New Build Foundry
I'm looking to build a foundry and I don't really know how far a 25kg bag of refractory cement will go? I know the volume I need but does anyone know how much volume 25kg fills?
I'm also looking for recommendations on a suitable high temperature thread sealant for the burner where the fittings are screwed together.
If anyone can help with these, it'd be appreciated.
Here is a great site for volume with a hole calculations. remember that the base and lid of the foundry wont have holes the same size so you need to calculate each part separate, and think of refractory as gravel when looking for kilograms.
It depends on the density of the specific refractory your using. It varies pretty widely depending on the type. It doesn't really expand or contract so whatever's in the bag is what you'll get in the furnace. The manufacturer is usually the best resource for that information.
As for thread sealer I just use teflon tape or regular pipe dope. The burner itself never gets hot enough to compromise it. What type of burner are you planning?
I did some calculations on 25kg of cement (similar to refractory) and this is what I came up with. Remember 1 inch of refractory is not very thick and you would want to back fill or wrap with an insulator such as ceramic wool.
This also only leaves an inch and a half of head space which will be needed for a plinth of some type. It is a close fit for tongs as well you may need to drop down to a A3 crucible but was trying to give you the most bang for your buck.
After looking at a real world example of this sketch I realize that an A4 crucible is not much different then my coffee cup. And to be honest that is pretty small I tend to go through two cups a morning.
You may want to look into getting an additional bag of refractory unless you are looking to do really small objects.
The density of refractory can vary significantly. Insulating castables are typically ~75lb/ft3. Non insulating dense castables ~150-160 lbs/ft3. I'd suggest you do an internet search for a data sheet on what you have and look for bulk or placement density of that material, then you can estimate weight from volume of your cast refractory pieces. For planning purposes I'd suggest you only plan on getting 80-90% utilization of your material. If you've never worked with castable refractory I'd further suggest you follow the water content for mixing precisely and make a small test batch to practice with. It's a different animal than concrete.
Originally Posted by cosmarchy
Thanks very much for your replies. I already have the volume as I have rough plans on CAD which gives me the volume of the part on screen however I think I'll have to try ,as some of you suggested, looking to the manufacturer as to the volume of a 25kg bag.
Well, this is going to take some explaining as it's not on CAD. Basically it will consist of off the shelf pipe fittings one inside the other. The inner will be gas and the outer connected to a fan. The idea with off the shelf fittings is that I can just screw them together but then this got me thinking about making sure the joints were sufficiently sealed.
Originally Posted by Petee716
This may not help you much, But I will tell you 1 bag DOES NOT go very far. It's by far the worlds most expensive "concrete" !!!
If in doubt, buy a 2nd bag, you'll want it to make plinths and for patching up later.
(sticking a location on you profile helps us....example, if you are in Austin, TX, I'd tell you about a local shop that sells it so no shipping woes)
Thanks for the offer but I'm in the UK.
Originally Posted by jagboy69
I've been in contact with the supplier who was very helpful with a quick reply stating that the bag will do a volume of 2130KG/M3 - for anyone else who might need to know this.
Originally Posted by cosmarchy
I agree with what everyone has said before, you'll need more than you think and will be glad of an extra bag when you are in the thick of the refractory casting.
Depends where you are for good UK suppliers but i have found specialplasters.co.uk refractory really good, they only have the one type (up to 1600oc but thats plenty for anything up to bronze) and its 20 quid a bag. they are based in birmingham so if you live far away there will be shipping on top.
Another good option is castreekilns.co.uk based in wales i think. They have a much wider range right up to 1800oc stuff and will ship too. I have used both these companies products and have had nothing but good products and service from both.
Good luck with the build