Bullseye - Shocky

Krysia@No98 · July 12, 2011, 10:25:18 PM

I have been working with bullseye rods for the last few weeks on a bobcat (doing a project for college.) I was using the rods straight from cold but was finding them frustratingly shocky, like half the rod gone before I's got any glass on a rod. I have been using the top of the kiln as a rod warmer but it's not been 100% successful.

Am I doing something wrong, should I be annealing them first or is this just what happens?

(thank you muchly)

awrylemming · July 12, 2011, 11:00:49 PM

I've always had less problems with bullseye than effetre, but then haven't used a bobcat before. I wish I could be even a little bit helpful ...

flame n fuse · July 12, 2011, 11:51:50 PM

I only use bullseye, and find the white rather shocky, but otherwise they are mostly fine. I just keep them on the table and bring them in gently at the top of the flame before getting them into the real heat (I use them on a bobcat and a hothead and don't notice any difference). I've never lost half a rod, more like a few chips fly off the end. Hope you manage to sort it out!

firedinglass · July 13, 2011, 07:33:45 AM

I find bullseye shocky too and so i warm the rods on top of my kiln (which is next to me). This seems to help

stuwaudby · July 14, 2011, 12:52:46 PM

I use bullseye / Effetre about 50/50. I find Bullseye less shocky than 104 if anything with the exception of White, Opaque Pink and in particular Clear / Pink Mix.

Krysia@No98 · July 14, 2011, 04:16:16 PM

humm that's about 50/50 on them being shocky then. Has anyone tried annealing their shocky rods and found it any better?

I have been using mostly greens and reds. It was a yellow rod that almost vanished.

When I have been using them from the top of the kiln I have found that I need to put them back on the kiln if I plan to use them again or the shockiness just returns. The only 104 that I have found that has been as bad is pistachio .

flame n fuse · July 14, 2011, 11:36:33 PM

you could try asking the bullseye forum - their technical people will respond

Trudi · July 15, 2011, 05:45:41 AM

Perhaps turn your torch down a little, I do this for any shocky rods and it seems to work out the best way for me.

Pat from Canvey · July 15, 2011, 08:31:29 AM

If I know a rod is shocky or extra thick, I put it into the cold kiln, ramp up and use from the kiln.

stuwaudby · July 19, 2011, 01:40:41 PM

Annealing the rods should help, suggest going to a higher temp than for finished products i.e. 540c.

Shocky rods are caused by a couple of issues:

1. The glass in the rod is not mixed properly. If there are two colours present (or lighter and darker) then the colours will radiate heat at different rates and heat up in the flame at different rates. The hotter expands faster than the other and causes stress. (ever tried to reheat a twisty of opaque and clear?) No amount of annealing will solve this. This is why pinks, whites and mixed rods tend to be shocky.

2. The rod has stress built in during manufacture. This could happen if it has been extruded and the die was cool or simply due to fast cooling. As a rod cools the surface will solidify first. The inside will then cool and contract causing tension down the centre and compression around the surfaces. The rod is then frit waiting to happen, the trapped energy in the tension and compression will cause any minor fracture caused by the torch heat to become a large crack. Annealing should resolve this.

Krysia@No98 · July 21, 2011, 12:33:11 PM

Thank you I shall put them through and see if that helps them.

I have finished the project I was doing for the moment. I shall put them all through so that they are ready for the next time.

I was trying to make some murini with a mixture of all the different colours. The murini came out ok but it was painful getting there.

Thank you for all your suggestions, It's much appreciated.