The Chopper Compendium

I've been giving some thought to brazing the bottom tree and spring perch plate to the rear legs instead of welding them. In doing so, the tree and perch plate would be beveled at a 45 degree angle (1/8" bevel) on the top and bottom sides of the tree and perch and brazed and finished with a small fillet braze.
The flux would be Peterson #1 blue and the rod would be 1/8" Hobart bare brazing rod.

Gary mentions brazing in the Final Welding section of The Rude and Crude Old School Springer Build:

"Pay special attention to the welds where the lower tree attaches to the rear fork tubes and use minimal heat and minimal penetration at this juncture. In fact this connection only really needs to be welded on the upper side of the tree and not on the bottom. For several years now I've been contemplating brazing this connection or using a Nickel solder, as this is where Springers fail on a routine basis."

I Googled Nickel solder and found a variety of percentages of silver - anywhere from 30% to 75%.

Questions:
Would the brazing method described in the first paragraph (using bare brazing rod) be strong enough for this purpose?
What percentage of silver solder wire would be best, if brazing rod isn't strong enough?

Thanks for any insight.

On the old days some of the guys who were building springers used conventional welding at the connection between the top of the bottom tree but used gunsmith solder at the bottom connection so there was no appreciable HAZ at that location. The perch should be welded top and bottom as it's under significant loading.

Back then we were all running much thinner tube legs than we do today so bottom fractures in the HAZ were common. With todays thicker material and Tig welding the heat damage is less.

I’m using 3/16 wall on the front legs and 1/4 wall on the rear legs. Any problem using MIG for these welds?

No problem so long as there is no weld under cutting in the tubing which is a problem seen on springers, girders and leafers.

Under cutting on tubing welds is one of the most common reasons for failure primarily because it reduces the tube wall thickness right in the middle of the HAZ which is the worse possible place.
Hopefully this little gif will illustrate the situation

Thanks - I appreciate the info. Next step is to make a simple welding jig to keep everything aligned, then weld ‘er up.

Don