Flux

[Alan Gordon 4Participant @alangordon4]

[Alan Gordon 4Participant @alangordon4]

Hi everyone, Can any one advise ? Rather than mix with water, silver solder flux, is there a ready mixed paste available. If so where I might get it would be helpful.

[David George 1Participant @davidgeorge1]

Hi Alan why don't you want to mix up flux as it is not affected by mixing and when dried out just works. You may have to dip the rod into a powder during use as well but if you want it to dry out quicker you can use metholated spirit's instead and wait til it has dried before starting. Dried out flux can be reused by adding more water or spirit's.

David

[Dave SParticipant @daves59043]

CuP alloys sell pastes.

never bought from them, but they do pop up on here with useful advice form time to time, so may well be along presently

Dave

[JasonBModerator @jasonb]

The paste that CuP sells also contains solder in a very fine powdered form, it is not just a paste flux.

Something like Harris 17 paste flux would be just flux in paste form

[nigel jones 5Participant @nigeljones5]

CUP do a paste but for some reason its not on their website and you need to buy it ib a big tub. I use it as a base and blend it with other fluxes to obtain exactly what I need, sometimes soldering up ten boilers in a day so it needs to be right. If you dont do much silv soldering you can buy solder and flux ready mixed in a paste – its about £15 for 10g in a syringe. loads if you google it.

[david homerParticipant @davidhomer12226]

Looking at their website it looks like they sell EF Flux paste 250g and 500g exactly the same price as powder. Their mix of 455 silver solder and flux is in a syringe.

David

[Alan Gordon 4Participant @alangordon4]

Thanks guys for all the excellent advice.

[noel shelleyParticipant @noelshelley55608]

PLAN B ! mix your flux and water. get a large medical syringe and fill with the mixture and addminister as needed. keep or make a cap to seal the nozzle when not used, it will keep for a long time. Noel.

[martin haysomParticipant @martinhaysom48469]

could just use it dry

[shaun meakin 1Participant @shaunmeakin1]

We sell flux paste in 250gr and 500gr containers please see https://www.cupalloys.co.uk/store/EF-Flux-Paste-250g-p276411631

Jason B is correct we also sell 455 as a paste including flux.

If you are to dip the rod in the flux, known as 'hot rodding' please only do this to add flux during the brazing operation. As soon as you heat the bare metal it will oxidise, pre placing flux acts as a barrier.

If you have flux powder we recommend mixing it into a paste with water and a few drops of washing up liquid. The detergent helps keep the powder in suspension, it also acts as an extra degreaser and if the flux goes hard it will remix with water and a few more drops of washing up liquid.

I hope that helps but as always we are at the end of a telephone for help and advice where necessary. – Shaun.

[Brian HParticipant @brianh50089]

Posted by shaun meakin 1 on 06/12/2021 09:46:26:

(Quote) If you have flux powder we recommend mixing it into a paste with water and a few drops of washing up liquid. The detergent helps keep the powder in suspension, it also acts as an extra degreaser and if the flux goes hard it will remix with water and a few more drops of washing up liquid.

Shaun.

End Quote)

This advice from Shaun is exactly what the Rolls-Royce Aero specification advises and if it's good enough for R-R then it's certainly good enough for anyone.

Brian

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