Spectre711 Posted January 17, 2011 Share Posted January 17, 2011 So I have been looking around and there seems to be a lot of stuff out there. Should I just pick up something like the Alumilite Mini-Kit or should I just piece together what I need. There is so much out there some I'm not sure what is what a modeler needs and what doesn't apply. I did a search but there just doesn't seem to be the info I'm looking for. Quote Link to post Share on other sites
Triarius Posted January 17, 2011 Share Posted January 17, 2011 Smooth-on. This is the premium stuff. Nearly as good, hobbiest friendly, and slightly less expensive: Bare-metal. Quote Link to post Share on other sites
Spectre711 Posted January 18, 2011 Author Share Posted January 18, 2011 Any idea of how those compare to the Alumilite products? I was thinking that I could buy the rubber and then a resin separately. I would then have to get some kind of release agent also I guess. What I would like to start off with is a two part mold (one part if I can get away with it) to cast 1/72 Phantom Nozzles. I have a few old 1/72 Revell kits and the nozzles are horrible. Thought I could cast the Hasegawa, Fujimi or maybe the newer Revell nozzles. Quote Link to post Share on other sites
Spectre711 Posted January 23, 2011 Author Share Posted January 23, 2011 Anybody else with 2 cents? Quote Link to post Share on other sites
PlasticWeapons Posted January 23, 2011 Share Posted January 23, 2011 Ugh, Alumilite. Buy either from Smooth On or Vagabond (I think they're under a different company now). Alumilite's resin shrinks quite a bit but if it's readily available to you, try out the starter kit. Make sure with whichever company you purchase your materials from, please follow the precautions and use personal protective equipment, such as latex/nitrile gloves, a face shield and plenty of ventilation. If you splash your skin with the resins, you can develop a sensitivity to it (contact dermatitis) which leaves an itchy, blistering "burn" and temporary scar. It happened to me as a first timer over a decade ago. Just something to warn you about, but resin casting is fun. Quote Link to post Share on other sites
Quailane Posted January 23, 2011 Share Posted January 23, 2011 If you want to make a mold that doesn't shrink (you do), use a platinum catalyzed rubber. More expensive, but it will let you make nearly exact replicas of the object you want to cast. Otherwise, other RTV rubbers shrink from a lot to a little and will leave you with castings that are noticeably smaller than the original, and the rubber can shrink more over time. Quote Link to post Share on other sites
Spectre711 Posted January 23, 2011 Author Share Posted January 23, 2011 Didn't kow that the rubber would shrink over time. With a two part mold would the Oomoo 25 or 30 be a good choice for casting resin exhaust nozzles? Quote Link to post Share on other sites
mightymax Posted January 23, 2011 Share Posted January 23, 2011 Many swear by Smooth On products and it is great stuff I hear, from everyone I know who uses it. I tried learning to cast a few years back and here is my suggestion. If you have a Hobby Lobby, they sell Alumilite stuff. Get some with the 40% off coupon. If you are like me the learning curve is going to be an expensive one, so I would practice with Alumilite until you are confident you can keep waste to a minimum My .02 Max Bryant Quote Link to post Share on other sites
Netz Posted January 23, 2011 Share Posted January 23, 2011 Are you planning on doing more than just replicating a few parts?? It seems like a steep investment for your intended purpose. Take into consideration that without a pressure pot, you might have allot of short shots or air bubbles to contend with, also the Alumilite resin you buy from the hobby shops have a very short work time, like 30 seconds, that is from the time the 2 chemicals touch, you need to mix and pour into the mold as this stuff is kicking off, if too think the resin will not fill/flow into the small cavities. I would suggest you try to find a local resin supplier and go to the shop and talk to them about your ideas, bring a sample of the intended parts you want to cast so they can see it, They can direct you to the best product to use, you really don't need to buy every gimmick to cast a part, just the basics, gloves, cups, stir sticks, and product. Buy the cheapest cups you can as you will be throwing them away, I get the small plastic condiment cups and mark a line on it with a marker for measurement. The Resin suppliers can also sell you sample size products, so I suggest you find someplace local and talk with them. Curt Quote Link to post Share on other sites
Spectre711 Posted January 23, 2011 Author Share Posted January 23, 2011 I would like to get involved in casting what I need from kit parts to other things around the house and in the garage. Heck, maybe I can start making a little side cash. Have no Hobby Lobby within 50+ miles and I can't seem to find a shop that sells casting resins in Central New Jersey. Craft stores in my area don't sell this stuff either. Quote Link to post Share on other sites
Uncle Uncool Posted January 23, 2011 Share Posted January 23, 2011 Awlright; me's just read the whole thread, 'n' got one question 'n' two related enquiries: Before gluin' 'em to his 1/32nd scale Tamiya F-4 Phantom build, a good mate o' mine has lent me his intake suckers, which I'm tryin' to cast. How IN THE WORLD do ya make a mold to cast hollow parts without destroyin' the parts in the process? If you want to make a mold that doesn't shrink (you do), use a platinum catalyzed rubber. Whut's platinum catalyzed rubber? Any specific brands ya'd suggest buy? Does Micro-Mark have it? Take into consideration that without a pressure pot, you might have allot of short shots or air bubbles to contend with, Whut's a pressure pot? Is it some sort of a vacuum device or sumthin'? Any pictures ya've got to post on here, Curt? Danke schön in advance for yer answers, everybody. Ya hear? Cheers, my blokes! Unc² Quote Link to post Share on other sites
Netz Posted January 24, 2011 Share Posted January 24, 2011 (edited) You should have both, a pressure pot for casting, and a vacuum chamber for removing bubbles/air from the RTV. but most hobbiests probably won't use the vacuum. Edit; in this thread is better explained the vacuum purpose. The pressure pot is just a modified (caped off) painters pot, once you pour the resin into the mold and it is still in liquid form, it needs to quickly be put into the pot and pressure added, this pushes out any air bubbles from the resin. Check here for the pot. As for setting up a mold for an intake......now you know why they cost so much........ You need to set up a 2 part mold or one with a tongue in it, yea it ain't easy. Curt Edited January 24, 2011 by Netz Quote Link to post Share on other sites
Spectre711 Posted January 24, 2011 Author Share Posted January 24, 2011 I figured making a pressure pot or vacuum chamber would not be that hard but was wondering if one was better than the other to use? Or maybe each has their own situations that which makes their use better? Quote Link to post Share on other sites
Netz Posted January 24, 2011 Share Posted January 24, 2011 They both serve a purpose, you need to vacuum your RTV before pouring, otherwise when your casting under pressure the mold will distort/collapse. But you can use the same tank for both processes, you just have to fab a plexiglass lid to serve the vacuum procedure. Check the link I put in above, there is an example of the pressure pot and modification for vacuum. Curt Quote Link to post Share on other sites
J.C. Bahr Posted January 25, 2011 Share Posted January 25, 2011 I just recently built a pressure/vacuum chamber from the Harbor Freight paint pot and after experimenting (and tons of reading everything I could find all over the internet), have come to the conclusion that the vacuum is not really necessary and that pressurizing the RTV while it is setting up is the way to go. Just have to make sure that your chamber is pretty air-tight in order to maintain the pressure for as long as the RTV requires to fully set-up... sometimes between 16-20 hours. Curt, in all the reading I've done, my understanding is that the pressure doesn't "push out" air bubbles from the RTV or the resin, but compresses them to microscopic sizes. One of the experiments I did was to take an older mould that had not been created under pressure and then cast resin into it with pressure and the resulting cast was a pretty impressive piece that was akin to a puffer fish: http://animals.nationalgeographic.co.uk/st...fish-puffed.jpg Was hard to believe there were that many air-bubbles trapped around the cavity in the non-pressured RTV. :) Since completing my vacuum chamber, I'm kicking myself that I dragged my feet for as long as I did before making the small investment into it. Makes things much nicer with a very very small percentage of errors and waste. Still requires some clever engineering of moulds with certain things and I also would recommend going with a resin that gives a little bit of working time so that you can take a tooth-pick to try to work out some of the largest air-bubbles that might be in a mould as I have had a few short-shots under pressure, but the tooth-pick trick has taken care of that issue. I also would recommend going with the Smooth-on stuff over Alumilite. I started out with Alumilite and the Smooth-on is much better stuff. Quote Link to post Share on other sites
Spectre711 Posted January 25, 2011 Author Share Posted January 25, 2011 How much air pressure do you use in the pot? Quote Link to post Share on other sites
J.C. Bahr Posted January 25, 2011 Share Posted January 25, 2011 How much air pressure do you use in the pot? 60 PSI seemed to be the magic number I kept running across on different sites and forums across the internet. The paint pot is not supposed to exceed 80 PSI if I remember correctly. Quote Link to post Share on other sites
Spectre711 Posted June 13, 2011 Author Share Posted June 13, 2011 I wound up finding an Utrecht art warehouse near me and bought the Smooth-On starter kit that was $50. Found a 20% off Winter special coupon that is still good till the end of July. They often have free shipping on orders over $50 also. Been playing around with it a while along with a paint pressure pot and have built my confidence enough to start playing around making masters of my own parts. Quote Link to post Share on other sites
Gundamhead Posted June 13, 2011 Share Posted June 13, 2011 $100.00 for the starter set. Or you just buy the already excellent nozzles already out there for $10.00. Quote Link to post Share on other sites
Spectre711 Posted June 14, 2011 Author Share Posted June 14, 2011 I wound up finding an Utrecht art warehouse near me and bought the Smooth-On starter kit that was $50. Found a 20% off Winter special coupon that is still good till the end of July. They often have free shipping on orders over $50 also. Paid $40 and have cast all sorts of stuff. Quote Link to post Share on other sites
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