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View Full Version : Can anyone tell me what Iam doing wrong with my cattwalk bead press


gypsy-gypsy
10-04-2006, 03:00 AM
Hi All, Hoping Iam doing this correctly as Iam a rookie here. I purchased a 1 1/2 inch lentil press, but every time I use it the bead splits along the mandrel, Iam using a hot head burner and wondered if it was not large enough. Can anyone help as it getting a bit costly for the wasted glass. Thanks gypsy

ShellyD
10-04-2006, 03:14 AM
Hi Gypsy,

Just my thoughts as I also have 'grief' trying to use presses. Mine is never enough glass or too little glass. Can be frustrating. As I understand when the bead is pressed, rapid cooling takes place, and especially along the mandrel as the glass would be thinner there. After you have pressed the bead are you fire polishing it (removing the chill marks made). I try and heat it gently along the mandrel, just quickly so as to heat up the glass a bit. Not sure I am entirely making sense. Then once the chill marks are removed and I am happy with the shape etc. , place it in the kiln for annealing.
Hopefully the pros can step in and help.

Later
Michelle :wave: :wave:

WeeMary
10-04-2006, 04:31 AM
Are you annealing your beads straight into the kiln from the torch? I'm only asking, because I lost a lot of pressed beads trying to use vermiculite to cool them. Something to do with the uneven thicknesses a pressed bead has. The larger lentils would be more prone to that as well. Maybe check your annealing schedule?

navarre
10-04-2006, 07:43 AM
Hello Gypsy

Is this your first bead press?

When I first started using a press I had similar issues (various shapes) until I learnt to give the bead sufficient heat in the "Post-press" phase.

The press can really suck the heat out of the surface - leaving a much warmer core and it this that creates a huge amount of residual stress. You need to warm the bead gently(ish) such that you balance out the heat again - and then move on to the so called "flame annealing" before placing in the kiln or vermiculite\blanket.

This is one of those times that practicing with plain black glass can help - as black is a good colour for seeing what heat the glass is. Try and re-warm the bead so it just gets a very dull red\orange colour (ie not all that hot) and try and get the bead balanced at that heat\colour before slowly moving the bead up the flame.

Regards
Navarre
Melbourne :-)

CalamitysClan
10-04-2006, 11:36 AM
Are you using bulk or small 1 lb. tanks? I remember when I was on a HH with a small tank I couldn't make a lentil to save my life. The tank always cooled too fast. I moved up to a larger tank and I never had that problem again.

lizajayne
10-04-2006, 12:43 PM
It sounds to me like they are stress cracks. I had this issue with my lentils at first too (and it was the first press I used). Basically, when the glass is pressed into the brass, the brass sucks a lot of the heat from the glass. And at the line of the mandrel, this is the thinnest part of glass, so it is greatly concentrated here.

One tip that has helped me a lot, and saved many lentils from breaking (and I looovvvee making lentils):

As soon as it comes out of the press, put it back in the flame, focusing most of the heat along the length of bead along the mandrel. Even if you had a little overflow, and instinct wants you to fix edges, do that after the length of bead along the mandrel is warm. And be sure to do it on both sides. This will help keep your bead edges crisp, but will keep them from cracking too.

And if you have to press again, be sure to warm up the length of bead along the mandrel after each press.

Edited to say: I am on a HH, and haven't had one crack in a very long time, since I found this tip in a previous thread.

mostlydetails
10-05-2006, 07:39 AM
I've had that happen if the bead cools too fast when I've worked it too long out of the flame before getting it into the kiln. You might be working it in the press too long and the glass is cooling off too quickly.

That's also a pretty big bead and would need to go straight into a kiln rather than batch annealing. If you're using a fiber blanket, that's probably the problem right there.

Linda FL
10-07-2006, 02:17 PM
I had the very same problem until I started using a crock pot filled with vermiculite and turned on high. Once the bead is made I run the flame from hole to hole because that is the weak point. The lentils that are encased are the ones that crack the easiest. I still use cool vermiculite if the bead is not encased and I only have trouble once in a while. I know that it is very frustrating. Good luck. :thumbsup:

Linda S

Leisa
10-07-2006, 07:35 PM
That's a really big bead to make on a HH. You have to keep it heated - sounds like it's time to upgrade! ~Leisa

thatgirl
10-08-2006, 07:47 PM
Yep, I think part of the problem would be that you're using a HH to make such a large bead. Getting the bead warm enough, quickly enough, after you press, may be an issue. I know many beadmakers who use a HH that do make large beads, but I guess it's just practice to get it right. I personally have always had the opposite problem.. I work TOO hot! Trying to find a 'happy medium' I think is the key.

imlettengo
10-08-2006, 11:10 PM
Hi, Gypsy...what they said AND and ....I use 3/16 mandrels and it seems to me that presses are made for 1/16. SO, I always check the thickness along the mandrel. If it looks to be thinner than the mandrel, I add a swath more glass on top and bottom. If it decorated, add clear. If you don't like the look, melt more clear over both sides. Does this make sense? You thicken the glass over the mandrel. And the hot vermiculite seems to help a bit. Good luck!!

kellyhorton
10-09-2006, 04:14 PM
I was always told, cracking along mandrel (like breaking right down the middle) is thermal shock, beads are cooling off too quick.