Member postings for shaun meakin

There are a few materials to help here, but by far the best way of controlling the flow of any soldering or brazing materials is to use the heat. Develop the right heat pattern for your particular joint design to ensure the right amount of alloy flows where it is needed. Keith Hale's latest book (available at http://www.cupalloys.co.uk/brazing-ancillaries/index.asp) offers advice on this and all other aspects of brazing and soldering. Might I suggest a perfect Christmas present for the Model Engineer?

Good morning Bill. Taking your questions in order;
HT5 has a working temperature of 500 - 1000 degrees C and therefore is suitable for use will the lower melting point alloys such as our 455 (630 - 660 degree C).
If you feel you are taking time to get to temperature then it is even more important to use HT5, although it is best brazing practice to get the joint up to brazing temperature as quickly as possible. Are you using a big enough burmer?
Don't worry about playing the flame on the flux, it is the rod you want to keep the flame away from, using the flame to 'attract' the solder to where you want it. The solder will always run to the hottest point.
Mix the flux with water and a drop of washing up liquid and apply all around and in the joint. Then heat the whole joint area where you have fluxed until the paste goes like water. You are now almost at brazing temperature. continue heating the area for a few more seconds then move the flame to one side of the joint and apply the rod at the other. Continue heating until the rod melts and it will run to the flame. It is a skilful process, but also simple if you stick to the principles. As with most things in life, practice makes perfect!
I don't like to advertise on the forum but hopefully I will be forgiven by saying there are lots of helpful advice and tips including a brief video demo on www.cupalloys.co.uk check out the dropdown menu from 'introduction to brazing' on the top navigation bar.
Just a final note, HT5 is a more aggressive flux than say EF. That is why it is recommended for stainless steel, as chromium oxides are difficult to remove. It follows therefore tat HT5 residues are more corrosive so please clean after as much as possible.
Hope this helps,
Shaun..

Hi Brian, the guys are right obviously soft solder melts and therefore remelts at a lower temperature than silver solder. It is also correct that a soft soldered joint won't withstand the pressures a silver soldered joint would, so therefore you have to make a judgement based on these facts. However, you do not need to be lead free as a model engineer, tin lead alloys are not banned and are freely available eg **LINK**

Hi David, firstly i feel i must declare I work for CuP Alloys Limited but I am not trying to advertise. The guys I think are right, you have a heating problem. This is very common, particularly since the ban on the cadmoim alloys as the cadmium free ones do need a bit more heat. Although you may still have the cadmium alloy. Propane is a more than suitable gas as long as you have a big enough burner on the other end. Sievert have burners from 0.25kw/hr right upto 86 kw/hr all of which fit on their pmpx torch kit. the kit will cost approx £94 inc vat and delivery. Jeff gives good advice about insulation, but if I may say firebricks do absorb heat and you might be better with kaolin wool. As I said I''m not wishing to advertise but there are lots of tips and information available on our website www.cupalloys.co.uk please feel free to peruse.

Silver soldering really is not that difficut if you get the piece clean, put on enough flux and apply enough heat. I am technical, not practical (often in danger of picking the rod up by the hot end!!!) but even I have silver soldered successfully!

I hope that with the other advice helps solve your problem and I have not broken any rules by mentioning my employment!