Basic patch panel "How to"

[legopnuematic]

It was suggested in my 79's thread to do some How to's, so here is one on making a basic patch panel.

First is to cut out the ugly, after that is done, make a quick template, some card stock or cardboard works well, cut it out with scissors, doesn't need to be perfect as the metal can be shaped to perfection.

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I find it helps to use a tracing type marker like this to get a closer and crisper edge. Although having a variety of sharpie markers, pencils and pens are useful too.

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Then trace it out on the metal. For my homemade patches I use 18 gauge cold rolled steel, whereas most commercial patches are made from 19 gauge metal, which doesn't make any difference at all when welding. Some people prefer using 20 gauge sheet stock as its easier to shape, I personally think it is a little on the thin side and may cause issues when welding. When doing stretching operations the metal will get thinner where it has been stretched, so with 20 things can get really thin.

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If there is anywhere to spend a little $, spend it on good cut off wheels. Get thin wheels 0.045 or thinner. I personally like 3m's silver cut off wheels and recently started using Weiler's Tiger Zirc wheels, which are about 0.040 thick, they work very well and last a long time due to their structure.

I avoid big box store wheels as they cost too much, too thick (typ 1/16"), and break down too quickly.

https://www.amazon.com/Weiler-Tiger-UltraCut-Cutting-Wheel/dp/B075S3QZKM?th=1
https://www.amazon.com/3M-Silver-Cut-Off-Wheel/dp/B078F5FMP2?th=1

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[legopnuematic]

I would recommend getting three angle grinders, a nice one for using cut off wheels (what I use this old Dynabrade for), two cheaper ones for flap discs and wire wheels or stripping wheels. Being able to not have to switch wheels over constantly is convenient and saves time.

The Harbor Freight Bauer grinder works well for around $40, however I have used the $10 specials with good success (until I broke them).

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Time to start cutting, Start with doing any features while its connected to the parent metal as then its easier to hold.

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Then cut the rest out of the sheet.

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If it has a flange (like this part is supposed to), remember to mark it out with the 1st piece and cut it to be bent instead of welded...

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But if you made an oopsie like me, a block of aluminum works well as a welding jig.

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[legopnuematic]

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After welded dress it with a sanding wheel to smooth it out.

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Then test fit it, use your flap wheel as needed to get the shape right while leaving a gap around so that when the weld cools it doesn't butt up and make a mountain top.

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[nabeshin]

So what would be the recommended welder settings for voltage and wire feed rate? You had mentioned Tig and Mig welding for various applications, can you elaborate on when to use what and why?

 

[legopnuematic]

So what would be the recommended welder settings for voltage and wire feed rate? You had mentioned Tig and Mig welding for various applications, can you elaborate on when to use what and why?

I'm going to try to be as specific as I can be, however due to the nature of welding thin metal, there are many, many variables that come in to play. So there is no "gospel," rather some starting points.

-Mig vs Tig-

These are my opinions, so your results may vary.
Mig- I like to use MIG for spot welding, things like replacing a kick panel where all of the welds are plug welds (rosette, spot welds). Mig is very handy for tacking pieces together either during the fit up process or at final assembly. Mig also is useful on non visual components, things like a floor pan where its going to be covered with carpet and insulation.

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Tig- I like tig for applications where I can get to the rear of the panel so that I can hammer and dolly it (planishing). Tig when done well will produce a very low profile weld bead that after planishing, will require very minor smoothing to dress the weld area. However tig does require more skill and things can be harder to tack, not as ideal for areas that the rear cannot be accessed.

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-Filler metals-
This is where the main difference between mig and tig are, for mild steel on mig the typical wire used is ER70s-6 whereas tig for mild steel the typical filler is ER70s-2. What you need to know is that the -2 is a softer alloy and creates a softer weld bead (which is why tig welds can be replenished out successfully) compared to the -6 which produces a harder weld bead which can crack if attempted to be planished out.

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-Feeds and Speeds-
There are many factors that affect how something welds, some of them being:

-Quality of house wiring
-Gas flow
-Distance from work
-Speed of travel
-Type of gas (C25 vs C100 for mig)

For example if you are using a welder on a 15 amp 110v circuit with an extension cord, the settings will likely be quite a bit higher than the same welder on the same circuit without an extension cord, or if it was on a 20 amp circuit. As long as the circuit isn't already loaded, most 135-140 amp 110 welders set to weld sheet metal will not trip a 110 15a breaker (just don't have your compressor on the same circuit on while welding...

My garage [parent's garage] was never set up for the stuff I do, so I run my welders off of the 20 amp breaker in the laundry/mudroom, or when I would weld in the backyard I would use the kitchen to steal power from.

For my Eastwood mig 135 the provided door chart is pretty good as a starting point, I have adjusted from there one letter and one number higher than what the recommended setting for 18 gauge.

My tig welder I run around 50 amps for 18 gauge, but that is going by what the knob says, so who knows how accurate that really is. At work we have a nice water cooled 300 amp Miller machine, and 50 amps on that machine is a lot hotter 50 amps than my machine is.

So my best advice is to get a junk panel and spend an afternoon tinkering around with settings until you find something that works for you, for mig I like a little hotter and a little faster wire speed.

At the end of the day it doesn't matter if you use tig, mig, or even flux core, as long as you take time to make sure not to overheat the metal and take your time they all can accomplish the same goal.