flux problems

george_42

I have been using Laco flux for 50 years ,but lately when soldering pex adapters to copper ,I have been getting leaks. I just found out at the supply house that the pex adapters are made from lead free brass and Laco flux will not work with lead free fittings . Many new brass fittings and valves are now using lead free thanks to our GOVT so be aware . Other fluxes are available for use with lead free, GEORGE

icesailor

Life in flux:

I've used the Crest soldering paste for almost as long as you have been using La-C0 paste. You must be older than I. I started on Nokorode. . I've never seen a problem.

I find the biggest problems occur when I use my LP TurboBlow Torch, I get leaks because I can easily over heat the part of the fittings that I can put the flame on and under heat the back or place I can't directly heat. I always wipe the goobers and paste off the fittings. I can also tell when I wipe if the fitting was hot enough. When overheated with the TurboBlow Torch, I can't always tell. I only use my portable turbo blowtorch for long crawls, thawing pipes or annealing tubing. I use my Prestolite #3 tip and "B" tank only. With a small (liked a #3) hot tip, I avoid burning the wood and get the fitting hot. I also have a Turboblow torch tip for my acetylene hose for those special heat-up jobs. I haven't used it in years. I can't remember the last time I used it.

I find that the Turboblow LP hand torches have a tendency to overheat and burn out the paste before the solder flows. Especially with the oil free water paste.

bob eck

Soldering lead free brass fittings

I hope this helps you out.





Soldering Lead-free Brass

“Lead-free” brass fittings and valves are manufactured from a dezincification-resistant, lead- free brass material, classified as C69300 by the Unified Numbering System (UNS). While this material is rated Excellent in soldering suitability2, it is important to recognize that lead-free brass is more sensitive to soldering conditions than traditional leaded (i.e., yellow) brass. Therefore, strict adherence to good soldering practices is paramount.

Lead-free brass has a lower thermal conductivity compared to leaded brass, as well as unique corrosion resistance due to its natural oxidative barrier, making for an exceptional lead-free brass product. Lead-free brass requires following proper brass soldering techniques to enable a good plumbing joint connection. See below for tips and techniques for soldering lead-free brass.

Soldering Tips and Techniques

Good preparation and cleaning — All metals should be properly cleaned prior to sol- dering, but because of the natural oxidative barrier of lead-free brass, a clean surface is im- perative to help remove oxide films and achieve a sound and uniform quality-soldered joint. Fluxing alone cannot substitute for adequate cleaning. Adequate cleaning requires the use of a mechanical abrasive product, such as a wire brush, sandpaper or a sanding cloth. Also, be sure to apply a sufficient coat of flux prior to soldering. Fluxing and soldering should be done immediately after cleaning as oxide films tend to reform quickly on the cleaned surfaces.

Flux with chloride compounds — Use only flux that contains chloride compounds. While most flux does contain chloride compounds, there is still some flux available without chloride compounds; however, it should not be used with lead-free brass.

Lead-free solder — Use only lead-free solder, preferably a 95/5 mix of tin/antimony.

Uniform heating — Uniform heating around the entire perimeter of the fitting/pipe juncture is critical to making a good joint. When soldering any brass, it is always good prac- tice to heat the component gradually, using a smaller tip, and continually moving the location of the flame around the joint. This is also true with lead-free brass.

Avoid excess heat — It is especially important not to overheat the metal. Lead-free brass will turn a distinctive brown color when overheated. This discoloration is an indicator that flux may have been burned out of the solder joint, resulting in a lack of complete solder coverage. If this condition occurs, the joint must be disassembled and the “good preparation” procedure reapplied.

Cool properly — Over-heating the joint and the subsequent delay in cooling (due to the low thermal conductivity of lead-free brass) may actually allow solder to weep from the joint, or allow the joint to be disrupted after soldering. Cooling the joint with a wet cloth im- mediately after soldering will speed the transfer of heat, reducing the risk of disrupted joints.

heatpro02920

Trusty Nokorode for me...

I use the cold in the winter, hot in the summer and I just picked up some of the aqua stuff for the lead free BS... and for pre tinning I keep some famous Amos around...



I find I am so used to nokorode and silverbrite that when I take one of my service guys trucks and they use something different, my joints look like sh!t... And I end up having to sand themdown, and reheat and wipe them to get them to look half way decent.. One of my techs swears by Oatey 95-5 and oatey #95 flux with scotch brite pads and steel wool for cleanig fittings, they look great when he is done, but I like silverbrite 100 with nokorode and I use a fitting brush and emry cloth... To each there own...



The Nokorode aqua stuff works well for me, worth a try...