Every Type of Weld Explained in 8 Minutes — Transcript

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1. 0:00Here's every major type of welding
2. 0:01explained and exactly [music] what each
3. 0:03one is for. MIG welding. MIG stands for
4. 0:05metal inert gas and it works by feeding
5. 0:08a solid wire electrode through the gun
6. 0:09while an external shielding gas, usually
7. 0:12a mix of argon and CO2, flows around the
8. 0:14arc to protect the weld puddle from the
9. 0:16air. Wire diameters typically run from
10. 0:19.023 to .045 in
11. 0:22and amperage scales with material
12. 0:23thickness, anywhere from 30 amps on thin
13. 0:25sheet metal up to 300 on heavier steel.
14. 0:28Straight CO2 gives deeper penetration
15. 0:30but more spatter and a rougher bead. A
16. 0:3375 over 25 argon and CO2 blend runs
17. 0:36smoother and cleaner, which is why most
18. 0:38shops default to it for anything that's
19. 0:39going to be seen. The gun is doing two
20. 0:42jobs at once, feeding wire and pushing
21. 0:44gas, which is what [music] makes this
22. 0:45the easiest process to learn. You pull
23. 0:47the trigger and the machine handles the
24. 0:49rest. But that shielding gas is also the
25. 0:51weak point. The moment you take a MIG
26. 0:53welder outside into any real wind, the
27. 0:55gas gets blown away from the puddle
28. 0:57before it can protect it and the weld
29. 0:59ends up full of porosity, tiny holes
30. 1:01where the atmosphere contaminated the
31. 1:03metal as it cooled. MIG belongs in a
32. 1:05garage or a shop with still air. Take it
33. 1:07outside and you're fighting the wind,
34. 1:09not welding.
35. 1:10TIG welding. Where MIG is fast and
36. 1:12forgiving, TIG is slow and unforgiving.
37. 1:15TIG stands for tungsten inert gas and
38. 1:17instead of feeding a consumable wire, it
39. 1:19uses a non-consumable tungsten electrode
40. 1:22to hold the arc while you feed a
41. 1:23separate filler rod in with your other
42. 1:25hand if [music] the joint needs filler
43. 1:26at all. Argon shields the weld. Amperage
44. 1:29runs slow, often under 200 amps, and
45. 1:32travel speed is a fraction of MIG's.
46. 1:34>> [music]
47. 1:34>> Current type matters as much as
48. 1:35amperage. DC works for steel and
49. 1:37stainless, but aluminum needs AC because
50. 1:40the polarity has to reverse to break up
51. 1:42the oxide layer that forms on aluminum
52. 1:44surface the moment it's exposed to air.
53. 1:46Run aluminum on DC and the weld won't
54. 1:48fuse properly no matter how hot you run
55. 1:50it. What you get in exchange is the
56. 1:52[music] cleanest, most precise weld of
57. 1:53any process on this list.
58. 1:56That precision comes with a strict
59. 1:58requirement. TIG demands a spotlessly
60. 2:00clean base metal. [music] No rust, no
61. 2:02paint, no mill scale, no oil. Any of
62. 2:05that contaminates the puddle and the
63. 2:06weld will look porous and weak,
64. 2:08sometimes cracking later under load.
65. 2:10This is why TIG shows up on aerospace
66. 2:12parts, thin stainless and aluminum,
67. 2:14anywhere the metal is clean to begin
68. 2:16with and the finish matters. Stick
69. 2:18welding. Stick, also called shielded
70. 2:20metal arc welding, replaces the wire
71. 2:22feed entirely with the flux-coated
72. 2:24electrode rod that burns down as you
73. 2:26weld. There's no external shielding gas.
74. 2:28The flux coating does that job itself,
75. 2:31burning to create a gas shield around
76. 2:32the arc and leaving a layer of slag on
77. 2:34top of the weld that you chip away once
78. 2:36it cools. Amperage depends on the rod,
79. 2:38typically 40 to 225 amps, with common
80. 2:41rods like 6011 for dirty or painted
81. 2:44metal and 7018 for structural strength.
82. 2:48That rod number isn't arbitrary. The
83. 2:50first two digits are tensile strength in
84. 2:51thousands of pounds per square inch. So,
85. 2:54a 7018 rod holds 70,000 PSI.
86. 2:57The last digit tells you the coating and
87. 2:59current type and for 7018, it also means
88. 3:02low hydrogen, which is why the rod has
89. 3:04to be kept dry. A 7018 rod that's
90. 3:07absorbed moisture introduces hydrogen
91. 3:08into the weld and that hydrogen causes
92. 3:10cracking that can show up hours or days
93. 3:12after the weld cools. Because it doesn't
94. 3:15rely on a gas cloud that wind can blow
95. 3:16away, stick welding is the one process
96. 3:19on this list that genuinely works
97. 3:20outdoors, in wind, on rusty or painted
98. 3:23material, MIG and TIG [music] can't
99. 3:25touch without cleaning first. The
100. 3:27trade-off is a rougher, slag-covered
101. 3:29weld that needs clean up and a slower
102. 3:31pace than MIG. Reach for stick when the
103. 3:33job site, not the shop, is where you're
104. 3:34welding. Flux-cored welding. This looks
105. 3:37like MIG from across the shop, same
106. 3:39wire-fed gun, same trigger pull, and
107. 3:41that similarity is exactly why people
108. 3:43grab the wrong spool.
109. 3:45Flux-cored uses a tubular wire with flux
110. 3:47packed inside instead of a solid wire
111. 3:49and And comes in two versions.
112. 3:51Gas-shielded flux core needs an external
113. 3:53gas bottle just like MIG. Self-shielded
114. 3:56flux core generates its own shielding
115. 3:58gas from the flux as it burns, [music]
116. 4:00the same way a stick electrode does,
117. 4:01which means it can go outside in wind
118. 4:03where MIG can't. Deposition rates are
119. 4:05[music] higher than MIG or stick, so it
120. 4:07lays down weld faster, which is why
121. 4:09structural steel and shipbuilding lean
122. 4:10on it for thick material.
123. 4:12Grab a gas-shielded spool for outdoor
124. 4:14work by mistake and you're back to the
125. 4:15same porosity problem MIG has in the
126. 4:17wind. Check which version is loaded
127. 4:19before you decide where you're welding,
128. 4:21not after. Oxyacetylene welding. Now
129. 4:23you're into a completely different
130. 4:25category of process. There's no
131. 4:26electricity involved at all. A torch
132. 4:29mixes oxygen and acetylene gas and burns
133. 4:31them together at the tip, producing a
134. 4:33flame around 6,000° F
135. 4:36that melts the metal directly with a
136. 4:38filler rod fed in by hand if needed. The
137. 4:41ratio of oxygen to acetylene sets the
138. 4:43flame type, [music] and getting it wrong
139. 4:44changes the weld itself.
140. 4:46A neutral flame, equal parts of both
141. 4:48gases, is correct for most steel. Too
142. 4:51much acetylene adds extra carbon into
143. 4:53the weld and makes it brittle. Too much
144. 4:55oxygen burns the metal and leaves a
145. 4:57porous, weak joint. No arc, no shielding
146. 5:00gas, no power source beyond the gas
147. 5:02bottles themselves, which makes it one
148. 5:04of the only welding processes that works
149. 5:06with zero electricity on site. The heat
150. 5:08is far less concentrated than an arc,
151. 5:10though, which means a wider
152. 5:11heat-affected zone and more warping on
153. 5:13anything but thin material.
154. 5:15This is a sheet metal and light repair
155. 5:17process and increasingly a brazing and
156. 5:19cutting torch more than a primary
157. 5:20welding method. Try to run a structural
158. 5:22joint with it and you'll spend twice as
159. 5:24long fighting heat distortion for a
160. 5:26weaker result than stick or flux core
161. 5:28would give you in a fraction of the
162. 5:29time.
163. 5:30Plasma arc welding.
164. 5:32Plasma pushes the arc through a narrow
165. 5:33constricting nozzle, turning it into a
166. 5:35focused plasma [music] jet that reaches
167. 5:37temperatures up to 40,000° F,
168. 5:40hotter and far more concentrated than
169. 5:41[music] a standard TIG arc.
170. 5:43That concentration is the entire selling
171. 5:45point. It lets you weld stainless
172. 5:47[music] and aluminum with more precision
173. 5:49and less heat affected zone than TIG
174. 5:51manages on the same material.
175. 5:53It also means less margin for error.
176. 5:55>> [music]
177. 5:55>> Because the heat is so focused, a
178. 5:57slightly slow hand blows through thin
179. 5:59material almost instantly, faster than
180. 6:01it would with TIG.
181. 6:03This is a process for someone who has
182. 6:04already mastered TIG and needs more
183. 6:06precision, not a starting point for a
184. 6:08beginner.
185. 6:09Resistance spot welding. This one
186. 6:11doesn't use a torch, a rod, or a wire
187. 6:13feed at all. Two copper electrodes clamp
188. 6:16down on overlapping sheets of metal
189. 6:17[music] and pass a massive current,
190. 6:19sometimes thousands of amps, through the
191. 6:21contact point for a fraction of a
192. 6:22second. The electrical resistance at
193. 6:25that point generates enough heat to fuse
194. 6:26the metal together with no filler
195. 6:28material added at any point in the
196. 6:30process. [music]
197. 6:31That's the part people forget. Every
198. 6:33other process on this list adds material
199. 6:35to the joint. Spot welding adds none. It
200. 6:37only works on thin sheet metal in an
201. 6:39overlapping or lap configuration, which
202. 6:42is exactly why it's the backbone of
203. 6:43automotive body assembly, where robotic
204. 6:46arms spot weld body panels together
205. 6:48thousands of times a shift. Try to use
206. 6:50it on a structural butt joint or
207. 6:52anything thicker than sheet gauge and it
208. 6:53simply won't work. Wrong joint geometry,
209. 6:55[music]
210. 6:56wrong process. Submerged arc welding.
211. 6:59Here the arc disappears entirely, buried
212. 7:01under a blanket of granular flux that
213. 7:03the machine feeds ahead of the wire
214. 7:05electrode. You can't actually see the
215. 7:07arc while it's running, which is where
216. 7:08the name comes from. That flux blanket
217. 7:10lets the process run at very high
218. 7:12amperage with almost no visible spatter
219. 7:14or arc flash, and it lays down weld
220. 7:16metal faster than any process above it,
221. 7:18which is why heavy structural steel,
222. 7:20pressure vessels, and shipbuilding use
223. 7:22it for long, thick, flat seams. The
224. 7:25catch is position. Submerged arc only
225. 7:27works flat or horizontal, since the flux
226. 7:29has to sit on top of the joint by
227. 7:31gravity. Try to run it vertical or
228. 7:33overhead and the flux falls right off,
229. 7:35taking the shielding with it. This is a
230. 7:37mechanized shop process, not a field
231. 7:39[music] repair tool. Laser welding. The
232. 7:41most modern process on this list and the
233. 7:43most demanding on setup. A focused laser
234. 7:46beam melts and fuses the metal directly,
235. 7:48producing an extremely narrow heat
236. 7:50affected zone and welds that need little
237. 7:52to no clean up [music] afterward. Speed
238. 7:54and precision are both far beyond
239. 7:56anything arc based, which is why
240. 7:57automotive, electronics, and medical
241. 7:59device manufacturing lean on it for high
242. 8:01volume robotic production lines. What it
243. 8:04doesn't forgive is a bad fit up. Stick
244. 8:06and flux core can bridge a gap between
245. 8:08two poorly fitted pieces because you're
246. 8:10adding filler metal to fill the space.
247. 8:12Laser welding has almost no filler to
248. 8:14spare, so the parts have to be
249. 8:16positioned exactly before the beam ever
250. 8:17fires. Good fixturing isn't optional
251. 8:20here, it's the whole process. That's
252. 8:22every major type of welding explained.
253. 8:24Nine processes, nine jobs, and picking
254. 8:27the wrong one either won't hold, [music]
255. 8:29won't finish clean, or won't strike an
256. 8:31arc at all.