Thursday, September 2, 2010

Part 3 - Which bronze clay to use - Prometheus, Hadar's or FastFire Bronzclay?

Finishing up from Tuesday and Wednesday's posts about comparing the three types of bronze clay - Prometheus Bronze, Hadar's Bronze and FastFire Bronzclay.......

Each of the bronze clays had their own individual firing schedules.  We didn't want to do three - actually 4 separate firings (as Hadar's has two firings) so decided to fire Hadar's pieces on their own according to her schedule and then fire the Prometheus and FastFire Bronzclay together.

Hadar's clay was fired according to her instructions which includes phase I for half an hour  in carbon and then cool followed by phase II for 3 hours in carbon.   All Hadar's pieces fired and sintered fine on this schedule.

For the other two clays, we followed the FastFire Bronzeclay schedule where you fire in carbon for 2 hours with full ramp but we had read that some people found that they needed to increase the temperature from 1525 to 1550 degrees F - so we went for the higher temperature.  That is higher than the temperature recommended for Prometheus - but we thought it worth a try.  Again - all pieces fired and sintered fine and there was no blistering on the Prometheus despite it firing at a higher temperature.

(As an aside....On my "anyone" piece I tried adding a hat to the FastFire Bronzclay made from Hadar's copper clay, and Marly tried combining Hadar's copper too on some of her beads but the copper didn't sinter on any of the pieces. Obviously combining the two metals and brands needs a little more fiddling with!)

We used our usual techniques for finishing and found quite a few differences between the clays.  I found that with Hadar's, getting a smooth finish was not easy.  On my bird, it seemed that there were "pits" - that couldn't be sanded out. I'm thinking that may have something to do with unevenness in the mixing and the pits are where there was concentrated binder but not metal??? but Marly really shook the powder well to begin with and mixed thoroughly and carefully......Finishing looked fine with the textured pieces but for that plain finish I guess I would have to refill and refire etc to get the finish I like.

From left to right: Fastfire Bronzclay (FF), Hadar's (H) and (unfinished) Prometheus (P)

Prometheus didn't seem to sand to a smooth finish - I just couldn't get it to have that lovely satiny silky feel that I like in my pieces.   I gave up even trying to do my bird in Prometheus I'm afraid.

The Fastfire Bronzclay finished really nicely however.  As you can see from the photos, I got that satiny silky finish on the bird and anyone (without his hat!!!) and it also finished really well on the textured and carved pieces.

There were big differences in shrinkage between the clays too as the photos show.  The beads I didn't make in uniform length but they were all made with three card thickness.  The least shrinkage occurred with FastFire Bronzclay and the most with Prometheus.

FF, H, P.  You can see the difference in how the clays take texture
FF, H, P.  All beads were rolled 3 cards thick. This photo shows the differences in shrinkage.

So the conclusion of all this is that I actually enjoyed working with the FastFire Bronzclay.  It is a totally different clay from the Bronzclay released 2 years ago and they have made some great improvements.  It was easily my favorite amongst the three types in all categories - and both Marly and Angie also chose it as their favorite too. For once, I am excited to try bronze on some larger pieces and see how it goes - but first I'll give it a try on something small in my kiln and keep my fingers crossed it works like Angie and Marly's kiln!!!


But I reiterate - using these clays is a very personal experience  - both in our individual senses  of what feels good and how we use it.  We are lucky to have choices in our clays that can used for different applications.

 Keep watching and I hope to show you some bronze pieces in the not too distant future!

I'd love to hear your experiences with any or all of these clays.  Do leave a comment and let me know what you think.

6 comments:

Kristi Bowman said...

Thank you Ruthie for sharing all of your experimentation. I have used Hadar's bronze and copper but haven't tried fast fire bronze or prometheus. I liked the original bronzclay so it sounds like I should like the ff bronze clay. Haven't used Hadar's outside of class yet, hope to in the near future! Thanks again for a very interesting and informative post!

Jennifer said...

Thank-you so much for this wonderful information. I've got all I need to start working with the FFBronze and this really helps.

Sue McNenly said...

Great info. Have never been remotely interested in trying it, but now may purchase a pack of the fast fire with my next order. Still bummed about needing to use carbon, etc. but you've made me a TINY bit excited:)

You know I really should never get REALLY excited....goodness knows what could happen!

Ruth said...

I look forward to hearing how you get on Kristi and Jennifer. I feel sure you'll like the fast fire!

And as for you Sue! As I was writing the post I was thinking 'I wonder if this will encourage Sue to give it a try' :=D We were all actually quite excited - definitely more than I'd have imagined. It really did feel nice and was easy to use.....I'll keep you updated!

Kristi Bowman said...

I'm back to report I've used the FF bronze clay numerous times and I'll never go back. Still have a pkg of Prometheus I haven't used. Took Hadar's class and did well with her clay. But I recently tried it at home and had a bit of trouble getting a nice finished product. Now re-reading your blog post I remember about shaking the container before you mix, I totally forgot that and it's been sitting for a long time so that could very well be my problem. Thanks again!

Oh and I noticed very little shrinkage with FF bronze, which is fantastic!!!

kim said...

thank you for posting your experiences! i'm about to try FFbronze and really appreciate these little details :)