Casting a lead house name plate.

[DJH]

Somebody said they would like to see how this is done so here we go...I suppose I should say that this is the way I do this and I'm not saying that it's right or wrong so please don't blame me.Other people might do it differently

A friend asked me to make him a house nameplate for his son who has just restored a period property. As I want to explain each step of the way along with the photos it's going to take some time so bear with me.

As he wanted an oval plate I've cut one out of some quarter inch birch faced ply which is most suitable for pattern making as it has an unblemished smooth face and doesn't warp as much as other plywoods.



The plastic letters are fixed to the pattern with glue in the configuration that in this case was thought best mainly because of the greater number of letters in the second part of the house name. The font is Times New Roman mainly because that's the only ones I held on to when I retired!



A coating of shellac made from poor little diddy widdy squashed beetles (apologies to Moo and Penners :lol: ) is applied to seal the wood to prevent sand sticking to the pattern later. There are pattern paints specifically made for coating patterns but shellac is perfectly good to use.

 

[DJH]

The next stage involves using casting boxes. In this case I've used some iron ones which I kept for old times sake. I forgot to put a ruler against them for the pictures but they are about 15" x 9" x 4" and they have locating pins on one box with corresponding holes on the other. The box on the left is a cope and the other a drag but even after all this time I still get them mixed up so they will be top and bottom from now on.

I think the picture explain themselves..

 

[DJH]

Along with the casting boxes the next step involves these tools.....



From the front left are soft mould brushes for dusting off particles in the mould. A pouring tube or sprue, and another pipe (not shown) for use to form a vent. A linen bag with parting powder (yes heard all that before :roll: ) in it to shake over the pattern later so that the sand doesn't stick to the pattern. A scoop for loading sand into the mould and two wooden rammers, one with a tapered wedge end, for ramming sand in around the edges of the boxes.



Bellows for blowing debris (loose sand) in the mould.



Everything clear so far?

Doug

 

[Jellyfire]

Just about I think, look forward to next instalment!

 

[Sonyaclegg]

Me too

 

[DJH]

The top,or cope casting box the one on the left,



is placed upside down on a board , that is with the alignment holes downwards (it'll become clear why soon :? ) and the pattern is placed centrally in it and given a dusting of parting powder ( attention those at the back, heard it all before :lol.



A sieve with about an eighth of an inch mesh is placed over the box and loaded with sand. This sand I'm using is greensand , although invariably it's red and it is pulverized sand with an amount of clay to aid it's binding properties. This particular sand is Mansfield Red.

 

[JoceAndChris]

So interesting! More please.

( and I'm not too fussed about the ickle wickly beetly woos)

 

[DJH]

I've rubbed this sand through the sieve and it comes through very fine and is referred to as 'facing sand'.....



which I've pushed firmly onto the face of the pattern below..



and then covered with a few inches of loose unsieved sand..



which I've rammed down with a wooden rammer. The sand at the sides of the box is rammed firstly with the wedge end of the rammer and then all over the box in a pattern which is hard to describe but its intended not to disturb the face sand on the pattern below.

 

[DJH]

This process is repeated until the box is slightly over filled with sand which I have removed by strickling the sand with a strickle or straight edge leaving a smooth surface which is level with the edges of the box.



Using the board beneath the box ( the one that the pattern is placed on) the box is turned over revealing the back of the pattern....



The sand will stay in the casting box and won't fall out because of the undercuts in the sides of the box and the firmness it has been rammed in. Sometimes a reinforce of wire mesh like chicken wire can be used to keep the sand together.

 

[Baron de Gynes]

Fascinating! My grandfather (recently deceased) wqas a patternmaker (many years ago) and had a tremendous love of wood. He worked in the engineering industry and would carve the mould from wood before the casts were made in iron.

 

[DJH]

Using a plasterers small tool, which is similar to a moulders heart and spoon, a small amount of loose sand is carved away around the pattern. It's not unusual to have loose sand like this near the edge of a pattern and it's easily removed using the brushes and bellows.



Because the first box was placed upside down and is now I've turned it over it's the the right way up now for the the locating pins of the other box to fit into the holes......



Another sprinkle of farting powder.(oops :lol: ) and the two pipes are placed in position by being gently pushed into the sand about an inch or so just so they can't move. The larger pipe will form the pouring hole or sprue and the smaller one will be the vent....



off for a cuppa now, more later..

 

[DJH]

The process of sieving facing sand on the back of the pattern and around the pipes and then ramming the backing sand to fill up the box is done and I've strickled the sand off flat ...



The top box has now been taken off and using the small tools I've cut 'ingates' from the sprue (pour) hole and into the vent.



I've cut ingates in matching positions in the sand on the top box.

 

[FamilyWiggs]

I'm literally breathless - this is one of the best posts we've ever had.

What happens next?!!

 

[DJH]

Now it's time to remove the pattern from the sand so a screw in a previously prepared hole gives me something hold as a lifting point. As this is a small light pattern there's no need for more elaborate methods of lifting the pattern out and I won't waste time explaining them. In this instance I'm using the screw as a' rapping pin' which is tapped (rapped) lightly as the pattern is lifted out. I've also gone over the back of the pattern gently with the hammer just to loosen any grip the sand may have on it..



I've used one of those Whatsit tools we had the other day just to smooth out the sand and to show one at work.

The lead is melting slowly over a small furnace. I was hoping for the sake of showing off to use an old paraffin fired melting pot but I couldn't find any paraffin.



As it's only a small melt I'm doing it in the workshop but I would normally melt out doors just to reduce the risks of breathing in any fumes which come mainly from the dirt and coating on the lead rather than the lead itself. Any fume given off of melting lead is insignificant under 500 C. In the normal course lead would not need to be heated to this temperature for casting in sand. There are other risks even so, particularly to women of child bearing age and children, but lead in it's stable state is not poisonous unless ingested by fume or from dirty hands when eating or wiping the mouth. Smoking particularly hand rolled cigarettes, with lead stained hands must be avoided. If the smoking doesn't kill you then the super heated lead fume given off from the dirty cigarette paper will. Most of this would apply to full time leadworkers but cleanliness is god always, even with clothing. Wear separate clothes such as overalls and gloves when working with lead and wash these clothes separately from the family wash.

These are the sensible precautions you should take but please check with H&S for full information. I hope you accept that I'm not lecturing but giving friendly advice so don't take my word for it..Look It Up.



The ladle on the left is one I've had 'man and boy' and the spout has twisted off and broken with the constant banging on the edge of the large furnace I used to have before. On the right is a small ladle with holes in it for removing dross which forms on the surface of the molten lead.

Next comes the best bit

Doug

 

[DJH]

Ok it's time to close the mould up by putting the top box back over the bottom one locating the pins in the corresponding holes..

Blimey who's this bloke. I asked Mrs DJH not to get me in the picture... :lol:



The boxes are back together now..

 

[DJH]

The all action shots to follow...

 

[Jellyfire]

Bah! I'm going be waiting until tomorrow aren't I?

 

[Owain]

Perhaps one day we might be able to see this in moving pictures on a kinetoscope.

 

[LadyArowana]

Bah! I'm going be waiting until tomorrow aren't I?

Quit complaining, spare a thought for me being 8 time zones in advance, I am probably going to have to wait till Wednesday evening for the rest of the story!

 

[Jellyfire]

If you're ahead, you've probably already seen it by now! (Doesn't it work like that? I always get confused by time zones on New Years Eve)