I have a surface made of wood (teak to be exact) I need to take a mould from it. However, I CANNOT damage the original. That means no sealers, primers, fillers, waxes etc. Will PVA alone be a good choice for this? The surface looks quite porous...

Once I've been advised by someone who suggested to use kitchen plastic paper (the one used to wrap food, u see ?). Never tried it though.

Heat shrink some unperforated release film over it.  It doesnt shrink much with heat but if its not too rough a surface you might get away with minimal creases.

You can wax and then dissolve the wax after or is it too delicate a surface?

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

I have taken at least half a dozen moulds from very highly polished and oiled wooden gunstocks, I cleaned them up with a cloth and rubbed wax on them, then put on flanges using tape and filleting wax..  Standard 4 layers of wax.. no problems so far with the gunstock oil already there.

After the mould was released, one of the owners of the original gunstock liked the cleaned up wax surface so much that it stayed that way

Normally a part made from Teak wood will be either oiled or waxed already ... it can be cleaned up with the finest grade steel wool and the apropriate Teak oil.

A totally untreated teak surface will bond VERY "nicely" to Epoxy or Polyester so something MUST be done... Shrink wrap may be the only way then.

You mention that the wood looks quite porous, that to me sounds like it is maybe without any surface treatment.

Good luck

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It's not that delicate, as long as the wax can actually be dissolved. If you look at the surface of the wood, you can see the pores in the grain, about human hair wide.

Over finished old wood I used 4 coats of wax with good time between layers of wax so they can adequately dry and not just wipe off previous coat, then spray a light mist of pva over that with automotive spray gun. Leaving the wax to sit between coats for a good length of time has been key for me in protecting old surfaces. Of course make sure you are buffing lightly to a shine after each coat. I use filleting wax for any edges that need it because I can shape it with custom tools and a heat gun easily.  Mold should pop out nicely.