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Author Topic: Surface treatments not staying / clay breaking  (Read 6644 times)

TaliB

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Surface treatments not staying / clay breaking
« on: December 11, 2015, 12:17:26 PM »
Hi, I've had a look a lot on the web (checked out Gingers articles on this, and also beads and beading) and I'm making things with Fimo Professional and then using Inka Gold and / or mica powders on them.

The first thing I'm finding is that Fimo Professional isn't as strong as I'd expected.  After curing, it bends a bit, and then snaps (on first bending and not at too much force), if I've made a thinish piece (perhaps 1-2 mm deep).  It's not crumbly and I've conditioned it well.  I'm wondering if it's the temp that I'm curing at, as my oven fluctuates and the setting i've got it on rolls between 110 c up to 121 c.  I know that Ginger cures her Fimo at 135 c, but that's above the max temp it says on the packet.  I've been curing for a good hour.  Has anyone else had this problem, or what temp do other folks cure their fimo professional at :) (I'm wondering if the 130 max is actually a really conservative guide, as ovens vary so much, and so if I've actually checked my oven, whether I can go a bit higher at the max range of my oven cycle?)

Also when I put the inka gold on raw, I then find that I can scratch it off after curing with a fingernail (which beads and beading testing it, didn't find, but I'm not sure which clay they used).

So a few questions?

I'm going to try other clays (just ordered cernit, kato premo and pardo) to see if they're stronger, but I'll also try pushing my cooker dial up so that the max temp is just under 130, to see if that helps make the fimo stronger.  anyone any other suggestions?

I think that what may be going on with the inka gold, is if the clay isn't curing quite fully, that may be why the inka gold isn't attaching as well as expected, or perhaps a different clay may help, so I'll try both of those, again any other suggestions? or anyone had good results with particular clay, particular technique (I wasn't burnishing it particularly hard, just with a finger until got a nice even coating, and I'm wondering if I have to put on layers and burnish each with a bit of kitchen towel or similar between each?) 

In the event that the inka gold will just continue to scratch off a bit, I've been using Darwi Vernis to protect it, I used one layer and it's not helped that much, so I wonder if anyone has experience of how many layers are needed (as it's expensive stuff, for a pretty small bottle, so want to try to be as efficient as possible).

And does anyone know, once I've covered the baked clay with the darwi vernis, can I then put the piece back into the oven to recure, and will that make the varnish harder and more resilient? As I saw that Ginger seems to do this with varathane?

I'm making pieces that are difficult to sand, and look good with the way the inka gold works, but as I want to use them as pendants, I'd like to find the most robust finish, as the way they are just now, a bit of wear against a zipper would damage them.

Also can't get varathane in the UK, and I wondered if anyone has long term experience of any other brand of polyurethane varnish that's available in the UK, that's a bit cheaper than Darwi vernis' tiny bottle :) (and again if you do use it, have you ever heat cured it after putting it on?)

Thanks in advance for any hints/tips you guys with experience can give me :)

JonB

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Re: Surface treatments not staying / clay breaking
« Reply #1 on: December 11, 2015, 01:56:36 PM »
Not sure about my depth of knowledge on this but I think a higher temp would be better. (others who know more will chime in on this)
Cernit and Kato are dead tough also. Fimo Pro 'should' be too. 2mm is quite thin though. You cold always 'laminate' it - a thin baked layer with a second thin raw layer added, then baked again. I rescued some buttons this way.
Have you thought of using kato clear liquid as a kind of varnish? it gets a good shine and is seriously hard wearing. You could put it on thin with brush. For less of a shine, renaissance wax is good and should play ok with inca gold. I don't think Inca Gold is tough enough on it's own, but you might find that you might have to polish it more vigorously than you are to make it tougher. But again, I am not an expert. I always ren wax and polish my stuff anyway.
Hope this helps

TaliB

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Re: Surface treatments not staying / clay breaking
« Reply #2 on: December 11, 2015, 11:04:56 PM »
Ta for that Jon :)  I think you're probably right re the baking the Fimo at a higher temp, as I have read so many places that it's supposed to be incredibly strong (and it looks from the people posting that they do seem to do quite thin stuff).  So I think I will have to try to work out my oven and find the point at which is goes up to, but no higher than 130.  My worry about going above 130 is that it does say that's the max, and I've read places that people think that it may be that that's the point at which it starts to send up noxious fumes :/

But that's a great idea re the 'laminate', I'd never thought about that, will definitely give that a go! Thanks :)

I tried fimo liquid as a glaze, but found that it seemed to dull the inka gold, but I think again having read about the kato liquid that could be a good one to try......... Again only thing bit worried about is that I think the liquid needs baked above 130, so higher than the max temp supposed to cure fimo professional at....... ug! It gets all so complicated! :)

Do you use renaissance wax before baking, or after? or use it then rebake?


MilleD

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Re: Surface treatments not staying / clay breaking
« Reply #3 on: December 12, 2015, 09:47:36 AM »
Hi, I don't use Fimo Professional so can't really help on that other to say are you sure the temp your oven says is what it actually is?

In the UK, Pledge Multi Surface Wax seems to be the equivalent of Varathane.  It used to be called Klear.

I also used a Wilko Quick Dry Varnish that I've got - it HAS to be water based.

Hope that's of use.

JonB

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Re: Surface treatments not staying / clay breaking
« Reply #4 on: December 12, 2015, 10:03:29 AM »
ren wax before baking. if you rebake it goes dull, but I sometimes need to rebake waxed things, I tried rebuffing once and it came up shiny again, another layer of wax is prob best in these circs, it polishes up even richer.
Try a couple of scrap clay experiments with your oven and see what happens when you up the temperature. Also Halogen ovens are cheap. . . (25 ish)
You can use a paint stripper type heat gun to cook the kato clear, but it can bubble and burn if you are not careful enough. It smells horrible. Do it outside ;-)

TaliB

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Re: Surface treatments not staying / clay breaking
« Reply #5 on: December 12, 2015, 11:56:21 AM »
Hi, I don't use Fimo Professional so can't really help on that other to say are you sure the temp your oven says is what it actually is?

In the UK, Pledge Multi Surface Wax seems to be the equivalent of Varathane.  It used to be called Klear.

I also used a Wilko Quick Dry Varnish that I've got - it HAS to be water based.

Hope that's of use.

Hi Millie :) re oven temp, yeh, I did tests on it (with external thermometer - though only the one, I know that some polyclayers use a couple for absolute certainty :) ) and found at the setting I'm baking at it goes from 110 - 121 and rolls between them.  It's on just now as I try to find that point at which I can get it up to but no more than 130 :)

I'd heard about pledge,  but thought it was the same as future floor finish not varathane?

Which Wilko quick dry varnish did you use, and did pieces get sticky over time? And did you put it on then cure it after, or put on after curing? The more info I can gather the better! :)

thanks muchly for info! :)

TaliB

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Re: Surface treatments not staying / clay breaking
« Reply #6 on: December 12, 2015, 12:02:43 PM »
ren wax before baking. if you rebake it goes dull, but I sometimes need to rebake waxed things, I tried rebuffing once and it came up shiny again, another layer of wax is prob best in these circs, it polishes up even richer.
Try a couple of scrap clay experiments with your oven and see what happens when you up the temperature. Also Halogen ovens are cheap. . . (25 ish)
You can use a paint stripper type heat gun to cook the kato clear, but it can bubble and burn if you are not careful enough. It smells horrible. Do it outside ;-)

ah excellent, thanks for that! :) I'll definitely pop that in my basket next online polyclay shopping "trip"!  I've been trying stuff on kinda scrap, as in stuff that's not taken very long to make, so it's not a huge problem with it breaking/scratching, but just that I'd like to make some stuff before chrimbo :)

Do Halogen ovens give a more constant heat?? If so that would be awesome, hadn't realised they are so cheap! As given that my oven rolls through the temps, it means that it's averaging a much lower temp (though I have made sure not to go under 110), so something that gives much more constant heat would be brilliant. 

Yet another thing to put on my list of goodies (heat gun), again I'd read about them being great for all sorts of things................ so another thing to add :)

Thanks so much for all this info, really really helpful!!

MilleD

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Re: Surface treatments not staying / clay breaking
« Reply #7 on: December 12, 2015, 12:27:59 PM »
It just says Wilko Quick Dry Varnish on it.  With Ultra Tough written across the top of the tin.

I always put my finishes on after baking and sanding etc.  If putting it on round beads, Emma's tutorial for her Illuminaire and Clarice beads has a brilliant technique in it  :)

Re: halogen ovens - I wouldn't use anything else.  The only thing I'd say is that I always cover whatever I'm baking (I use a metal cake tin turned upside down) as the heat from the lamp can be fairly intense.

TaliB

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Re: Surface treatments not staying / clay breaking
« Reply #8 on: December 12, 2015, 09:24:03 PM »
It just says Wilko Quick Dry Varnish on it.  With Ultra Tough written across the top of the tin.

I always put my finishes on after baking and sanding etc.  If putting it on round beads, Emma's tutorial for her Illuminaire and Clarice beads has a brilliant technique in it  :)

Re: halogen ovens - I wouldn't use anything else.  The only thing I'd say is that I always cover whatever I'm baking (I use a metal cake tin turned upside down) as the heat from the lamp can be fairly intense.

Re halogen ovens I can't seem to find anywhere what the temp range of each heating cycle is?  On my (main oven) it's 10 degrees, between the lowest temp that the oven falls to and the max temp that it rises to, each cycle of the element going off/coming on (which I think is about 3 and a half mins once it's up to heat, if I remember correctly from when I was testing it.  I had felt that was pretty stable, but if I could get info on the temp range for halogen ovens and it's vastly reduced then it would make it worth investing in one :)

Carrie

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Re: Surface treatments not staying / clay breaking
« Reply #9 on: December 13, 2015, 02:45:22 PM »
Yes - Pledge/Klear/Future.  A very good sealer for mica powders, metal leaf and InkaGold etc.  One light coat isn't shiny.  It can disturb the powders etc a bit when you put it on though, so a light finger dabbing may be best.

Debbie Crothers in Australia uses Kato liquid as a glaze and uses a 'real' heat gun rather than a craft one....l find it all a bit of a faff to tell the truth and if l want shine l use a made-for-polymer varnish.  Interested to read that Caire has used a Wilco varnish though...keep us posted on that one, Claire!

I use a small halogen oven with a Fimo oven thermometer from Emma's shop. Once the correct temp is reached it seems to maintain a steady temperature, though l do adjust the dial a bit, starting a bit higher then turning down once temp. is reached.   Great tip about cake tin, Claire!  I hadn't thought of that - the things l've tried tend to blow about.  I hardly cook any more...l'm sure l can spare a cake tin.... ::)

TaliB

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Re: Surface treatments not staying / clay breaking
« Reply #10 on: December 13, 2015, 03:39:08 PM »
Yes - Pledge/Klear/Future.  A very good sealer for mica powders, metal leaf and InkaGold etc.  One light coat isn't shiny.  It can disturb the powders etc a bit when you put it on though, so a light finger dabbing may be best.

Debbie Crothers in Australia uses Kato liquid as a glaze and uses a 'real' heat gun rather than a craft one....l find it all a bit of a faff to tell the truth and if l want shine l use a made-for-polymer varnish.  Interested to read that Caire has used a Wilco varnish though...keep us posted on that one, Claire!

I use a small halogen oven with a Fimo oven thermometer from Emma's shop. Once the correct temp is reached it seems to maintain a steady temperature, though l do adjust the dial a bit, starting a bit higher then turning down once temp. is reached.   Great tip about cake tin, Claire!  I hadn't thought of that - the things l've tried tend to blow about.  I hardly cook any more...l'm sure l can spare a cake tin.... ::)

Thank you muchly for that, I'll give the pledge a go, I've got pymII as well (but was really pricey, so want to use sparingly) so I can use that as a base coat for mica to stop smearing, then pledge on top.  Do you put pledge onto baked pieces then leave, or bake it on?

I'll give the kato liquid a try, I like the idea of treatments being baked in, rather than put on, as having had a look at Ginger at Blue bottle trees blog, it does seem that baked polyclay is much stronger, more long lasting than any surface treatment.........

that's excellent re the halogen oven, I've seen one for 30 that looks good (the dial seems to go lower than 125 degrees), so I think I'll pop that on my priority list (which seems to be every growing!)!!  I've already got an oven thermometer, a digital one, which is really quick to respond so I think I should be ok continuing to use that, I had read how great the fimo ones that Emma sells are, if I didn't have one already I'd definitely go for that :)

thanks everyone for all the info!! Really really helpful! :D

Carrie

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Re: Surface treatments not staying / clay breaking
« Reply #11 on: December 13, 2015, 07:40:30 PM »
I haven't used the Pledge version of Klear/Future but with the latter l haven't rebaked, but it doesn't harm it.  I got some PYM11 as well and hope it'll last forever!  You might not need to use anything after spraying mica powders etc with that (that's what l bought it for) but if you want to add a shiny top coat that'll work beautifully....

From what l've read, most people oven-bake their Kato liquid covered pieces then use the heat gun afterwards to boost the temp for perfect clarity.  Fimo liquid can be beautifully clear as well but has a more rubbery feel which l don't like. 

I expect the dial on the oven you've seen can be set anywhere, rather than clicking through different pre-set temps.  Worth checking.

ejralph

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Re: Surface treatments not staying / clay breaking
« Reply #12 on: December 14, 2015, 10:01:51 AM »
Fimo Professional is pretty strong when baked, so if you are having severe problems with strength, its worth checking your baking schedule - ie, are you sure your oven thermometer is accurate? Are you baking long enough etc?

Also, we have to remember that its all relative. We are not firing porcelain here and even the strongest baked clay will snap when you set out to do that. It just a question of when and how easily it reaches breaking point. (Like us all really  ;D ) . So we always have to work with the material and not expect miracles from it.

In tests I did, I found that Fimo professional would bake up almost as strong as Cernit - Cernit won, but then Cernit bakes incredibly strong. But Fimo Professional certainly was leaps ahead of the old Fimo formulation or Premo for example.

As for halogen ovens - I am a big fan. I find they hold the heat much, much more reliably than small table-top ovens. It is important to stack halogen ovens correctly. If you use both shelves, there needs to be plenty of space around whatever covers the top shelf for air flow.

My best results with them is to put items for baking on the bottom shelf. On the top shelf I arrange two small ceramic tiles to act as a heat sink and also sheild the work below from direct heat. This has proven very reliable for me - and often I have have hundreds of pounds worth of beads baking at one time if I am in production mode, so any baking disasters are very costly.

Emma
Emma from Sunny Sussex, UK
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TaliB

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Re: Surface treatments not staying / clay breaking
« Reply #13 on: December 14, 2015, 10:40:45 AM »
I haven't used the Pledge version of Klear/Future but with the latter l haven't rebaked, but it doesn't harm it.  I got some PYM11 as well and hope it'll last forever!  You might not need to use anything after spraying mica powders etc with that (that's what l bought it for) but if you want to add a shiny top coat that'll work beautifully....

From what l've read, most people oven-bake their Kato liquid covered pieces then use the heat gun afterwards to boost the temp for perfect clarity.  Fimo liquid can be beautifully clear as well but has a more rubbery feel which l don't like. 

I expect the dial on the oven you've seen can be set anywhere, rather than clicking through different pre-set temps.  Worth checking.

Thanks for that, really helpful :)  Re the oven, yep it seems to go much lower than lowest temp setting (which of course may not be accurate) which is 125, I think I saw that some people were having problems with their halogen ovens not going lower than about 125 when had a look :)

TaliB

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Re: Surface treatments not staying / clay breaking
« Reply #14 on: December 14, 2015, 10:48:38 AM »
Fimo Professional is pretty strong when baked, so if you are having severe problems with strength, its worth checking your baking schedule - ie, are you sure your oven thermometer is accurate? Are you baking long enough etc?

Also, we have to remember that its all relative. We are not firing porcelain here and even the strongest baked clay will snap when you set out to do that. It just a question of when and how easily it reaches breaking point. (Like us all really  ;D ) . So we always have to work with the material and not expect miracles from it.

In tests I did, I found that Fimo professional would bake up almost as strong as Cernit - Cernit won, but then Cernit bakes incredibly strong. But Fimo Professional certainly was leaps ahead of the old Fimo formulation or Premo for example.

As for halogen ovens - I am a big fan. I find they hold the heat much, much more reliably than small table-top ovens. It is important to stack halogen ovens correctly. If you use both shelves, there needs to be plenty of space around whatever covers the top shelf for air flow.

My best results with them is to put items for baking on the bottom shelf. On the top shelf I arrange two small ceramic tiles to act as a heat sink and also sheild the work below from direct heat. This has proven very reliable for me - and often I have have hundreds of pounds worth of beads baking at one time if I am in production mode, so any baking disasters are very costly.

Emma

It's not at all strong, the slightest pressure on it to snap it and it's going, it's not even as hard to break as a water biscuit), my assumption would be that it should be stronger than that? 

I've tried the temp up higher, (with it cycling between 134 and 122 I think was the bottom temp) and I made a wee bird, with a tail of the same thickness of the piece that I tested that broke.  I didn't try actively to break the tail (put quite a bit of work into sculpting the robin, and as it's for sitting on a shelf I wasn't quite so worried about it breaking) but I did buff it up, and it survived fairly rigourous buffing, which the other piece wouldn't so I think baking at a higher temp seems to be doing the trick :)  I've definitely been baking long enough, as been baking for an hour for pieces that are considerably less than 1/4 of an inch (about 1 mm thick).  It does now look like perhaps my digital thermometer isn't accurate, if it's not til it's up into an average temp of 130 before I'm getting the strength.

Thanks muchly for the info on how to bake (and the other comments on here about using a tin etc to stop pieces blowing about), that's all really really helpful and if I do buy a halogen oven (which I may do, as I get completely addicted to this hobby!) will be a huge help! :) and thanks for all the other bits of info on here, everyone so helpful, kind and informative! Thanks everyone! :)