The MG RX-78 Gundam 3.0 looks incredibly cool when completed, but aren't you annoyed by the shoulder armor coming off so easily and dangling?
Today, I'd like to share some ideas to fix this. 😅
All you need is a black resin washer. I was able to get hold of some poly slider washers, so I'll use those.
I think an outer diameter of 7 or 8 would be better, but 6.5 would be fine. A thinner thickness is better, so a strong poly slider would be ideal.
Metal washers are easier to obtain, but if you can get them, they'll minimize damage to the shoulder joint parts.

MG RX-78 Gundam 3.0 Shoulder Armor Improvements | はならっきょ's Gunpla works