resist to both sides of the brass and expose the rear completely. etching time will be double as the etchant can only eat through the brass from one side so has twice as much go through to meet the other side. I'll make updates to this as I find new things but in the meantime good luck! Mark

I have a bottle of water clear polyester casting resin, its in what appears to be a HDPE plastic bottle but the smell seems to be coming from the bottle continuously when it been sealed, this continues even after the bottle has been sealed weeks ago, The bottle is not leaking. I've tried putting the bottle in a zip lock bag to seal it but the smell seems to penetrate through the bag (the bag is properly sealed too), even after putting it in a second bag, bottle in a bag in a bag! I live in a flat so I don't have any ware outside to store it, Anyone have any ideas how to seal it

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.

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.

That Chippy of yours certainly did that!

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

Fantastic skills, the effort has paid off!

Been trying to work out how to get the Cherokee badge on the nose, etching was probably the only way to make the letter but fitting it was always an issue, tried etching the individual components but was too fiddly to, tried a name plate sort of rectangle but looked too much like it should be on the side of a railway locomotive. I couldnt feather the brass into the nose with out damaging the wording it just looked like a railway name plate, then I had an Idea make the whole panel from brass.... I got the shape by making an impression on a small piece of kitchen foil pushing it into the scribed panel markings. the foil was then opened up on a flat surface and scanned into the computer. From this I made the artwork for the PE. Cowling fasteners were include too. I carefully aligned the edge of the PE with the top scribe line and glued it in place bit by bit round the curve with thin CA. In other news I've made a template to get the window cut outs correct, the artwork was made from L&R side photo scaled to size. I'm starting to get the hang of making PE now so ill try to get a 'how to' on the forum soon. Going to be away with work for a couple of days so while im away I have an RTV mould of the new nose setting on the work bench, should be ready for a cast or two when I get back. Thanks for looking

Given the stand a wood effect (thanks for the tips chaps), HU62 > Coat of perfumed klear > HU70 streaked or course > coat of klear.

Yes not a straight forward kit to assemble, required a jig to get the positioning right. struts are in the wrong place and legs therefore are the wrong length. Tedious build but worth it in the end. don't think ill make another one.