Advice for building things that shall be burnt

[Feeline]

I am volunteering at a small European regional and helping develop plans for the effigy and temple. I would appreciate advice on what materials are best. Our budget is really low so we were considering using plywood for some parts, however I have been told that when this burns it can delaminate and blow off larger chunks of floating embers.
Just wondering how much of a problem is this and are there ways to mitigate it so it's not such a fire hazard?
What alternatives might be better?
Any and all advice from those more experienced is greatly appreciated.

[AntiM]

Moderator note: moved to Building and making art as that is a better fit.

[Ratty]

Feeline, Welcome to eplaya. Maybe you could narrow your search by going to the BM site. Look for the volunteer dept and then contact the appropriate person. Try the Temple contact. Maybe they can hook you up.

[Token]

I’m not sure how lumber is treated in Europe but in the US you can get different grade of lumber that do NOT have fire retardant impregnated in it.

Generally we call that green fir, short for Douglas Fir - a common pine type of lumber. Usually heavy when bought, not dried, and warps like crazy over time.

Now any plywood is a wood and glue laminate, so you will be burning the glue and any other chemicals put in the wood to make it more pliable, fire resistant, rot resistant etc.

In general, burning plywood is not good.

If you are able to design your art in a way that you do not need the structural strength of plywood, that is the way to go.

I have done solid wood trus designs where we used sheets of burlap to simulate the look of plywood without the toxic fumes. You can add brown butcher paper with a wheat flower glue to it, etc.

The key is to burn clean materials.

[Token]

Ideas:

Old shipping pallets - European shipping palets are AWESOME! Mostly oak, they burn good and long.

I find them in the US every now and then and buy them up. Much nicer than our cedar pallets and they can’t be used here because of the Metric vs SEA conversion. Built many-a-floor with them.

Discarded shipping boxes with mix of structural cardboard, wood ... things computer data centers dump loads of. Can give that planar rigidity with fewer toxics on the smoke.

Put on your scavenger hat and go looking in the places most people avoid. Shipping docks, industrial areas, goods distribution centers.

Edit to fix bad spelling.

[Feeline]

as far as I am aware, here in the UK most wood does not come pre-treated with fire retardants.

thank you all for the advice. scavenging cheap wood would obviously be really useful, though we also want to laser cut some things so might not be best for that.

[motskyroonmatick]

In my experience air flow is the key to a good burn and large timbers take a really long time to burn. Glue Laminated Beams are usually self extinguishing unless exposed to continuous fire. If heavy structural elements are needed consider making them in a box form with inlets for fire and air or out of more small lumber that is bolted together with spacers between so fire can get to all sides of the individual pieces. Heavy timbers and Glue Laminated Beams have caused burn structures to stay standing for a very long time after the burn process has begun.

The times I have seen large pieces of plywood floating away from a burn it was used in near full sheet form. I think small (1/8th sheet pieces) and especially laser cut pieces with voids will not spawn large sheets of embers.