Reusable Pouring Basin - Lost Foam Casting

Materials and techniques for building a reusable pouring cup for lost foam casting.

[@RUSTICW0LF]

Thank you for this great information. 👍

[@johntenhave1]

lovely work well explained! Thank you.

[@evanlane1690]

Very cool. This plus just using sand instead of green sand makes this a much less involved process during the pour for non cosmetic castings.

[@kellycoffield533]

Non-cosmetic? You might be surprised at the finishes that are possible. If you coat the pattern before molding the finish of the patterns will dictate the ultimate finish of the casting. If you sand the foam pattern up to 320 grit, your finishes will be fine petrobond or better. Best, Kelly

[@stevesrt8]

i've been just using a tin can around my sprue. Not pouring directly onto the sand seems like it would be a real benefit. thanks for sharing. I'm really looking forward to trying some of your tips.

[@kellycoffield533]

I used a short section of 2 1/2" steel tube (or "Kush Cup" as people say) for the first several years. The tube could be slid off the slug and reused. I started adding a conical transition from the tube/cup to sprue made from aluminum HVAC tape which was an improvement, but cones and cylinders tend to aspirate and entrain air as they flow. The re-usable offset pouring basins were far better in all regards and they don't rob heat from your pour. They could be made from sodium silicate bound sand for high temp alloy lost foam pours but wouldn't be reusable. Best, Kelly

[@stevesrt8]

@@kellycoffield533 i will work on my delivery system for sure. Your cups are perfect. maybe i'll try something that one day. but i don't have a kiln yet. Cheers

[@samcheeseman7413]

Great video, these are very awesome. Without a kiln could one fashion one of these using an existing small round dish crucible by drilling a hole in the bottom?

[@kellycoffield533]

It wouldn't perform as well. Both the material and shape of the cup make a big difference. The moldable ceramic fiber is an excellent insulator and robs almost no heat from the melt whereas more dense refractory materials will. This means your pour temp is much closer to your pre-pour measurement. The MCF (or ceramic fiber board) is also completely unwetted by aluminum and most non-ferrous metals which is what makes them reusable wheras other materials are not. The shape of the cup and the Wier in particular tends to float any dross and prevent it from being ingetsed at the sprue. I was really surprised what an improvement they were when I started using them. Best, Kelly

[@samcheeseman7413]

@@kellycoffield533 great info thanks that makes complete sense. Wondering what I can use instead now then without a kiln. I've seen your tutorial on kush cups which is very interesting also. I do metal spinning and machining with which I could make a stainless steel funnel and fashion the bottom part with a wier. I'm planning casting with silicon bronze and lost foam so I've just joined the forum and am awaiting notification.

[@kellycoffield533]

@@samcheeseman7413 Pretty sure I saw and approved your membership. If not you may need to reapply. I use you make expendable foil funnels to adapt from Kush cup to sprue but funnels/cylinders aspirate air due to coriolis affect. Best, Kelly

[@tmophoto]

Awesome videos. could this material be used to make a pouring cup with a bunch of tiny holes in it for making metal shot? looking for ways to make more consistent bronze and aluminum shot.

[@kellycoffield533]

Maybe, but it's not very durable. Have you tried boron nitride coatings on metal? Best, Kelly

[@volodkovich]

Thanks for these videos Kelly, very informative! You do great work. I was wondering what you think about using this material (suitably reinforced of course) as reusable lining for aluminium melt crucibles? It seems to me it could work well and be a lot easier to make and fire (as well as being lighter) than traditional castable liners. Thanks!

[@kellycoffield533]

Unfortunately, it would make a very poor melting crucible because it has super low thermal conductivity and not great strength. However, it would make and outstanding ladle liner. Best, Kelly

[@delauneyfrancois7411]

Hello, I always admire your work, and you have the gift of explaining it perfectly. Thank you very much for that. I want to ask you a question: Do you think it possible to use your way of casting to make bronze pieces? On the other hand, do you think it possible to coat the plaster foam parts, like a thick paint, and drown the whole thing in compacted sand to have a more refined finish? Thank you in advance for your answer. With my gratitude and my warmest regards Francois DELAUNEY, Normandy

[@kellycoffield533]

Yes, Bronze casting by lost foam methodis works fine. In general the refractory coatings are compatible. My commercial coating is reommended for all non-ferrous work and drywall joint compound should serv fine as well. It is possible to paint or dip with plaster based coatings. It's just a metter of how much thinning is required. When I brush coat, I thin it just to the point it beguns to freely run off the brush. Thank you for your kind words. They are much appreciated. Best, Kelly

[@delauneyfrancois7411]

Hello Kelly, I just found your answer... among the spams, which explains the delay of my answer. Thank you very much for the details you have provided, in addition to your formal answer to the question on the possibility of using your method to cast bronze. Obviously, this opens up a lot of possibilities for manufacturing complex parts. Simply, it is essential to have a 3D cutting device, in order to produce the positives which will be embedded in the sand. One last (?) question: when you make foam positives, do you take into account the dimensional differences resulting from the expansion of the metal due to heat? With, again, all my gratitude for your sharing of experience. Friendly greeting from Normandy

[@kellycoffield533]

@@delauneyfrancois7411 Yes, to compensate for the aluminum shinkage, the patterns are made 1.3% larger than desired for the resulting casting. Best, Kelly

[@MRGF78]

Could you use that as a reusable form for the outside and use sand for inner ports??? Would it hold up with aluminum for many pours without cracking instead of using foam??? I like the possibilities with using this product... thanks Good session...

[@kellycoffield533]

Not sure what the advantage would be but if you mean using it like permanent mold tooling, you may get a couple uses, but it would take forever to solidify because it is such a great insulator.

[@matus1976]

Thanks for posting all these, I'm struggling with some failed pours. I just tried to do a pour of an 8" ring that was about .75" thick and 1" wide, it had 3 sprues feeding it each about 1" inch square, they met in the middle about 10" above the ring into a 2" square sprue. All pink polystyrene from big box store. My pour didn't fill out the ring in one of the areas furthest from two of the 3 sprue, I had plenty of extra material that could have filled it out. I'm not using a pour cup with a dam, and was pouring right into the 2" square sprue, could that cause this? I thought the height would provide the extra pressure to fill it. Maybe I poured too fast? I also see alot more black smoke then I see in your pours, like 10x as much for similar volume parts. Also I was wondering where you get the 1" round foam sprue from, do you turn those on a lathe? Thank you in advance if you have the time to answer! I'll be watching all your videos and making a pouring basin for sure.

[@kellycoffield533]

My first Q would be what was your pouring temp? What is your coating and how thick? I'd tilt that ring at 45 degrees and sprue into the top face with a 1" square sprue. Use a pouring cup even if it is just a can. It helps insure you dont interupt a continuous pour. A 2x2 sprue is large and is probably creating the excess smoke and flame. I cut the round sprues with a woodworking tenon cutter in a drill press but there's no magic to them and I think square is a better sprue shape. I made my small pouring cups years ago and they are round sprue. My larger more recent cups are square sprue. Replies and dialogue like this a really better done on web forums. You can post pictures (like of the castig fail) and diagrams (like how/where to sprue gate) quickly. You might consider joining www.TheHomeFoundry.org. I'm an admin there and there are lots informational threads to search/browse and friendly folks to offer help and advice. Best, Kelly

[@matus1976]

@@kellycoffield533 Thanks for the response! I'll post over on the forum, just created an account yesterday and waiting on approval (same root username matus)

[@kellycoffield533]

@@matus1976 I approved your membership application yesterday. Best, Kelly

[@jeremycrisp4488]

What is the purpose of the weir?

[@kellycoffield533]

Floats the dross and oxides and allows sprue to draw cleaner metal from the bottom of the cup with less turbulence. Best, Kelly.

[@alanverissimo6852]

Very nice video my friend! you earning a subscriber! What kind of foam are this? Where can i buy?

[@kellycoffield533]

Hi Alan, I have a video called "Pattern Materials for Lost Foam Casting" that discusses the type of foam and where to get it. Just search the title. Best, Kelly

[@kellycoffield533]

I bought the moldable and pumpable ceramic fiber from my local refractory supply distributor. Inswool is a Harbison Walker brand but there are many, like Kawool, Fiberfrax, and others. They are all air setting moldable alumina silicate mixes, usually available in a caulking tube, 1 gal, 5 gal sizes. Moldable is putty like, and pumpable is like pudding. Moldable works best for forming shapes, pumpable as glue, filling cracks and patching. It can be bought online. Search "moldable ceramic fiber". You can occasionally find it on eBay and Amazon. Shop price.....it can vary significantly but is all the same stuff. Also, search my channel for a video entitled "Reusable Pouring Basin" for more info. Best, Kelly