Degradation of lead and Britannia fittings

[John Allen]

Appears I may be stuck with lead fittings with Mamoli CSS Aabama. Can they be properly treated other than primer or watered down white glue to slow down the degradation of the lead over the long run. Does this problem also plague Brittania metal fittings.

Would wood or brass copies when feasible be better. Could not find Metal for dummies #2 at Amazon.

[Jaager]

John,

 

I would think that a clear coat of the organic solvent sort would buy you time, but if the "white glue" is PVA, that has the potential to be a disaster.  The final product in lead disease is lead acetate -I believe.

I am not sure how much if any acetate is in bookbinders PVA,  but all other woodworkers PVA has as much acetic acid as 5% vinegar.  My guess is that a PVA coat would accelerate the disintegration of a lead casting.  

The clear coat using lacquer et al. has the disadvantage of not being glass and thus allowing gases to migrate across it.  A quick smell of vinegar tells you that acetic acid is partially a gas at RT.  

[Snug Harbor Johnny]

  Lead (or more likely tin/lead) fittings will be soft and bendable.  If primed on all surfaces (not sure which primer works best for tin/lead - but what is sold for cast military figures and 'flats' is obviously suitable), then painted with enamel (not acrylic) - they can last a long time without oxidation, since oxygen won't go through the coatings.  I found a painted CW tin/lead soldier I cast as a boy over 50 years ago, and it is in perfect condition.  Antique figures can be so found, as long as the coatings don't get scratched or chipped.

 

  Any lead in these figures has been banned for some time, so tin based 'pewters' have been used.  95/5 tin/antimony is "out" these days because of the antimony.  Something like 2% copper is alloyed with tin ( to make Britannia metal), since pure tin degrades under freezing temperatures.  (Napoleon's soldiers buttons fell apart on the road back from Moscow.)  One can see 'Britannia metal' (tin-copper) plate wear over 200 years old on display in museums in excellent condition, whereas the cheaper stuff with lead go dark grey and can oxidize in high humidity.  Conclusion ... Britannia metal is fine without painting for centuries - now I'm not talking about buried in soil, which will ruin anything other than gold (or platinum).

 

  Some kits have zinc metal castings, since anything with lead these days is a no-no.  Zinc can likely take the same primer, although zinc chromate is the best.  Some early zinc cast toy locomotives had zinc with contaminants and suffered from an internal degradation that caused them to crumble from the inside in spite of coatings.  I'm talking about stuff from the 1920s and 30s.  Since then, there are no reports of 'bad' zinc.   Johnny

 

  

 

 

[John Allen]

jaager-Johnny

 

thanks

[Bob Cleek]

This is all you need to know about lead oxidization in ship models. Read it carefully, It's the "bible" on the subject.

 

Nautical Research Journal - Vol 43 (thenrg.org)

[Essayons]

If you are able, cast your parts in Type R pewter (no lead). It flows well but it melts at 575 degrees F which will shorten your mold life. I believe  archivists classify as some pewters as archive grade.

[thibaultron]

I read that copper plating the fittings will seal them. Also some flow thru ventalation in the display case helps. Completely sealing the model accelerates the problem.

[MOURADATOR]

Hello dear new friends

I'm new on this forum (from France)

I received a Mamoli Britannia model, just splendid

My issue is that I don't have the Instruction notice

Any chance to find a Pdf or a scan somewhere ?
Thank you for your support

[allanyed]

40 minutes ago, MOURADATOR said:

I'm new on this forum (from France)

I received a Mamoli Britannia model, just splendid

My issue is that I don't have the Instruction notice

Any chance to find a Pdf or a scan somewhere ?

Bonjour Moura,

You should start a post in the plans section here at MSW as you are looking for plans for the Mamoli model Brittania, not the metal called britannia. More members will see your post there than here.    https://modelshipworld.com/forum/13-discussions-for-ships-plans-and-project-research-general-research-on-specific-vessels-and-ship-types/   Did you contact the owner at Mamoli to get a set of plans?  With the fire seven years ago, most everything was lost but Daniel Dusek is a member here and you can PM him to see if there are still any plans.      https://modelshipworld.com/topic/13542-mamoli-model-kits-are-back/

Allan

Edited July 31, 2023 by allanyed