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I am pretty good at soldering small pipe without any problems. I am in the process of making a 3" boka and was trying to solder in my slant plates. I only have propane on hand and I know it is not getting hot enough for a good joint. I have used acetylene/oxygen in the past but I don't have any access to it right now. I have never tried MAPP gas but I have read that it is hotter.

What does everyone else use when soldering larger diameter pipe?

I know it is better but I just dont feel like dropping $200 - $300 right now.

Mapp with a 32 tip works wonders. I use it to solder 4" all the time.

Have you tried to get a lpg torch?, heats 4" up in no time!!.

Mapp changed a few years ago, and isn't quite as hot. But I think the new Map is hotter than propane. Either need to borrow a Map torch, or get a second propane if what you have ins't working.

If you know a roofer borrow their single ply torch.....puts out enough heat to soldier 3 inch in about 15 to 30 seconds....alternately you can preheat the entire pipe on a gas stove.Lay it over the burners with the area you want to soldier inbetween.....just be careful setting down the active propane torch near your cabinets.....yeah don't ask.

stairman wrote:If you know a roofer borrow their single ply torch.....

I just don't think I want to work around that much of a flame, that is a tad bit to big for my project.

stairman wrote:just be careful setting down the active propane torch near your cabinets.....yeah don't ask.

I pictured in my mind a black burnt spot on the cabinet while I was reading this. That is funny, but I'm sure the misses didn't like it.


Thanks guys for all of your replies.
I guess I will go buy a MAPP gas torch and try it, unless someone has a better idea, or is willing to offer some free service.

So I tried the MAPP gas tonight and that stuff is super hot. It heated up the 3" in less than a minute and was ready to solder. I only wish I would have had it before now.

I know I am a bit late to the party, as usual, but I have great results by putting the items in a big piece of round ductwork or flue pipe. It keeps heat in and reflects it back at the piece you are working on. Its a cheap blast cabinet Kinda.

Glad you have it sorted. Just 1 comment though.

It is not really a question of how hot the flame is. I use hand held MAPP for virtually everything. I still use the basic propane hand torch on 1/2" stuff, but on the bigger items it is MAPP. Soldering is fine but brazing is a different issue. The flame is hot enough - the torch just can't deliver sufficient volume of heat. Sometimes you just need MORE heat not hotter heat.

My torch only gives out about 3 kW and if I am brazing with for example a 55% silver solder, I can only work with about 4" lengths of 2" tube. Longer lengths just soak up the heat so the joint never gets hot enough. Even though the flame temperature is many times greater than the melting point of the solder.

Working on large pipe will always be an issue, if you can pre-heat in an oven it really does help. The MAPP can then lift the joint area up to working temperature. I have brazed longer lengths before but had to use a secondary heat source to provide background heat to the entire work piece.

I'm not sure it was just the heat level. I think the problem I had was because I was soldering in the slant plates on the BOKA. I could heat up both sides of the plate and it would stick, (to the sides) but it was not sticking to the plates that were inserted. I think I needed a hotter flame to get the plates hot enough to hold the solder. If you think about it the plates are only being heated by the edge.
I would like to know how the BOKA makers overcome this problem, or is it just me?
I still have the thermo tube and take-off port to install, but I don't see that as a problem.

I have been "burning" (soldering or brazing) pipe most of my life
Generally I use mapp from 1/2" to 2" but use 20# tank, regulator,hose and Turbo-Torch with a T-6 head for everything from 3" to 6" it makes very fast nice work. I have brazed up to 4" with this setup. It's a great rig especially because you could swap out the heads for the size you want makeing it very versatile

WERAT wrote:I'm not sure it was just the heat level. I think the problem I had was because I was soldering in the slant plates on the BOKA. I could heat up both sides of the plate and it would stick, (to the sides) but it was not sticking to the plates that were inserted. I think I needed a hotter flame to get the plates hot enough to hold the solder. If you think about it the plates are only being heated by the edge.
I would like to know how the BOKA makers overcome this problem, or is it just me?
I still have the thermo tube and take-off port to install, but I don't see that as a problem.

WERAT you have to get the entire joint hot. Solder depends on capillary flow into the gap between the 2 bits of metal and that will only happen when they are both hot.

For things like the slant plates it helps if you heat the plate and the column (at the same time) from the outside of the column and apply the solder from the inside - or the other way round depending on your tools. That way the heat travels through the joint towards the solder. When the joint is hot enough to melt the solder it rapidly flows towards the heat source.

It is different with brazing where you can apply heat through the flux, but in general with soldering this is a bad idea. Wherever possible have the heat on 1 side of the copper and the flux and solder on the other.

+1on what Myles said. Are you holding the heat there long enough?. When I started this hobby, all I had was a cheap ass small propane torch and I could solder 4" with ease, just took longer. Stick the flame down the column to heat the plates inside if need be, get the heat everywhere, not in single spots.

to be honest the best thing for that type of pipe so u can truly get the heat to flow is using a oxy acet set up. i have a rose but tip for larger pipe and it works amazing