02-07-2006, 09:29 PM
Yesterday I would have said no. But now I have to say maybe.
The tin appears to bond easily at low temperatures to copper and copper alloys, but not much else. This bonding appears to occur well below the melting point, and I am not sure what the mechanism is. Most experts I've consulted say that I'm wrong and that it just doesn't work at all. To them I say "Kiss my tin Coolus." ;-) )
It is slightly possible however that the reason that the tin does not bond to the previous tin layer has to do with a slight, invisible oxidation layer on the tin. Tin oxidizes more rapidly when heated. Therefore a light acid bath before attempting a second layer might (I repeat might) lead to a second layer. Of course you can bump temperature up above 425 in order to actually melt another layer of tin. However this results in a much more uneven surface. You lose the smooth finish that looks so lovely on a helmet, and may lose detail of small parts for items like belt plates. Though I wouldn't bet on it working.
The process of this low temperature bonding to copper is simply too different. I just don't think this low temperature bonding it will work on tin.
But please find a way and prove me wrong.
I find that re-layering is important to insure complete coverage. I find for some difficult spots, cleaning with acid again does help.
A couple of details I left out:
--------------------------------
1. The oven I am using is convection. Meaning the air is circulated around so this might help create the consistency of results I've had.
2. The oven I am using is electric. Thus it does not have the kind of air flow you get with a gas oven. At higher temperature where the flux burns this results in an oxygen starved environment. This can be seen when you open the door and the flux suddenly releases a cloud of smoke. Though again this is really more an issue at higher temperatures.
(please see discussion of taking precaution to insure adequate ventillation.
The tin appears to bond easily at low temperatures to copper and copper alloys, but not much else. This bonding appears to occur well below the melting point, and I am not sure what the mechanism is. Most experts I've consulted say that I'm wrong and that it just doesn't work at all. To them I say "Kiss my tin Coolus." ;-) )
It is slightly possible however that the reason that the tin does not bond to the previous tin layer has to do with a slight, invisible oxidation layer on the tin. Tin oxidizes more rapidly when heated. Therefore a light acid bath before attempting a second layer might (I repeat might) lead to a second layer. Of course you can bump temperature up above 425 in order to actually melt another layer of tin. However this results in a much more uneven surface. You lose the smooth finish that looks so lovely on a helmet, and may lose detail of small parts for items like belt plates. Though I wouldn't bet on it working.
The process of this low temperature bonding to copper is simply too different. I just don't think this low temperature bonding it will work on tin.
But please find a way and prove me wrong.
I find that re-layering is important to insure complete coverage. I find for some difficult spots, cleaning with acid again does help.
A couple of details I left out:
--------------------------------
1. The oven I am using is convection. Meaning the air is circulated around so this might help create the consistency of results I've had.
2. The oven I am using is electric. Thus it does not have the kind of air flow you get with a gas oven. At higher temperature where the flux burns this results in an oxygen starved environment. This can be seen when you open the door and the flux suddenly releases a cloud of smoke. Though again this is really more an issue at higher temperatures.
(please see discussion of taking precaution to insure adequate ventillation.
>|P. Dominus Antonius|<
Leg XX VV
Tony Dah m
Oderint dum metuant - Cicero
Si vis pacem, para bellum - Vegetius
Leg XX VV
Tony Dah m
Oderint dum metuant - Cicero
Si vis pacem, para bellum - Vegetius
