Gathering / casting parts

[Starryeyes]

Time did not permit me to enter the contest... And I have 2 projects in the works now... HOWEVER.. I had to stop and cast a couple tire/wheels to toss in the box of a FUTURE project... The BOSS FINK !! This tire and wheel combo just might work for a FUTURE Deals Wheels build as well...

[TooOld]

Now that's a RARE one !
I almost bought a resin conversion kit once for around $50 but never did , I should have !

[Fletch]

Boy - that sure is a rare one. That is the only Roth kit I never saw in a store new and was never able to find anywhere since and never built.

Instead of the wheels you should cast the Boss Fink and buzzard figures!

[Starryeyes]

Apr 2, 2015 21:18:22 GMT -5 Fletch said:

Boy - that sure is a rare one. That is the only Roth kit I never saw in a store new and was never able to find anywhere since and never built.

Instead of the wheels you should cast the Boss Fink and buzzard figures!

The boss figure I have is a SUPER thin and fragile piece .. I thought about casting it but I didn't want to jeopardize the one and only I've ever had my mitts on ... Lol.. Thin as a potato chip I swear .. Casting him in one piece would outweigh the Tweedy Pie 3 times easily ... I'm really anxious to get this project underway as soon as I finish old SuicideSam the Surfer.. Yep the Boss Fink is one I never saw on shelves either ...

[wardster]

Just throwing some (badly edited!?) "food for thought" type suggestions out there ...

Have you tried doing something like adding something like thin, rolled-out sheets of epoxy putty (that is, Magic Sculpt or similar) to the insides of the (if they're not yet assembled?) castings and/or original model part?

Or even brushing on something like the epoxy "glue" that model airplane guys use with fiberglass cloth, to build up the existing parts to a semi-safe level (but without the 'glass cloth, in this instance) ... and then, once it's thick enough to do more to it, to strengthen it further with sheets of epoxy putty? Or perhaps slush casting a layer or two of casting resin, inside the thin-walled parts; once they had been built up enough via the other methods? Or brushing in multiple very thin watery layers of something like a high-grade, plaster-like material (I use "Presto-Patch" by DAP, myself, a lot, for various uses; and know that it brushes on just fine, inside rubber molds)? With those various ideas being suggested just to build the initial thickness up to where the walls were, say, an eighth inch or so.

Seems like any random, already-hollow kit part could be used as practice.

If the parts are pre-assembled, and in one-piece form, then another suggestion might be to "get goofy" and instead of trying to make it be "solid" or "hard," in one step, to instead pour a very small batch of mixed RTV rubber inside the thin-walled pieces. (So that you have a "solid" final part for final mold making-- but "slightly flexibly solid" instead of using an "inflexibly hard" material to do the filling-up.)

Because it may fight you, you'd either have to let the mixed rubber sit, and harden a bit, so it wasn't so runny; and then, pour it? Or pour regular, thin-and-runny batches; but maybe do so in many small batches, a little each evening or morning or something? In other words, supporting the pre-assembled parts so that they can't move around, and aren't distorted or anything as you're doing this work -- with the idea being to think of a limited area in the interior being sort of like the "ground" or "earth" portion of a "small pond, waiting to happen" in just one area of the interior -- say, the front / back / left side / right side -- at a time. Sort of like slush-casting; but since the rubber's thinness won't allow that to happen, too much, you'd be stretching (pardon the pun) the job out over several days. The overall idea being that, once you have "filled a small pond" and then rotated the part to do it again, somewhere else, a bunch of times, you'd have completely sealed the interior of the model, with enough rubber under the plastic surface to have made the "hybrid" parts much less likely to flex or crack or whatever. Once you arrive at that step, you could do a straight-forward "fill up the entire interior with RTV rubber" sort of pour. Then, with the interior filled, make a final mold.

As further food for thought: I've used regular "pour" style silicon RTV casting rubbers, in the past, as a "brush on" rubber. Takes multiple layers to get it done, and gravity will fight you, and (of course) it ruins brushes (but even dollar store cheapies work fine for this, so it hardly matters) ... but I've found that it is possible to use those styles of rubber to build things up in thin layers, a bit at a time. Maybe you could build up enough of a coating, on the exterior, to seal up any possible cracks or gaps (I'm assuming, again, that the parts may be pre-assembled?) ... allowing you to safely slush cast thin layers of quick-setting resin, in the interior? (Aiming at a solid part, for later molding ... but doing it in a safer way than just filling it up, all at once -- since the parts sound thin enough to bend and flex!?)

One thing that just occurred to me, while I was typing this, was using the kind of rubber they sell in hardware stores for sealing up the ends of spliced electrical wires; and making such joints water-proof. "Liquid Electrical Tape" I think it's sometimes called. Keep in mind that I have not used it for the purpose I'm talking about, and it's made to stick a lot (unlike silicone rubbers) so with this method, you'd have to be sealing the interior up, not brushing it on the exterior ... and as a result, considerable practice and experimentation would be needed -- but it may work well enough on "practice parts" (as a permanently-attached, brush-in or brush-on rubber) just to seal up the hollow interiors of the thin-walled parts, so that nothing liquid is likely to leak out. Then, it seems like you would have a good "vessel" to pour in ordinary RTV casting rubber, as a final fill material; and/or to gently build layers up, on the interior, using ordinary fast-setting casting resins. (All intended to make a stronger piece, which you'd then use to make a "normal" style of RTV rubber mold, to cast up the exterior portions of the parts.)

It occurs that another way to do it would be a combination of one or more of the above methods. Maybe filling the parts (if they're pre-assembled) with water, and looking for any area where it leaks; and then, using a brush-on material (one that won't hurt the exterior parts, if it leaks a bit) to seal those areas up, until the casting will hold water okay ... and then, either slush-casting in several thin layers of casting resin, or making several "fill pours" with RTV rubber, or ...?

If you were intending to do a fill-up of the interior, but were worried about the final weight and mass, perhaps you could experiment (on less-rare kit parts, of course!) with using things like the plastic BB's that are sometimes sold at places where kid's BB guns are sold. Using those (sort of like giant versions of the "micro-balloons" that are used with R/C planes, etc.) as an initial fill, just to take up space / volume, without adding much mass ... figuring that any resin or rubber poured into such a space would get into / through the empty spaces between each little orb; and would end up making a lighter-mass-but-solid interior.

Just tossing ideas out there. I'm sure others have other ways of doing things, that I'd have never "thunk of".

[Starryeyes]

Wardster !! Thanks so much for all your input... When I received the 2 halves they were missing small bits and pieces possibly results from a bad pour or possibly a "second" where one side was missing, the opposite gave me a demension to follow... It started out just being tacked together... Then one thing led to another and before I knew it my OCD took over and BOOM! I had this thing practically welded together with CA... After repairing all the voids and rebuilding small missing areas I thought about doing an external RTV brush-on with a temporary parting line using tape and attempting an external mold.. The skull and buzzard are actually fixed parts of the figure so I'm working with only 2 pieces- a front and back.. I could pour one side with the "face" down half way up and repeat the back portion.. Then do a slush type cast.. Lots of possibilities and a new challenge trying this procedure ... IF I do not build this project this summer ( which I guessing will not happen) I may take a shot at it at a later date..

[itsonlyakit]

Just had a thought, yup it happens. Wardster's input has me suggesting this. 3 D printing is coming along and if one were to take a lot of photos of the build, down the road, the technology be there and out pops what you desire. Take controlled photos of the assembled figure on a turntable and shoot every 30 degrees. Just a thought.
Cheers Eh!

[grandpamcgurk]

Did someone say 3-D printing? I think Chuck has a pretty good understanding of what's involved with having a master "printed". It's very do-able but not inexpensive. My thinking would to be to fill it (make one solid piece) to use as a master. Cut it into pieces (arms,head,upper body etc.) and then cast the individual parts to be assembled by the builder as a resin kit. This way, as long as the molds hold up replacement parts or just the buzzard etc. could be cast without having to cast the whole thing again. If a mold gives out a new one could be made from a cast resin part. Just a thought.

[Starryeyes]

Apr 9, 2015 5:53:51 GMT -5 grandpamcgurk said:

Did someone say 3-D printing? I think Chuck has a pretty good understanding of what's involved with having a master "printed". It's very do-able but not inexpensive. My thinking would to be to fill it (make one solid piece) to use as a master. Cut it into pieces (arms,head,upper body etc.) and then cast the individual parts to be assembled by the builder as a resin kit. This way, as long as the molds hold up replacement parts or just the buzzard etc. could be cast without having to cast the whole thing again. If a mold gives out a new one could be made from a cast resin part. Just a thought.

Amen on the 3D brother Don !! I TOTALLY understand the process thanks to you and the boys at TDR INNOVATIONS .. I like your anology on the casting input ... Might be the best and simplest way to go... I've always liked the way you roll Don ...

[brizio]

I saw one for sale in a swap meet years ago, but I had to sell at least a kidney for it.
Agree on what grandpamcgurk said about the casting, easiest way and simple.