sodium formate

Can anyone tell me how to mix sodium formate to give 60% formic acid please

You can (in a laboratory) make sodium formate from formic acid but I don't think that you can easily go back the way. Even if you could, formic acid is nasty stuff and not the kind of thing to play around with. I bought some from Thornes years ago and have never used it.

OK thanks for that. I have come to the conclusion that the hives need an effective spring treatment to prevent varroa expansion along with the brood. I've tried afew of the alternatives with limited success, I use OA in winter
Have you found any successful alternatives

If you catch them just before they start raising much drone brood and place a shallow frame each side of the brood nest you'll trap most Varroa in the sealed brood. Feed it to the birds. If they already have drone brood all over the place the colony should be in a good state for Apiguard or another thymol-based method.

Not sure I'll acheive the level of brood nest thats needed this year. This has been the worst year for losses since varroa impact. Ironically the queen with the largest broodnest and in best condition after winter had far and away the highest varroa counts last year prior to treatment.
Is it fair to say that all the beekeepers worrying about swarming at this time have access to OSR while the more marginal areas are building on blossom.

I don't think we have any OSR over here, certainly not noticed any. That was one of the benefits of moving over to the West from Yorkshire as it's a nightmare for the hayfeaver. Both my hives have now been split in the past week due to finding lots of queen cells in each & other local bee keepers have found the same. Whatever it was they were finding was in abundance in April and the colonies just seemed to boom.

Sunny Renfrew sound like a nice sycamore woodland in the area. I think it's too wet in the west for OSR, this year the blossom in the clyde valley on the higher ground was about 2 weeks later and the weather was bad when the sycamore was out. To be fair as I said the remaing hives came through weak. From a previous note it appears to be nosema ceranae. I'm also blaming the first OA trickle treatment, where previously I used sublimation