Showing posts with label Beads. Show all posts
Showing posts with label Beads. Show all posts

Tuesday 10 July 2012

Stuck Beads


Sometimes beads refuse to come off the mandrel with normal twisting of the bead on the mandrel. In these cases I use two methods.

I lock a small vice grip (locking pliers) on the mandrel near the middle and hold bead with non slip material. Then I twist back and forth to loosen the bead on the mandrel. When it frees from the mandrel, I pull toward the end continuing to twist.

If it does not loosen, or come off the end, I soak the whole in water over night and then repeat the above procedure again.

If these two do not work, I sacrifice the bead, as even using soft jawed vices normally leads to the crushing of the bead.

Saturday 14 August 2010

Effect of Variations in Size on Bead Annealing

When annealing beads with varying thicknesses, I apply a rule of thumb to be safe.

I take the difference between the thickest and the thinnest part and add that to the thickest part to get the diameter at which I should anneal.

So a bead with a thickest part being 8mm and the thinnest 2mm, gives a difference of 6mm which I add to the 8mm (thickest) part giving 14mm as the diameter to which I anneal.

Tuesday 10 August 2010

Annealing Beads of different sizes and shapes

It is possible to anneal beads of different sizes and shapes at the same time, if you anneal for the beads which require the most care. It will not matter for the smaller beads or easier shapes if they are annealed longer than the minimum requirement.

Friday 6 August 2010

Effect of Shape on Bead Annealing

The shape of the bead has significant effects on the annealing time required. This is because the shape has an effect on the speed at which the centre can cool. Spheres have the most even transmission of heat, because the heat can radiate equally in all directions. Cylinders are more restricted in heat radiation because they can radiate heat from the circumference but not so effectively along the length. Flat shapes can radiate heat in only two directions, making them the most difficult to anneal.

As indicated, spheres can be annealed most quickly. The annealing schedules given in this blog apply to spheres as this is the most common form for beads.

Cylinders which by definition are longer than the diameter need to be annealed at two thirds the rate of spheres. So, from the tables you choose the annealing rate for a piece 1.5 times larger than the diameter of your cylinder.

Flat shapes require the most care in annealing so you should choose the rate that is three times the thickness of the piece you are annealing.

These cautions will help to adequately anneal your beads, what ever their shape.

Monday 2 August 2010

Bead Annealing Schedules for Spectrum Beads

Bead Annealing Schedules for Spectrum Beads
This table is based on James Kirwin’s work on bead making with variations. This is for cold beads being heated for a secure anneal.

Up to 10mm dia.: afap to 520C, 30 mins; anneal at 300C/hr to 370C; afap to 40C
12mm dia.: 1000C/hr to 520C,30mins; anneal at 210C/hr; 600C/hr to 40C
14mm dia.: 1000C/hr to 520C, 30mins; anneal at 155C/hr; 460C/hr to 40C
16mm dia.: 950C/hr to 520C, 30mins; anneal at 120C/hr; 350C/hr to 40C
18mm dia.: 740C/hr to 520C, 30mins; anneal at 94C/hr; 280C/hr to 40C
20mm dia.: 600C/hr to 520C, 30mins; anneal at 75C/hr; 230C/hr to 40C
22mm dia.: 500C/hr to 520C, 30mins; anneal at 62C/hr; 185C/hr to 40C
24mm dia.: 420C/hr to 520C, 30mins; anneal at 53C/hr; 155C/hr to 40C
30mm dia.: 270C/hr to 520C, 36mins; anneal at 33C/hr; 100C/hr to 40C
38mm dia.: 165C/hr to 520C, 39mins; anneal at 21C/hr; 60C/hr to 40C
50mm dia.: 95C/hr to 520C, 46mins; anneal at 12C/hr; 36C/hr to 40C

Remember this table is for spheres. For cylinders choose the diameter that is 1.5 times the diameter of your cylinder, and for flat shapes choose the diameter that is 3 times the thickness of your piece.

For other information on annealing of beads go here

Friday 30 July 2010

Bead Annealing Schedule for Effetre Beads

This table is based on James Kirwin’s work on bead making with variations. This is for cold beads being heated for a secure anneal.

Up to 10mm dia.: afap to 530C, 30 mins; cool at 280C/hr to 360C; 840C to 40C.
12mm dia.: Go at 1000C/hr to 530C, 30mins.; cool at 194C/hr to 360C; at 580C/hr to 40C
14mm dia.: Go at 1000C/hr to 530C, 30mins.; cool at 142C/hr to 360C; at 425C/hr to 40C
16mm dia.: Go at 870C/hr to 530C, 30mins.; cool at 109C/hr to 360C; at 330C/hr to 40C
18mm dia.: Go at 690C/hr to 530C, 30mins.; cool at 86C/hr to 360C; at 260C/hr to 40C
20mm dia.: Go at 560C/hr to 530C, 30mins.; cool at 70C/hr to 360C; at 210C/hr to 40C
22mm dia.: Go at 460C/hr to 530C, 30mins.; cool at 57C/hr to 360C; at 175C/hr to 40C
24mm dia.: Go at 390C/hr to 530C, 30mins.; cool at 48C/hr to 360C; at 145C/hr to 40C
30mm dia.: Go at 245C/hr to 530C, 36mins.; cool at 31C/hr to 360C; at 95C/hr to 40C
38mm dia.: Go at 155C/hr to 530C, 39mins.; cool at 19C/hr to 360C; at 60C/hr to 40C
50mm dia.: Go at 90C/hr to 530C, 46mins.; cool at 12C/hr to 360C; at 36C/hr to 40C


Remember this table is for spheres. For cylinders choose the diameter that is 1.5 times the diameter of your cylinder, and for flat shapes choose the diameter that is 3 times the thickness of your piece.

For other information on annealing of beads go here

Monday 26 July 2010

Bead Annealing Schedule for Bullseye Beads

This table is based on James Kirwin’s work on bead making with variations. This is for cold beads being heated for a secure anneal.

Up to 10mm dia.: afap to 540C, soak for 30min., cool at 300C/hr to 370C; afap to 40C.
12mm dia.: 1000C/hr to 540C, soak for 30min., cool at 220C/hr to 370C; 600C/hr to 40C
14mm dia.: 1000C/hr to 540C, soak for 30min., cool at 165C/hr to 370C; 480C/hr to 40C
16mm dia.: 1000C/hr to 540C, soak for 30min., cool at 125C/hr to 370C; 375C/hr to 40C
18mm dia.: 900C/hr to 540C, soak for 30min., cool at 100C/hr to 370C; 300C/hr to 40C
20mm dia.: 600C/hr to 540C, soak for 30min., cool at 80C/hr to 370C; 240C/hr to 40C
22mm dia.: 535C/hr to 540C, soak for 30min., cool at 67C/hr to 370C; 200C/hr to 40C
24mm dia.: 450C/hr to 540C, soak for 30min., cool at 55C/hr to 370C; 165C/hr to 40C
30mm dia.: 280C/hr to 540C, soak for 36min., cool at 36C/hr to 370C; 110C/hr to 40C
38mm dia.: 180C/hr to 540C, soak for 36min., cool at 22C/hr to 370C; 66C/hr to 40C
50mm dia.: 100C/hr to 540C, soak for 46min., cool at 13C/hr to 370C; 36C/hr to 40C

Remember this table is for spheres. For cylinders choose the diameter that is 1.5 times the diameter of your cylinder, and for flat shapes choose the diameter that is 3 times the thickness of your piece.

For other information on annealing of beads go here

Thursday 22 July 2010

Bead Annealing Schedule for Borosilicate Beads

This table is based on James Kirwin’s work on bead making with variations. This is for cold beads being heated for a secure anneal.
Up to 10mm dia: afap to 570C, soak 30 mins; anneal at 900C/hr to 500C; afap to 40C
12mm dia: 1000C/hr to 570C, soak 30mins; anneal at 630C/hr to 500C; afap to 40C
14mm dia: 1000C/hr to 570C, soak 30mins; anneal at 468C/hr to 500C; 1000C to 40C
16mm dia: 1000C/hr to 570C, soak 30mins; anneal at 355C/hr to 500C; 1000C to 40C
18mm dia: 1000C/hr to 570C, soak 30mins; anneal at 280C/hr to 500C; 840C to 40C
20mm dia: 1000C/hr to 570C, soak 30mins; anneal at226C/hr to 500C; 675C to 40C
22mm dia: 1000C/hr to 570C, soak 30mins; anneal at 187C/hr to 500C; 560C to 40C
24mm dia: 1000C/hr to 570C, soak 30mins; anneal at 157C/hr to 500C; 470C to 40C
30mm dia: 800C/hr to 570C, soak 36mins; anneal at 100C/hr to 500C; 300C to 40C
38mm dia: 500C/hr to 570C, soak 39mins; anneal at 60C/hr to 500C; 180C to 40C
50mm dia: 285C/hr to 570C, soak 46mins; anneal at 36C/hr to 500C; 100C to 40C


Remember this table is for spheres. For cylinders choose the diameter that is 1.5 times the diameter of your cylinder, and for flat shapes choose the diameter that is 3 times the thickness of your piece.

For other information on annealing of beads go here

Sunday 18 July 2010

Bead Annealing

There are two approaches to annealing beads.

One is to keep them warm as you make them and when the session is finished, anneal all the beads sitting in the kiln. Assuming you are using soda lime glasses rather than borosilicate, you need to have the kiln idling at around 500C. When you have evened the heat throughout the bead, you place it in the kiln. Gloves and other heat protection attire will be needed when you open the door/lid to put the bead on the mandrel into it.

When you have finished the bead making session, you then take the temperature up to about 520C – 540C and soak there for about half an hour – both depend on the type of glass and the thickness and shape. The object is to take the glass up to a temperature where the annealing process can work, but without being so high in temperature that the bead takes up marks from the kiln shelf. More information on the soak and annealing of various shapes, sizes and types are given in later tips.

The second method applies if you have cooled the beads in vermiculite, blanket or other means to cool them slowly and you now have a group of cold beads that you wish to ensure are correctly annealed. You need to start the kiln from cold. Place the beads in the kiln and begin the firing. You need to take the beads up slowly – not more than 300C/hr - to between 520C and 540C, and soak there for about an hour. More information is given in further tips.

In both the cases described you now have the beads with the temperature equalised throughout the bead, and the annealing can begin. The annealing is the controlled cooling below the annealing soak. It is generally safe to take the temperature down at about 80C/hr to 360C. After this point you can speed up the cool down to something like 200C/hr, or if you kiln cools slowly enough, just turn it off and wait for the temperature to come down toward room temperature. This again depends on the type of glass, its size and shape.

Variations according to glass type used, sizes and shapes follow in further tips.
Annealing of Borosilicate Beads
Annealing of Bullseye Beads
Annealing Effetre Beads
Annealing Spectrum 96 Beads
Effect of Shape
Effect of Size
Effect of Variations in Sizes

Wednesday 14 July 2010

Removing Beads Stuck to the Mandrel

You may need to hold the mandrel in pliers or in vice grips while holding the bead with a scrubbing pad or jar opening rubber pad.

If this does not work, try soaking the bead and mandrel in water for a few hours. This often is enough to release the bead.

A little more drastic method is to then place the bead and mandrel in the freezer. After being frozen, the bead will most often come off as the water in the bead release thaws.

A final attempt can be made with a pop rivet gun. Insert the mandrel and operate the levers, and it will push the bead off the mandrel.

If all other things fail and you really want your mandrel back, you can warm the bead in the flame and dump it in water. It will break apart with the shock from the water. You can then clean up the mandrel for future use.