High Temp DIY crucible cement bowl parabola mirror-like finish

greenpowerscience.com/
Portland Cement pure, no sand makes a strong, stone like formation that if done correctly, has a mirrored like finish with NO GLAZE.

[@Cylon39]

One quick warning I am sure you already know about. Cement can Explode if there is any moisture in it when you heat it up to high temperatures. I had a homemade foundry and I used Cement as a cheap refractory and only let it set up for about a week before firing up the furnace. It worked really well for about an hour before it exploded like a grenade. Fortunately I had stepped away for a moment to get something when it went up.

[@scotthunt9782]

If you can't find something constructive to say...don't say anything. This guy shared his time and experience with us for no gain. If you don't like what he has to say... don't watch. Beating him up is pointless and it reveals your character. Try creating your own videos and share your wealth of experience and knowledge. Do you have any??

[@SN00PICUS]

lol He is showing improper and dangerous techniques. Why don't you just go for it and give this a shot and watch what happens when you grab the crucible with pliers.

[@meshadidit]

I was a professional mold maker for 15 years. If you want a hi density shiny surface, any non porous smooth surface will work fine for the mold. Depending on your skill level, any shape can be made this way. Particularly easy is to coat with polyester resin with a non logging non ball up additive so you can sand it with up to 1200 grit sandpaper. Then a nice coat and polish of mold release wax is all thats needed. Mix, vibrate and or degas the portland as usual. When nesting bowl molds, temporarily stick some small equal size blocks to the lip of the bottom bowl as spacers. This will allow you to easily get a uniform thickness of the cement bowl when compressing them together instead of eyeballing it. Tables, countertops and the like are most easily built and cast while upside down and reversed and a shiny laminate is used as the mold surface and edges. I have even used textured sheet glass for a very cool finished surface. as for your commenting on your slab and its surface density, it was not pure cement back then, it was still traditional concrete but most likely had a higher portland to aggregate mix and was finished properly at the right set time. Now days, power trowels are frequently used to achieve the shine for lower quality concrete mixes. Even with low quality slabs, mirror finishes are easily made with diamond floor polishers .. but that's best left to the pros with the equipment. Cheers!

[@edwardcoleman9291]

What did you just say, and what does it have to do with high temperature crusible,?

[@nashathp.m8297]

I need to make few mould in ceramic clay or crucible material. My what's app no is 0091-8883696791. Please contact me. I need your help. God bless you. Thank you.

[@Stormrunner0002]

I would suggest the vacuum chamber for those crucibles Dan. Any air pockets in the crucible will expand with the high heat. The stronger the cement the more violent the cracking of the crucible will be.

[@raisethecolours]

At what point in the process would you use the vaccuum chamber?

[@Aweber87]

Good video! A little hint about concrete. You will have a much easier time "popping" the bowls loose by coating them with vegetable oil rather than water. The water will act just as the water you mixed into the Portland.. (Evaporate) The vegi oil will not "mix" or evaporate with the other moisture. Also will help from popping the smooth finish in spots that stick to the metal dishes. Lightly pour oil on/in the bowl and wipe any excess off with a napkin. Just leaving a moist residue of vegi oil.

[@lagsaxl]

Well, I have no words to thank you, you are the best! Can't wait for more videos by GREENPOWERSCIENCE!

[@sleazybtd]

Outdoor concrete is given a rough finish specifically for the slip-resistant properties. It's actually required in many building codes. Dan, instead of using pure portland cement, please see what happens if you use a grout mix. You won't find it in a home store. You have to get it at a specialty construction store. Grout is a cement and sand mix, but the sand is graded so that the mix can be poured like a liquid. Air bubbles out easier with a grout mix.

[@JeffyNguyen]

I loved the slow-motion clip of the cement sifting. Very appropriate! Hahaha great vid

[@EdgeRetro]

Regarding the strength of concrete in a structural/construction setting - (speaking as a layman), yes higher cement to sand = higher strength, but I believe this is only to a point.Aggregate is a structural component glued together by the cement. Even more important is the water content. Most of the water will eventually leave, so more water in the mix = a more porous, weaker concrete. The trick is getting the air out of a dry mix.

[@danz409]

thanks for a long full version! hope to see more "full version" complete videos :D

[@GREENPOWERSCIENCE]

For mirrored marble, add permanent dyes to a small mix and swirl in. Like plater of paris, pure cement powder copies all textures perfectly but cement is many x stronger. Set in a high humidity area and mist wet every 4 hours. Do not flood until 24 - 48 hours or you can create sediment settling. A slow cool set is best as the endothermic heat created from curing process is increased with larger masses of pure cement vs standard 3:1 ratios. Table tops can be de-molded in 12 - 48 hours depending.

[@AydaWalsh]

Your videos are AWESOME!

[@delron44]

One superb video, thanks for posting.

[@GREENPOWERSCIENCE]

Thank you Derek!

[@ig33ku]

60 years ago they took pride in their work.. pity there are no more master craftsmen anymore.

[@Visionarydave444]

Always informative videos ... This is a hella affordable way to make your own crucible. Thanks Dan : ) !!! ...

[@carlyleporter5388]

'Maybe reminds them of something', huh? Good one! Your heart's in the right place bro.

[@dennyrich]

VERY GOOD I SHALL HAVE A GO MYSELF AND SEE HOW IT GOES , KEEP THE GOODWORK UP .

[@ElGatoLoco698]

I was just thinking, you could make one of those crucible holder thingys with sodium silicate as the binder and fire clay or perlite/vermiculite as the material. Would probably refract the heat even more and last longer. Not to mention lighter.

[@GREENPOWERSCIENCE]

Artist & scientist, the mirrored finish is achieved from a very smooth mold surface. For a tabletop example, sheet of perfect acrylic, on a flat surface. Pour pure cement mix, vibrate, and set upside down. Once released the surface will NOT need buffed. A mirrored surface is duplicated by ULTRAFINE portland. Sand would screw it up. Many never try pure because of cement myths. I thought the same until I had a bag set in water for 3 months. Beautiful unbreakable 92lb stone:-) No additives needed

[@chrisgreen8539]

You could pick up a cheap palm sander from a pawn shop or the like for $10-$15, wrap it in two layers of thick plastic, and use that as an effective vibrator for projects like this. (remove the sandpaper if it still has some...) This is useful for when vibrating concrete forms.

[@scrapwomblecreatives6944]

very interesting with the value pc metal recovery nice

[@KayakFisher01]

I have two books on cement bowls, crafts and recommend wiping the molds with vegetable oil before adding the cement. It makes the molds easier to separate but don't use too much or it will alter the shape.

[@sleazybtd]

With grout, you can set your forms to the exact spacing that you want, then pour the grout in between them afterwards. It should give you better control over thicknesses. I don't know what kind of finish you'll get with grout, since I've never pulled anything off the grout afterwards. While you're getting the grout, look into something called "form oil". It's oil that carpenters spray onto the formwork to prevent the concrete from sticking. It makes form removal easier.

[@ngogo70]

adding sodium silicate (Na2SiO3) or known as liquid glass or water glass to the portlant cement water mixture makes the bowls completely impervious. Work fast it hardens in an instant to make it more workable add potash you can add upto 25% pot ash without compromising the strength of the cement, also a mixture of cement liquid glass and perlite is excellent insulation material

[@rbearden71]

Portland cement assn recommends 50/50 by weight cement and water = aprox 25k psi mix after 28 days! Sidewalk concrete = 2500 psi. Cement is to flour as concrete is to bread. Smooth form = smooth finish. Just about anything that is plastic mold injected must be smooth and tapered to release. Makes great concrete forms. Thanks for sharing your ideas.

[@lagroubemo4888]

great job. As we say in French : chapeau bas.

[@broodertomas1160]

I will try to make it,Portland cement can easily got in my town,tnhk

[@aaronfrancis276]

Oh yeah im definitely gonna make a crucible thanks for the video cause i wanted a cement crucible

[@GREENPOWERSCIENCE]

aaron francis Thank you for the nice comment.

[@aaronfrancis276]

I seriously meant tht thanks :)

[@SEThatered]

Very nice!

[@GREENPOWERSCIENCE]

They are low cost fillers. One 92 POUND BAG OF PURE PORTLAND CEMENT produces only 1 cubic foot of mix. For a one cubic yard pour of pure portland cement, you would need 27 bags = $270. Adding sand and or gravel triples the volume allowing a cheaper cost of about $90 a cubic yard with more than enough strength. Mixed cement comes in different strengths, more gravel/sand, lower pound per sq inch and less cost. Stronger mixtures cost more because more pure cement is need for higher strengths.

[@bengr71]

It would be a good idea to caution people about the dangers of thermal spalling (explosion/flying debris) that can occur when cement or concrete is brought to a high temperature. Water trapped in the cement/concrete can change to steam fast than it can escape (without rupturing). The problem can usually be mitigated by heating the cement/concrete very slowly after it has cured, up to the maximum expected working temperature. A couple days may be required depending on thickness and material.

[@GREENPOWERSCIENCE]

The pure cement should be fine, any fillers to dilute the cement should be play/beach sand vs recycled crushed concrete.

[@DaveG1]

concrete is a very precise chemistry. Different formulas for every conceivable situation. Warehouse floors poured in -20 vs. home foundation in 30 degree celcius. Lots of variables (strength, cost, curing temperature, application, look, colour) Its all possible. You should try some form release agent on your concrete forms.

[@kevincronin60181]

Interesting! Nicely done video. I'm looking to make a crucible / bowl to melt glass in and I have a few questions, if I may ask? Can Your Portland Cement bowl be reheated to 2300 degrees multiply times without it cracking? I know from past experience heating up concrete can explode due to the moisture content. Thanks in advance for any info. Kevin

[@maitlandmoore6426]

I wonder if lime would work, that's what porcelain cement is after cooking it. We use about 1/5 the amount of natural gas to make it . Check out hemp Crete .

[@elhasnaouiaziz4458]

Peace be upon you, Professor. Is it possible to make a pot of refracti? I want an effective recipe. Thank you very much

[@lymanterrell]

I'd be interested in knowing if using graphite rods (or some other graphite) would assist in capturing some of the heat and reflecting it into the metal you are attempting to melt. You mentioned that the reflective nature of silver (and other metals) increased the size of the lens that you need to use. Perhaps carbon rods could be used the absorb the sunlight (dark/black surface) and transfer it to the metal. Rio Grand has graphite stirring rods that could be used in a simple test.

[@stinga562]

Whats the link where you got the stainless steel food industry cups?

[@rionmotley2514]

Hey, just a quick tip: Copper will eat iron. Iron's incredibly soluble in molten copper- I cast a copper ingot some years ago, and used a stainless crucible, thinking "oh, pfft, the temps are way low enough!" - and then all I had was a chromium foil cup left after two pours. Fairly certain the nickel dissolved out as well. Yay.

[@RepairmanJared]

How do these hold up to multiple firings? I was under the impression portland cement lost its holding ability at high heat. You have to use lime to retain integrity in high heat. The refractory cement mixes I have seen all add lime, cement to get it set up quick and lime to keep it hard once heated.

[@delphinny]

Could whack them with the hammer from the other side (the side your not using that is flat not round) to test them for strength, too

[@sleazybtd]

Your concrete blocks look like blocks which were intended to be exposed. Masons don't slap on blocks any old way and then cover up the imperfections with stucco. If the architect specifies stucco, then the masons work accordingly. There is no need be as accurate with a stucco finish. Less accuracy -> faster work -> lower cost for owner. However, if an exposed block-face is required, then the special blocks are used and the masons WILL work slower to provide a proper finish.

[@lagsaxl]

Thank you so much for your prompt reply! So,if i want to make some small scale objects,like concrete jewelry, or housewares,you do recommend plain portland? I've read that others add marblestone, metakaolin,etc, but why? If you are creating sth so small there is no significant cost reduction by using additives... What about that mirror finish??? Also, are you a scientist, artist, or what? I've lost my job due to the economic crisis, and try to make my living with concrete because I just love it!

[@yoyoda67]

I would imagine that the cement softens thin plastic as it releases heat and that would make the surface smoother in some cases. If you put the mold inside an airtight container with some water, will that result in slower setting and a harder object?

[@markallen200]

I wonder if you add fiberglass reinforcing strands to the mix if it would still come out mirror smooth? The strands would strengthen the bowl quite a bit.

[@lagsaxl]

I've been visiting your videos for months...please, please, please, share with us the way to achieve that mirror like finish... I can really help you with beton cire, marmorino, etc, if you need any advice any time... Also I have a question for you, if plain portland cement is stronger, why everybody adds sand and aggregate in the mixture??? What do they offer? Thank you very much!

[@davidmoore657]

Wrong! The terms cement and concrete are not interchangeable. The strength of concrete comes from the aggregates used (sand and crushed stone). They must be clean and of the right size and in the right ratio for the project at hand. Cement is only a binder.

[@freedumenergy2440]

hey, dan how did you mold those bigger parabola portland pieces. you never say? thanks.. i'd like to make some plant pots. and maybe a out door bricks and build a rocket stove.

[@robertbelanger5770]

Have you ever tried to use sodium silicate ie, water glass , instead of water? Fireproof and less flaking from extreme heat .

[@hmarillejla7]

Instead of weighing down with wood etc fill with water.

[@kabrogan1]

So, what happens when you put a solid masonry cement crucible into a 2200F foundry??? I got a pretty good idea......

[@sevinPackage]

The last few videos have me thinking a lot about the project all these items are coming together to create. Although I can't wait to see what you have in store for us, I also don't mind the suspense. One question: is there a particular reason why the finished product shouldn't be done with a glaze? Thanks for the full-length video! 3 minutes was barely enough for this demonstration.

[@jessemercury5238]

Yeah for sieve that is automated and sealed that you can do indoors.. I am thinking an electric motor (about 4 HP at least) and bearings.. and like a metal trashcan or your playwood encased "Lemonade Stand" then multiple concentric rings of mesh that as you go out in the rings they get finer and finer... and like have that on a horizontal axis and a sealing lid.. and well "put it on the spin cycle" LOLz.....but you know using centripetal force to create a silly silo type gravity effect and make the particles sieve themself out into a much finer and smaller particulate well yeah.. (and you can do it indoors LOL) .. oh and you can have on the outer layer a solid layer for collection that well operated in a slower speed (think rock tumbler) with large marbles in it (or stainless steel ball bearings) added.. well would before you use said machine as a sieve be in fact an automatic mortar and pestle to grind pretty much any solid down LOL... or a really neat large scale rock tumbler LOL ... man I love science!

[@yoyoda67]

Have you ever tried a thin coat of oil or wax on the molds? Also, water in a plastic bag makes a very even and heavy weight if your surface is level.

[@lea1mercian]

use a cordless drill power or hand powered and grab a whisp anput it in the drill

[@GREENPOWERSCIENCE]

Third:-) Shorter 3 minute version on our channel.

[@MrEh5]

I like to put grease on my molds.They release easier.

[@sleazybtd]

Dan, I love your videos, but I need to point out a few mistakes. The reason why your section of concrete floor didn't look as smooth as the original was because you didn't know what you were doing (no offense is intended). Masons go to school to learn how to work concrete to the finish that they want. Working with experienced masons add to their knowledge. To make a smooth glass-like finish, you need to trowel it to death. Not just how, but you also have to know WHEN you can start troweling.

[@TheNewNimrod]

Can you melt metals inside a concrete crucible? Can you only use concrete to melt your metals? If not can you explain why?

[@IllumTheMessage]

How do you think it will hold up to heat exposure? I heard hight heat like that weakens cement greatly. You think the crucible will hold up?

[@ponkiebonk]

can you please make conical versions of them and sell them on ebay and amazon and ship to New Zealand thanks

[@townsand72]

So, you have used these to melt metal?

[@lezbriddon]

Dan, dont press top bowl into bottom and then add weight, 'rotate' aka 'screw' it down and then add the weight, I cant explain why it makes a difference I'm not a fluid engineer, but i have seen it done in the old days so there must be a reason

[@RuneChaosMarine]

vacuum these items while still wet, upside down, and it will reduce the bubbles in the crucible and bowl. i think stainless becomes toxic at high temperatures.

[@notmyrealname1437]

Yes, vacuuming is used to eliminate air bubbles in various laboratory and industrial processes.

[@danielvandertorre368]

instead of water use sodium silicate and aluminum oxide and some crushed Pyrex glass to a powder and some silicon carbide and some graphite .

[@snowballis2cute]

6th Like Nice job Dan! Do ya put the whole thing in the smelting furnacr?

[@jimturner6400]

Interesting ! thanks .... do you do this for a living ? Jim UK

[@theodoreroberts3407]

I could use a large 3,000° F furnace, about 15" × 15" × 8" cavity exposure inside, preferably electric, but I didn't see anything like that. What I did see couldn't be that simple. Something is missing, probably important. You got something to help me, let me know.

[@classicwoodman]

would it be possible to make a oven to do your own glass blowing? also making a parblola mirror would it be possible to make lens by matching you two pieces then use one to grind the other?

[@craigwg]

So what does one do with a cement bowl? Serious question. Are we talking art projects here?

[@carriebrk]

Craig Greenwood - put a short piece of dowel or a cork in the bottom center and it makes a wonderful planter :)

[@Hannah-451]

What would the crucible's thermal limit be? Have you found it?

[@robot797]

sounds good were to get it?

[@johnlbales2773]

Same trick, car wax, on inner surface of plastic mold of crucible.

[@PaganWizard]

Have you made that portland cement table top yet??

[@inboxtv1208]

I’m confused. Is this video about a crucible or the cement. Can I see you use the crucible?

[@johnlbales2773]

Try a little car wax on the outside of the crucible inner cup before setting it into the cement to aid in removal when dry.

[@GREENPOWERSCIENCE]

John L Bales Thank you for the info John!

[@johnlbales2773]

:)

[@maxdecphoenix]

+John L Bales other things in a pinch i would add: petroleum jelly, cooking spray, or motor oil.

[@johnlbales2773]

Yes, right. Very good.

[@RickMcQuay]

+John L Bales Put some Crisco on it.

[@lvd2001]

Rub it because it reminds of something... hahaha Love your language and sense of humour. Greate video

[@GREENPOWERSCIENCE]

Liem Duong :-)

[@techmago]

Can i melt alluminum on this?

[@trekranger]

crucible made with portland cememt can be heated to melt copper and brass?

[@yoyoda67]

You need some texture if you are making a patio or stairs so you don't slip when it is wet.

[@ThePyropossum]

When you put the clay in the form, if you want to get more bubbles out, clamp the planks down on top, then leave it on a stand-up (vertical loading) washing machine or dryer. Also, why do you keep calling it Portland cement? I can't buy that brand here, will any other type of cement work?

[@chrisgreen8539]

ThePyropossum It isn't a brand name. "Portland cement" is the generic term for a mixture a guy came up with in the UK in the mid 19th C. Made with lime made from limestone. It was named Portland Cement because the colour reminded people of the building stone found in a place named Portland in the UK. Unless you order a magnesium-based cement powder like Sorrel cement, or more recent variations, you will get PC. Also, mason's cement is a bit different and is normally white. It can be coloured by adding colourants like iron oxides.

[@mybawlsackinyourface4835]

You look like John from the KZbin channel Growing Your Greens .

[@GREENPOWERSCIENCE]

Wow, I see it. I get comments that I look like a lot of people.

[@scrollfinger]

spray the inner cup w/ WD40 before putting it in the cement. comes out easier. you won't break the concrete.

[@colinsteam]

Glad I used the fast forward to get through most of what turned out to be a total waste of time.

[@BRENDANTHERED]

Glad people like you have the initiative to simply leave and not pollute the video with waste of time comments...

[@yoyoda67]

What kind of dyes are permanent? Where would you get them?

[@brinnonvallere]

how safe are these cement bowls for growing edible foods?

[@Kabodanki]

You don't know what you are talking about, cause increasing the amount of cement increases the strength. Beyond a certain point, it also acts negatively

[@numisaccent6723]

Can you use plaster of Paris to make the bowl if you don't have Portland cement?

[@GREENPOWERSCIENCE]

Numisaccent This is plaster of paris: kzbin.info/www/bejne/qaekgayviq-IedE Plaster part starts about 1:45 in the video

[@auto-did-act]

No, Plaster of Paris won't stand up to the heat of a furnace

[@tahanlaoboy]

if you were to apply the oil on the bowl surface you will not have the hardest time to pull it out

[@carriebrk]

Aire Lao -you are right

[@bisholim5377]

I dont know if anyone has asked you before or not? :) Do you know what is ordinary cement higest temperature? I mean what is the higest temperature cement can be warmed up? can one melt metal with Cement? Thank's :)

[@GREENPOWERSCIENCE]

Bisholi M The mass of the cement is large so you will not melt it but it begins to melt at 2000 ˚F and crystalize at 2,300 ˚F.

[@gustavferdman214]

+GREENPOWERSCIENCE The mass? When you heat up the whole thing the mass does not matter... Stop sniffing cement

[@FierceMotorworks]

this should be called concrete chef: the bowl

[@manoman0]

yep. I heard it. He clearly said "cake".

[@randomwordbot]

Portland or cement

[@jiakaiwan8520]

are you sponsored by portland cement?

[@ig33ku]

21:36 reminds me of a one bun of a bum lol

[@ryancl03]

reminds them of something... wonder what that could be. hahaha if you stick the project in a vacuum, you will get the surface you were alluding to.

[@freakman420]

Lol nice save, turned an embarrassing oops moment into a funny joke

[@FoolishOptimistPrime]

Why do you make cement parabolas?

[@GREENPOWERSCIENCE]

no, wish I had a sponsor,. They do not need sponsors, only game in town:-) $9 for a 92 lb bag, almost free:-)

[@manoman0]

Home Depot? =D