IbuildScaleModels
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Posts posted by IbuildScaleModels
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lighter fluid... interesting.... ok. I actually have some at home on the shelf... back to the drawing board.
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1 minute ago, peteski said:
Like I said, adding solvent to rubber material which normally hardens by a chemical reaction (not by solvent evaporation) will make the final product shrink. But if you want a solvent, use Naphtha instead of mineral spirits. It is also a petroleum distillate, but it have much faster evaporation rate. But it will shrink. I know people that use it specifically to produce molds smaller than the original (shrink it).
From what I read about naphtha is that it is a mineral spirit with higher purity and faster evaporation rate. Doesn't sell here in Montreal from what I saw.
You can use mineral spirits/naphtha to either shrink or grow a mold. Also silicone molds shrink over time and you soak them in mineral spirits to get them to grow.
I'll look into it more Pete, thanks for your help!
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11 hours ago, Ace-Garageguy said:
Who knows? He might discover the secret to table-top cold fusion.
hahaha... I've heard that exact comment too many times. I have also heard I should work for Microsoft or Nasa. Just not interested...
Also the corn starch with the rubber does harden it. Tested it last night. Unfortunately it makes it too brittle. I will try today mixing the starch with the mineral spirits first to make a thick syrup base and then mix the RTV rubber in it to see if it will work. Unfortunately mineral spirits greatly increases the drying time. If I had a vacuum chamber I would be able to do a more accurate test.
Luckily, the corn starch in the silicone makes the mold super solid and gives it great detail. I think I will use a gloss spray coat on the silicone as a mold release instead of a vaseline (petroleum jelly)/mineral spirit mix like they use in cinema prop molds. the petroleum jelly causes the mold to lose some definition as it is adding an extra layer of interference. Maybe if I airbrushed it on it would work better... Just thinking out loud right now.
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17 hours ago, Bugatti Fan said:
Justin, Wingrove's book has gone to reprint a few times. I think that the latest publisher was Haynes Publishers in the UK. Not sure if still in print or not, but Amazon or eBay may be a good bet if not. HTH.
He has also written a Complete Car Modeller 2 book that mainly describes his Weinberger Bugatti Royale build. Regards Noel
Thanks Noel. Unfortunately I can't find it in pdf format and will have to order it unless someone can photograph just those pages for me. MY 2 part mold works... sorta... but its the hole that is driving me nuts and I understand that is where the 3 part mold comes in. just driving me batty trying to figure this out. and my new mold test works great... good ol corn starch with silicone to act as a catalyst and hardener. might try it out with the rtv by mixing in mineral spirits to thin it but also mix in a bit of starch to help it become a bit stiffer. Forgot to put a vent port in my mold so that makes it a fail. Good old home supplies to help in the build process!
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On 6/16/2020 at 2:00 AM, Bugatti Fan said:
Gerald Wingrove's book The Complete Car Modelled No1 has a tyre moulding process explained in detail within. The book was written back in the 80's but the techniques have not changed. Howevef, newer moulding materials have been developed since then.
Awesome! thanks Noel... going hunting for the book now
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22 hours ago, Richard Bartrop said:
Sorry, I didn't take any photos when I did this, but I thought I was pretty clear that the stuff was too viscous to pour like resin. However, if you slowly coax it into the individual mould halves, it will fill the various nooks and crannies.
You only need a three part mould if you are trying to make hollow tires.
Do you still have the molds kicking around? I am looking around for 3 part mold tutorials. I'm just not grasping how to do it for the tires. I would prefer the pour line / tree joint to be on the inside of the tire to leave the tire im casting as much in place as possible.
Maybe im just not understanding how to do it properly and could use your or someone else's assistance in doing so. Hell point me in the direction of a good tutorial on how to do it it even and I'm happy.
Thanks.
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Richard, again... I'm lost on the 3 part mold. I'm trying to figure out how to get a good impression in the silicone mold from the tire and then finding a way to make a port hole to pour the rtv into. Please do share your process with photos.
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2 hours ago, Richard Bartrop said:
I''ve had satisfactory results making tires with Dow Corning Silastic. Silastic H is white, and is pretty viscous, but it takes 24 hours to set, so you do have lots of time to get it into the mould. As far as tinting goes, I think you're probably better off using a dry pigment. You can buy jars of powdered carbon black from art supply stores, which is the stuff they use in full sized tires.
Here's a tire I made for an armoured car project, with a little carbon black added.
ohhh please share a tutorial on your mold making process!
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On 6/11/2020 at 10:43 PM, CabDriver said:
@IbuildScaleModels, out of interest, how soft is “too soft” for a rubber tire? Presumably any RTV mould material will sustain the weight of about any kit and is tough enough to make a tire that you can stretch into a rim. What’s the problem that you are running into with them?
Mainly asking because I was just contemplating doing the same thing myself - mix some resin dye with RTV and see if I can make some usable tires!
i used kleenflo rtv gasket rubber. It feels too flimsy/spongy versus harder rubber. I know it is all in the preparation. maybe need to degas it or let it cure longer. Don't know... still doing tests.
On 6/11/2020 at 2:58 PM, peteski said:Mixing CA with RTV rubber will not do what you expect. Use the proper materials Luke! Like Ace and I mentioned, there are urethane (and even RTV) resins which different hardnesses available.
Pete, duly noted. Again, still testing things out. Also, what is available to me on a limited budget isn't a lot. The 2 part silicone, and urethanes are more expensive in Canada (from what I have found) unless i buy in large quantities.
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1 hour ago, Ace-Garageguy said:
Most will.
Smooth-On, for instance, will happily sell "trial size" units of about 2 pounds of material (resin and catalyst), for around $30.
The industrial prototyping (using plastics) I've done over the years has been primarily of small medical devices, components for toys and sporting goods, and hand tools...so my purchases have usually been small quantities.
I've never been required to provide any documentation other than a shipping address.
The rules for online sellers collecting sales tax HAVE changed however (if you buy much on eBay you will have seen many sellers now collect it), but as far as I'm concerned, it's a non-issue. Sales tax on $30 isn't much.
Found the "trial-size" of casting resin. Yah, already used this stuff. Expensive for the size. I have to improve my castings first.
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18 hours ago, peteski said:
Couple of observations:
1. Who says that scale model tires have to be soft? They can be cast form regular hard urethane resin, then painted to look like rubber. This is often the way tires in military models are done. With the right color and sheen, they often look more like rubber than the standard model car sift vinyl tires.
2. If you really want then soft, Smooth-On has a range of flexible (soft) urethane resins. Or even cast them using one of the harder RTV mold-making materials tinted with black dye.
I am using RTV in small quantities, but it makes the tire too soft. I want them stiffer. Using resins is out of my budget... buying a sherline broke the bank...
17 hours ago, Ace-Garageguy said:I would also caution against trying to reinvent the wheel where chemistry is involved.
Several manufacturers make softer casting resins in a variety of Shore hardnesses, specifically for making things like handle grips, movie special-effects masks and prosthetics, and various kinds of modeling.
Polytek has been my go-to supplier for this kind of stuff for decades, and they also offer a range of dyes that are compatible with their products.
Again, not trying to make them soft, trying to make them harder. I am looking at the chemistry actually. I am using silicone caulking to make my molds and using RTV to make the tires. But the RTV is too soft. Buying large quantities when I haven't tested a method is pointless and will run me into the ground. Instead, I want to test out several methods before actually investing more money. Hell to get 1 gallon of 2 part resin in canada will cost me close to 200-300$ shipped. Not worth it in my opinion if I can find cheaper alternatives that work. But yes, I am aware of the more expensive tried and tested methods. Unfortunately, I have to go the DIY/scratch building route on the cheap.
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Man, making rubber tires... new scratchbuilding territory.
Have to make a silicone mold, and then use HTV rubber sealant for the tires. Unfortunately forgetting to put a release agent is not fun. Also, need to find a way to harden the rubber a bit. Going to try a bit of CA in the rubber mix and hope it doesn't catalyze too fast. It probably will.. but hey.. that's what this is all about. HAHA
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13 hours ago, CabDriver said:
Found this post today whilst looking for something else - a BUNCH of interesting reference material on scratchbuilding:
Nice! Good references! Thank you very much!
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On 5/28/2020 at 2:31 AM, Bugatti Fan said:
Funnily enough, ship bottling can be done with certain plastic kits. I made a ship in a bottle many years ago using the hull from the little Airfix kit that I still have. I also put the little Airfix Victory in a bottle by buying two kits and sectioning the hull into 4 to build up inside the bottle So it can be done. Some of the little Heller Cadets ship series would lend themselves to this such as the Gorch Fock and their little Pamir.
I will eventually get into ships in a bottle. funny enough. even funnier is that we are old guys that have accepted to use technology. we are "advanced" hahaha
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2 minutes ago, Richard Bartrop said:
Gluing together preformed bits of plastic? Everyone knows that's not REAL modeling
let me pull out my pocket knife and start whittling away this piece of balsa... now in a few moments... *POOF* i'll just be putting this Santa Maria in a bottle. Let's see you do that with your fancy plastic kits.
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2 minutes ago, Tom Geiger said:
Have fun with your balsa wood models... that new fangled plastic stuff will never catch on! ?
bah. Plastics? That's for the new fangled kids. Now get off my lawn while i shake my fist at you. D**N Yougin!
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1 minute ago, Tom Geiger said:
There are still people in this hobby who don’t even own a cell phone. Or have any Internet access or even newspapers!
The week of NNL East’s original date, I got a half dozen calls asking if the show was still on! We had it all over the web, on our website and it was in the news that New Jersey was on lockdown. Makes me wonder if these folks have a TV or even electricity!?!
What's the point of all that fancy electronimachle stuff? I have scale models and I do stuffs by hand! HAHAH
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On 5/25/2020 at 1:40 PM, AmericanMuscleFan said:
You have created a monster Justin!
Your original question remain hard to answer based on all the interventions and replies from ours fellow members! Scratch building mean to me build something from zero or adding some details and/or improving some details using basic or more advanced tooling. That's doesn't mean that basic tooling can't create amazing results, we can see some everywhere on this forum! Based on the huge amount and very diverse opinions expressed on this (very interesting) thread, my own conclusion is that scratch building is a thing and cost is another based on the budget available and the choice of spending for hobbies that is obviously very different for each of us.
Scratch building is fun and rewarding so let's go and make scratch build at our own way...
Hahah! Thanks Francis! I wanted a scratch building discussion to see what pops up. What techniques are used. What are the issues that others find they run into. For example, machining for scratch building... materials and tools become an issue because you are always limited to budget. Also, knowledge. Even if you have a tool, if you don't know how to use it, then you are f****d. I also wanted to know the reasons for scratch building for other members on the forum. Sometimes the answer is as simple as "because the part I needed didn't exist." But then when you need to create your own part, you have to figure it out. And what if some one already figured out the answer, then the issue is finding the answer or the person who knows.
Sometimes, I look at my model and then start modifying it. All of a sudden I say to myself "i can't start putting this much detail into one thing if I don't do the other stuff." It just doesn't make sense to me. Especially if I ever want to enter a contest. Someone will always say "So, you made a moving stick shift... you put that much detail into it, but didnt bother doing the dash guages?" (as an example). So all of a sudden, I start doing more and more. Then I have to build the parts that don't exist.
Like others have said, some issues are related to sourcing materials. Luckily I found a reasonable source for Albion Alloys, which in my mind is THE SOURCE for miniature tubing and rods, made for engineering and hobbyists.
But getting into machining, I need to find another source for metals, I have asked a buddy of mine who is a machinist/tool and die maker if he could source me some stock metal from his work. Luckily he said no problem, just have to pay for it. So now my metal comes in a bit cheaper. But then... the tools... oh man... the tools.
This is the monster that I unleashed by starting this topic of "issues with scratch building."
As for IPMS... yah... no comments on that one. HAHAHAHA
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18 hours ago, blunc said:
I found this quite fascinating:
However, I'm not EVEN going to start with that (unless I win the grand prize of the Powerball).
This thing runs at 6000$ for the base unit. I would love to have this, but then I fell like it takes the fun out of scale modelling. The building it for yourself versus programming a machine to do the impossible tasks you try to do manually. Maybe just me.
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On 5/22/2020 at 12:10 AM, Pete J. said:
....and be prepared for sticker shock. It ain't cheap
If Renshape isn't cheap, why not just use styrene? Pardon my ignorance.
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14 hours ago, landman said:
That's like us calling all facial tissues Kleenex and all cameras Kodaks. Although whike Kleenex endures, Kodaks seem to have fallen by the wayside in favor of cameras.
What's a Kodak? HAHAHA Just kidding... but honestly what the hell is Renshape? I just looked it up and it's like, what, foamcore or something? Like the foam stuff you put fake flowers into?
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2 hours ago, Codi said:
Ah Justin, good to see you took my advice to buy the book I recommended. btw, the quote you just described in the book was kind of my point that I shared with you earlier, in that if you want to get the most out of learning HOW to machine and if you can afford it, buy the mill FIRST. You'll learn more and be more capable after the fact if you can learn to use the mill properly. A couple years after I bought my mill, when I finally ordered a lathe from Sherline, it was like ho-hum....set it up and ran it. Just that much simpler. I'm sure you'll love your Sherline lathe when you get it. cheers, Codi
Ahhhh Tim.... You are so right. The thing is, I should have got the mill first and grabbed a cheap "toy" lathe to do the rest. Thing is... all the "other" stuff I needed, if I started with the mill kit, came already with the lathe. After totaling everything up, for some reason the lathe setup was cheaper to start with. Go figure? But yah, I got the book... reading it like a novel even if it suggests not to. HAHA
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Just read this in the Tabletop Machinist Handbook by Joe Martin of Sherline
QuoteDo you need a lathe, a mill or both?
Which tool is the most important when getting started? The lathe is the first complex piece of machinery an apprentice machinist will use to cut metal. A mill is the machine an apprentice machinist will use to make his or her first complex part. Lathes have always been a great way to learn about cutting metal, but as soon as you have that urge to build a miniature version of a steam engine, you'll find out that a mill is needed more than a lathe. The truth is, to make complex parts you need both.
I would estimate I have spent 90% of my time working with a mill compared to a lathe; however, when a part has to be turned and threaded you need a lathe. A lathe is a good place for a novice to start. It will allow you to find out about cutting metal and requires a smaller investment.
I don' t recommend buying every metal cutting tool in sight until you know you like cutting metal. Metal cutting is a complex, slow process that should be enjoyable before any large investment is made. I would suggest that if your funds are limited and you still want full machine shop capabilities, get started by buying the best mill you can afford and the least expensive lathe you can get by with. The reason is that most likely the majority of critical operations you will perform will require a vertical milling machine.
Well F*** me. LOL!
The issues with scratch building
in Tips, Tricks, and Tutorials
Posted
Pete, I was asking to confirm the details of naphtha and mineral spirits being the same thing. From what I see, they can be the same thing sometimes but not always. But the lighter fluid is a good substitute and easily available here. Also from the wikipedia page, it says coleman camp fuel is naphtha also. Again, readily available.
thanks!