Tinning Brass Coolus - Tips

[marsvigilia]

I have come up with I think a novel way of tin plating brass and other copper alloys.
The method is fairly cheap, easy and low temperature, but may not produce the most perfect result.
Since I just did it the other day, I can make no claims for its long term durability.
This is what I did. Try at your own risk.

The only materials needed are Oatey's Tinning Flux #95, a large pyrex pan, an oven, and a tolerant wife.
(Oatey's H2O 95 may also work and make water cleanup easier. I haven't tried it yet.)

That said, I really do like the result on my Coolus.

1. Clean brass of all rust and tarnish. A light acid spray like "BAM" cleaner may be helpful.
2. Preheat oven and pyrex pan to 200 - 250 degrees Fahrenheit.
(250 requires less time in the oven but more time cooling between coatings and could theoretically result in accelerated tarnishing of any exposed areas.)
3. Coat the entire piece with with Oatey's Tinning Flux #95. Coating doesn't have to be too thick.
4. Cook in oven for 10 minutes at 250, or 20 minutes at 200.
5. Remove from oven. And allow to cool. (Here is where you save time if you go with 200.)
6. Wash with soap and water to remove all the greasy flux.
7. Dry well.
8. Inspect for completeness of tinning.
9. Go to step 3 and repeat as necessary with special attention to missed spots.
(May require rotating or repositioning piece to minimize run-off of tinning flux.)

The tin does not appear to build up and is limited to a very thin plating, which allows lots of detail to remain un-obscured, but doubtless means the tinning will not last as long.

This process does not appear to work with steel. :-( (

Note: I did not find it necessary to remove cheek pieces. Not enough tin was deposited to interfere with the hinges.

Attached are two pictures of the helmet.
Vader never looked so good as he does defending the Empire wearing his tinned Coolus.
http://www.geocities.com/fm253737/vader ... olus_1.jpg
http://www.geocities.com/fm253737/vader ... olus_2.jpg

[Tarbicus]

Tony, nice job!! Great advice Thanks.

That's a lot of niello on the facemask. Kalkriese reconstruction?

[Robert Vermaat]

Cool! Even I could try that....

[arklore70]

How badly does it stink up the kitchen?

Could I use tin foil on the bottom of the pan, to avoid angering my wife?

Cheers!!

Mike

[richsc]

Makes me wonder, since my hotplate can achieve 212' F, if a covered pyrex dish on a hotplate would work as well? It would avoid stinking up the oven!

[marsvigilia]

The real issue is the greasy mess. I strongly recommend using one of those disposable aluminum oven liner trays trays in the bottom of the oven.

Perhaps I have become used to the smell of flux cooking, but I don't think that this stinks up to badly really. You see it isn't hot enough for the flux to really burn. Flux is mad to stand up to propane torches and such. Much higher temperatures.

I've never had the smoke detectors go off at 200 - 250. (At higher temperatures? Well more on that later. My results aren't ready to present.)

Weather permitting, I still like to keep a window at least partially open.

[Theodosius the Great]

Hi Tony,

I heard about your method from Matt, and I'm intrigued with your method and impressed by the results.

is limited to a very thin plating, which allows lots of detail to remain un-obscured, but doubtless means the tinning will not last as long.

To increase the life of the plating, have you tried spraying the helmet afterward with lacquer ?

I recently used lacquer on my plated helmet (which was tinned using a simpler method) and the tin lasts longer.

[marsvigilia]

I haven't tried lacquer yet. I just finished the helmet, and I'd like to see how it does on it's own this time. But thanks for the suggestion I may try it when I have to replate. Replating could get old fast.

What is lacquer made from any way? Does any one know? Is it period?

[Theodosius the Great]

I just finished the helmet, and I'd like to see how it does on it's own this time

Okay, gotcha. Sounds sensible.

Is it period?

I doubt it, but it's cheaper in the long run (and probably the short one too) - like you said : replating can get old really fast :wink: You should be able find it at your local hobby shop.

[Matthew Amt]

Thanks for posting that, Tony! Folks, I saw that helmet on Saturday and almost dropped my teeth! Amazing. Especially since the brief test that Richard and I did with Oatey's #95 last month seemed to indicate that it was just flux, with no metal...

Afraid I'll have to veto the idea of lacquer or other coating for Legio XX use, though, unless you can document it. Same old song.

PLEASE use as much ventilation as possible for stuff like this! I've heard too many real horror stories. There might not be a lot of metal fumes involved, but far better safe than sorry. I'll do my first experiments with a toaster oven outdoors. If I try a helmet I'll likely use the torch, also outdoors.

Thanks again! Valete,

Matthew

[marsvigilia]

Fumes are a real concern.

Particularly when you play with the higher temperatures. 500 degrees makes flux really smoke.

[Primvs Pavlvs]

Is there any lead in this, or is it pure tin?

[marsvigilia]

According to the the product container and the MATERIAL SAFETY DATA SHEET, Oatey's #95 is lead free. That unfortunately does not mean that it is risk free.

The Contents by weight follow:
----------------------------------
Petrolatum 60 - 70%
Zinc Chloride 15 - 25%
Ammonium Chloride 1 - 5%
Tin 4 – 8%
Copper 0 – 1%
Bismuth 0 – 1%

It probably does pay to exercise caution.

I am definitely going to follow Matt's advise and increase my ventilation. I plan to mount a fan in the kitchen window facing out and open opposite windows to create a draw and cross current.

Better safe than sorry.

This stuff is made to be burned off with blow torches, but probably not in the quantities I've been working with. Plumbers would never use as much in an evening as I did last night, but they also are likely to have years of exposure. This "might" argue that the long term risks are minimal. Short term... Well... as I said I plan on increasing ventilation.

[Magnus]

Awesome Job!

I guess belt plates could be tinned the same way eh?

Anyone know if you can get the Oatey's here in Canada?

Would it also be possible to tin a second layer on in this fashion? To increase it's durability?

[marsvigilia]

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.