Sievert Propane Torches, Burners & Hearths

The most common form of heating is to use a gas torch. There are many on the market and it can be difficult to assess the true value of a torch when it comes to brazing using silver solder. Some are excellent at browning custard, skinning tomatoes, or lighting a firelighter but nothing else!

The basic premise is to have a torch that will produce a focused flame capable of generating sufficient heat quickly enough to achieve penetration of the silver solder into the gap to produce a strong leak tight joint. Ideally this is a defined flame that will enable you to control the heat, create the right ''heat pattern'' that will determine where the silver solder flows.


The flame temperature of a torch is not indicative of it's heating capacity. An oxy-acetylene torch burning at 350

C often has less heating capacity than a propane torch.
An oxy-acetylene torch produces intense heat in a small area. It produces more localised thermal stresses due to local expansion and contraction. It can generate sufficient heat to attain surface temperatures sufficient for silver soldering. The alloy will be seen to melt and flow on the surface (produce a sound joint?) and the flame moves on.

Propane with a ''not so fierce flame'' not only gets the surface hot but generates ''through heat'' necessary for the alloy to penetrate the joint.

Unless great skill is used, it is very easy to overheat the alloy with an oxy-acetylene flame. This can induce centre line cracking or porosity in the alloy leading to weak joints.
Using the wrong part of the flame can also induce embrittlement of copper.
Protracted overheating of a cadmium bearing alloy over an extended period can also lead to health risks.

The average model engineer causes more problems for himself with oxy-acetylene torches than any other heating medium. Available via CuP Alloys Ltd are torches that ensure good performance to meet any application.

Butane Torches

These are refillable torches running on lighter fuel. They have small well defined flames ideal for soft soldering or silver soldering small components. The Pencil Torch has a fixed flame and burns for about 15 minutes. The Multi-purpose Torch burns for about 1 hour and also features soldering tips, hot knife and hot air attachments. 

Propane Torches

The most popular torches are propane torches. Your gas supply is not governed by annual contracts or administration charges. Propane is readily available. The torches can be simply and quickly modified by fitting different burners to achieve different heating needs encountered during brazing. Many torches simply blast out heat but these Sievert torches and nozzles will help you develop heat patterns to achieve and control capillary flow through the joint so creating sounder joints.

Start with the Sievert PMPX kit. It has a variable 1-4 bar regulator, 2m of hose, a 3486 bandle, 3511 neck tube and SV 2941 burner.
Simply connect to a gas bottle and apply a match!
or build up your own system by selecting a regulator, hose, handle, neck tube and burners from the selection below.

Cyclone burners draw in the air further back down the neck tube. This allows the flame to burn in enclosed areas where otherwise the flame would extinguish due to oxygen starvation. 

Oxy-Propane Torches

The addition of oxygen to the flame increases the flame temperature and produces a smaller more concentrated heat source.

Insulation Materials

The performance of all torches will be improved by using heat reflecting bricks and/or an insulating blanket to prevent heat being absorbed. Not all bricks are suitable. Some bricks, eg those taken fom storage heaters, actually absorb heat and can act as a "heat sink" slowing the process down.
Vermiculite blocks and plates have a lower thermal mass and so absorb less heat. They can be cut or shaped to suit your individual requirements using simple hand tools.
Insulation blanket, based on clay wool, absorbs even less and reflects even more of the heat. Although 25mm thick, it can be readily cut with scissors.

Prices and more details of burner performances etc can be found by clicking on the links below.

• Sievert Burners
• Sievert Handles
• Sievert Hose
• Sievert Neck Tubes
• Sievert Regulators

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Brazing Hearth Hearth consists of 3 vermiculite blocks plus 1 plate (200mm x 230mm) and insulation blanket to fit Our price: £36.00

Insulation Blanket Heat reflecting blanket to improve the heating efficiency when brazing. It will withstand temperatures in excess of 1000 deg C. Kaolin Wool blanket 300 x 450 x 25mm. It can be split to provide... Our price: £8.30

Lightline General Purpose Torch In terms of performance, this torch sits between the multipurpose soldering kit and the PMPX kit. It comprises of a refillable, 340gm propane bottle, neck tube and P8719 burner producing a 3kw flame... Our price: £76.80

Lightline Neck Tube Connects to Primus 2000 re-fillable propane canister. Fit SV8842 or P8719, P8720 or P8725 burners Price includes VAT and P&P Our price: £23.00

Multipurpose Torch This is a cordless safe and simple to use torch. Burning more gas than the pencil torch, (more heat) with an equally well defined but larger needle flame, for precision soldering brazing and hot air... Our price: £47.50

Pencil Torch A small torch producing a very small focused flame. Ideal for small joints or soft soldering. Refillable with lighter fuel Our price: £6.80

PMPX Propane Torch Kit PMPX Propane torch kit is a cost effective way of creating a flexible, versatile heating system for the model engineer. It has a variable regulator (1 - 4  bar), 2 metres of hose, handle, neck... Our price: £92.00

Turbotorch 90 Oxy-propane torch using disposable gas canisters. Comes complete with gas supply, hose, flashback arresters, handle and a range of micro-burners for fine precision brazing/soldering. Also supplied is... Our price: £145.00

Turbotorch 90 Gas Canister Disposible Propane/Butane gas cylinder for Turbotorch 90 Price applicable for pre-orders collected at exbhibitions. Carriage charge by courier £10 Price includes VAT and P&P Our price: £17.90

Turbotorch 90 Oxygen canister Diposible oxygen canister for Turbotorch 90. Price applicable to pre-orders for collection. Price includes VAT and P&P Our price: £23.50

Vermiculite Blocks. Speed the heating process with heat reflecting vermiculite blocks. Size 230 x 115 x 25mm Our price: £9.50

Vermiculite Plates Heat reflecting plate to speed the heating process. Can be cut or shaped using conventional hand tools. Size 230 x 200 x 15mm Our price: £13.80

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