LSP_Kevin Posted May 10, 2018 Share Posted May 10, 2018 Howdy folks, Our own Chris Nicoll reviews a new set of replacement exhausts for the Revell Mustang: Model Monkey P-51D 3D-Printed Exhausts Thanks, Chris! Kev Out2gtcha, LSP_K2, Model_Monkey and 3 others 6 Link to comment Share on other sites More sharing options...
Out2gtcha Posted May 10, 2018 Share Posted May 10, 2018 Great review! I wonder how they compare in size/shape/texture to the Eduard/Brassin exhausts. Zero77 and Model_Monkey 2 Link to comment Share on other sites More sharing options...
BiggTim Posted May 10, 2018 Share Posted May 10, 2018 Wow, that was excellent! I'm still in the paint process on mine, but will post some comments when I finish Model_Monkey 1 Link to comment Share on other sites More sharing options...
Patrick HMD Posted May 10, 2018 Share Posted May 10, 2018 I like the unshrouded look. It gives the P-51 an 'in it's work clothes appearance'. Easier maintenance, or better engine cooling? I don't know. BiggTim and Model_Monkey 2 Link to comment Share on other sites More sharing options...
Old Dog Posted May 11, 2018 Share Posted May 11, 2018 Slightly confused, if 3D printed why would they need to be cleaned and treated like resin and subjected to UV for curing. I wasn't aware that they 3D printed using resin material. Model_Monkey 1 Link to comment Share on other sites More sharing options...
Model_Monkey Posted May 11, 2018 Share Posted May 11, 2018 (edited) That's a great question! The material in which the product is created is not the same kind of resin we are accustomed to. It has some unusual properties and so has to be prepared a bit differently than typical modeling resins. I'll explain, please bear with me, the explanation may help you avoid some headaches. The exhausts are created from an acrylic plastic called "Frosted Detail". For some products, it comes as either "Frosted Ultra Detail" ("FUD") or "Frosted Extreme Detail" ("FXD"). These exhausts are printed in FXD, the better detailed and smoother of the two. FUD/FXD behaves differently than does injection-molded polystyrene or chemically-cured resins normally used to create other superb aftermarket products for models. FUD/FXD is chemically related to Plexiglas. FUD/FXD is not the same material you see used by the kind of 3D printer used by hobbyists at home or in schools. Those printers often extrude a material that is chemically related to nylon and looks and behaves like nylon. That is not what these exhausts are made from. The 3D printer that produces these exhausts costs a whopping $70,000-90,000 USD. That is no garage printer. Compared to resin products cast in a mold, there is no casting block to remove. Bonus. The acrylic resin here is made using a liquid acrylic resin that is cured by exposure to ultraviolet light. There are actually two materials laid down by the printer when the model is made, the acrylic plastic itself, and a waxy material that supports overhanging features during printing. (The wax is later melted away in a low-temperature oven at the factory before it is packaged and shipped to you, leaving you with just the acrylic parts.) The nature of the acrylic resin in its liquid state causes it to naturally harden quite quickly, nearly instantly. But it must remain in a liquid state in order to be extruded from a 3D printer. So, a chemical inhibitor is introduced to the formulation that prevents the resin liquid from hardening. It is ultraviolet (UV) light that destroys the inhibitor permitting the resin to naturally, nearly instantly, harden. The 3D printer lays down a layer of liquid acrylic, flashes it with UV light hardening it. Then the next layer is laid down on top and flashed with UV light, layer by layer, creating the model. The presence of any microscopic bits of intact inhibitor trapped within the resin can keep enamel paint from hardening. This is why I strongly advise customers to expose their products to direct sunlight for several hours before painting. The sun's UV light will destroy any remaining inhibitor permitting the use of enamels. Called "post-curing", sunlight exposure is critical to painting success with enamels. Generally, acrylic paints are not affected. There are some exceptions, so post-cure your parts even if you intend to use acrylic paint. Sometimes, tiny bits of wax remain, too. A good soaking in common liquid dishwashing detergent ("Dawn", "Fairy", "Simple Green", etc.) can remove those stubborn bits. Please be advised that FUD and FXD can be harmed by strong chemicals like acetone. Acetone can melt FUD/FXD. Some modelers like to use acetone, acetate (found in acetone-free nail polish remover) and Bestine (heptane) to clean FUD/FXD. Some designers recommend it. I do not. Too many of my customers have reported that acetone, acetate or Bestine damaged the acrylic. I recommend only mild, water-based detergents like Dawn, Fairy, baby shampoo (no conditioner) or Simple Green in warm water to clean FUD/FXD. Those products have never caused me any problems personally nor have I received any reports that they caused problems for customers. General rule of thumb: if you wouldn't use a cleaning product to clean Plexiglas, don't use it to clean FUD/FXD. Some plastic modelers are accustomed to using methyl ethyl ketone (MEK) as thinner for airbrushing enamels on injection-molded polystyrene models. Don't use MEK with FUD/FXD. One of my customers used MEK on a large product printed in FUD. He discovered and reported that a white powdery residue formed on the surface of the paint some time later. There was no harm to the product, but it was a nuisance to remove the residue, requiring a second cleaning. Based on his experience, I advise against using MEK as a paint thinner on FUD/FXD.Hope this helps! Edited May 11, 2018 by Model_Monkey Gerhard, Kilroy Was Here, Zero77 and 1 other 4 Link to comment Share on other sites More sharing options...
Old Dog Posted May 11, 2018 Share Posted May 11, 2018 Thanks for the explanation, it makes sense now ! BiggTim and Model_Monkey 2 Link to comment Share on other sites More sharing options...
Zero77 Posted May 22, 2018 Share Posted May 22, 2018 Great review! I wonder how they compare in size/shape/texture to the Eduard/Brassin exhausts. I have two sets of the Eduard/brassin exhausts. Perfect casting as usual, but they are VERY skinny. Definitely too skinny, i can even say anemic. I then drilled the kit exhaust, and they look nice, too, but lack the detail of the resin, and are also pretty skinny compared to what i see on the pictures. So yesterday i ordered two of these 3D printed exhaust. They look better in proportion. quang, Model_Monkey, CANicoll and 1 other 4 Link to comment Share on other sites More sharing options...
Guest Maxim Posted May 22, 2018 Share Posted May 22, 2018 (edited) I used many of Model_Monkeys parts in the past on ships models and his parts are really nice in Extreme detail. Just be careful that it is brittle so if you think about drilling anything 3D printed be very careful. Also good advise to expose the part to UV light for an hour or so. I have used mostly acrylic lacquer paints and had no problems with paint not adhering. I've used MRP, Mr Color, Tamiya lacquer sprays without problems. Edited May 22, 2018 by Maxim Link to comment Share on other sites More sharing options...
Model_Monkey Posted May 22, 2018 Share Posted May 22, 2018 Thanks to all for your comments and patronage! Please be advised that Shapeways has changed the names of many of the materials it uses (just a marketing thing). "Frosted Extreme Detail" (FXD) is now called "Smoothest Fine Detail" plastic. Same material and process, different name. BiggTim, CANicoll and Uncarina 3 Link to comment Share on other sites More sharing options...
Night Hog Posted June 4, 2018 Share Posted June 4, 2018 Any thought for carb air intake plates (perforated). Your product looks great Model_Monkey 1 Link to comment Share on other sites More sharing options...
Model_Monkey Posted June 4, 2018 Share Posted June 4, 2018 Thanks for the compliments! Regarding the intake plates, due to present 3D-printing requirements, the plates would have to be designed unrealistically thick if 3D-printed. IMHO, photo-etch remains the more realistic material for the perforated plates. Eduard makes a basic photo-etch set that includes the perforated plates (please click here). There may be other sets available, too. Hope this helps and thanks again! Uncarina 1 Link to comment Share on other sites More sharing options...
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