272 replies to this topic

[willd]

how much did you pay for your fishing weights and how well do they last

[tajmiester]

I think they where ?3 for 10 and they last pretty well. I suppose its been milling for around 1000 hours and there still OK, a bit shiney though.

Tris

[Stuart]

Does anybody know the temprature of the flame of meths?

Stuart

[PanMaster]

hmm, CH3OH, 600C-800C

if you wanna make some heat then its easy, get a load of bricks, or dig a hole in the ground, mix 1 part water to 1 part vegetable oil, use a feed, hook it up, light a fire and tunnel in a hole with a haridryer blowing in air, then feed in the fuel/water mix and it burns hot

[Stuart]

Could it be used to melt KNO3 then or would it burn too hot?

Stuart

[PanMaster]

i'm talking about melting steel

a pile of paper could melt KNO3 easily

[lord_dranack]

Just out of interest, why do you want to melt steel?

[BigG]

i'm talking about melting steel

a pile of paper could melt KNO3 easily

hmmm, I think you will need a tempurture of 2500C+ to melt steel.

[Gor]

OK basic lesson in temperatures.

There is a huge difference between HEAT and TEMPERATURE.

A flame can burn at 1500 deg c but it will melt nothing if the 'thing' can shed the heat faster than the flame can give it.

Steel actually begins to soften at about 1000 deg c (red heat) and becomes bendy only a little hotter. By 1500 ( white heat) it is well molten.

If you want to melt steel you need to get the heat onto it and keep it there, hence a furnace, which is usually well insulated. There are lots of ways to generate the heat, from a propane torch up.

If you want to use oil and water you have to feed them separately or else the oil floats and you just get water coming out of your pipe, which doesn't burn so well. Best way is to drip them onto a piece of angle iron which runs down into the fire box. You still have to get the fire box hot enough first or else you end up with a sticky mess. The reason why oil and water works is that the water instantly turns to steam, thereby blowing the oil into tiny droplets which burn. It takes a bit of work to set this up.

[BigG]

Steel actually begins to soften at about 1000 deg c (red heat) and becomes bendy only a little hotter. By 1500 ( white heat) it is well molten.

My mistake - I read the boiling point colom rather then melting point...

[tomu]

About milling media:

I got my lead from a tire shop, they throw away the old lead weights when they balance a tire. This is hardened lead and works creat for making lead balls.

I made the mold out of plaster of paris and a marble as model. Works great.

[bernie]

You should be using hdpe milling media

Any idea what's in them wheel weights?

Edited by bernie, 11 December 2003 - 11:22 PM.

[tomu]

The weights are made of a lead and antimony alloy. There are two types of weights ones with a steel clamp and ones without. The steel clamps must be removed from the molten lead, obviously.

BTW I use about 200 short pieces of brass pipe about 8 mm in diameter and 20 mm in length filled with lead as milling media. It's a sysiphus job to make them but they work great and last forever.

Edited by tomu, 12 December 2003 - 03:10 PM.

[tajmiester]

I've just found some fairly cheap media being sold as weight for scuba diving BCDs (Buoyancy Control Devices). The problem is I dont know how big it is from the photo, just that there's one kilo of it? Does the size of each individual shot matter or do you think this would be ok.

Lead Shot

Tris

[BigG]

Looks too small. You need around 1/2 inch minimum for the balls to become useful. Small lead shots can be used in a different type of mill ? ?a shaker mill?, but I think this is considerably harder for an amateur to built.