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Onoff
In the land of the unfinished project I am King!
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Have had laddo change the font and increase the letter spacing. Bigger letters and bigger gaps between each should minimise bleed through between letters. It's meant bringing it down to one cut out either side.
Going to print a female PVA mould and I'll try the wax again, this time measured accurately.
Going to print a female PVA mould and I'll try the wax again, this time measured accurately.
JMS1972
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I'd still try making a silicone moldTo get rid of the PVA quicker I figure a cheap aquarium heater to keep the water warm. Then I need something to make "bubbles". An aquarium air stone maybe?
Ideas on a post card please!
De-molding is easy and you can make lots of wax patterns for when more people want them.
Onoff
In the land of the unfinished project I am King!
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I'd still try making a silicone mold
De-molding is easy and you can make lots of wax patterns for when more people want them.
You mean pour silicone over the 3D printed model, peel off, then pour wax into the silicone ( and peel off)?
Got a link to suitable silicone?
Cheers
JMS1972
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Yes. Exactly.
Something like this, there may be cheaper available..
Or possibly high temperature stuff you could cast pewter into directly?
Vibrate for a few minutes to get rid of bubbles.
Use vaseline thinned with IPA as a mold release....
Something like this, there may be cheaper available..
Quality 500ml Liquid Silicone Moulding Rubber Mold Making Casting Mould Kit 500g | eBay
Find many great new & used options and get the best deals for Quality 500ml Liquid Silicone Moulding Rubber Mold Making Casting Mould Kit 500g at the best online prices at eBay! Free delivery for many products.
www.ebay.co.uk
Or possibly high temperature stuff you could cast pewter into directly?
Vibrate for a few minutes to get rid of bubbles.
Use vaseline thinned with IPA as a mold release....
Onoff
In the land of the unfinished project I am King!
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Johnnybravo
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You need a degassing chamber to get rid of the air bubbles in the siliconYes. Exactly.
Something like this, there may be cheaper available..
Quality 500ml Liquid Silicone Moulding Rubber Mold Making Casting Mould Kit 500g | eBay
Find many great new & used options and get the best deals for Quality 500ml Liquid Silicone Moulding Rubber Mold Making Casting Mould Kit 500g at the best online prices at eBay! Free delivery for many products.www.ebay.co.uk
Or possibly high temperature stuff you could cast pewter into directly?
Vibrate for a few minutes to get rid of bubbles.
Use vaseline thinned with IPA as a mold release....
JMS1972
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No you don't. It's nice to have but vibration or rapping will get bubbles out. And careful pouring into one corner of the mold also helps.
Onoff
In the land of the unfinished project I am King!
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Just for @Kram then...
Some hard wax beans made especially for lady parts:
Problem number one, you have to whack the temperature up much higher than the 52degC for the proper casting wax. At 65degC the beans are barely melting. Too high and you risk melting/deforming the PVA. This wax too is then more "smeary" than "runny". I'd say for this sort of work it's in fact crap. At 80degC and it's melted but is barely pourable. At 100degC probably just about pourable but thick and oh so slow!
Still, the fans demand these things so....
The pouring video:
The resultant wax lump is much softer than proper casting wax, like an American hard gum almost. It doesn't flow rapidly around the mould.
The only "plus" is that as the wax has a higher melting point you can up the water temperature to melt the PVA and it melts rapid too!
I could see one horn was missing so couldn't be bothered to wait. Might have run the tap a bit hot tbh...
This wax and the proper casting wax are two different animals, really. This one is stretchy, peely, designed for sack, back and crack!
Some hard wax beans made especially for lady parts:
Problem number one, you have to whack the temperature up much higher than the 52degC for the proper casting wax. At 65degC the beans are barely melting. Too high and you risk melting/deforming the PVA. This wax too is then more "smeary" than "runny". I'd say for this sort of work it's in fact crap. At 80degC and it's melted but is barely pourable. At 100degC probably just about pourable but thick and oh so slow!
Still, the fans demand these things so....
The pouring video:
The resultant wax lump is much softer than proper casting wax, like an American hard gum almost. It doesn't flow rapidly around the mould.
The only "plus" is that as the wax has a higher melting point you can up the water temperature to melt the PVA and it melts rapid too!
I could see one horn was missing so couldn't be bothered to wait. Might have run the tap a bit hot tbh...
This wax and the proper casting wax are two different animals, really. This one is stretchy, peely, designed for sack, back and crack!
Onoff
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Just finished a PVA mould that looks good in all respects. Right, final shape, letters well spaced and defined. It should need minimal cleaning up with tweezers and a scalpel to make it ready to pour the wax in.
My lad has cut down on the PVA used greatly and what's left has a greater surface area than before. The hope is it'll dissolve quicker.
@Kram , we'll have options I reckon. A fine detail PLA or wax model to cast in investment plaster & melt out.
My lad has cut down on the PVA used greatly and what's left has a greater surface area than before. The hope is it'll dissolve quicker.
@Kram , we'll have options I reckon. A fine detail PLA or wax model to cast in investment plaster & melt out.
Barking Mat
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Very interesting thread, don't know how I missed it.
Fair play to everyone involved.
Looking forward to the rest of this crazy endeavour.
Fair play to everyone involved.
Looking forward to the rest of this crazy endeavour.
Johnnybravo
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You’ve obviously been lucky then.
I tried and air bubbles were an issue. Landed up getting it done by my ex next door neighbor who makes silicon molds for the ceramics industry. Two minutes in his degassing chamber and the results were like night and day. Zero airbubbles.
Onoff
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I blame the idiot who started this. All so he can stand drunkenly at the bar and say "My boy did that...hic"
The investment plaster I have is "proper" casting stuff and very air permeable if that's the right word. I reckon a vacuum chamber is on the cards similar to the one VOG makes on his channel. I may knock one up shortly.
Pretty sure that as well as the plaster moulds being ultra dry you don't want air bubbles in the cast. From the videos I've watched if damp, it tends to turn the moisture to steam that then explodes up through the molten metal! Damaging to the finish as well as potentially dangerous. Ditto air pockets.
Though you can apparently achieve decent results getting the air out by holding a small sander against the side, I think I'll make a chamber for what it'll cost.
Here's a mad idea...I use a waterproofing admix when mixing mortar and concrete. It states on the label it has a de-aerator in it. Certainly cuts down on the tamping needed and makes for a lot less bubbles coming to the surface. I wonder if I could knock my plaster up with some of that in the water used?
prepman
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Onoff
In the land of the unfinished project I am King!
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prepman
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About to do 1st mix. Looking at the components of the refractory mix...the main ingredient is alu oxide. This is used in bulk in grit blasting.....If I could get a cheap load of that and use my Bentonite (Wylko kitty litter) and perlite with extra rapid cement which is alumina based not calcium.....bingo
prepman
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Cut up the old furnace frame to mod it. Quite a perfectionist 
Fitted the K wool and cut burner hole with a sharpened plastic tube....
Removed the paint tin former before it sets as I don't want to have to hack a full paint tin to bits to get it out. (done this before).
It's now obvious I've not got enough refractory to do the lid. Although it's listed a £25 it's a plus + plus total and ends up at £41 delivered. So I'm tempted to use my old recipe for it. If it fails it's no big problem. Wheras the main body would be. Finish top off and lift mechanism tomorrow.
Fitted the K wool and cut burner hole with a sharpened plastic tube....
Removed the paint tin former before it sets as I don't want to have to hack a full paint tin to bits to get it out. (done this before).
It's now obvious I've not got enough refractory to do the lid. Although it's listed a £25 it's a plus + plus total and ends up at £41 delivered. So I'm tempted to use my old recipe for it. If it fails it's no big problem. Wheras the main body would be. Finish top off and lift mechanism tomorrow.
