Contact Pouring Ladle

Thanks OIF. I did buy a gallon some time ago and it was expensive......$200. Hopefully a (near) lifetime supply and not because I prematurely kick the bucket. There are a number of versions of it including sprays. The one most optimal for coating metal tools is BN Hard Coat. I bought Lubricoat because I wanted to coat refractory surfaces too and that stuff is supposed to be completely non-wetting, "like Teflon" to molten aluminum. This is my first go with it.

https://www.zypcoatings.com/top-selling-boron-nitride-coatings/bn-lubricoat-lubricoat-blue/

I can't say I was overly impressed with how it applied. Instructions say it applies like house paint, two coats with a foam brush. I mixed the stuff with a small Jiffy mixer because some of it had come out of suspension. When mixed it was like creamy thick latex paint. There was no direction about the desired coating thickness. I applied several thin coats drying between each coat. It didn't cover very uniformly. I had media blasted the metal so it was very clean with fine media finish. I'd have thought that would have been optimal for adhesion.

As I coated it, it was a little streaky with what looked like possibly rust. When I fired it, it blistered in several places which I touched up. Maybe coating was too thick or fired too soon? Instructions say it need not be dry between coats but if it isn't, you just move the first coat around with the second.

It applied to ceramic surfaces much better. Maybe I should have bought the hard coat version? Dunno. We'll have to see how it performs in use.

Best,
Kelly

 

I did see that as one of the applications. I've looked and it seems to be the going rate for the stuff.

Best,
K

 

Had about an hour in the shop today. Not much but enough to finish up the ladle. Here’s the mechanism for loading the seat and opening.



Not pretty but effective. It produces a ½” lift in the open position which should be plenty for the diameter of the plug.



I’m still messing around with the base, but think it’s ready too. Now just need a window to test it out.

Best,
Kelly

 

Been raining every day for seemingly for weeks now. Finally got a dry day so gave the contact ladle a test drive. The pour went fine but I think it may need to make a couple of tweaks to the pouring and construction process.

The only foam pattern I had left was a thermostat housing…..so that was it. Place, fill, vibrate, place the contact base.



I had charged the A10 with aluminum and fired up the furnace. The melt was large compared to the mass of the ladle so I thought I might get away without preheating the ladle. I must not have had the boron nitride coating or the molded ceramic fiber plunger sufficiently fired because when I immersed it in the melt, after a 10-15 seconds it produced a couple bubbles in the melt inside the ladle. This produced a thin oxide skin that laid on top the melt which if you must have such occur, is where you would want it, but between that and my big fat gloved hand, you couldn’t see squat in the video as to how the shot left the ladle so I didn’t bother posting it.

As I was fiddling with opening the plug, I jostled it around a bit and it leaked a small amount of the melt between the ladle and the contact base…..but not too bad.



The part came out fine but these thermostat housings never give me much trouble.



I was a little disappointed in the coating's condition after one use. I think I applied it way too thick. I put on four thin coats and I would say the outer two sluffed off in places but there is still coating where most of the blistering occurred. I think I will media blast it, try two thin coats and cook the piss out of it before it sees molten metal again.



On the bright side, the inside looked pretty good, the moldable foam plunger seemed to hang in there well, and the coating really was non wetting. There was a thin residual foil in about half the interior and plunger. It was easily removed with my finger after the ladle had cooled.



The contact base didn’t fair very well. I was surprised by this because the offset pouring basins I have made from the moldable ceramic fiber have held up very well. It didn’t adhere to the insulating fire brick well. I’m thinking I’ll make a base from insulating castable refractory and use a small donut of the moldable ceramic fiber for the seal.



I thought it was promising enough I started making its big brother. This one will hold a 15 lb shot.



Part of my interest in the contact ladle is for parts too large to pour with an A10 and requiring the use of my A20 crucible. For parts like my automotive upright and intake manifold lids to fit, the sprue needs to be centered in the flask. The A20 also needs to be about ¾ full and the combination causes an excessively high pouring height which makes for quite the turbulent commotion in the pouring basin. Even if the pouring basin can be nearer the edge of the flask it’s still suboptimal. So maybe the bigger ladle can help out with that.

Best,
Kelly

 

Thanks OIF. Encouraging....sample size of 1. Will keep working it.

I'm fine but not everyone in the area can say the same and that's a shame.

It's limited exposure time for sure, but Fe contamination aside, I don't think I'd ever get the ladle clean between pours or keep the plunger from fouling without it.

Yes! and then I put what was left back in the crucible in the furnace and dipped the crucible a few more times.

I had not, but think I'd probably just pour from the crucible at that point.

No smoke. No flame. Nada.....but it was a very small part.

Then you're ahead of me

Best,
Kelly

 

It's only aluminum but with the weight of the crucible, a full charge, and a shank that was originally built for my pouring cart, it's probably in the vicinity of 35-40 pounds which can be a bit to sling around. I have a steady rest on my lost foam rig but the weight aside, the A20 is over 11" tall and when full, that means you have to initially spill the metal from that height into pouring basins that are centrally located in the flask. I suppose I could try to fashion some sort of sand filled cylindrical sprue extension or pouring trough to allow the crucible spout to become adjacent to the pouring surface but that would add sprue height, increase the opportunity for run outs, and expose the melt to more air and heat loss, so I figured a contact ladle made sense in those situations.

Best,
Kelly

 

Haven’t had much shop time lately but I did finish up the fab work on the larger contact ladle.



It still needs to be media blasted and coated with Boron Nitride. I think I’m going to media blast the smaller ladle and recoat it, this time thinner.

Since the moldable ceramic fiber (MCF) coated IFB contact base didn’t fair very well, and since it’s kind of a pain trowling on the MCF and waiting for it to dry, I was thinking about other candidate materials for the contact base and plunger and remembered that ceramic fiber board properties were essentially the same properties of the molded ceramic fiber,…..and like the MCF, it is also rated for molten aluminum contact. So I bought a board online. Still waiting for it to arrive. Machining pieces should be much faster than molding the parts.

I can hang the small ladle through the vent in my furnace lid to preheat it, but I’m going to need to come up with something else to preheat the larger ladle. I may just make an insulated sleeve from some leftover ceramic wool and place it and the lade over the furnace vent hole….we’ll see.

Best,
Kelly

 

Thanks Andy. Been busy at work and with better weather finally (hopefully) here, other duties have been calling so hobby progress has slowed down. I have a handful of projects to finish up and the ever present desire to start more.....

Best,
Kelly

 

I media blasted both ladles and wiped them down with acetone….spic and span.



Then I coated both of them with the Boron Nitride and got what I concluded was rust staining since the body of the smaller ladle was stainless and it didn’t exhibit the streaking. I thought what the heck?



So I called ZPY tech support and here is what I learned.

Both their BN Hardcoat and Lubricoat Boron Nitride Coatings are water based. Lubricoat is Acidic and that is what is causing the rust staining. BN Hard Coat is Basic. BN will still cause some rust staining but much less tendency. The best of both worlds for toughness and non-wetting is a base coat of BN with a topcoat of Lubricoat. The BN must be heated (300F-500F) before applying the Lubricoat to change the Ph because the basic BN won’t like the acid Lubricoat layer on top without doing so. He said the adhesion of either is similar but BN is much harder and abrasion resistant.

He also said the rust staining won’t occur if it is applied (sprayed) with the metal heated to about 300F. He said dipping creates too thick of a coating and thinning it for dipping creates trouble wetting metal surfaces.

I asked if he thought the rust staining was much of a concern as far Fe/FeO3 contamination of an aluminum melt and he said no, commenting that some of their coatings actually contain FeO3. The stain may fade and even disappear after one use in molten metal service.

For coating thickness, he did say one coat coverage is sufficient if full coverage can be achieved and said thicker applications are prone to flaking/sluffing. He also said that any areas that become uncoated seem to be more aggressively attacked than if the entire ladle was bare so touch up work is advised when needed.

He added that burnishing Lubricoat with a soft rag will even further improve the non-wetting nature.

Though I don’t like the looks of it, I think I’m just going to use the ladle as is.

Best,
Kelly

 

It's $210/gal for what I bought.....but prices are pretty much the same across all brands.

Best,
Kelly

 

I took the advice of the ZYP coatings tech guy, heated the ladle to about 300F and coated it. That eliminated the rusting caused by the acidic mixture. But then I fired it to 1600F and promptly cooked the coating off the top of the ladle.



I didn’t ramp the furnace temperature. I suspect the top of the furnace was much hotter and the top of the ladle saw high radiant heat exceeding 1800F…….where the coating breaks down. So I media blasted it to bare metal, heated and applied a new coat, and ramped about 100F every 10 minutes. This produced a much better result. Here it is after firing.



Here’s the pair. I still need to make bases for them. I bought some 2600F ceramic fiber board for that. We’ll see how that goes.



Best,
Kelly