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It is possible to make a firewall using flat irons and a perforated plate. To achieve this, it is desirable to have basic knowledge of metal working and to be able to use a bi-gas or electric welding machine.

Realize a firewall for the fireplace with the braze solder technique

The braze welding consists in assembling two metal parts with for metal filler sticks of coated brass.

A rise in temperature thanks to the brazing

The brazing is carried out using a bi-gas welding machine that uses oxygen and a combustion gas (butane / propane, Kyrene or acetylene). It produces a high temperature flame of 2,850 to 3,000° C which allows welding parts thanks to a filler metal and without melting the metal parts (only a flame up to 3000° C allows autogenous welding, that is to say without any filler metal).

A precise flame adjustment for the torch

The blowpipe has the shape of a gun with a nozzle terminated by a nozzle. Adjustment valves on the torch itself and / or at the level of the bottles allow to dose the flame. The adjustment directly to the regulator with stop-and-go valve on the torch has the advantage of allowingadapt the flame once and for all for a specific job. The torch can receive different nozzles or burners depending on the work to be done. The flame should be set to a bright blue hue. A purple color indicates too much oxygen and a white color a lack of oxygen. With the sting of the blowtorch, it is necessary heat the metal, until it takes a cherry red hue and approach the solder rod; the latter must spin, by capillarity, between the two parts. The torch is then removed so that the solder cools down.

Strict security measures for the use of a welding machine

A welding machine is not dangerous if used with the usual precautions. Manufacturers now offer kits to facilitate their use. The oxy-acetylene torch remains professional or semi-professional. But respect for some safety instructions elementary is essential: never change the bottles near a flame, do not seek to repair the device itself in case of malfunction and do not disassemble the oxygen valve. The parts of a blow torch must never be coated with oil or fat because these products canignite. Finally, it is better to work in a ventilated room or outside and, most importantly, wear safety glasses and gloves.

make a precise firewall plan

  • Draw a precise firewall plan on thick paper to determine which parts to bending necessary for the upper part of the accessory.

Saw the iron to the measures

  • Record the measurements of the sides of the frame and mark them on the iron with a scribe.
  • Using a hacksaw, saw following the cut line.

bevel the metal

  • At the file, bevel the end of the two parts to be assembled to form a "V": the filler metal will be housed in this space to weld the two elements.

bend the bars

  • Place the bars between the jaws of the vice and the arch giving small strokes with the hammer failure.
  • If you have an anvil, work on the bigorne (mouth of the anvil).

assembly of the safety barrier for heating

  • Assemble all parts of the firewall blank and check the straightness of the angles with a square.
  • If necessary, rectify the contact areas with a few lime strokes.

solder the firewall

  • Immobilize the metal parts on an insulating and refractory work plate.
  • Start by solder the elements that make up the sides of the two-gas torch firewall.

weld on the grill of the firewall

  • Cut the grid panel into a sheet of perforated sheet metal using large shears.
  • Position it in the frame.
  • Soudobraser the frame on the fence.

clean the welds

  • With the file, clean all welds made by removing excessive thicknesses of chilled metal.
  • In finishing, pass the specific paint for the parts exposed to the fire.

Handyman's Tips

  • The clamps are essential tools to block the parts to be assembled. Be careful not to grab them with bare hands immediately after welding: they are heat-conducting and can be very hot.
  • Before carrying out the brazing, it is necessary to pass the stripping flux on the parts to be assembled, which degreases them and avoids the oxidation of the metal during the operation.

Video Instruction: The Fab School: TIG brazing using silicon bronze