Casting An HO Scale Locomotive - Part 2

In Part 1 we molded this model locomotive body in a silicone rubber squish mold. In this video we make urethane resin castings. But the mold had flaws. More often than not, flawed molds mean flawed castings.
Watch Part 1 here: • Squish Molding An HO S...
Thanks to Art Resin for providing the resin dyes used this video. www.artresin.com
I get my rubber, resin and other casting materials from www.silpak.com
The train model 3757 is made by the Märklin Company. For more info about their products visit:
www.marklin.com
The actual train this model is based on is a BR 103 locomotive.
The footage comes from the KZbin channel Sebastián López. Check it out at: • BR 103 113-7 Stuttgart...
Here is a list of suppliers for many of the materials I use in my videos:
www.dropbox.co...
Do you have a project to suggest for the channel?
Here’s a .pdf with everything you need to know:
www.dropbox.co...

[@emachine898]

Hi Robert. I do this type of work often, and my solution to the small holes that break off from the mold is this: Before pouring the mold, fill the small holes with clay and then use a tool with a rounded tip to make a dimple in the clay on the outside face. The dimple will leave - a dimple - on the surface of the casting and you can come back with a drill later and open up those holes. Makes sure you can locate where the holes should be. You open them with the exact size hole thats required and the mold doesn't break down so quickly. Hope this helps! Big fan of your work, I've learned a lot over the last year.

[@arichutfles9550]

Great idea!

[@RobertTolone]

Yes that is a good process. Also one that I do every time there has to be a deep hole drilled into a casting. Problem here was that many of those small holes are square, or rectangular. It’s a minor detail but it’s definitely in the original casting.

[@MrHankomatic]

Hi Robert, A great technique for avoiding bubbles in a casting is dusting the mold with baby powder. The powder breaks any surface tension and disappears into the resin.

[@Ianart26]

just found your channel because I needed help with a mold for one of my movie props, SUPER helpful you are a wizard!!!!!

[@ComicClub01]

The seldom times I do a squish mold I always do vents to evacuate the resin, so the resin does not "open" my mold. Fan of your Tube, binge watching it, all the vids.

[@TAJAM_PEDIA]

Part 2 great result 😀👍👍🥳🥳🥳

[@professorsnape6848]

This is awesome

[@NickWalters571]

Another very interesting mold and casting Robert. I love that you take on jobs you know are going to be difficult and show us how to solve the issues that come up along the way. Knowing how to deal with problems on the fly is a lifesaver on jobs like this.

[@emachine898]

I have another idea on how you can improve the casting from this damaged mold. You have a tight-fitting mold box, place some thin double-sided tape along the edge with the damage, place the mold in the box and press the side of the mold against the tape. You're getting those ugly divots on the one side because as the resin squishes out it forces it's way past the marks, which draws the side of the mold closer to the cavity. By 'gluing' the side to the mold box it may hold the edge away and allow a better casting.

[@allalphazerobeta8643]

Here is how I'd attempt to repair the trains without making a whole new mold. I'd make a mini mold of the damaged section and remove the damaged section from the part and recast if possible onto the part. If not as a separate glue in. I've used this to even repair sections of damaged plastic parts were I could grab a mini-mold that was identical to how the damaged section looked. For example. plastic grill. I took a mold from an identical section. Or in the case of damaged clip in features for my laptop, I grab molds from other clips, came out good outside of air bubbles. I also used clay to make them a bit beefier before making the mold. I used JB, weld plastic bounder and injected it into the mold with a mixing nozzle from Amazon. I'm not sure how well urethane resin sticks to cured resin but If memory serves it sticks damn well. Love the VIDEOS wish, I'd seen them years ago when I did some casting for prototype work! PS, I painted the repairs with gold paint to give it a Kintsugi look.

[@nekrataali]

I like the flaws because for me it would make for great terrain (like a rusted out boxcar) or the base of an Ork vehicle. We're chopping that bad boy up and nailing it back together with armor plating anyway!

[@ArcticFlies56]

Robert, you certainly are tenacious.

[@f.d.6667]

Awesome video - as usual! ... also, bonus points for showing my hometown for a few milliseconds in the intro!

[@danthemakerman]

It's still damn impressive!

[@johndix6101]

It's just like you robert

[@txikitofandango]

I can't believe how uniform those walls are

[@yugos.oficial]

Despite the complications, it is a great work.

[@annekabrimhall1059]

We’ll done, Bob! Bien hecho! Sometimes things work out😀

[@NM-wd7kx]

Something I've worked with is degassing resin in the mould to make sure it runs into each tiny detailed, though I don't have a pressure pot so it's extra useful for me

[@OtherWorldExplorers]

What a stiffer mold be advisable. I mean with all those small intricate pieces it seems like a stiffer mold would hold up better.

[@speedandstyletony]

Need weight! 💡 Box of screws!

[@DimensionMachine]

Fun to watch the master at work!

[@ActionModeler]

I knew he would have this problem an offered my suggestion. It doesn't sound like he used the mold box on any of the pours. This let the side blow out away from the section stuck to the top mold. If he used the box to hold the mold in shape it wouldn't be so bad. Same concept as rubber bands he's used actually.The mold keyed in place at the bottom but not at he top holding the sides in. The mold walls aren't as firm as he thinks when that resin starts to gel by the time you fiddle with those bubbles. I told him to cut vent holes in the top portion of the mold that mates with the flat area so the extra resin from squeeze out can actually squeeze out an not have try to make it to the outer edges. If any caster gets flash that thick then this is your problem. After using metal tube to cut holes I found they do make metal punches in different sizes. Also fixing that mold is not that messy if you can get the part to fit back in as it was. Have the sides clamped to the inside of the part an the outside so the part is absolutely flush. If it has a gap then yeah that ruins the mold. Then pour in some new silicone till its flush, silicone sticks to itself. Cut the chunk from the top an done.

[@USALibertarian]

A valiant effort. Very informative.

[@wiesejay]

Content-om nom nom 🤤

[@sirioth]

another killer video man

[@MarkATrombley]

Did you make the proper sacrifices to the casting gods before pouring the resin?

[@RobertTolone]

No. That is why the Casting Gods saw fit to inflict public embarrassment upon me.

[@upperwarlord7744]

I was thinking about sending a E8 or my FP45 to see if he could do it

[@RobertTolone]

The challenges would be very similar to this one.

[@tawanabatemon9493]

Hi Mr. Robert I make baskets and was wondering how to make a mold for a claw foot bathtub basket. I can’t figure it out.

[@GeorgeGraves]

Would love to see more "engineering" type casting (such as this) vs the more artistic type work. Seems to be much more of a challenge.

[@RobertTolone]

Much more of a challenge for me since most of my career has been sculpting and casting characters. I almost never did mechanical or functional parts. So it’s fun for me to give it a go on the channel.

[@GeorgeGraves]

@@RobertTolone Thanks - I'm learning a lot from you!

[@farmerdave7965]

Fourth law of thermodynamics : Things get worse under pressure

[@roger.agburn]

"I'm not satisfied with the mold, I dislike the cleanup, here we have some hideous flaws ... I hope you liked the video." :-D To bad it didn't work out good enough, but indeed, yes I liked the video. Have a nice weekend!

[@RobertTolone]

I’m always hoping that the video has some merit even when my methods have none - except as examples of what not to do.

[@truegret7778]

Very cool follow-up. Would the cost vs benefit analysis suggest making a new mold (since cast repair attempts almost always make it worse)?

[@RobertTolone]

The cleanest way to repair the defect would be make two castings. Cut the damaged panel out on one of the castings and replace it with a panel from the other casting. This only works because the panels on each side of the train are symmetrical. If I had to make a bunch of these castings I would definitely remake the mold.

[@EasterlyArt]

What I adore about this kind of casting is that it can be applied to things like 1/64 scale cars like Hot Wheels. Granted you would want to use some metal if you want to have the same feel, and need to be extra careful when handling hot metal, but the end result can be pretty amazing. This goes especially for those who want to make custom toy cars. I may be one of a few, but I still enjoy playing with my toys, as silly as it sounds, but I have the benefit where my career encourages play. I would be too eager to want to play with something with sculpy on it and end up wrecking my build, versus using the initial design as the original to make molds of. So knowing another method on how I could cast my own cars is pretty spectacular.

[@joek600]

If there wasnt that small accident while taking apart the silicone, the casting would work so I dont see this as a failure. Btw isntead of filling those tiny holes manualy, you could put the mold in the vacuum chamber, draw the air out and then put it in the pressure pot

[@RobertTolone]

I could have used a vacuum chamber if I substituted a slower curing resin. The problem is that a vacuum chamber takes a while to do its work and the Fastcast I was using sets up in minutes.

[@joek600]

@@RobertTolone The only resin I can find locally has about 3min potlife, I use my vacuum chamber after pouring the resin in molds to ensure that there are no air pockets left in difficult spots. I have taken joggling molds in and out the chamber to break-dance levels lol

[@ScottBourke]

Would a bunch of registration keys around the outer edges faces between the 2 parts of the mold have helped avoid miss-alignment?

[@RobertTolone]

Possibly. I usually use mold keys in 2-part molds and wanted to experiment with a different system for this video

[@jamesbrown99991]

Can you cut those defects off Part B of the mold and glue them into their rightful place on Part A of the mold, to reduce the damage to the end product?

[@RobertTolone]

Yes, you could.

[@burgermaster4u2]

Hi….Robert….love your work…..just seen this how to make a mould..but I cant get part one….how do I do this please….many thanks Dave

[@RobertTolone]

kzbin.info/www/bejne/gHTEn6uAlNemnc0si=h--i1HVRMWem-_5R

[@dodgeramsport01]

So the resin, Its plastic?

[@professorsnape6848]

I was using sculptors clay before I used silicone to mold to make a "rough cast and I found that when I did that it was a challenge but would you ever attempt a cast with molding clay

[@wereshnefer]

Would it be fair to say that the best way to address the longevity issue of molds on a part like this is to only go with injection molding? Would a more rigid or more flexible rubber stand up to the tearouts better? Using a mold release?

[@nekrataali]

I'd bet money the original was done via injection molding, especially on mass-produced plastic kits. We see why in this video a lot of model companies are investing in injection molding. Some places still do rubber molds and it shows 😄

[@RobertTolone]

Mold release could possibly help with preventing tear-out of the small window parts. It would certainly be worth a try. The original piece that I was casting from was clearly made by injection molding.

[@kevinwatson5833]

Im curious robert do you think a different mold style would suit this better or just redoing the mold and try to avoid the flaws?

[@RobertTolone]

I would definitely remake the mold. But I would work up a better method for applying the mold release so I would not repeat the failure of the first attempt.

[@joelnoles4530]

I have a model I want to make a mold of. It was sealed with spray lacquer. Do you think that could cause cure inhibition? I would test it with my silicone but I don’t currently have another model to pour the extra silicone around and I hate to waste a whole batch. It’s tin cure not platinum.

[@RobertTolone]

Mix up a tiny batch of rubber and test it on an easy-to-clean part of your model.

[@albertcostell6034]

nice work Robert!, do you think better results can be achived by making mould similar to your video tiny car?

[@RobertTolone]

I could not figure out how to vent and sprue this train body using that same method. Also, pouring those long thin walls would be extremely difficult that way.

[@professorsnape6848]

I sent and Email to ya please read!!! thank you youre awesome and just the best thanks robert!

[@johnathannyc]

Did you attempt to use the mold box for any of the castings? Would it have made a difference with the alignment of the broken chunks? ... Also curious how the leakage from the mold within the mold box may contribute to pressure on the mold walls, negating the benefit of the box itself.

[@nekrataali]

I was wondering this, too. Wouldn't the mold box help prevent any defects? You probably wouldn't have much overflow if you weighed the casts and resin, pouring only an exact amount.

[@RobertTolone]

I might revisit this mold and do the castings inside the original mold case as planned. Also I would cut channels into the molds to relieve the squeeze out. How much this will help is an open question. But it is worth investigating

[@mikehext]

Do you ever reuse scrap resin to fill like chunkies for the actual thicker molded items?

[@roger.agburn]

I know someone who does and as far as I have seen it can cause nasty bubbles.

[@BIGJIM1934]

I do all the time but only on very thick solid parts.

[@RobertTolone]

I don’t ever do it. And I always make sure to use the exact same kind of rubber. That is because I want to retain the flexibility of the mold and also make sure that the chunkies bond completely to the new rubber. If the mold doesn’t have to flex much you could in theory use resin chunks or other inert materials as mold filler.

[@BIGJIM1934]

@@RobertTolone I think you misunderstood what he was saying. He was asking about using scrap chunks of resin in casting thicker resin parts to lower the cost of resin. I cast some 1/8th scale engine parts that are over a 1/2 inch thick so I add scrap chunks of resin to lower my costs. I would never add resin chunks to silicone. That's a recipe for disaster.

[@RobertTolone]

@@BIGJIM1934 I think you’re correct. Mike, if you meant do I ever use resin chunks to fill castings the answer is no. in certain circumstances it might work very well, but I never have that much resin scrap on hand anyway. So I’ve never even tried it. There are many good inert fillers for resin that can lower the cost of your castings. But they also change the characteristics of the castings.

[@taxidermiedhuman1523]

Hi Robert! After watching your videos for a long time I have finally started doing same casting myself and thought I should invest in some sticky wax. The problem is that the only distributers I could find are in the US and I would prefer to buy from Europe (where I live) because it would get to expensive otherwise. However the only thing I could find are sticky wax for diamond painting. Do you know if it’s the same thing and would work? Thank you!

[@RobertTolone]

I don’t know anything about wax for diamond painting. Jewelry making and dental lab suppliers are good sources for sticky wax and there must be many in Europe. Also art foundry suppliers.

[@professorsnape6848]

What type of rubber do you use

[@RobertTolone]

In this video I’m using Econosil-25 from www.silpak.com

[@pietcement9603]

Hi Robert like I wrote in the comment on your last video, I've been a long time follower of your channel with the single goal of just that: making copies of my H0 scale (locomotive) models. as I mentioned I finished my first mold ever just before you posted part 1 of this video. Now I've just finished watching this video and my experiences are the similar to yours. I found that the two mold half's align very well but i did however brace the sides a little so the mold would stay straight. the biggest issues i run into are bubbles, trapped within the cast. and since the size of them are rather big, it seems that it's a case of underfilling the mold (i fill it enough but it runs out) could that be a result of pushing down on the mold too much or is your pressure pot the reason that you don't seem to have that particular problem?

[@RobertTolone]

The truth is, I had no idea whether this mold would work at all because I have never made a squish mold this deep. If the mold had not been flawed I would have gotten very nice castings out of it. So I am encouraged to try it on more similar projects.

[@levinebette15]

Did I miss #1?

[@RobertTolone]

Last week.

[@levinebette15]

@@RobertTolone it showed up after I saw #2.

[@levinebette15]

Schmutz=dirt!

[@pingASS_]

I like chocolate

[@RobertTolone]

Random, but me too.

[@Jkauppa]

try ceramic molds that dont brick, pun intended, I mean, ceramic burned "cup" instead of rubber as the casting mold

[@Jkauppa]

yes I mean pottery burned at 1000C, with smooth clean surfaces, like plates, cups, paintings, ceramic mold

[@Jkauppa]

should auto-detach because of the smooth surface glassed

[@Jkauppa]

auto punch out molds, so that the cast line is not at the clean lines, some extra instead of needing to be cleaning stuff again

[@reymed1670]

Just do it over

[@RobertTolone]

Not the first time I’ve had to toss a mold and do it over! 😭