Vespaeda Posted June 20, 2005 Share Posted June 20, 2005 I don't know if this is common knowledge among resin mold parts makers but in order to minimize bubbling in the finished pieces, has anyone tried pre-warming or applying additional heat to the molds during cure? I have not used modelling resin, only adhesive & laminating epoxies, and they generate their own heat during cure. Applying additional heat usually hastens cure. A method for removing bubbles in r/c plane lamination w/resin includes playing hot air over difficult spots to smooth surfaces & pop bubbles(using a heat gun--just enough to encourage runniness) I didn't get this trick from an r/c plane site, incidently. I learned it years ago in a microbiology lab while learning to purify DNA & RNA for sequencing(pre-rapid PCR days, circa 1987 for those in the know). 2 German grad students showed me neat tricks for removing unwanted air bubbles from media & electrophoretic gels. I miss those stressful, intrepid days.... Just my 2 Canadian cents. and, again... superb work Honneamise! Quote Link to comment Share on other sites More sharing options...
Lo-pan Posted June 20, 2005 Share Posted June 20, 2005 I'm in for one. Shouldn't be, but like a bad crack habit, I can't say no. Quote Link to comment Share on other sites More sharing options...
Zentrandude Posted June 20, 2005 Share Posted June 20, 2005 A method for removing bubbles in r/c plane lamination w/resin includes playing hot air over difficult spots to smooth surfaces & pop bubbles(using a heat gun--just enough to encourage runniness) I didn't get this trick from an r/c plane site, incidently. I learned it years ago in a microbiology lab while learning to purify DNA & RNA for sequencing(pre-rapid PCR days, circa 1987 for those in the know). 2 German grad students showed me neat tricks for removing unwanted air bubbles from media & electrophoretic gels. I miss those stressful, intrepid days.... Just my 2 Canadian cents. and, again... superb work Honneamise! Also used in decals for vechicals like mining trucks. makes it very easy than trying to force it out with a tool to push it out that could deform or tear into the decal. the price is the final price or just an estimate atm? Quote Link to comment Share on other sites More sharing options...
stratos Posted June 21, 2005 Share Posted June 21, 2005 Just saw this, Hope I am not to late. I would like one as well. Put me down and tell me when and who to pay. Thanks! Looks great honneamise!! Quote Link to comment Share on other sites More sharing options...
cobywan Posted June 21, 2005 Share Posted June 21, 2005 Dusting your molds with talcum powder works wonders as well. Quote Link to comment Share on other sites More sharing options...
honneamise Posted June 21, 2005 Author Share Posted June 21, 2005 Thank you all for the useful hints! My problem with bubbles were just on one side of the engine and were generated by tiny air bubbles in the mold. Generally the best method to get rid of the bubbles is putting the mold under pressure. Too low pressure and tiny air bubbles rise up and get stuck in the surface of the part (and there are some air bubbles in the mold surface as well). More pressure and the bubbles vanish! The only drawback is that the part has then some tiny bubbles on the outside because the resin gets into the bubbles in the mold as well, but these are easily removed with a light sanding or maybe just snapping them off with a knive. After all, this occurs on only one side. I could have avoided ANY bubble by putting pressure to the RTV silicone while curing, but this failed! I found out this only works with solid master parts. Most of my parts such as the hull or the engines are built up with many pieces and there is of course air trapped inside - and guess what, placing the molds in the pressure pot not only crushed the air bubbles in the RTV, it also drove the air out of the parts itself, creating big bubbles which got trapped in the hardening RTV! Mold useless, so I had to go with the traditional method and now it is somewhat a compromise... As for the heat, the resin poured into the engine mold creates lots of it - it really hurts if I pull the part out too early! As for the price, the 65 EURO is OK (plus shipping of course and this will not be 18 EURO as stated earlier thanks to Grayson72!), wasting RTV while playing around with air pressure comes courtesy of my own wallet of course! By the way, do you all want a display stand? I found the one which comes with the ARII 1/100 VF Fighters quite useful so I could duplicate these (round with UN Spacy sign on it but quite small) but if you all want to make your own it will not be worth the effort. Any comments welcome! Quote Link to comment Share on other sites More sharing options...
cobywan Posted June 21, 2005 Share Posted June 21, 2005 Actually what you need to do is put your freshly mixed rubber into a vaccuum chamber to evacuate the bubbles out before you pour the mold. My experiment with pressurizing mold rubber was a miserable failure. Pressure really is usefull in casting the resin parts only. In my opinion. Have you seen the design for my Lacer II base? http://home.comcast.net/~cobywan/Templates/Lncrmdl.htm It could easily be adapted to your use. The current base has a raised "Kite" emblem and name plate. I can redo the nameplate to read Oberth yadda yadda. Quote Link to comment Share on other sites More sharing options...
Goshawk Posted June 21, 2005 Share Posted June 21, 2005 Cobyman that is sweet. looks great. I have to admit I do like the base on it and personally I would love a base for the Oberth to sit on. Quote Link to comment Share on other sites More sharing options...
Grayson72 Posted June 21, 2005 Share Posted June 21, 2005 A display stand would be great, better than having to buy one of those clear acrylic stands from Valkyrie exchange for 20 bucks. Quote Link to comment Share on other sites More sharing options...
cobywan Posted June 21, 2005 Share Posted June 21, 2005 I could modify the base and send the copies to Grayson for shipment with the kits. Of I could send a new base to Honneamise. Quote Link to comment Share on other sites More sharing options...
fernarias Posted June 21, 2005 Share Posted June 21, 2005 You can use a foodsaver to vacuum your RTV and Resin: http://www.childofmecha.com/Modeling/Resin...BasicResin.html The new foodsaver handhelds are only $59: http://www.foodsaver.com/products.ad2?Prod...&CatalogID=1000 F. Quote Link to comment Share on other sites More sharing options...
Valkyrie Posted June 21, 2005 Share Posted June 21, 2005 I can't imagine those things pulling enough of a vacuum to degass silicone effectively. You need to get it to around 28in/Hg (inches of mercury) to do the job well. Quote Link to comment Share on other sites More sharing options...
flyboy Posted June 21, 2005 Share Posted June 21, 2005 I can't imagine those things pulling enough of a vacuum to degass silicone effectively. You need to get it to around 28in/Hg (inches of mercury) to do the job well. Not to hijack this thread, but.... Where's the best place to find a vacuum pump suitable for de-airing molds? I did a search a while back, and wasn't able to find any useful information other than someone mentioning using a compressor from an old fridge. And what about vacuum chambers? Felix Quote Link to comment Share on other sites More sharing options...
cobywan Posted June 21, 2005 Share Posted June 21, 2005 You're looking for either a venturi pump or a refrigerator pump. The venturi style gizmo can be had at Harbour Frieght for about $14. But you need a good compressor to use it. http://www.harborfreight.com/cpi/ctaf/Disp...itemnumber=3952 Quote Link to comment Share on other sites More sharing options...
Valkyrie Posted June 21, 2005 Share Posted June 21, 2005 (edited) I tried that Venturi pump once. Hated it. I had to borrow a friend's 20 gallon (i think) compressor to use it, and even even after I emptied the tank through the Venturi, re-filled it, then emptied it again, I was still only at about 25in/Hg. Not even enough to degas resin. It was a waste of $15. I eventually gave up on finding a cheap solution, and got a Robinair 6CFM pro grade vacuum pump. Last I checked, you could still get them on ebay for around $200. They're kinda expensive, but they're worth every penny. Edited June 21, 2005 by Valkyrie Quote Link to comment Share on other sites More sharing options...
cobywan Posted June 21, 2005 Share Posted June 21, 2005 The one I got works fine. I've been using it with one of those 4 gallon compressors from Costco. You need to set up some lever valves to get full use of it though. But it can be made to work great. It's better than doing nothing. Quote Link to comment Share on other sites More sharing options...
THOR Posted June 22, 2005 Share Posted June 22, 2005 This guy quoted me a degassing system. Don't know if this is a good price... WE HAVE BUILT A NUMBER OF EPOXY DEGASSING UNITS IN THE PAST, AND FOR A COMPLETE UNIT THAT JUST MOUNTS ON YOUR BENCH WITH A PUMP UNDERNEATH IT WOULD COST YOU COMPLETE AROUND $1450. Dot1don2@aol.com Quote Link to comment Share on other sites More sharing options...
newbie Posted June 22, 2005 Share Posted June 22, 2005 I'll definitely be in for one! Quote Link to comment Share on other sites More sharing options...
cobywan Posted June 22, 2005 Share Posted June 22, 2005 I'll definitely be in for one! You got that much money laying around? Quote Link to comment Share on other sites More sharing options...
cobywan Posted June 22, 2005 Share Posted June 22, 2005 This guy quoted me a degassing system. Don't know if this is a good price...WE HAVE BUILT A NUMBER OF EPOXY DEGASSING UNITS IN THE PAST, AND FOR A COMPLETE UNIT THAT JUST MOUNTS ON YOUR BENCH WITH A PUMP UNDERNEATH IT WOULD COST YOU COMPLETE AROUND $1450. Dot1don2@aol.com That is a bell jar vacuum system. Not necasarry for our type of stuff. You could spend that on a lot of tools and better options for degassing. Quote Link to comment Share on other sites More sharing options...
honneamise Posted June 22, 2005 Author Share Posted June 22, 2005 This is an awesome display stand, Cobywan, much better than my lame proposal. If you´re making these I´m in for two. After I found out the hard way that RTV can´t be properly degassed by pressure and I don´t have a vacuum machine (but like to get one) I tried to simply pressing air onto the surface of the RTV with an airbrush. Works quite well, the little bubbles are almost driven to the surface and vanish quickly. Fernarias that link to the resin casting tutorial is cool. I have got something similar in a Model Graphix Magazine but it is in Japanese so I had to guess from the pictures. As I can see now I almost did it by the numbers so there was no unpleasant surprise here But I´ll have to visit the LEGO store soon... Quote Link to comment Share on other sites More sharing options...
fernarias Posted June 22, 2005 Share Posted June 22, 2005 (edited) fulcy translated the Suku-Suku casting pages at hobbyfanatics.com. Here's the link: http://www.hobbyfanatics.com/index.php?showtopic=5150 Hope this also helps. F. Edited June 22, 2005 by fernarias Quote Link to comment Share on other sites More sharing options...
Viceland Posted June 22, 2005 Share Posted June 22, 2005 *Opens up a can of worms* Heck Coby, if you're gonna put that much effort into your Lancer II base for Honneamese's project, why not make some new molds for the Lancer II kit itself while your at it!?!? I would take a few for sure!! Quote Link to comment Share on other sites More sharing options...
cobywan Posted June 22, 2005 Share Posted June 22, 2005 I was offering to cut a new nameplate and send the master to Honneamise. Not in so many words of course. That is a whole lot less effort than redoing the LancerII project. Besides I have people banging at my door for my impending Galactica kit. I HAVE to move on. Also I said the Lancer was retired. It needs to stay that way. Otherwise I would be a liar. Quote Link to comment Share on other sites More sharing options...
Lo-pan Posted June 22, 2005 Share Posted June 22, 2005 Besides I have people banging at my door for my impending Galactica kit. ...and some just waiting quietly in line. In regards to the stand for the Oberth...would you be using a thicker pylon for the support? While the stand is perfect for the Lancer, might the Oberth be a bit heavier? Other than that, the overall shape, along with the logo, wold be spot on. I could put the Oberth next to my Lancer and point proudly at representations of a combined 5.2 seconds of screen time. Quote Link to comment Share on other sites More sharing options...
Viceland Posted June 22, 2005 Share Posted June 22, 2005 *... and closes the can* Coby, please accept my appologies, I promise that was the last time I ever bother you with the Lancer. Quote Link to comment Share on other sites More sharing options...
Grayson72 Posted June 22, 2005 Share Posted June 22, 2005 (edited) Besides I have people banging at my door for my impending Galactica kit. ...and some just waiting quietly in line. In regards to the stand for the Oberth...would you be using a thicker pylon for the support? While the stand is perfect for the Lancer, might the Oberth be a bit heavier? Other than that, the overall shape, along with the logo, wold be spot on. I could put the Oberth next to my Lancer and point proudly at representations of a combined 5.2 seconds of screen time. Lo-pan, are you saying you'd like to put in an order for an Oberth? cuz you ain't on the list. Also, I agree that the pylon would need to be made more sturdy, the Oberth will be a much bigger chunk of resin. Edited June 22, 2005 by Grayson72 Quote Link to comment Share on other sites More sharing options...
cobywan Posted June 22, 2005 Share Posted June 22, 2005 If I were to do the Oberth stand I would need to re-design the post to fit that kit. I also wonder if the base is too small though. Quote Link to comment Share on other sites More sharing options...
cobywan Posted June 22, 2005 Share Posted June 22, 2005 *... and closes the can*Coby, please accept my appologies, I promise that was the last time I ever bother you with the Lancer. I wasn't bothered at all. On the contrary. I am quite flattered that people are still interested in them. Quote Link to comment Share on other sites More sharing options...
RT junkie Posted June 23, 2005 Share Posted June 23, 2005 I'm interested in one of those babies too, but I'm afraid I joined the community a little too late. Maybe when you release the "25th" anniversary edition I can jump on board (complete with special edition 25th anniversary stand, so it wouldn't really be the retired original). Quote Link to comment Share on other sites More sharing options...
Grayson72 Posted June 23, 2005 Share Posted June 23, 2005 (edited) I have an extra one I may be willing to sell, for the right price. Here's a link to the one I built. Lancer II build Edited June 23, 2005 by Grayson72 Quote Link to comment Share on other sites More sharing options...
Viceland Posted June 23, 2005 Share Posted June 23, 2005 Well now, is that a PM I just sent? Quote Link to comment Share on other sites More sharing options...
Grayson72 Posted July 16, 2005 Share Posted July 16, 2005 Any updates on this? Quote Link to comment Share on other sites More sharing options...
neptunesurvey Posted July 20, 2005 Share Posted July 20, 2005 Quote Link to comment Share on other sites More sharing options...
honneamise Posted July 25, 2005 Author Share Posted July 25, 2005 Hi I´m back after 2 weeks in France . I nearly forgot my own holidays over the Oberth, and when I realised I´d soon be away, MW was down so I could not tell anyone here about the hiatus. I left with an uneasy feeling with MW down for so long but it turned out my favourite site is online again, great!! While I haven´t been able to finish casting completely, the kit is well under way. 21 hulls and most of the smaller parts are ready, as expected the engine mold finished its life way too early and I´ll have to make a new one. Secondary engines and the left and right intakes need new molds, too. I´m currently waiting for more rubber, but I hope I´ll be ready in about two more weeks. I´ll have to find appropriate boxes and make an instruction sheet and then the kits should be ready to ship. I´m just building my own ship right now. Even though I use parts with bubbles or other little defects (the ones I can not sell but still look ok) it seems it is going to be a beautiful model. Parts fit is good although I had to abandon the pins for the nose-hull-assembly - they were impossible to cast but even without them it is pretty easy to align the parts. I´ll soon post pictures of the progress. Quote Link to comment Share on other sites More sharing options...
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