Cyano adhesive vs lead/brass reaction.

Never had it happen myself. And I’ve been using CA with lead shot as my preferred weights for many years. 

There are at least two types of CA, and lots of casting metals that get called lead.

I did a little research because I'm about to put together a 54mm figure and was curious to know what the hot set up is. Most writers like Gorilla Glue CA or Loctite CA.

I don't use lead for weight, as it does end up in the environment. If I had a bunch around, I might.

I like to use steel nuts and bolts. Not as dense but they do the job.

I've mixed all types of metals in models, separately and mixed, for weights and used CA to keep it there with no problems. If possible I usually use nuts/n/bolts with fine brass shot as a filler for the spaces. Have never had any type of reactions.

Jim   

I just don’t see CA swelling. If anything it tends to contract as it dries and cures. And metals only expand or contract due to major heating and cooling. The styrene would be softened long before the metal heated enough to expand. 

I wonder if it might be something like a sulfate reaction, like that crystalline growth that happens on car batty terminals. Sufficient growth of this substance in an enclosed space could force seams apart.

Metal can be a funny thing. Most "lead" and white metal are compound alloys with formulas which vary dramatically from manufacturer to manufacturer. If you go heavy on the zinc (Zn) in your process, you can develop Mazak rot as it reacts to the presence of contaminants in the lead (Pb). Muzak rot causes some degree of expansion, but it usually makes the metal crumble to dust when handled. If you go too heavy on the tin (Sn), your metal becomes susceptible to moisture and humidity, which causes expansion and tin pest ("tin soldiers' disease", tin rot, tin bloom, etc.), which leaves something resembling crystals and almost algae-looking blemishes to crop up, even under layers of paint.

Fortunately, metallurgy has come a long ways in this hobby, so it isn't as prevalent a problem as in the past. Most commercially available white metals, BBs, shot, fishing weights, and so on are pretty reliable over time.

Hi all -

Thanks so much for all of the replies, much appreciated. I checked closely at the full length of the seams where the ballast was placed, all is good.

For a short time I've used stainless nuts in a variety of sizes, agreed, they do work well. I also switched to the thick contact cements, like 3M and Weldon, it secures everything well so nothing will break loose and rattle around.

Nice of you all to chip in with advice, thanks again.

Patrick