If tack welding is just for the purpose of holding the part in place then the welding tack size should be enough to hold it in place and should not exceed the final welding size. Spacing and number of tacks can vary depending on your requirement, but if enough space is available then try to avoid the consecutive tacks in the heat affected zone area of the previous welded tack. Usually spacing of 25 to 30mm is enough, increase the spacing as there is an increase in the leg size of the tack weld.
proposenately
A number of factors go into this: base material thickness, joining material thickness, wire thickness, shielding gas composition, angle of weld, etc. The best way to determine this is to measure your material, then open your MIG welder, find the wire size of the spool, and read the chart inside of the MIG Welder door.
It depends on how hot it gets, but if you are talking about welding temperature then most definately.
The thickness of the laser welding machine depends on the power of the laser generator inside the Laser Welding Machine, the thickness of the object to be welded. These two points are the most important.
two reasons i can think of: 1 - Probably dont need to, usually welding material of constant thickness. 2 - The transformer is mechanically adjusted on most welders, this means that that there would be a possibility for electricity jumping in the transformer, and premature failure, or fire.
4MM..
For welding 8 mm thickness metals, common methods include MIG (Metal Inert Gas) welding, TIG (Tungsten Inert Gas) welding, and stick welding (SMAW - Shielded Metal Arc Welding). The choice depends on the type of metal and specific requirements.
See preceding question re: Mig welding.
A device that can generate heat. Melted material and the welding operation is performed.
The minimum thickness for SMAW welding is about 18 ga. with a steady hand.
AWS D1.1 is the American Welding Society structural welding code for carbon steel of 1/8 inch or greater thickness.
Tac welding is not a specific material. Tac welding is a form of welding, that welder's use in order to hold two pieces' of metal together to get a proper fit. The tac weld can be easily broken if the two pieces' of metal aren't in the right place. So if you tac weld anything, the filler is going to be whatever material you are welding.