Model Railway Forum

RSR Engineer wrote: ↑Wed Nov 28, 2018 3:43 pm

Malcolm 0-6-0 wrote: ↑Mon Nov 05, 2018 9:38 am

Steve M wrote: ↑Mon Nov 05, 2018 9:24 am Time for a cautionary note.
If using weights you may be tempted to fix it in place with PVA - after all it’s the ‘go to’ adhesive in most cases - but don’t, lead and PVA will slowly react over time and expand causing the models to split and crack.

In the past I have used ‘Liquid Gravity’ which I believe does not react and is easy to pour into suitable areas on the model such as fuel/water tanks and battery boxes as well as inderframes on wagons.

Very true. The problem is that lead oxidizes and as it does the oxidization forms on the surface which causes it to expand in size and if that is contained in a confined space it will eventually deform the plastic or crack it. That's why I use Blue Tac because that allows the lead to expand but gives it room to do so. It's a similar process to concrete cancer caused when rebar contain in reinforced concrete rusts causing the concrete to either flake off or crack.

Seems lead's a lot more trouble than it's worth. Why not use nice non-toxic gold? It's also denser. ;o) ;o) ;o)

Cheers,
Artur

Lead isn't such a huge problem if you allow for the expansion which isn't actually all that rapid and also depends upon the metals in the mix. It is pure lead that is the most subject to oxidization. As for the toxicity, that's a little over exaggerated. Providing you don't eat it you should be OK and one should discourage children from eating however if a child is eating parts of a model train then I suggest that there is something wrong with the child that implies that they shouldn't be allowed to do anything unsupervised.