coatings for a cardboard helmet

Hey guys, new to the forum and i thought id just ask - what do people suggest for coating the helmet once its been made from cardboard?

Mid build and iv read up about using "spackle paste" in the US, and here in the UK an all purpose filler is pretty much the same thing as far as i can tell, but is there any other suggestions people could suggest that wouldnt be as brittle - or a coating once its been done that might give it a bit more durability?

The costumes got to hold up behind a bar all night whilst im working, and not that im intending on throwing it around or anything, but i want it to at least be able to take a bit of a knock or 2 if i catch a shelf without it cracking

Cheers again, Chris

Fiberglass works well

What i did with mine was coat the outside with polyester resin. The same resin you would use for fiberglass. I then coated the inside as well, and layed some fiberglass in it. you should be good to go doing that

You'll want to do just as DVH said. Don't gesso the carboard before you use the fiberglassing resin, you want the cardboard to absorb it into its interior as much as possible and the gesso will seal the liquids out. For the dome you should use Automotive Body Filler (brand name is Bondo in the US). Any equivalent of this in the UK should do. If your local hardware store doesn't have it try an Auto Parts store or an Auto Repair shop as a last resort.