Messing about with pewter
 

You may recall I thought I was going to be able to unload a bunch of pewter miniature figurines onto UT for eventual profit! but a wrench was thrown into those plans. And you may even recall that I had given my son a sampling of those figurines, assuming he might like them.

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Most of these things come disassembled. You are supposed to trim the little casting marks off the pieces and glue them together using epoxy. Well, my boy thought they were really cool until it came time to glue them together. Turns out we didn't have any of the appropriate kind of glue in the house. So he tried using a soldering iron to see if he could melt the little guys arm stub and melt the socket and jamb them together. It didn't work. But he did discover the incredibly low melting temperature of pewter.

We got to talking about what we could do with a pound or two of pewter. I explained what little I knew about making molds, and we racked our brains to come up with a cool nick knack to make.

It was decided that we would carve a mold out of plaster of paris, which I did have on hand, and try making a neckerchief slide. A neckerchief is kind of a bandanna that Boy Scouts wear around their necks, and the slide holds the whole thing together. There is an official Boy Scout slide, and we both own one of those, but there is a long tradition of specialty slides being made to commemorate different stuff. We thought it would be cool to make a slide that is unique to our troop, and just show up wearing them one day at a meeting.

So the first thing to do is to mix up some plaster.

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We used yogurt container bottoms to be the molds for the little pucks we were gonna carve into slides.

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While the plaster took an hour or so to set up hard, we needed some source material.

I grabbed a neckerchief because it had a nice embroidered logo I could scan.
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I grabbed some nearby stuff to weigh it down flat on the glass and scan it.
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Then I opened the file in GIMP and trimmed away the extra stuff. Resized it too so it would fit the hockey puck.
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And printed it out. Here is a sheet next to a plaster puck.

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And then to prepare the hockey puck we had to microwave them for a while to drive out all the moisture, and then also sand them nice and flat.

Then we spread newspaper on the dining room table, and we could cut out the seal and use a glue stick to stick it to the puck.
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I got to work with an x-acto knife. These magnifying visor things are awesome.
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It took about half an hour to trace each shape with the x-acto knife. I had to press hard enough to cut through the paper, but if I was too hard, the plaster would crumble. It was a little tricky.
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After I was done tracing all the outlines, I peeled the paper off, and started carving out the depth. this part was very meticulous and tricky. The plaster wanted to crumble. I used a knife to outline shapes and a jeweler's screwdriver to scrape material away and leave a flat bottom.
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This is the finished product and is what the pewter slide will look like. I'm tempted to try to build up some of the letter edges that crumbled away, but I also am contemplating leaving it looking a little more organic and doing less work.
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Next, I have to cover this carved plaster puck with a mold release and pour some other mold material over it to get a negative. I originally thought of just using more plaster, but we tried a test doing that, and it didn't work out too well. So I ordered some high temperature silicone material online. When it comes, I'll post the rest of our progress.

Nifty. You should subscribe to the "Tested" YouTube channel, if you haven't yet. They have a lot of stuff on molds.

Arlington Vagina! :speechls:

Since those toy parts were probably made offshore there's a good chance they contain lead. Melt in a well ventilated area.

The silicon sealer they have in autoparts stores is good for 500 degrees and the Hi-Temp is 650 degrees. Your pewter should melt around 400 degrees, a little lower if it has lead.

I was thinking about getting RTV gasket material that comes in a tube, but I wasn't sure how that would pour over the plaster mold I made. It needs to get into all the crevices without bubbles. Maybe painting it on would work. I don't know.

I ordered a sample size of the material that is meant specifically for this application. So it should work.

Funny how I was fine with doing it the cheap route until after I invested a full day making the plaster mold. Now I don't want to lose a day of work just to save $30.

How funny, I just made a plaster mold to pour some lead ducks for fairing boat lines. (relax, it's only a model)

I learned lost wax bronze casting and mold making in school. You can pour lead or pewter into a plaster mold, but you sort of did it backwards, Make your master positive out of something like wood or wax then make a plaster mold of your master positive. If there are no undercuts the positive should pop out once the plaster sets up. You can use your carved plaster as a positive if you seal it really well and use silicone or something as a release agent. When you've made tour plaster mold let it dry thoroughly. an hour or so in a low oven should do it. You can now pour the pewter into the plaster mold.

Another way to get a really detailed mold for one-offs is to get some dental alginate to make your mold. You can pour several wax positives with it before it dries up or falls apart. Then you can pour plaster over the wax positives, encasing them fully but allowing for a sprue and a vent, You melt the wax out of them (outside, low campfire coals be sure to add sand to the plaster to give it strength) Then while still somewhat hot you pour the metal.

I accidently forgot to take some Bismuth alloy out of my pocket, and brought it home. It's bad if you get fired taking something out but a damn fool if you get caught bringing something back.
This Bismuth alloy melts at 158 degrees F (yes it'll melt in hot water), we used it in tooling to locate bushings in drill fixtures where the old bushing was ripped out leaving a huge hole. It also expands slightly when it cools holding the bushing tight.

My buddy used to do a bunch of wood carving and he bought some silicone mold material so we cast several of his carvings. This one is about 3" high and has good detail. I mounted on a piece of Cocobolo scrap with some stars above and a wood chip that looks like a butte below, calling it, "Between Heaven and Earth"

Crafty!!!

Something to do while his chick did laundry at my place. :blush:

Very nice

ftfy

Very nice Bruce!

You should document the model making here. I'd enjoy that, and I know others would too.

OK. Will do.

This package was waiting for me last night.

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See that? Advanced Materials. Not only that, but "We are here to help." makes me want to buy lots of stuff from them.

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And how about this? "High heat resistance." And even more important to a guy, "very low linear shrinkage." I hate when that happens.

Why I never go swimming.

That is fun stuff. can't wait to see.

Does it stay flexible when cured?

A little

Good, that will allow removal of your casting easier and maybe reuse of the mold.

After sleeping late this morning and getting some breakfast, we headed down into the shop to start the next step. The silicone rubber takes 24 hours to cure, so we had to do it Saturday morning to be able to pour pewter on Sunday.

I had gone over to my cousin's house that I am selling and that is full of a lifetime of junk, and picked through his stamp collecting organizing bins. In all the empty tubs of margarine, and plastic bowls were these chicken pot pie plates. Not sure if he bought these new or saved them and cleaned them, but they were the perfect size. We hot glued our plaster emblem things to the bottom of these little pie plates.
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And I applied Vaseline as a sealer and mold release. If you ever have the chance yourself, don't do that. It was a mistake. The Vaseline filled in all the detail. I tried using an artist's brush to remove some, but it didn't work.
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So I though about it a bit and went upstairs to get a hair dryer. I heated the thing up, and the Vaseline just melted and dripped right off. Perfect.
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So the detail is back!
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Most of the Vaseline had melted off, and I wanted a release agent on there, so I got out my can of expensive silicone lubricant and gave it a heavy spray.
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I opened the silicone rubber package. The instructions said I should mix the part A first since some ingredients might settle to the bottom in shipping. It was thicker and harder to mix than I expected. And very messy. It wants to jump out at you and get onto your elbow and then into your ear. So I wore gloves and covered my scale with plastic wrap.
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I put a mixing cup on the scale and zeroed it. A precise scale is crucial, because you are supposed to mix 100 parts of A with 3 parts of B (by weight.)
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I poured in 300 grams of part A. It just seemed like the right amount.
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And I added 9 grams of part B. Except the scale jumped to an addition 10 grams just as I stopped pouring. Dammit. Probably doesn't matter. Only a gram. But that's off by 10%.
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Now I had to mix and mix. The pot life is 40 minutes, so I mixed some more. I've worked with epoxy before, and mixing thoroughly is very important with this stuff.
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First I poured into my son's pie plate. Better to make any mistakes on his, since it has way less detail.
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But it went smoothly and I was afraid I didn't leave enough material for mine, so I moved along.
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All that mixing had introduced bubbles, so we had to tap the molds for a few minutes to encourage the bubbles to rise away from our precious plaster emblems and pop at the surface.
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These were supposed to set up for 24 hours before we use them, but my son was impatient and he attacked his after three hours. It was set up nicely. So I started peeling the foil side of the pie plate away from my new rubber mold.
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I kept peeling and even peeled the foil away from the hot glue that held it to the plaster.
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And then I pulled back on the rubber edge a little, and it separated pretty easily from the plaster.
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And the plaster emblem pulls right out.
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It's clean as a whistle.
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I'm very pleased with the level of detail this rubber mold provides.
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And you can see it will be larger than a regular neckerchief slide.
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Tomorrow afternoon, we melt plaster.

My plan is to heat the rubber mold up on the top rack of our propane grill. Meanwhile, heat a "crucible" of pewter on a camp stove. And pour it into the hot mold, letting things gradually cool down.

The one thing I haven't figured out is how to do the hoop behind the emblem to capture the neckerchiefs. It might just be a small loop of bailing wire heated up an pressed into the molten back of the pewter.

Looks good anxious to see how it turns out. :thumb:

However, a drug dealer's scale, and narcotic effect. Hmm hope you get to pour the metal before the NSA kicks your door in. :lol2:

Good luck melting the plaster. You'll have better luck melting the pewter, but to each his own. ;)

I imagine that slide will be much heavier than the stock version so the loop should be tighter on the kerchief shouldn't it?

I bent a wire into loops and twisted the ends around to rest against the mold. The bottom of these loops will rest below the high water line of the melted pewter and will hopefully be held in place as the pewter solidifies.
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I snagged some pewter knicknacks from my cousin's house. They may be a higher quality alloy since they have an actual hallmark on the bottom.
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This is gathering almost everything together before heading outside to melt. Missing are a cookie sheet and wire rack I made out of hardware cloth.
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I have the cookie sheet here to diffuse the radiant heat from the burners and the wire rack I made to lift the rubber molds off the cookie sheet. I want them to be heated evenly, like an oven would.
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The directions say to use talcum powder in the rubber molds to allow the molten pewter to flow well.
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I blow the excess out with canned air so an even film remains.
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The fuel tank on the camp stove needs to be pumped up.
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With the flame going, it's beginning to melt.
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Now it's mostly melted.
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And the molds in the gas grill are up to about 200 degrees F.
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We scrape the scum on the surface to the side.
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And here, I'm pouring into my mold. It was too busy for an action shot. The loops wanted to float up on the surface, and also I realized the grill is not level.
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I went first and used most of the pewter, so we added some more and melted that.
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My son scrapes scum to the side.
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And he pours his into his mold.
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He made a different style of loop, and I have to admit it looks better.
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But his loop really wants to float on the surface of the molten pewter. He has to hold it down with a spoon as the pewter cools a little and solidifies.
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Here's his loop in the pewter.
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And mine had hardened by now,
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So I popped it out. Not bad, but one area didn't flow properly and there is a crater.

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I wanted to give it another try. The rubber mold is still in great shape, so I melted some more pewter.
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I leveled up the wire screen rack I made by bending one of the legs so it wasn't as tall.
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It looks much better and more even in thickness.
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I jammed my wire hoops in place.
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My son also wanted a second shot at making his. So he pours another.
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And my second try had cooled enough, so I popped it out of the mold.
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Anticipation...
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The wire loop pokes through the face a little bit, but other than that, it's much better. I plan to coat the background in black ink or paint, and I think the hoop will be hidden.
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So I experimented with black spray paint wiped off immediately with a paper towel. That was on the crater one. It's OK, but not great.

So with the second one, I put a heavy coat of black paint on it an allow it to dry.
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It's drying now, and I'll go down later to sand the high spots down to bright bare metal. I'm hoping it will look really good with the contrast between black and bright shiny metal.

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Hopefully more soon...

Bravo!

this guy does some cool stuff with foam , you may want to try , lamguage is a bit "Shopish " so be ware

and yes he finally got it

You're getting the hang of it but you have to streamline the operation before you go into full production for national distribution. :haha:

I started by placing a sheet of sandpaper on my flat table saw and trying to sand off all the high spots in the same plane to make it look really crisp.

But it didn't look great. Some of the letters were shallower than others and didn't get polished up.

So I switched to a dremel with a little abrasive bit and traced the tops of the letters. The dremel produces different facets, so it doesn't shine for the camera shooting from a single point. But it looks pretty good in person when you have two eyes and see it from different angles.
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And I folded the loops back a little flat to grab the neckerchief securely. I gave it the hop up and down test, and it stayed put.
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I'm pretty happy with it.
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I love AvE! Subscribed to him a while ago.

You ought to get a badge for that. :thumb:

Nice work. Try a maroon scotchbrite pad with a hard backer. That should help smooth the facets and not go into the black, depending on how deep it is.

Yeah, AvE is great fun.

Very cool!

Success!

We wore them to last night's scout meeting. Lots of "oohs and aaahs." I noticed the extra weight around my neck and didn't like it, but in short order I became used to it and forgot I was wearing it.

Now I kind of feel like trying it again, but pouring a thinner final product. I also noticed when I was digging around for some black spray paint that I had a partial can of Bondo in the basement. Does that stuff go bad? It must be ten years old. Bondo would have been a lot easier than plaster to shape initially. It starts off nice and soft when it sets up and doesn't reach full hardness for a while. I suspect I could carve a cleaner positive mold with some...

Wax is good too. You can buy special wax for that, it comes in varying degrees of hardness, You can also soften paraffin with some microcellulose wax, available at your harware store in the plumbing section as wax toilet rings. They are very soft and sticky so only add a little bit at a time to the paraffin. Or just buy the right stuff.

https://www.smooth-on.com/

Cool. Wax is probably even easier. I have a couple extra wax toilet rings. Not sure if I have any paraffin. It's easy enough to get for cheap.

The paraffin will hold the best detail but is somewhat brittle, adding the microcrystaline (not microcellulose) wax will help

I was just reading that same article

I wasn't familiar with that term so I asked google, didn't even have to go to a link to find out as much as I wanted to know about it. :haha:

Whereas I need only click the New Posts button.


Thank you, gentlemen.