Hello From Medford Oregon USA, 9KG Furnace Kit??

I have been looking at this site for a few months. I found it from a lost foam casting video on youtube by Kelly Coffield. I did cast a few things in aluminum in high school about 40 years ago, but havent done anything else.
Last week I ordered this kit off Amazon to see if I could get the hang of sand casting once again. https://www.amazon.com/dp/B0CQP6VS9X is this kit OK? The reason I put it off was everyone on youtube and forums seemed to have a different opinion of what was a good starter set up. So last week I just bought something to get started. I haven't done anything but open the box just incase it was a mistake, but so far it looks to be fairly well thought out and if it's a keeper I think the next step is ordering the refractory cement to coat the inside?

 

Hi DonF, welcome to the forum.

The tongs and pouring shank look nicer on that setup than the pliers that came with mine.
If the burner inlet is not off to one side enough (tangential to crucible) the furnace may be slower to heat.

The burner is seems to be missing a small sliding baffle to regulate air on the inlet , which could be rigged with a pipe nipple and a thumbscrew. I see than many do not have them any more online and some have a more elaborate baffle system.

I coated the inside of mine with the wrong stuff but it stuck well enough to be serviceable.

What are you hoping to cast? Are you thinking green sand or Petrobond?

 

I bought 50lbs of petrobond on ebay last night. I was going to cheap out and try kitty litter and fine sand, but I read where making sand that produces good results can be tricky. The plan is to store it in a 5 gallon bucket for now to keep it sealed up and clean. Thanks for the burner tips. I will try it as is but look for improving it soon. The burner is offset slightly to the rear of the furnace, but its pointed flush with the wall. I want to try casting a sand rammer first. It seems like a fairly easy project.

 

Yes PPE is my next purchase. Thank you for the reassurance. I didn't expect it to be great for the price, just hoping its something usable that I can drag out now and then to experiment and learn with. Is this the refractory compound I should get? https://www.amazon.com/Volcano-Refectory-Satanite-Ceramic-Blanket/dp/B095XJ1BDB? It seems to have the right name.

 

I do like Petrobond as 'starter' sand, takes out a bunch of learning curve time in the beginning.

As Kelly mentioned, lost foam is neat too, I was just making some foam patterns last night...

A 12" (30cm) piece of 5/4 or 6/4 (32 or 38mm) hardwood with one end flat and one end looking like an oversized dull chisel /slotted screwdriver makes a nice smaller sized rammer. I use one like that more than the fancy wood one I ran out on the CNC...

That Satanite looks about right. I used Mizzou which is a dense castable meant to be applied thicker and not as a wash.

 

Thank you for the information, Tops! Castible Mizzou was what I had bookmarked before Kelly mentioned the other brand. Now I understand why castible was in all caps. I am glad I asked. I am not in a big rush. I would rather do it a little slower and learn from others advice. I did watch a few videos showing what the air adjustment sleeve does. I think I need to cobble up one soon. I have a lathe so that's an easy job if I happen to have some scrap that is close.

 

You are welcome Don! And remember, we like pictures of gear and project and stuff...

 

Thanks for the info Jeff. I checked the fit last night. It does hold the crucible high, and the crucible they sent doesn't look like the picture and has no taper until the last bottom third. Of course they are pliers so constant force has to be held on the two handles, but the diameter looks to grip well for the 6kg and 9kg graphite crucibles. I am just estimating from the OD measurements on the 6 as the 9 is all I have now but being pliers they have some range. The tab really isn't necessary as long as you are pushing the handles together, so if it's better to grab lower I can take that off? The furnace they sell in the 9kg kit has the same measurements as the 12kg kit. So I think the furnace could be used with a 12 kg crucible.

 

https://www.flickr.com/photos/134252471@N07/albums No casting pictures yet!

 

Thank you for the tips, Kelly! I will order some and hope for the best.

 

Kelly, my little Amazon furnace does have a coat of Mizzou, I did not understand the difference at the time and I could get it by the pound from the ceramics supply house before I became acquainted with the firebrick supply place a half mile down the road. They have since sold me Kastolite 30i for hot facing and Minro Z as a wash.

 

Welcome to the forum!

Tip on PPE (credit goes to someone else here): I just got this chainsaw helmet, and indeed it does have a metal face-shield screen. You can unscrew the brackets holding on the ear-muffs and remove them to save weight. The headgear has a ratchet tightening mechanism on the back which seems reasonably well made for the price. About my only complaint is the face-shield doesn't protect my neck much, so I'm thinking of sewing on strips of (metal) window screen or similar.



As an added bonus, replacement screens aren't very expensive either.

 

Welcome Don. That looks like a pretty decent starter kit. The other guys have touched on some pretty relevant stuff. You could get a couple inches of PVC of a close ID and open it up on the lathe to slide onto the burner tube to open or choke the air. Sometimes your burner may need adjustment as things heat up and it's nice to be able to adjust your air as well as fuel pressure. Once you get your feet wet you may want to add forced air, but that's a conversation for another day.
As for youtube videos, if you see something that looks sketchy it probably is. Short pants, flip-flops, no face shield, etc.
One thing alot of youtube guys seem to do is quench their castings. It's probably just for visual effect. There's nothing wrong with it in most instances, but it's unnecessary. Most aluminum is cool enough to handle in a half hour or so. But there is a real safety issue with water around molten metal in general. Anywhere water can be captured by molten metal it will flash to steam and pop drops or blobs of molten metal in the air and whatever it lands on (like your body, house, garage, dog) could very well end up on fire or with a hole in it. Most times you will have extra metal in the crucible that needs to be poured off into an ingot mold. Alot of folks use cupcake pans. Try to find one's with no teflon or else wire brush it off. It's quite toxic when burned. Always preheat your steel ingot molds over your furnace exhaust to red heat in order to drive off any moisture hiding under the oxide layer.
Just a couple thoughts that came to mind.

Pete

 

Thank you all for the tips! Yes, I saw the muffin pans in a lot of videos online. Other forums say the muffin pans with two piece stampings (the cups are pressed in to the flat part and crimped) fail quickly if used for ingot molds. They also recommended finding pans without coating, like you did. So I started looking for once piece muffim pans with no coatings and this is the only one I found https://www.amazon.com/Fox-Run-Stainless-Muffin-Cupcake/dp/B0CXYM169J? I can weld my own ingot trays up if that would be better. Like everyone else though I already have too many projects so if the stainless steel muffin pan is a good choice, that's another project I don't have to make myself.

 

Sometimes the secondhand/charity shops will have used cookware stuff like that. Our local will sort through them and put ones 'not good enough' in a different spot to be used for crafts or part bins. Mine is a 3-egg poaching tray that got separated from its pan. I should be more systematic about preheating it well above the boiling point of water before I pull the molten crucible and pour metal.

 

The trouble with the crimped cupcake tins is that when you overflow the cup the aluminum finds its way under the crimp and solidifies. Then you end up prying or beating the ingots out and their condition and usefulness deteriorate rapidly. Outside of that, a good steel cupcake pan will last for years if it doesn’t get banged up and you don't leave it outside. The aluminum doesn’t stick at all, and the ingots are a convenient size and store well in a 5 gallon bucket. I pour extruded aluminum into dog food (and smaller) cans for lathe-turning blanks too. You just have to cut them out of the can.lol. Goodwill, yard sales, dirt-floor auction houses, etc.
Thats just for aluminum though. Copper and copper alloys will either “weld” to it or burn through thin steel. Neither are gratifying, believe me. I have trays I’ve made out of angle iron for that. I ground the mill scale off of those when I made them and keep them outside so they’ve got a good coat of rust to keep the bronze from sticking. That might not be the best way, but that’s what I do.
It seems like a trivial matter, but when you have a half of a crucible left over, you’ve got to do something with it!

Pete