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Thermal insulation for a toaster oven

Thermal insulation for a toaster oven

2012-03-10 by ftkalcevic

I'd like to improve the efficiency of my cheap toaster oven.

I suspect it is like all ovens - a thin sheet metal oven in a thin sheet metal enclosure.  And no thermal protection around the control electrics.

I'd like to use a thermal insulator, either wrapped around the oven, or just something stuffed into the gap between oven and shell.  I'd also like to protect the gap on the right where electronics will go.

Any idea what kind of cheap insulator I can use for that?  I've used ceramic blanket before, but a strip 50mm wide was very expensive.

Is household fibreglass insulation wool capable of withstanding the 300C+ temps?

Thanks,
Frank

Re: [Homebrew_PCBs] Thermal insulation for a toaster oven

2012-03-10 by Harvey White

On Sat, 10 Mar 2012 03:48:51 -0000, you wrote:

>I'd like to improve the efficiency of my cheap toaster oven.
>
>I suspect it is like all ovens - a thin sheet metal oven in a thin sheet metal enclosure.  And no thermal protection around the control electrics.
>
>I'd like to use a thermal insulator, either wrapped around the oven, or just something stuffed into the gap between oven and shell.  I'd also like to protect the gap on the right where electronics will go.
>
>Any idea what kind of cheap insulator I can use for that?  I've used ceramic blanket before, but a strip 50mm wide was very expensive.
>
>Is household fibreglass insulation wool capable of withstanding the 300C+ temps?

Not sure, consider firebrick, it might work.  Needs some reworking of
the oven, though.

Harvey
Show quoted textHide quoted text
>
>Thanks,
>Frank

Re: [Homebrew_PCBs] Thermal insulation for a toaster oven

2012-03-10 by KeepIt SimpleStupid

I don't know where to get this stuff, but it works well.  Used to use it at work.  http://www.fiberfrax.com/

--- On Fri, 3/9/12, Harvey White <madyn@...> wrote:
Show quoted textHide quoted text
From: Harvey White <madyn@dragonworks.info>
Subject: Re: [Homebrew_PCBs] Thermal insulation for a toaster oven
To: Homebrew_PCBs@yahoogroups.com
Date: Friday, March 9, 2012, 11:24 PM
















 



  


    
      
      
      On Sat, 10 Mar 2012 03:48:51 -0000, you wrote:



>I'd like to improve the efficiency of my cheap toaster oven.

>

>I suspect it is like all ovens - a thin sheet metal oven in a thin sheet metal enclosure.  And no thermal protection around the control electrics.

>

>I'd like to use a thermal insulator, either wrapped around the oven, or just something stuffed into the gap between oven and shell.  I'd also like to protect the gap on the right where electronics will go.

>

>Any idea what kind of cheap insulator I can use for that?  I've used ceramic blanket before, but a strip 50mm wide was very expensive.

>

>Is household fibreglass insulation wool capable of withstanding the 300C+ temps?



Not sure, consider firebrick, it might work.  Needs some reworking of

the oven, though.



Harvey



>

>Thanks,

>Frank





    
     

    
    






  










[Non-text portions of this message have been removed]

RE: [Homebrew_PCBs] Thermal insulation for a toaster oven

2012-03-10 by MIKE DURKIN

Why? How often are you going to use it? My toaster oven hits 425°F in 10 minutes and have done a few boards in it with no issues. I use aluminum foil as a infrared shield from the heating elements. Check the heat profile for flux paste. I'm heating and cooling slower that the curve ... and its not by choice but simply the way it is.

Mike KC7NOA
Show quoted textHide quoted text
-----Original Message-----

From: ftkalcevic
Sent: 10 Mar 2012 03:48:57 GMT
To: Homebrew_PCBs@yahoogroups.com
Subject: [Homebrew_PCBs] Thermal insulation for a toaster oven

I'd like to improve the efficiency of my cheap toaster oven.

I suspect it is like all ovens - a thin sheet metal oven in a thin sheet metal enclosure.  And no thermal protection around the control electrics.

I'd like to use a thermal insulator, either wrapped around the oven, or just something stuffed into the gap between oven and shell.  I'd also like to protect the gap on the right where electronics will go.

Any idea what kind of cheap insulator I can use for that?  I've used ceramic blanket before, but a strip 50mm wide was very expensive.

Is household fibreglass insulation wool capable of withstanding the 300C+ temps?

Thanks,
Frank



[Non-text portions of this message have been removed]

Re: Thermal insulation for a toaster oven

2012-03-10 by ftkalcevic

I'm using it as a general purpose heating oven too (not food).  I was using it to preheat some moulds.  Sitting at 250C, the "Caution Hot Surface" sticker on the top was at 110C.

--- In Homebrew_PCBs@yahoogroups.com, MIKE DURKIN <Patriot121@...> wrote:
Show quoted textHide quoted text
>
> Why? How often are you going to use it? My toaster oven hits 425°F in 10 minutes and have done a few boards in it with no issues. I use aluminum foil as a infrared shield from the heating elements. Check the heat profile for flux paste. I'm heating and cooling slower that the curve ... and its not by choice but simply the way it is.
> 
> Mike KC7NOA
> 
> -----Original Message-----
> 
> From: ftkalcevic
> Sent: 10 Mar 2012 03:48:57 GMT
> To: Homebrew_PCBs@yahoogroups.com
> Subject: [Homebrew_PCBs] Thermal insulation for a toaster oven
> 
> I'd like to improve the efficiency of my cheap toaster oven.
> 
> I suspect it is like all ovens - a thin sheet metal oven in a thin sheet metal enclosure.  And no thermal protection around the control electrics.
> 
> I'd like to use a thermal insulator, either wrapped around the oven, or just something stuffed into the gap between oven and shell.  I'd also like to protect the gap on the right where electronics will go.
> 
> Any idea what kind of cheap insulator I can use for that?  I've used ceramic blanket before, but a strip 50mm wide was very expensive.
> 
> Is household fibreglass insulation wool capable of withstanding the 300C+ temps?
> 
> Thanks,
> Frank
> 
> 
> 
> [Non-text portions of this message have been removed]
>

Re: [Homebrew_PCBs] Re: Thermal insulation for a toaster oven

2012-03-10 by Stefan Trethan

You should use mineral wool, it has a significantly higher operating
temperature (750°C).
Theoretically glass wool should suffice with 500°C but it may be
hotter than expected very near the heating elements.

There are also ceramic fiber wools with even better temperature
rating, but much more expensive than the regular building materials.

Mind that you will defeat the thermostat if you insulate the oven.
With cheap ones the bimetallic element sits right behind the dial and
is controlled by guesswork and wishful thinking rather than the actual
oven chamber temperature. But I expect you replaced that long ago
anyway.

The oven may also rely on thermal losses to keep the heat away from
certain parts (plastic etc.). You will use your own judgement to
identify and remedy such problems.

ST
Show quoted textHide quoted text
On Sat, Mar 10, 2012 at 7:39 AM, ftkalcevic <frank@...> wrote:
> I'm using it as a general purpose heating oven too (not food).  I was using it to preheat some moulds.  Sitting at 250C, the "Caution Hot Surface" sticker on the top was at 110C.
>

Re: [Homebrew_PCBs] Re: Thermal insulation for a toaster oven

2012-03-10 by Stefan Trethan

I found the correct translation would be rock wool. The term mineral
wool includes both.
Looks more greenish compared to glass wool.

ST
Show quoted textHide quoted text
On Sat, Mar 10, 2012 at 9:56 AM, Stefan Trethan <stefan_trethan@...> wrote:
> You should use mineral wool, it has a significantly higher operating
> temperature (750°C).
> Theoretically glass wool should suffice with 500°C but it may be
> hotter than expected very near the heating elements.
>
> There are also ceramic fiber wools with even better temperature
> rating, but much more expensive than the regular building materials.
>
> Mind that you will defeat the thermostat if you insulate the oven.
> With cheap ones the bimetallic element sits right behind the dial and
> is controlled by guesswork and wishful thinking rather than the actual
> oven chamber temperature. But I expect you replaced that long ago
> anyway.
>
> The oven may also rely on thermal losses to keep the heat away from
> certain parts (plastic etc.). You will use your own judgement to
> identify and remedy such problems.
>
> ST
>
> On Sat, Mar 10, 2012 at 7:39 AM, ftkalcevic <frank@...m.au> wrote:
>> I'm using it as a general purpose heating oven too (not food).  I was using it to preheat some moulds.  Sitting at 250C, the "Caution Hot Surface" sticker on the top was at 110C.
>>

Re: Thermal insulation for a toaster oven

2012-03-10 by David

Don't want to over simplify your issue, but couldn't you put a piece of the fibreglass wool [grab a bit from your attic insulation] in the 
oven, set it to the highest temperature and leave it for a couple of hours and see what happens? being fibreglass i would imagine it could withstand well over 250c
hope this helps


--- In Homebrew_PCBs@yahoogroups.com, "ftkalcevic" <frank@...> wrote:
Show quoted textHide quoted text
>
> I'd like to improve the efficiency of my cheap toaster oven.
> 
> I suspect it is like all ovens - a thin sheet metal oven in a thin sheet metal enclosure.  And no thermal protection around the control electrics.
> 
> I'd like to use a thermal insulator, either wrapped around the oven, or just something stuffed into the gap between oven and shell.  I'd also like to protect the gap on the right where electronics will go.
> 
> Any idea what kind of cheap insulator I can use for that?  I've used ceramic blanket before, but a strip 50mm wide was very expensive.
> 
> Is household fibreglass insulation wool capable of withstanding the 300C+ temps?
> 
> Thanks,
> Frank
>

Re: [Homebrew_PCBs] Thermal insulation for a toaster oven

2012-03-10 by Paul Whatton

Hi Frank

I have a kiln here which I fire up to 1260C. (I don't put my PCBs in it 
BTW!) It is constructed from fire bricks, ceramic fiber insulation and a 
stainless steel skin. At the extreme high end the insulation makes a lot 
of difference to how well firings work and whether the kiln reaches its 
max temperature at all. (BTW I have never done it, I use the kiln to 
make pots, but I guess I have the technology to make custom high voltage 
porcelain or glass standoff insulators).

In kilns the electronic controller is usually in a seperate box and 
connected to the heating elements and thermocouple by a cable so you 
might want to consider making your oven two piece?

I would suggest ceramic fiber is the right stuff for the job, it will be 
safe at the "low" :-) temperatures used for PCB work and won't catch fire.

I don't know how big your toaster oven is? But it wouldn't be that 
expensive to do. On ebay UK cut ceramic fiber is available & piece a 
metre x 60cm and 25mm thick, costs about GBP10.00 plus postage. Ceramic 
kiln "paper" 2mm or 3mm thick is also available in cut pieces and might 
be suitable for the gaps inside the case and for protecting the electronics?

Or how about ceramic exhaust tape? a roll 2mm thick, 10m long & 2" wide 
is about GBP 10.00.

Regards

Paul

On 10/03/2012 03:48, ftkalcevic wrote:
>
> I'd like to improve the efficiency of my cheap toaster oven.
>
> I suspect it is like all ovens - a thin sheet metal oven in a thin 
> sheet metal enclosure. And no thermal protection around the control 
> electrics.
>
> I'd like to use a thermal insulator, either wrapped around the oven, 
> or just something stuffed into the gap between oven and shell. I'd 
> also like to protect the gap on the right where electronics will go.
>
> Any idea what kind of cheap insulator I can use for that? I've used 
> ceramic blanket before, but a strip 50mm wide was very expensive.
>
> Is household fibreglass insulation wool capable of withstanding the 
> 300C+ temps?
>
> Thanks,
> Frank
>
> 



[Non-text portions of this message have been removed]

Re: [Homebrew_PCBs] Thermal insulation for a toaster oven

2012-03-10 by Stefan Trethan

One more thing to be aware of is that building insulation type wool
often has binders added to keep the shape. This will burn off at low
temperatures so you may want to let this happen outside.

Ceramic high temperature wool would be the ideal solution of course.

ST
Show quoted textHide quoted text
On Sat, Mar 10, 2012 at 11:35 AM, Paul Whatton <paul@...> wrote:
> Hi Frank
>
> I have a kiln here which I fire up to 1260C. (I don't put my PCBs in it
> BTW!) It is constructed from fire bricks, ceramic fiber insulation and a
> stainless steel skin. At the extreme high end the insulation makes a lot
> of difference to how well firings work and whether the kiln reaches its
> max temperature at all. (BTW I have never done it, I use the kiln to
> make pots, but I guess I have the technology to make custom high voltage
> porcelain or glass standoff insulators).
>
> In kilns the electronic controller is usually in a seperate box and
> connected to the heating elements and thermocouple by a cable so you
> might want to consider making your oven two piece?
>
> I would suggest ceramic fiber is the right stuff for the job, it will be
> safe at the "low" :-) temperatures used for PCB work and won't catch fire.
>
> I don't know how big your toaster oven is? But it wouldn't be that
> expensive to do. On ebay UK cut ceramic fiber is available & piece a
> metre x 60cm and 25mm thick, costs about GBP10.00 plus postage. Ceramic
> kiln "paper" 2mm or 3mm thick is also available in cut pieces and might
> be suitable for the gaps inside the case and for protecting the electronics?
>
> Or how about ceramic exhaust tape? a roll 2mm thick, 10m long & 2" wide
> is about GBP 10.00.
>
> Regards
>
> Paul
>
> On 10/03/2012 03:48, ftkalcevic wrote:
>>
>> I'd like to improve the efficiency of my cheap toaster oven.
>>
>> I suspect it is like all ovens - a thin sheet metal oven in a thin
>> sheet metal enclosure. And no thermal protection around the control
>> electrics.
>>
>> I'd like to use a thermal insulator, either wrapped around the oven,
>> or just something stuffed into the gap between oven and shell. I'd
>> also like to protect the gap on the right where electronics will go.
>>
>> Any idea what kind of cheap insulator I can use for that? I've used
>> ceramic blanket before, but a strip 50mm wide was very expensive.
>>
>> Is household fibreglass insulation wool capable of withstanding the
>> 300C+ temps?
>>
>> Thanks,
>> Frank
>>
>>
>
>
>
> [Non-text portions of this message have been removed]
>
>
>
> ------------------------------------
>
> Be sure to visit the group home and check for new Links, Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>
>
>

Re: Thermal insulation for a toaster oven

2012-03-11 by rkbradshaw1

One thing you need to consider is that firebrick will hold the heat for a while. This will incease your cool-down and not provide much help on the warm-up since the thermal mass of the brick will take some of the energy. This will be true of most insulators other than reflective.
Since you want to control the time at temperature your money might be better spent on a PID controller for your existing oven.
Thanks,
Randy

--- In Homebrew_PCBs@yahoogroups.com, "ftkalcevic" <frank@...> wrote:
Show quoted textHide quoted text
>
> I'd like to improve the efficiency of my cheap toaster oven.
> 
> I suspect it is like all ovens - a thin sheet metal oven in a thin sheet metal enclosure.  And no thermal protection around the control electrics.
> 
> I'd like to use a thermal insulator, either wrapped around the oven, or just something stuffed into the gap between oven and shell.  I'd also like to protect the gap on the right where electronics will go.
> 
> Any idea what kind of cheap insulator I can use for that?  I've used ceramic blanket before, but a strip 50mm wide was very expensive.
> 
> Is household fibreglass insulation wool capable of withstanding the 300C+ temps?
> 
> Thanks,
> Frank
>

Re: [Homebrew_PCBs] Re: Reflective Thermal insulation for a toaster oven

2012-03-12 by Kim Kemmerly

I have a question about what might be a good reflective thermal insulator for the project under discussion?  I am planning on modifiying a similar project and thought of using firebrick but would rather use a reflecting insulator as to not hold the heat as firebrick would.  Any suggestions would be appreciated.
Thanks,
Kim


________________________________
Show quoted textHide quoted text
From: rkbradshaw1 <rkbradshaw1@...>
To: Homebrew_PCBs@yahoogroups.com 
Sent: Sunday, March 11, 2012 1:42 PM
Subject: [Homebrew_PCBs] Re: Thermal insulation for a toaster oven


  
One thing you need to consider is that firebrick will hold the heat for a while. This will incease your cool-down and not provide much help on the warm-up since the thermal mass of the brick will take some of the energy. This will be true of most insulators other than reflective.
Since you want to control the time at temperature your money might be better spent on a PID controller for your existing oven.
Thanks,
Randy

--- In Homebrew_PCBs@yahoogroups.com, "ftkalcevic" <frank@...> wrote:
>
> I'd like to improve the efficiency of my cheap toaster oven.
> 
> I suspect it is like all ovens - a thin sheet metal oven in a thin sheet metal enclosure. And no thermal protection around the control electrics.
> 
> I'd like to use a thermal insulator, either wrapped around the oven, or just something stuffed into the gap between oven and shell. I'd also like to protect the gap on the right where electronics will go.
> 
> Any idea what kind of cheap insulator I can use for that? I've used ceramic blanket before, but a strip 50mm wide was very expensive.
> 
> Is household fibreglass insulation wool capable of withstanding the 300C+ temps?
> 
> Thanks,
> Frank
>




[Non-text portions of this message have been removed]

RE: [Homebrew_PCBs] Re: Thermal insulation for a toaster oven

2012-03-13 by Tony Smith

Been there, done that.

The usual stuff works up to 300C, depending on your definition of works.  At
higher temperatures it goes brittle and breaks down.  I wouldn't use it for
over 250C, and even that'll probably break down after a while.  It works ok
at 200C.  YMMV.

As said, you want the 'other' stuff that's rated for higher temperatures.

You can get various paints as well meant for kilns, may be work looking at.


Tony


> Don't want to over simplify your issue, but couldn't you put a piece of
the
> fibreglass wool [grab a bit from your attic insulation] in the oven, set
it to the
> highest temperature and leave it for a couple of hours and see what
> happens? being fibreglass i would imagine it could withstand well over
250c
> hope this helps
> 
> 
> --- In Homebrew_PCBs@yahoogroups.com, "ftkalcevic" <frank@...> wrote:
> >
> > I'd like to improve the efficiency of my cheap toaster oven.
> >
> > I suspect it is like all ovens - a thin sheet metal oven in a thin sheet
metal
> enclosure.  And no thermal protection around the control electrics.
> >
> > I'd like to use a thermal insulator, either wrapped around the oven, or
just
> something stuffed into the gap between oven and shell.  I'd also like to
> protect the gap on the right where electronics will go.
> >
> > Any idea what kind of cheap insulator I can use for that?  I've used
ceramic
> blanket before, but a strip 50mm wide was very expensive.
> >
> > Is household fibreglass insulation wool capable of withstanding the
300C+
Show quoted textHide quoted text
> temps?
> >
> > Thanks,
> > Frank

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