We are considering using the T-Drill model T-D35 (www.t-drill.com) to replace many of the T fittings that we now use in our copper water headers. The web site and sales brochures always look good, but I'd like to hear from people who have actually used it. Did it live up to your expectations? What were some of the unexpected benefits as well as any unforeseen problems, if any? How were they overcome? Additionally, what brazing alloy did you find to work best for copper to copper?
Thanks,
Dave
Hi Dave -
Sorry no one has answered your request to date.
T-drill works very well on copper tubing and makes very good brazed joints. We used the process on steel tubing some time ago but not recently. For the best strength the brazed joint overlap should be 3 times the thinner member. The joint clearance should be 0.001-0.003 in. for torch brazing. A number of brazing filler metals can be used for the copper application, look in AWS Specification AWS A5.8 Specification for Filler Metals for Brazing and Braze Welding. BAg-8 is a silver copper-eutectic melting at 1435°F, BAg-7, a silver-copper-zinc filler metal with a solidus of 1145°F and liquidus of 1205°F and a brazing range of 1205-1400°F. The low temperature white flux is suitable.
Bob Peaslee
248-585-6400 x240
Bob,
It's great to see you responding to brazing questions here. I read your column in the Welding Journal and have found it to be very educational and helpful. Thanks for your contributions.
I have used a t drill recently, but not that particular t drill. At first they dont seem to be any faster than using fittings (when using copper tubing). But once you run it a while you get used to it. I loved it and think it is a real efficent way to make tie ins.
We mainly use stay-sil 15, flows nice and no need for flux.
Hope this helps...
Hi,
T-Drill has been widely used in the HVAC industry for over 20 years with excellent success. Joints have to be brazed, however, not soldered. They will work for a while with solder but they will fail in a few months because solder creeps at room temperature. As Bob Peaslee says, 3t overlap is all you need and that is about what you get with T-Drill. Also, for those using large copper fittings, you might want to check out www.brazingdimpler.com
Walt Sperko
aye dave we used the T DRILL for HVAC and it works ok.u got to aneil(?) the pipe (heat it with a torch like brazing,then drill. after u drill threw and gota turn the chuck to bring out the forming prongs..they dont always come out.and its a B to get them to come out.maybe theyre not brokrn in cause its kinda new..but its alot hassle and it basicly has to b prefabbed on the ground.but its cool to use.
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