Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work.

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  #1   Report Post  
Spurtle
 
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Default Tin plating

Greetings,

I have some old special pie baking tins which I use, but alas the tin
plate has worn away and rust now stains the pastry in places.
I would like to know how to re-plate them myself. I would prefer using
hot dip method to gain maximum coating thickness. I sent some of them
away for (very expensive) electro re-plating a few years ago, but the
electro's have worn out already while some that have never been
re-plated are still going OK.

Have googled and been to my local library without finding any advice.
Looking for preferably a step by step "how to".

Cheers
Spurtle
  #2   Report Post  
Andrew Mawson
 
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Default


"Spurtle" wrote in message
...
Greetings,

I have some old special pie baking tins which I use, but alas the

tin
plate has worn away and rust now stains the pastry in places.
I would like to know how to re-plate them myself. I would prefer

using
hot dip method to gain maximum coating thickness. I sent some of

them
away for (very expensive) electro re-plating a few years ago, but

the
electro's have worn out already while some that have never been
re-plated are still going OK.

Have googled and been to my local library without finding any

advice.
Looking for preferably a step by step "how to".

Cheers
Spurtle



I think it is no more than getting them ABSOLUTELY clean and hot
dipping in molten tin. Certainly this is how bearing caps are done.
The problem is the cleaning to chemically clean bare metal - possibly
you could sand blast them ?

AWEM


  #3   Report Post  
Spurtle
 
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Andrew Mawson wrote:

I think it is no more than getting them ABSOLUTELY clean and hot
dipping in molten tin. Certainly this is how bearing caps are done.
The problem is the cleaning to chemically clean bare metal - possibly
you could sand blast them ?

AWEM


Thanks AWEM
Would have to be chem clean as they have a small rolled edge that would
be difficult to blast clean in the crevice where it meets the mould
side. I have tried cleaning in a strong caustic solution and achieved
visible removal of carbon, grease etc. Is that sufficient?

No flux?
Would the item be dipped cold, or preheated?
As it is for food contact, does it require pure tin?

Appreciate your help.

Cheers
Spurtle
  #4   Report Post  
Bugs
 
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Default

Small areas can be physically cleaned and repaired with a soldering
iron, with all trace of lead removed of course. Finding a source of tin
is the problem here. Regular acid flux [ZnCl] works fine.
Bugs

  #5   Report Post  
Andrew Mawson
 
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Default


"Spurtle" wrote in message
...
Andrew Mawson wrote:

I think it is no more than getting them ABSOLUTELY clean and hot
dipping in molten tin. Certainly this is how bearing caps are

done.
The problem is the cleaning to chemically clean bare metal -

possibly
you could sand blast them ?

AWEM


Thanks AWEM
Would have to be chem clean as they have a small rolled edge that

would
be difficult to blast clean in the crevice where it meets the mould
side. I have tried cleaning in a strong caustic solution and

achieved
visible removal of carbon, grease etc. Is that sufficient?

No flux?
Would the item be dipped cold, or preheated?
As it is for food contact, does it require pure tin?

Appreciate your help.

Cheers
Spurtle


Your problem is keeping the items clean between blasting / acid dip /
caustic dip or whatever and the tin dipping, as probably they won't be
done either in the same room or the same time ! Fry's make (made? -
long ago since I used it!) a tinning flux that if sprayed onto the
cleaned metal would keep it clean.

If you have rolled joins that can trap moisture, you have another
problem when dipping - the moisture will form steam explosively when
dipped and splash tin everywhere.

As to the purity of the tin I don't know, but tin tends to be
associated in nature with lead and arsenic so I assume that their
percentages should be microscopic for your application !


AWEM




  #6   Report Post  
Karl Vorwerk
 
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Default

You might want to try the old way. http://www.finishing.com/255/53.shtml
I've tried to do it this way once using nontoxic pewter and my results were
good in some places and not so good in others. It certainly seems like
something that could be learned with some practice. I don't remember but I
probably used a wadded paper towel as the swab. I seem to remember the paper
towel browned and smoked but didn't ignite. I think my main problem was
insufficient prep in the cleaning. I used a torch. I think charcoal would be
better for more even heat or maybe a gas stove top.
Karl

Karl

"Spurtle" wrote in message
...
Greetings,

I have some old special pie baking tins which I use, but alas the tin
plate has worn away and rust now stains the pastry in places.
I would like to know how to re-plate them myself. I would prefer using hot
dip method to gain maximum coating thickness. I sent some of them away
for (very expensive) electro re-plating a few years ago, but the electro's
have worn out already while some that have never been re-plated are still
going OK.

Have googled and been to my local library without finding any advice.
Looking for preferably a step by step "how to".

Cheers
Spurtle



  #7   Report Post  
Glenn Ashmore
 
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Default

You can send it off to a professional tinker or do it yourself.

The professional way is to use bar tin and flux over a hearth of crushed
firebrick but there is an easier way that works almost as well. You can get
most of the material from a stained glass supplier. Just make sure the
solder is pure tin.

I used Johnson's E-127 Flux N Solder pure tin to retin some copper pots. It
is a paste of flux and pure tin powder. Clean the pan well and make sure it
is free of grease. Sand off any rust. I used some fresh carburator cleaner
and then rensed off thoroughly. Coat anything that you don't want the tin
to get on with whiting chalk and set it aside to dry. Brush the paste on
thinly and evenly then heat the pan with a propane torch (preferably from
the outside) until the solder melts. About 450F. Don't over heat and keep
the torch moving to prevent hot spots.

A much better way to do it if you have a propane fish cooker is to set a
larger pan full of 1/4" chunks of crushed fire brick on the cooker and set
the pan to be retinned down into the bed of crushed brick. It will heat a
lot more evenly. Don't use fine stuff because if any gets into the tin it is
impossible to get it out.

Once the tin is all melted swish it around to make sure all the metal is
coated and pour out the excess. Quickly, while still molten, wipe the pan
with a thick piece of wool to level the tin.

Steel is a little harder to heat evenly than copper but a steel pie tin will
be easier to do than a copper pot because you don't have to worrry about
getting the tin on the outside copper.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Spurtle" wrote in message
...
Greetings,

I have some old special pie baking tins which I use, but alas the tin
plate has worn away and rust now stains the pastry in places.
I would like to know how to re-plate them myself. I would prefer using
hot dip method to gain maximum coating thickness. I sent some of them
away for (very expensive) electro re-plating a few years ago, but the
electro's have worn out already while some that have never been
re-plated are still going OK.

Have googled and been to my local library without finding any advice.
Looking for preferably a step by step "how to".

Cheers
Spurtle



  #8   Report Post  
machineman
 
Posts: n/a
Default

There is a tinning compound that comes in paste form, we use it to line
contact areas on pressure vessels. I am not sure of its use for food
items though. A better choice would be pure tin bars and try applying
it directly but it may need some kind of flux to bond to the steel ??.
I found some in the McMaster carr site, 100% virgin tin for about
$17/lb. item #8886K11
I also found this site http://www.retinning.com/

Glenn Ashmore wrote:
You can send it off to a professional tinker or do it yourself.

The professional way is to use bar tin and flux over a hearth of crushed
firebrick but there is an easier way that works almost as well. You can get
most of the material from a stained glass supplier. Just make sure the
solder is pure tin.

I used Johnson's E-127 Flux N Solder pure tin to retin some copper pots. It
is a paste of flux and pure tin powder. Clean the pan well and make sure it
is free of grease. Sand off any rust. I used some fresh carburator cleaner
and then rensed off thoroughly. Coat anything that you don't want the tin
to get on with whiting chalk and set it aside to dry. Brush the paste on
thinly and evenly then heat the pan with a propane torch (preferably from
the outside) until the solder melts. About 450F. Don't over heat and keep
the torch moving to prevent hot spots.

A much better way to do it if you have a propane fish cooker is to set a
larger pan full of 1/4" chunks of crushed fire brick on the cooker and set
the pan to be retinned down into the bed of crushed brick. It will heat a
lot more evenly. Don't use fine stuff because if any gets into the tin it is
impossible to get it out.

Once the tin is all melted swish it around to make sure all the metal is
coated and pour out the excess. Quickly, while still molten, wipe the pan
with a thick piece of wool to level the tin.

Steel is a little harder to heat evenly than copper but a steel pie tin will
be easier to do than a copper pot because you don't have to worrry about
getting the tin on the outside copper.

  #9   Report Post  
Glenn Ashmore
 
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Default

The Johnson E-127 is probably the paste you are thinking about. It is a
mixture of tin and flux. Johnson also sells tinning flux for steel and bar
tin but that takes a lot of practice and a real tinning forge to maintain
even heat.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"machineman" wrote in message
news:YYCYd.45737$fc4.39275@edtnps89...
There is a tinning compound that comes in paste form, we use it to line
contact areas on pressure vessels. I am not sure of its use for food
items though. A better choice would be pure tin bars and try applying
it directly but it may need some kind of flux to bond to the steel ??.
I found some in the McMaster carr site, 100% virgin tin for about
$17/lb. item #8886K11
I also found this site http://www.retinning.com/

Glenn Ashmore wrote:
You can send it off to a professional tinker or do it yourself.

The professional way is to use bar tin and flux over a hearth of crushed
firebrick but there is an easier way that works almost as well. You can

get
most of the material from a stained glass supplier. Just make sure the
solder is pure tin.

I used Johnson's E-127 Flux N Solder pure tin to retin some copper pots.

It
is a paste of flux and pure tin powder. Clean the pan well and make

sure it
is free of grease. Sand off any rust. I used some fresh carburator

cleaner
and then rensed off thoroughly. Coat anything that you don't want the

tin
to get on with whiting chalk and set it aside to dry. Brush the paste

on
thinly and evenly then heat the pan with a propane torch (preferably

from
the outside) until the solder melts. About 450F. Don't over heat and

keep
the torch moving to prevent hot spots.

A much better way to do it if you have a propane fish cooker is to set a
larger pan full of 1/4" chunks of crushed fire brick on the cooker and

set
the pan to be retinned down into the bed of crushed brick. It will

heat a
lot more evenly. Don't use fine stuff because if any gets into the tin

it is
impossible to get it out.

Once the tin is all melted swish it around to make sure all the metal is
coated and pour out the excess. Quickly, while still molten, wipe the

pan
with a thick piece of wool to level the tin.

Steel is a little harder to heat evenly than copper but a steel pie tin

will
be easier to do than a copper pot because you don't have to worrry about
getting the tin on the outside copper.



  #10   Report Post  
R. O'Brian
 
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Default

96% tin - 4% silver solder is made by several suppliers. Harris Allstate,
and Brownells are some of them.. It melts at 475° F.

Randy


"Bugs" wrote in message
oups.com...
Small areas can be physically cleaned and repaired with a soldering
iron, with all trace of lead removed of course. Finding a source of tin
is the problem here. Regular acid flux [ZnCl] works fine.
Bugs





  #11   Report Post  
Mark
 
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Well, unless the paranoids have taken it out of circulation, there is
liquid tinning stuff sold in electronics shops (got mine a future/active
a few years ago). Dip Copper, brush on, etc. NOW, it may not like the
base metal enough to plate out. Sn is more active than Cu, but if the
pan is Iron, forget it. /mark


Spurtle wrote:

Greetings,

I have some old special pie baking tins which I use, but alas the tin
plate has worn away and rust now stains the pastry in places.
I would like to know how to re-plate them myself. I would prefer using
hot dip method to gain maximum coating thickness. I sent some of them
away for (very expensive) electro re-plating a few years ago, but the
electro's have worn out already while some that have never been
re-plated are still going OK.

Have googled and been to my local library without finding any advice.
Looking for preferably a step by step "how to".

Cheers
Spurtle

  #12   Report Post  
Bob
 
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When I was in France last year, I watched coppersmiths tinning cooking
pots with zinc chloride flux and bar tin. They made it look easy (of
course they were pro's) and were doing it over a plain gas ring. Clean
the pan, flux the part you are tinning, resist the rest (they used a
chalk wash), then heat over the gas flame while rubbing with the bar
tin. When it starts to deposit, run it all over the pan, then take a
heavy cloth and wipe it around evenly. All done. Didn't take more
than a couple minutes per pan.

I suspect the end result improves dramatically with practice! :-)
These guys probably tin thousands of pots a year.

Regards,

Bob

  #13   Report Post  
Spurtle
 
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Default


Many thanks to all for the tips.

Project defered while I deal with an unpleasant crisis.

Cheers.
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