I’ve got a 1/72 Academy PBY Catalina that comes with vinyl/PVC/rubber tires on the main beaching gear. I hate this kind of tire. I want to make molds of a scratchbuilt fishtail exhaust and of the vinyl beaching gear tires with their plastic hubs. I really don’t want to shell out for a resin starter set right now and there isn’t a Hobby Lobby near me that I can get the alumilite stuff with a 50% off coupon. I’ve been doing some thinking, and some looking online, and now I have a few questions.
Can I use RTV Gasket silicone (like you use on a car engine or transmission) to make my mold? It doesn’t have much for detail, and I would need a total of 4 fishtails and 4 wheels for my Catalina. I might build up to 3 more assorted Catalinas that may or may not need fishtails but will definitely need the beaching gear.
Can I use some sort of two part epoxy for the actual casting? If so, what kind? I was looking at some of the Zap epoxies.
I am interested in getting into resin casting at some point, but I’ve spent enough on my spray booth for a while. Thanks for the help, guys![tup]
There are several good documents, videos, and FAQ there which will answer many of your questions.
Smooth-On also sells some starter kits which have everthing you need to get started. They are priced reasonably. I use OOMOO-25 RTV and Smooth-cast resin.
I have not heard of anyone having a great deal of success using jury-rigged materials and methods. Your mileage may vary
You could try this. I had mixed results with using this technique to cast a pilot figure, but that is pretty complex. It would probably work better with something simple like a wheel.
The concoction mixed to make the mold is really nasty though. Do not mix this inside your house. A respirator would be wise too.
Simple modeling clay can be used too. I’ve done several parts this way. One sided piece such as tires are easy…especially when you are casting a piece with two halves.
You might also try picking through your spares stash…those tire/wheels aren’t anything really special. No spares! Try asking if anyone here has a set you could bum or buy.
Hi Eric, thanks for the input…I was wondering about some form of caulk, and now I know, I’m at least not alone. [tup]
Hi Ed,
I’ve looked at the sites of both Smooth-On and Micro-Mark, and liked what I’ve seen. Eventually, I’d like to get serious about this, and I’ll probably use one of these two. However, for now, I’m not looking to spend the $50-$80 it will take to get properly set up. Thanks for your input, and I’m sure I’ll be around asking more questions once I do try this seriously. [:)]
Hi Dave,
Now that is what I’m looking for…someone who’s been there, and taking the time to write it up. That way will take a couple of tries and more time, but will not break the bank. Thanks for the link!
Hey Gerald,
Modeling clay, eh? The kind that hardens on its own? Interesting…Can I use something like vaseline as a mold release agent with clay? Do you have any recommendations for a brand/type of clay to use? Sculpey?
The kit part is a one piece injected plastic hub, with a one piece PVC tire that wraps around the hub, so if I used clay it would have to be able to do a 2 part mold. Do you know if that’s feasible? I’m really liking Dave’s link’s idea of using two part epoxy for the actual cast.
Thanks for all the help, guys! [bow] I’ll post and let you know how it works out for me.
I didn’t come up with the idea, or do the writeup, I just came across it a while back and tried it. Most of the stuff I already had on hand so I figured what the heck.
I spent quite a while looking through my spares to no avail. I’ve also posted a want for 2 500lb US bombs, 2 1000lb US bombs, and the beaching gear wheels on a few sites that allow such things, but haven’t heard anything yet. The problem is that there’s only been a few Catalina kits that have beaching gear in 1/72, and they are OOP or are Academy’s vinyl trash. Thanks for the idea though.
You can use the modeling clay you pick up for kids…many of the molding kits include this stuff to use to make your RTV masters. I just make a glob on the workbench and plunge the part half way into the blob. Then carefully pull the piece back out…you can use a lubricant such as vasoline or even a water based type such as KY. Then fill the impression with resin. It may take a few attempts to get the impression done right, but for simple one offs it is an effective method.
There is another molding medium…visit your dentist and ask him for a packet of the molding stuff they use to cast teeth/mouth impressions…it mixes with water and it will work also…tastes like grapes.
Email me your list of ordinance…I have enough on hand to equip several dozen squadrons of aircraft. lol
A note of caution here. Many tin-cure products will be affected by clays which contain even minute amounts of sulfur. Cure will be inhibited, resulting in a gooey mess. With luck you may be able to extract the master parts, clean them up, and try again. Be sure that your product does not contain sulfur or make a trial run before committing your master to hazard.
Again, refer to the information at Smooth-On or other such sites on selection of clays and materials.
Hey Gerald, thanks for the info! I’m gonna head to Michael’s or Joann’s tomorrow, and see what kind of clay they have. I’m fine with having to try multiple times. PM inbound on the bombs! Thanks! [bow]
Hi Ed, thanks for the warning. Correct me if I’m wrong here, but it sounds like if I use clay as my mold material and 2 part epoxy as my casting material, then I don’t need to worry about tin-cure reactions, as I’m not using anything with silcon rubber. I’ve been browsing the websites of smooth-on and alumilite for clay suggestions, but all I’ve found is specialty clays for avoiding the tin-cure reaction with silicon. I think I’m going to start cheap with Crayola Model Magic clay for my mold, and 2 part epoxy for my cast.
Well in california it causes cancer. Also it is a Class 8 Corrosive which says you should protect your eyes and skin and should not breath in the fumes.
Good stuff there. Now do I want to look at the MSDS for the rest of my modeling stuff???