Sem panel adhesive amazon almost same price as ebay within pennies. https://amzn.to/2QwGcoL
Panel adhesive 3m same size amazon https://amzn.to/3biwPCN
panel bonding adhesive gun 3m https://amzn.to/32Byejz
This gun may work as well but I havent tried it. if you buy one let us know in the comments. Says it will in the description I would try it for much less than 3m
https://amzn.to/2EN9FI9