If someone had these chemicals at that strength, would one just work out the amount they need to be diluted to get to 85% formic and 35% H2O2 and proceed from there? Assuming the standard buffered performic of course.

I hate variables!

Raf had 50% H₂O₂ and he used tap water for dilution and just checked density.You must calculate to get the amounts needed.It's easy,at least it was for me.

I assume you're talking about aqueous solutions. To make a 85% formic solution, mix 85mL formic per 100mL of the total (i.e., for every 100mL you have, 85mL should be formic, and 15mL water). To get 35% solution from a 50% solution, mix 70mL peroxide per 100mL (i.e., a 100 mL solution would be made up of 70mL peroxide and 30mL water). I wouldn't use tap water... I would use distilled/de-ionized water. Good luck peace

No,density of formic acid and it's solutions is always above 1 and so are solutions of perhydrole you can't use volume here but weight.
Let me do a calculation for you.Let's say you want 500 grams of 35% perhydrole.
500x0,35=175
You need 175 grams of 50% perhydrole
and 500-175=325 grams of water to get 500 grams of 35% perhydrole.All % are weight %

Iff you have 100% perhydrole rafkie is right, else multiply with 2 *loL*

(As in 175*x=350g 50% prehydrole and 150gwather=500g 35% perhydrol)

damn some mistake jumped in...glad you noticed...

Could you help swim find a complete procedure using formic acid and H2O2 swim has looked everywhere and cant find anything could you point swim in the right direction?

Could you help swim find a complete procedure using formic acid and H2O2

For what? If the actual mixing, everything you need to know can be found above. If you want a procedure using the mixture, UTFSE for "performic acid oxidation"...