Time for a giveaway!

In celebration of my new blog I am going to run 2 giveaways.

Giveaway 1

To enter all you need to do is be a follower, I will use a random number generator to pick a follower, with 1 being the first follower. Those of you who are already following me here, thank you, you will be entered.

This is the prize for giveaway 1

Giveaway 2

To enter this you need to link to my blog. A blog, or facebook post, or tweet - about my blog in general or the giveaway will count as one entry (you can do all three and get 3 entries if you want). A link in your blog roll will count as 3 entries! Leave a comment to let me know you have made a link to my www.carajane.co.uk blog site so I can enter you in the giveaway. If you have problems leaving a comment please email me at carajaneuk'at'gmail.com (replacing the 'at' for @ ). For this one I will enter all your names into a hat the corresponding number of times and get my lovely daughter to pick one out.

This is the prize for giveaway 2 (It can be swapped for a pendant if you aren't an earring wearer)

***DEADLINE NOW EXTENDED TIL 19TH JULY!!!! ***

 

The closing date for both giveaways is 17th July 2011 so you have plenty of time. I will post overseas. Make sure I have some way of contacting you, email address on your blogger profile or leave your email in the comment - or email me. If I can't contact the winner I will redraw.

Thank you for reading my  blog, I enjoy writing it and it's so nice to know that people actually read it!

Good luck to you all!

Cara

Strong can be too hard!

I used what I'd learnt from my recent strength test experiments to make sure my latest polymer clay jewellery was cured to make it good and strong. The pieces were cured at 160ºC for 30 mins. I was pleased when I handled them, they seemed good and strong. Then I tried to sand them. Yup they are strong, and hard and that makes them really hard to polish! I spent about 4 times longer than I normally would polishing this flower pendant and I am still not at all happy with the finish.

So my advice is, think about what you are making and what it's purpose is before you decide how to cure it! Make it strong enough, but not too strong!

Giving up the coke can - bangles almost solved

You may recall I've been having problems making bangles. I've had trouble with them cracking.

In my usual style I did a little experiment to see how curing on different 'bangle forms' changed things.

I had a suggestion from Jo who writes the FloRaeMe blog that perhaps the coke can being flimsy might move, undermining the strength of the bangle and that I should try using cardboard tube. I tried to make a cardboard tube the size I wanted a bangle but the join where the cardboard overlapped made the bracelet a wonky shape so I gave up on that. I think it would be ideal if you could find a nice round cardboard tube ready made (hmm just eyeing up my sellotape roll...)

Here's what I did try

The first support (top row on the left) was a catering ring (supplied by the lovely Carol Blackburn at her Bangle workshop), lined with paper - oh I see I muddled up the bangles in the picture the middle bangle was the catering ring one - I can tell cause it's larger, and round.

The middle support was just a paper lining. I formed the bangle on the coke can (which incidentally is filled with plaster of Paris so sturdy to work on) and then slipped it off and baked on a tile, this is the first bangle, it's a bit wonky, so I wouldn't recommend that way.

The last support was the plaster of Paris filled coke can. I made 2 bangle on this at the same time and one of them I gently removed from the can at the end of the curing time whilst still warm and then gently rested the paper lining over the top of the can and put back in the oven to cool down slowly (check out  my baking experiment results if you haven't already). The other I just left as it was. When I went back to the oven the one I had left on the can had popped off - as in completely broken  - on it's own! That's not good! The one I had taken off whilst warm seemed good though.

I gave them all a good squeeze, gently to start with, them remembering how strong the well cured specimens were in my previous experiments very firmly. At this point I heard a crunch from the coke can cured bangle

... and there was a crack, not at any seam or join, just a crack. The other 2 bangles remained intact and crack free.

What I am finding so infuriating is I know that plenty of people cure polymer clay bangles on coke cans with no problems (well not that they report). I looked through about 5 different bangle tutorials and  4 of them used a coke can. None of them mentioned using a release agent (I am using the paper as a release agent to make sure the polymer clay doesn't stick to the can - a very helpful suggestion by friends on the PCC forum and also from Carol Blackburn). So why does it work for other people and not me?

Anyway that's it for me and coke cans for bangles. When the one came out broken before I had even touched it I knew it just wasn't working for me.

The bangle formed on the catering ring has been decorated with cane slices and baked again and I am confident it is strong. It was a little on the large size so I added an extra thick lining of polymer clay so it fits a average size hand and now it is just right. They come in different sizes so I shall investigate. If you have any other ideas of things to form bangles on please do comment, or email (see the contact me page)

Getting there with the bangles but still not perfected yet.

The stages of making my purple flowery cabochon

I have been asked a couple of questions about my purple flowery cabochon pendant so here's a little more information  about how I made it. Looking at the colour differences due to the lighting in my pictures I really should go back to using my  photography set up but I took these pictures as a record for me rather than for sharing with you.

First I made 2 canes (typically I made them with little bits left over from another project so they were tiny and of course beautiful! If I had made them larger they wouldn't have been so nice, it's the cane law!).

The purple flower canes

I then hand formed a cabochon shape from scrap clay, starting with a ball shape which I cut in half and smoothed it down onto my work surface. I don't get the shape perfect at this stage as it will be squashed about when I add the decoration.


I covered the scrap clay cabochon shape with thin slices of the cane pressing them in firmly once I am happy with their arrangement and not worrying too much about the distortion of the shape of the pendant. I use a knitting needle (a short double ended metal one, it's my favourite smoothing tool) to smooth the cane slices so the joins were no longer visible. The cabochon then needs a little reforming (OK quite a lot sometimes!) and then gentle smoothing to remove finger marks. It is then baked, for more information about getting the ideal curing conditions  see my latest curing experiments

Cabochon after first baking, unsanded (yes this is a different one from pictures below)

When making this pendant I couldn't decide whether to give it a border 'frame' or not. So I took a picture without then added one and took a picture with the border so I could compare side by side. I decided the 'frame' added to the look of the pendant so was worth the extra time.

These pendants have been sanded but not buffed. I make the basic shape, bake and sand it then I add the backing, bail and a border. It's then baked and  repolished with the last few grades of sand paper only and buffed with my homemade dremel buffing wheel. I have tested it out and found you don't get a better shine particularly by sanding and rebaking but it does mean it is easier to sand right to the edge if there isn't a border in the way. It is better to add the backing, bail and border to a baked cabochon as you don't distort it whilst doing so.

Here's the finished piece!

Hopefully that answered the questions, if you have any more feel free to ask either by comment here or email me (see the contact me link above or to the left). Also if you are having trouble leaving comments can you let me know - by email I guess.  Thanks

Cara

Welcome to the new home of the surfingcat blog - about the journey here!

I started my surfingcat polymer clay blog a bit over 2 years ago to share my journey in developing my ability with polymer clay. I first discovered polymer clay 30 years ago when I made a tea set for my dolls, aged 7. Since then it has been a hobby of mine and I have tried out lots of things over the years. When I discovered Flickr a few years ago I discovered that polymer clay had moved on, people were producing fantastically beautiful things from polymer clay and I wanted to be able to do the same. So I set about to learn. I bought some new books, some online tutorials, I experimented and I surfed the web - a lot! I found a whole wealth of information shared on blogs and websites by wonderfully talented and generous people, this inspired me to start a blog and I named it Surfingcat's journey with polymer clay. Surfingcat was an online name I had used before (becuase I like cats and surfing, the real wet riding waves kind as well as the online type).

When I started selling my jewellery I chose the name Cara Jane Contemporary Jewellery, but I kept my blog the same.It all started to get a bit confusing having two online polymer clay presences so I have decided to streamline it a bit and so have moved all the content of my blog to this one.

Please come and follow me here - the content will continue to be the same, only the name has changed.

Thanks for joining me here at www.carajane.co.uk

Cara Jane Hayman (aka surfingcat!)

Curing experiments part 2 - with videos!

So in part 1 I discovered that for optimum strength you should turn your oven off at the end of the curing cycle and leave your polymer clay pieces to cool down slowly in the cooling oven. This was just an initial test to see if the set up was going to work before I made lots of samples with more complicated curing, and something I had always been curious about. I was happy that the test worked and set about making more samples (got a blister from the extruder - am thinking it might be time to look at those walnut hollow ones....).

For these tests I chose to cool all my samples at room temperature, although I knew they would be stronger if I let them cool slowly. It was easier to control the curing, meaning I didn't have to reheat the oven for each curing and also the testing would be quicker if the specimens weren't as strong There will be a third round of tests where I search for the real optimum curing based on what I have learnt so far. As before samples are all made from very well conditioned scrap Kato polymer clay. They are extruded cylinders and are approximately 10 cm long and 6mm in diameter. You may note, looking at the results below, that I only repeated each test twice this time. I made three samples each time but as the results were reasonably close and there were a lot to test I decided that two was enough! I haven't got round to polishing the samples yet, to see how shine is affected by cure time/temp - that's a job for another day!

Cure time tests
I  tried curing samples for different amounts of time. The temperature for all the samples was 150°C and they were removed from the oven at the end of their cure time to cool at room temperature. The samples cured for 40 min had some longitudinal cracks on them when they were removed from the oven, however there was no sign of the cracks when they had cooled.

Cure time results
10 min -breaking point weight -  501g, 481g
20 min - 2035g*, 1986g*
40 min - 1900g*, 1935g*
*weight of water when specimen bent out of jig.

The weights given for the 20 and 40 min cure samples are not particularly relevant as these samples didn't break, they curved so much they slipped through the test rig. You can see this happening and the test set up in the video below.

Video showing the test set up and how the strong samples bent and slipped out of test jig.

Having looked at the samples I conclude that for 6mm thick pieces 20 minutes curing is sufficient for  strength and perhaps 40 min is too much due to the presence of the cracks on the warm sample, although this wasn't proved to make them weaker.

Oven temperature tests
All samples had 10 min in the oven at a set temperature that was verified with an oven thermometer, they were then removed and cooled at room temperature.

Oven temp results

140°C (~280F)- breaking point weight -440g, 380g

150°C (~300F) - breaking point weight -501g, 481g

160°C (~320F)- breaking point weight -1076g, 900g

170°C (~338F)- breaking point weight -1567g, 1498g

As you can see that change from 150°C to 160°C and again to 170°C makes a significant increase in strength!

Here's a video of a 140°C sample so you can see how little it flexed before breaking, compared to the 150°C for 20 min sample  in the video above.

Video showing a test where the 140°C for 10 min cure specimen breaks without much bend

In a recent post on the Kato facebook page (31st March if you want to look back and find it, can't find a way to make a direct link to that post) Tony Aquino,  the technical director at Van Aken, who manufacture Kato polyclay, discussed curing temperatures (great timing thank you Tony!). He said that higher temperature of curing would mean stronger clay, my tests show this too.

Conclusion of my experiments so far

Increasing the cure temperature increased the strength of the sample significantly but the samples still all broke. Increasing the cure time meant that the samples were much stronger and held about  2kg, or 2 litres of water before they bent so much they slipped through the test jig.  That may be to do with the increased time allowing the temperature in centre of the specimen to reach the correct temperature or some other factor, I'm not sure.

 I would like to do some more tests looking at cure time against thickness of specimen so that I would know the ideal time for all thickness of clay. Next time I am bored I guess!

I will cure my next specimens at 160oC (320F) for 20 min, and leave them to cool in the oven as it cools down. This would seem to be the best way to cure 6mm thick Kato Polyclay  for optimum strength. I will test this and let you know the results.

This blog will soon be finding a new home, I do hope you'll move with me - I'll keep you posted

Have fun with your polymer clay
Cara