Monday, December 22, 2008

Superman Returns Belt - Pouring The Mold

Made some more progress on the belt today. In fact, this is the last step before I can start pouring up a brand new belt. So pretty exciting.

But first, a little note on tools. One tool that I accidentally made a number of years ago, but has served me very well, is this little gem:

It's left over silicone rubber from a mold I once made. I obviously mixed up too much, and this was left in the mixing bucket. I use this on almost EVERY project I do, as it is the perfect surface for mixing putty. Any time I'm using some two part putty, like the stuff I used earlier in this build, I mix it on this. I will also squirt the air dry putty on here, and then scoop it off with an exacto or pallet knife to apply it to my master. Why?? Because nothing sticks to this! It makes for super easy clean up once the putty cures, as it just flakes off. Some people like to use post it notes or paper for mixing, but I find this solution to be much cleaner and easier. Anyhow, just wanted to pass that along.

Like you care.

But enough of this episode of "Tool Time", let's get down to business.

Tonight I'm pouring rubber on the belt master, that currently resides in a foam core box, sitting on top of a very flat famed poster. Nice!

I'll be using a Sil-Pak product tonight. The deal with this stuff is that you mix it 10 to 1 by weight. But who has time for that? I'm going to do it by volume. The good thing about RTV is that the mixing ratio is very forgiving. So if you pour in too much or too little catalyst, it will still kick. It will just change the time it takes to cure, and the resiliency of the final product. So if you OVER catalyze the rubber, you'll end up with a mold that cures faster. It will be more rigid, and it will provide fewer pulls. It will be a bit more frail. If you under catalyze it, you get the opposite. It cures slower, but will be more flexible and softer.

Ideally, you would mix it at the recommended ratio. For the hobbyist, this is fine, though in professional situations, where time is of the essence, and you don't expect to need more than a few pulls, you may end up having to "hot rod" your mold.

Here's the stuff. My expectation is to do two, ten ounce mixes. I've got my mixing cups and stiring rods at the ready.

No real trick to mixing the stuff. I pour in the rubber first, and the catalyst goes on top of it. I use the markings on the side of the cups to indicate how much I need to pour. I use a different stirring stick for each mixing. That's a good habit in general, though it may not be necessary in this case.

Also important is NOT to pour and catalyze both containers at once. Pour one, mix it, dump it, THEN move onto the next one.

Next up is probably the single most important piece of the mold making process, and is the step that most people forego. Folks, if you want good molds, you've GOT to vac the rubber. The idea here is that when you mix up your rubber, you stir in air bubbles. When you pour the mold, some of those air bubbles will escape, but many will remain. Why are air bubbles in your mold bad?? Because they screw up your positives! For the most part, when you pour a resin into a mold, it heats up. That heat causes the air trapped in the rubber to expand, pushing INWARD on your resin, resulting in tons of little pock marks. That sucks, and usually means TONS of time spent filling those in, sanding them, etc. It's just a giant mess. I'd ALMOST go so far as to say that it's just not worth making a mold unless you can vac the rubber. But, since most people don't have access to one, I guess I'll have to back down off that.

If you don't have a vac chamber, the next thing to do is pour your rubber from high up. I mean really high up. Like standing on your toes, with your arm stretched above your head. By pouring high, you stretch the liquid rubber out into a thin stream. Because it's all stretched out, the bubbles tend to burst on their way down. It's not HALF as good as vacuumed rubber, but it's better than just dumping it onto the mold.

I prepped my molding surface by making sure it was level. My garage floor, er, I mean my WORKSHOP floor is graded, so I like to level the surface off so that the mold pours flat. I guess it's not manditory, but it saves time when it comes time to pour up the master. Here you can see the level sitting on top of the frame, with popsicle sticks stacked up underneath it to set it level.

Then I just dumped it into the mold. That's why this type of mold is often referred to as a "dump mold". It's also called a "one part mold", because, well, it's one part. Open faced mold? The list goes on.

Despite all the prep work that had to be done, and all the effort that went into mixing, vac'ing, and pouring the rubber, this is still the easiest type of mold that can be made. It only gets more complex from here. If you're new to molding, I'd recommend starting with a simple "dump mold" like this, and then moving on to try something more complex like a two part mold.

The catalyst I used for this rubber makes it kick in about six hours, but I always like to let it sit overnight just in case. So by this time tomorrow, I should be all set to pour up a positive. yay.

Friday, December 19, 2008

Superman Returns Belt - Prepping for the mold

I've decided to start in with a more intelligent naming convention for these posts. Stuff like "Superman Returns Belt - Part MXIIV" gets tedious pretty fast. So I'm switching to a more intuitive name for each post. Clearly, dear reader, you should have figured out by now that this post is going to be all about getting everything set to pour rubber.

But first, it's time for something completely different.

In a separate production pipeline are the boots for this costume. Though I'm not making them, I'm doing whatever I can to help make sure they turn out great. This initially started with providing reference material. When the movie hit theaters, a couple of complete suits went on tour around the country. A few of my online pals were kind enough to document the heck out of the suit. Many of the photos taken revealed a ton of detail on the boots. All good.

I collected all of these photos, and when the time came to get the boots made, I passed on all the relevant reference to the company that is going to make the boots, Incredible Costumes. Just like their namesake, they do indeed make incredible stuff. They do phenomenal work, and I highly recommend them. They did a real bang up job on my Christopher Reeve era costume boots, so I naturally turned to them to build the Returns boots.

One of the complicated parts of the boots is the leather that is used on part of the inner boot. It is stamped with the same micro s pattern that is found on the chest emblem. Good news is, I own a chest emblem. Using a scanner and adobe illustrator, I was able to create a digital version of that S pattern, and send it down to the folks at Incredible Costumes. They then used that pattern to make a die, which they have just sent me some photos of. They also sent a photo of the first test press of the die into some sample leather. Take a look:

Pretty snazzy, huh? Here's a link to the website of the company that is making the boots for me. They do not have this item listed for sale, as this is the first pair they are making.

But let's get back to the belt, shall we? When we last saw our belt, it was all polished and ready to be molded. In this entry, I build the box that will be used to house the belt during the molding process. Nice!

I always use foam core to build my boxes when molding. Unless you happen to have a pre-built box on hand that fits the item you are going to mold, I recommend foam core. Or Foam Board, as some people call it. You can pick it up at any good art supply store. Though I absolutely HATE Michaels with a passion, they do tend to carry the stuff. Ugh.

Anyhow, I start by laying the belt down on a sheet of foam core, and tracing the general shape. I do this so that I can build the box without having to have the belt lying on the board. You never know when a random goo of hot glue might go flying and land somewhere you don't want it to. ESPECIALLY on your master. Yikes.

The belt has a pretty low profile. No more than a half an inch anywhere. So this won't be a very deep mold. The next step is to cut strips of foam core that will be used as the actual walls of the mold. Depending on how deep your pour will need to be, you need to make sure your walls will accomodate you. I use a big old t-square and a box knife to cut my strips. As long as one side is flat, you're golden.

In the mean time, I prepared these little squares of styrene. These will be placed into the mold box, at the end of the belt. I'm including these so that there are holes in the mold where I can lay some webbing when it comes time to pour up a urethene positive. That way, the web belt, which will be used to secure the thing to a person, will lay flush with the belt itself. Just a minor concern, and probably not necessary, but it seemed like the right thing to do.

I tried something that ultimately didn't work out, but I'll show it to you anyway. The idea was to glue thin strips of styrene to the back of the buckle, covering the openings. That way, rubber wouldn't pour through them, making it so that I would have to cut the belt out of the mold. Ultimately, the styrene and glue was a little too much, and made the belt sit unevenly. This proved problematic when it came time to glue the right hand strap back onto the belt. So I scrapped the idea. This just means that I'll have a little bit of razor blade work to do once the rubber has cured.

Skipping ahead, as there's no real magic here, you can see the finished box. I used a hot glue gun to run a bead of glue along the outside endge where the walls hit the base. I made shallow cuts into the foam core where I wanted it to bend a little. You can see where I also made rounded edges out of scored foam core. Pretty nice!

I then glued into place the little styrene squares I had cut out earlier.

And here it is, all finished and ready to pour rubber into.

If you're wondering what those cans of paint and rubber are doing around the edges, I put those on the base to make sure it was sitting flat. It's difficult to find a sheet of foam core that is perfectly flat, especially after it's been sitting around your garage for a while. So the weight on the corners ensures it's sitting flat. I am doing the entire project on top of a framed poster. Again, just to ensure flatness. I figure a nice flat piece of glass is about as flat as I'll need to get.

I had planned on pouring rubber tonight, but I just got a little too tired. And I know that when I get tired, I get sloppy and make mistakes. The last thing I want to do is screw this up so close to the end, so I took a step back and called it a night.

With any luck, I'll have the rubber poured this weekend, and the mold will be ready to start producing belts by next week. Should be good!!

Thursday, December 18, 2008

Superman Returns Belt - Part VII

Tonight saw the last step in prep for the master. Very exciting times we live in.

After wetsanding the belt, and getting it pretty smooth, it was time to give it a final polishing. I use some pretty expensive and hard to find tools for this step:

Toothpaste and a sock.

Yup, regular old toothpaste. None of that fancy, new fangled whitening stuff either. Just your off the shelf, white Colgate. Sock provided by Target.

The methodology is similar to wetsanding. Add some water, add some toothpaste, and polish with the sock. Repeat until happy.

Along the way, the polished surface will no doubt reveal flaws that you didn't see before. You just need to decide exactly how "perfect" you want the surface to be. Since this is going to be cast in urethene and probably painted, I didn't feel the need to go TOO crazy.

Here's one of the straps after I've polished it. Probably not too easy to see how good it looks from this photo, but trust me, it's lookin' pretty good.

And here's the buckle. You can see there are a lot of burn-throughs in the paint, but I don't care. It's level, and it's polished, so when it gets molded, none of those will be visible.

And that's it! The belt is now ready to be molded. I'm thinking one session in the garage should be enough to get that finished, as it's a very straightforward dump mold. I'll be sure to blog that when it's done, so you won't miss a thing.

In other news, the weather has finally cleared up around here. Now, don't get me wrong. When I say "Cleared up", what that means is that our light rain and some clouds went away. Here in Southern California, we tend to miss all of the truly harsh weather. In exchange, we get things like earthquakes, brush fires, mud slides, OJ, you know. But it all pans out. Today, I could see snow on Saddleback Mountain from my balcony! Very nice!!

Catch you next time!

Superman Returns Belt - Part VI


Ah, the joys and majesty of wetsanding. It's not that fun, can be a bit tedious, is usually quite messy, but it is in this step that the final product really appears.

In a nutshell, wetsanding is just what it sounds like: sanding, but with water involved. I don't know what the chemistry is behind it, but for some reason, when you sand with a wet piece of sandpaper, you can end up with a rediculously smooth surface. Maybe it's because the powder from the sanded paint ends up fusing into the micro fissures from earlier sanding? I don't know. But either way, the belt is now in for just such a treatment.

I realized I only had 320 grit sand paper on hand, so I needed to head down to home depot to pick up some higher grit stuff for the final sanding job. I grabbed this stuff:

It's found in the paint section, and is specifically designed for wetsanding. If you get regular sand paper, it's likely to break apart once it gets wet.

To make sanding easier, I cut little strips out of the bigger sheets. I'm going to be doing a lot of nook and crannie sanding, so smaller pieces are called for.

I can't really think of a whole bunch of "tips" to give out for wetsanding, other than be patient and go slowly. I guess from a technical perspective, I did something on this project that I would recommend if you plan on going for a super smooth mirror finish. Use two different colors of primer. I started with dark grey, then moved to a lighter grey for a couple of coats, and finished with a couple of coats of dark grey. The reason this is good is so that you can detect burn throughs. A "burn through" is when you sand too far, and go too deep. Worst case scenario is if you sand all the way down to the resin, or worse to the putty. You don't want that stuff exposed in your final master. By using different colored primers, you can see when you burn through, and you'll know when you absolutely have to stop sanding. This technique is really only applicable in the mastering situation. If I was wet sanding a product for display, or a finished piece, I wouldn't want burn throughs showing AT ALL.

So the trick is, go slowly, be meticulous, and gradually increase the grain. Previously, I had sanded the primer off with 320 grit, wet. This allowed me to quickly knock down the primer to a good smoothness. Got rid of all the pits and dimples that are inherent with an off the shelf rattle can type of paint.

Here's how it looked as I began tonight. Not really easy to see, but there's some swirling patterns from my sanding, and it's not all that reflective and smooth.

After an attack with the 400, and then the 600, I have this result. Note that the strap on the bottom is the completed one, with the 320-only sanded strap on the top. Again, sort of hard to tell the difference, but in person it's night and day.

The two straps took some time. Another trick is to dry the pieces off as you go along. It's hard to see any progress you have made while the thing is soaking wet, so keep a paper towel handy to wipe it down to see how you're doing.

The last part I tackled was the buckle. With all those curves and angles, it was a little more time consuming. You'll notice that there were a lot of burn throughs on this part, but that's totally cool, as those will totally disappear once it is molded. There's still some gunk left over on the buckle that needs to be wiped down with a wet towel before moving on to molding.

The last step, which I have not yet completed, it the final polishing. This is where you get a glass like surface. The trick for this is to use regular old Colgate tooth paste, and a nice soft sock. Yup. You read that right. It's a trick I picked up from Harvey Mudd college from a friend who had to build a screwdriver with a clear acrylic handle. The way to get that handle water clear was to go at it with a sock and some toothpaste. Hey, if it worked for a lab project at an engineering school, it'll work for a Superman Returns belt. I'm a UCIrvine guy myself, but I still think those Mudders know a thing or two :)

Tuesday, December 16, 2008

Superman Returns Belt - Part V

Almost there now.

I've been spending an hour or so each night over the past few days refining the belt master, and it's coming along really nicely. I levelled off all the lumps that were in the straps by using a block sander and a bunch of patience. I find that a block sander suits this purpose best, as it takes all of the organic guesswork out of sanding that usually accompanies hand sanding.

So if you're going for a flat surface, use that block.

The most time consuming part turned out to be the buckle. So many compound curves and hard to reach places. It's really come a long way from the lumpy mess it was that I started with. And that's not meant to discredit the original sculptor. It's a beautiful sculpt. It just got warped during handling and my molding/casting process. So there were a lot of boogers and junk to clean up.

I think most impressive are the way the straps turned out. Not only are the lumps gone, but a lot of the inconsistencies along the ridges have been cleaned up. I have to say, I'm even a little surprised at how good it turned out. Just goes to show what a little patience and a lot of primer and putty can do.

As of these pictures, the entire belt has been coated with its last coat of primer. The only remaining task is to wetsand the entire thing until it is mirror smooth. I figure I can bang that out in a night, which still puts me one day ahead of schedule. So I'm pretty stoked.

Just for giggles, I've put together a little comparison shot. You know, before and after magic. The top picture is the master as it came out of the mold. The bottom is how it stands tonight. Granted, the angle is a little off, and the focus isn't as sharp on the after, but I think you get the idea.

There's obviously a MAJOR difference between the two. All of the macro lumps are gone, and all of the fissures caused by the cracking finish are totally gone. Heck, all trace of them are gone.

So yeah, I'd say it's coming along nicely.

Superman Returns Underpants

Nothing to show in this post, but I thought I should document all progress, for those that are following the build.

Tonight I did an initial drawing of the diamond pattern that will appear on the red briefs. I found a source in Australia that has access to a die-sub printer, which is capable of printing onto fabric. Cool trick! So the idea is to die-sub all the little diamonds onto some frabric, rather than screen print them.

Not sure how it's going to turn out, but that's what test runs are for.

Monday, December 15, 2008

Superman Returns Belt - IV

It's been a very productive weekend over here, though not necessarily dedicated to the belt project. Still, it's coming along very nicely. The pictures included in this post are not the most current pictures, but instead show the status as of friday. So consider this a brief journey back into time.

But let's start off with a few factoids surrounding the build, namely some of the materials I'm using.

For shallow holes, minor scrapes, and thin build ups, I use this stuff:

It's an air dry putty. It's NOT good for building up large areas, or filling in deep holes. Not at all. It also tends not to stick very well, so don't try using it on edges or the tips of angles, or stuff like that. It does have some benefits though. It doesn't smell AT ALL. This may not sound like that big of a deal, but trust me, an odorless product is often a godsend. It also sands really easily. That's probably its best characteristic.

For larger areas, or where you need some really solid adhesion, I use this stuff:

It's a high end auto putty, and is worth every penny. It's catalyst kicked, meaning that you mix in a little drop of blue stuff and that starts it hardening. Depending on how much catalyst (or "kick") you put into it, the faster it will cure. The stuff adheres like a mofo, and also stinks like one too. It cures VERY rigid. Often more rigid than the resin you're attaching it to, meaning that you've got to be careful when sanding it.

I know people who ONLY use bondo for ALL of their puttying needs. Now, don't get me wrong, Bondo is a fine product. (Technicaly, Bondo is a brand name, and they make a variety of products. But I'm talking about the large scale body filler that is very commonly available. You can get it at ANY auto supply store) But bondo is not perfect for every application. If you're covering a HUGE area, like a foot across and half an inch deep, I say go for bondo, then finish the edges with Evercoat. But bondo just doesn't have the same qualities as this Evercoat stuff does. Bondo tends to be clumpy, and a bit tacky. I don't mean stylistically either. I mean it has some low surface adhesion, even after it has cured. It's just not as easy to handle as Evercoat either. Anyhow, you can obviously tell where I stand on the issue!

Anyhow, let's move on to the project update.

This is a shot of one side of the belt strap after I had done an initial sanding, laid down some red putty, and then sanded that smooth.

You can see that there is A LOT of fine surface detail that needs to be cleaned up, as each spot of red stuff indicates something that has been filled. So yeah, it was a mess.

After getting that as smooth as possible, I blast it with a coat of automotive primer. I've recently gotten to really liking plasti-kotes self etching primer. Not because of its etching properties, but because of its color. It's a nice, dark grey. After it has dried, you give it a really light sanding with a high grit sand paper, and it reveals EVERY flaw. EVERY flaw. This is great in a project like this, as I am aiming to eliminate those flaws.

Here's how one of the straps looks after its initial blasting.

After that, it's really just a looping on those steps until you get the surface to the condition you want it to be. Each coat of primer reveals flaws that you then putty over, sand down, and re-spray. Repeat.

As of this very moment, I'd say I'm about two iterations away from being done. The buckle is proving to be a bit problematic, as there's so many little undercuts and hard-to-reach areas that require clean up. But I'm not going to go overly obsessisve-nuts over it, I swear. I think I'll put a moratorium on work for this belt at Wednesday. So no matter how far away it is from being "perfect", no matter what, I'll stop on Wednesday and start prepping it for molding. Otherwise, I'd just noodle it to death until the end of time.

Ok, that's it for today. Thanks again for reading.

Friday, December 12, 2008

Superman Returns Belt - Part III

Not a lot to report today, but I wanted to put up some progress pictures before the weekend gets here. Today on my lunch break, I demolded the pours that I did yesterday.

Here is the smaller section:

And here's the entire belt.

All of the warping and lumps that you see in this casting were present in the original. Good or bad, this is a near identical replica of the real-deal belt I got ahold of.

I am VERY pleased with the results. These pulls are exactly what I was hoping for, and will make for excellent starting points for the new master. If you take a look at this picture of the full belt, you can see how well the details of the peeling paint were captured:

I suppose it's sort of a mixed bag, as it would have been great had all that detail been lost!! But it does illustrate how well the silicone and 1630 combination work to capture details, while maintaining size.

Now comes the not-so-fun part of the clean up. I'll probably just do a single posting about how I'm going to approach it, and then do another when it's all finished. There's really not a lot to see along the way, but if something cool comes up, I'll let you know.

Thursday, December 11, 2008

Superman Returns Belt - Part II

Greetings, and welcome back. Just yesterday, I laid up the jackets for the two superman returns molds, and today, I'm ready to pour up a new master. Like Tone Loc always says: Let's Do It!

Superman Returns Belt - Part II

Greetings, and welcome back. Just yesterday, I laid up the jackets for the two superman returns molds, and today, I'm ready to pour up a new master. Like Tone Loc always says: Let's Do It!

I'm very pleased to learn that I've gotten a few new readers to the blog recently, so I thought this would be a good opportunity to revisit some of the things that I take for granted when I'm doing a project like this, but wasn't told early enough for me to save myself some trouble. So along the way, I'll be throwing in a few hobbyist tips.

For example, the first thing I do when I walk into my workshop/garage, is put on a pair of latex gloves. You can get 100 of them for about five bucks at home depot, and let me tell you, they are life savers. I don't wear them for my health, by the way, though I'm sure it's of benefit not to be handling all kinds of chemicals and solvents directly. I wear them simply because I don't want to spent five hours scrubbing my hands and under my fingernails after each session in the garage. That's one lesson I learned the hard way in my early days of slinging resin.

Here's the big belt in its matrix that I poured up last night. Oh, I forgot. So a matrix is not only a structure used in linear algebra and other kinds of math, but in this context, think of it as a rigid cradle for something flexible. That's what a matrix is. Oh, I think they also made a movie or two using that word in the title. Always makes you sound pretty sophisticated when you use it in casual conversation. I highly recommend it.

And here's how it looks now that it's all cured.

First order of business is to take a look at the small mold. Here's how it looks right after I pulled the foil off the back:

Pretty darn good, though there is some excess resin bleeding into the area of the mold I want to pour up, so I'm going to clean that out. I used a rubber mallet and a flat head screwdriver to gently chisel the stuff out.

I assume everyone has a jar of vaseline and a chip brush lying around. Right?? Well, it's time to make good use of them. The bummer/advantage of most resins is that they adhere to themselves to some degree. So if you pour wet resin over dry resin, there's a good chance it will stick. The way I poured up my matrices (That's the proper plural of Matrix, by the way. Not "Matrixes". That's a fake word) is such that there's a couple tiny points where there could be some resin-on-resin contact. So I'm going to slather vaseline over those parts to make sure that they will not stick, just in case there's some contact. For good measure, I'll slather some all around the edges too, just in case I get sloppy.

There was a corner of the mold that proved a little too deep to fill with a slathering of resin, so I just jammed some clay in there. That should do nicely.

Next up is the baby powder. This is KEY to running resin in ANY RTV mold. Oh, RTV stands for Room Temperature Vulcanization, and basically means a two part silicone rubber. The baby powder uses capilary action to draw resin into the tiny nooks and crannies of your molds. Your positives will come out 100 times better if you powder your molds before pouring anything into them.

I usually just splash baby powder around the inside of the mold, brush it around with a chip brush, then blow it out.

With the mold all prepped, I levelled it by using little clumps of clay around the corners. Clay allows me to maneuver the mold to perfect flatness during the pouring process. I sometimes use a stack of popsicle sticks under an offending, low hanging corner, but I chose to use clay this time.

With the mold all prepped, it's time to pour it up.

For some reason, it was only very recently that I realized how easy it is to pour out equal amounts of a substance when you're going into clear cups. I usually use the typical red cups, and they've served me well for years. I like them for smaller amounts of resin, because there are ridges on the cups that you can use as indicators.

A reminder about 1630: it is NOT a good choice for casting up resin parts that will see action. It's actually designed for reproducing molds, but makes for a great gel coat, and is optimal (in my opinion) for making masters.

For extra credit, the bold reader can check out this data sheet on 1630 for more information. I order most of my stuff from Burman Industries, up in the valley. Great people, and they've been supplying stuff to hobbyists and the industry for as long as I've been playing with this stuff.

I started my pour into the mold, and this is where some real artistry comes in. I pour slowly, so I can see the way the resin is flowing. That allows me to detect if the mold is not lying flat. I can add more clay under one corner, or push down on another if that is the case. As you can see from the inital pour, it's actually pretty good.

With the mold confirmed as lying flat, I finish up the pour, and bring the resin up the very edge of the mold. It bulges over a bit, but that's how I want it.

Now I just repeat the process on the large mold. I'll skip the first few steps, and go straight to the different parts.

I may be going overboard on the large one, but I wanted to make REALLY sure that the belt was sitting level, so I pulled out my level. Checked it on the X and Z axis to make sure it was totally laying flat.

Then I just repeated the mixing and pouring process, and it was all done.

And here is the finished product. Well, finished for now. Because 1630 needs 24 hours to fully cure (another GREAT reason NOT to use it as a traditional casting resin) I still have to demold tomorrow. But I'm very happy with today's results.

Wednesday, December 10, 2008

Superman Returns Belt

Hi everyone! Been a while since I've contributed to my blog. In between triathlon training, recording a new rock and roll album, and scanning in my entire photo collection, I guess I've been distracted with other projects.

But I've still got a few things cooking that I think are worth documenting.

Right now, I'm working on reproducing the belt from Superman Returns. Though not a very popular version of the costume, I am a fan. I am lucky enough to have access to a few made-for-production costume pieces, and I got my hands on a belt recently. I only had it for a very short time, so I needed to mold it quickly. The paint job on the belt was also VERY frail, and was cracking all over the place. For that reason, I decided to mold it using silicone putty, instead of the traditional "pourable" stuff. I figured this would not only kick much faster (it cures in an hour) but would also eliminate some of the problems I would have encountered using regular liquid RTV. Namely, I didn't want to do any further damage to the paint job, and I was unsure how it would react with the fabric elements embedded in the belt underneath, should it accidentally seep under.

Fortunately, I had a stash of the stuff sitting around, so I didn't have to order any. It worked really well.

I ended up taking two molds of the belt. One of the buckle, just as a test mold, and one of the entire belt. As luck/unluck would have it, the smaller mold of the buckle captured a bit more detail than the larger mold. I guess the work time with the putty is pretty short, and it had started to kick by the time I got to the buckle on the large mold.

Here's the large mold of the entire belt. Oh, and don't even get me started on the trouble I had to go through to get the belt to lay flat for molding. TOTAL pain in the rear. But it all panned out.

Here's the smaller mold of the buckle.

The overall plan is this: mold the belt, pour up a new master, clean it up, then re-mold using regular RTV, then cast one up in urethene. I'm doing this because of all the damage that was done to the original paint job, which was subsequently captured in the mold. So I've got to clean it up.

The first step is casting up a positive from the mold, which I can then clean up using putty and sand paper. The challenge now is working with my putty molds. Because it's not a straight-up liquid, it will not sit perfectly flat when placed on its back. Cuz you know, it's all lumpy and whatnot. So I've decided to make rigid jackets for the molds. That way, when I go to pour up the rigid positive for remastering, it will be as flat as the original.

To make the jackets, and the positives, I'm using a product by BJB called TC-1630. I've probably written about it before on this blog, as my managloare rifle is cast from it. 1630 has some really interesting properties that make it a good choice for this project. First and foremost, it has almost ZERO shrinkage upon curing. It's completely undetectable. So it's also a good choice for a gel-coat application, or something like that. That's also the main reason I'm using it to pour my positive master. Zero shrinkage, and it's also really easy to work with. Sands really nice, and putty/paint take to it very well. The downside is that it's not terribly strong. So you wouldn't cast like a solid resin blaster or something with it, as it would probably break if you dropped it. There are better resins available for casting positives as far as strenght goes. But since my main concern is size, I've decided to go with it.

I still had my mixing drill bits from my mangalore rifle project, and put them to good use here. They made short work of mixing up the different halves of the 1630. You do NOT want to try to mix this stuff by hand. It's like a gooey liquid on top, and hard packed sand on the bottom. Takes about 10 to 15 minutes WITH the drill bit. I cannot imagine how long it would take without.

I figured I would start with the smaller mold, just to prove out my concept. And because it's easier to work with. I started by laying aluminum foil down over a piece of plexiglass. I wanted a very flat base, and I needed the jacket to be removable. Didn't want it sticking to the plex.

I mixed up a red cup of 1630, and got to work. The stuff kicks pretty fast. It has about five minutes of work time, and then it just turns into increasing degrees of thicker maple syrup. You can push it around with a brush for like 15 minutes, but after five minutes, it's too thick to do anything useful with it. After that, it's 24 hours before full cure.

I start with a wet coat directly on the mold. Because the stuff is at its most fluid at this point, I want to make sure all the nooks and crannies are wet with it. I don't want the mold buckling under the weight of itself during final pour up.

With the mold nice and wet, I start laying in fiber. You know, the stuff for fiberglass? This makes the 1630 much stronger. It's amazing stuff. I pull the fibers apart a bit, to loosen them up, then place it over the wet 1630. Then, using a chip brush, I glorp 1630 over the top of it, tapping down on it gently to work it through the fibers.

I worked from left to right, then did another round from right to left. Probably overkill, but I didn't want to waste any 1630.

So here you have it. Jacket is all set, and is curing.

I'll do the larger mold next, but probably won't document it, since the process will be the same.

Next up, I'll pour the master.