Need recomendations on a MIG welder

[knucklesplitter]

I don't buy very much plain steel. PDM is perhaps the best place, but they have a minimum order - either $75 or $150, I forget.

Reno Salvage on 4th St. used to sell *new* steel stock and they were cheaper with much less minimum order if any (cash only). Cheap/no cut charge too. I thought they stopped selling new material, but maybe not.

Next I would try Metal Masters in Sparks I guess.

Really though, unless it is really heavy I often do McMaster.com or onlinemetals.com. I order quickly, forget about it, and it shows up on my doorstep a couple days later. 6' of 1/8" x 2" hot rolled steel would probably be $6 or $8 each, but shipping may suck.

BTW what you are looking for is generally called "flat bar", and generally it doesn't come in gauges. 1/8" is close enough to 10ga (and overkill for what you're doing). Yes, you can get steel "strip" or sheared sheet in 10ga. but I never have in 20+ years.

[sperry]

Originally Posted by knucklesplitter

I don't buy very much plain steel. PDM is perhaps the best place, but they have a minimum order - either $75 or $150, I forget.

Reno Salvage on 4th St. used to sell *new* steel stock and they were cheaper with much less minimum order if any (cash only). Cheap/no cut charge too. I thought they stopped selling new material, but maybe not.

Next I would try Metal Masters in Sparks I guess.

Really though, unless it is really heavy I often do McMaster.com or onlinemetals.com. I order quickly, forget about it, and it shows up on my doorstep a couple days later. 6' of 1/8" x 2" hot rolled steel would probably be $6 or $8 each, but shipping may suck.

BTW what you are looking for is generally called "flat bar", and generally it doesn't come in gauges. 1/8" is close enough to 10ga (and overkill for what you're doing). Yes, you can get steel "strip" or sheared sheet in 10ga. but I never have in 20+ years.

Well, I measured the steel used in my RaceTech seat brackets and they were 3.5mm, which is 10 gauge. 1/8" is probably thick enough at ~3.1mm, but I was erring on the side of too big. Plus, it's easier to weld heavier steel.

[knucklesplitter]

Originally Posted by sperry

Well, I measured the steel used in my RaceTech seat brackets and they were 3.5mm, which is 10 gauge. 1/8" is probably thick enough at ~3.1mm, but I was erring on the side of too big. Plus, it's easier to weld heavier steel.

They likely sheared or plasma-cut 10ga. sheet. If you want 2" wide strip then it is either gonna be 1/8" or 3/16" thick unless you have it sheared.

[AtomicLabMonkey]

1/8" is plenty easy to weld.

[knucklesplitter]

The guys at Hood Machine tell me that ProtoFab on Glendale will sell steel in small quantities. Check them out, Scott.

http://www.protofabinc.com/

[sperry]

Originally Posted by knucklesplitter

The guys at Hood Machine tell me that ProtoFab on Glendale will sell steel in small quantities. Check them out, Scott.

http://www.protofabinc.com/

Cool!

What's the difference between cold rolled and hot rolled flat bar?

[100_Percent_Juice]

Just use hot rolled.

[sperry]

Originally Posted by 100_Percent_Juice

Just use hot rolled.

Thanks for the informative post.

[sperry]

http://www.spaco.org/hrvscr.htm

Here’s an email that I received today. It asks a pretty common question:
“> Hello Pete, need some help understanding the difference between hot
> roll and cold roll steel, and the reasoning for the preference for one
> over the other???? Can you please answer this question????? “

Theoretically, the only difference between hot rolled and cold rolled steels is that hot rolled steel is rolled to its final dimensions while hot enough to scale (over 1700 degrees F) while cold rolled steel is rolled to its final dimensions well below scaling temperatures.
So----- If you are making ½” square hot rolled steel, you have to estimate what the final size will be after the product cools, whereas you can finish the cold rolled steel to much closer tolerances right in the sizing rollers and that is what you get. There are some other things to consider, too:

-The finished tolerances on hot rolled steels are looser than on cold rolled. Not only the plus or minus tolerance from nominal size, but the "square-ness" of the product. And, I can tell you from personal experience that there’s a lot of trapezoidal A36 out there. So, if you need a specific size and you are going to go to a “surplus” place, bring your ruler, square and micrometer to make sure you get what you need.

- I have been told that, in order to get the cold rolled steel to come out with a nice finish, they might use "cleaner" ingots from which to roll the product. This means that you’d get fewer slag or carbon inclusions with cold rolled steels.

-Note that I haven't talked about the chemistry of the steel at all. You can get cold rolled or hot rolled 1045 and you can perform either process on C1018. But since we often talk about using "mild" steels, the two steels that we end up having around most often are C1018----which is quite often sold in cold rolled form and A36 which is always hot rolled.
-One other difference that may be of interest to the blacksmith is that if you buy "1018”cold rolled steel", you can be pretty sure that it has close to a 0.18% carbon content and few other impurities. But the spec for A36 can let the carbon content go as high as 0.29% and it can contain many more impurities. More carbon makes it harder to forge.
-You generally have to pay about twice as much money for cold rolled steel as for hot rolled steel, for reasons which are probably obvious from the above.

So far, you are probably feeling that, in dealing with mild steels, cold rolled steel is clearly the better stuff to have if you can afford it. Well, yes, usually, but---- since the hot rolled steel IS rolled while hot, it has a chance to normalize after the last rollers, so it is pretty much stress free when you get it. But machinists who usually buy cold rolled steel, often have the stuff twist and warp on them as they machine the first side or two. This is because the cold rolled steel actually work-hardens in the rolling process.
For blacksmiths, this isn't much of a problem, since we are usually going to heat it up and reform it anyway.

There is also an in-between finishing hot rolling process called "P & O" (Pickled and Oiled). In this case, the hot rolled steel is pickled in acid to remove the mill scale and then oiled to keep it from rusting. The cost is somewhere in between that of regular hot rolled and cold rolled.

Finally, in my experience, the more popular (to the steel yard) sizes of mild steel usually come in both cold and hot rolled. I buy hot rolled whenever I can for blacksmithing. Except if I'm going to put a LOT of work into a piece. Then I buy cold rolled steel to minimize the possibility of having a crack appear in the shaft of my fancy flesh fork after about an hour of forging and an hour of filing and chasing. But in some sizes, for instance 1/4" square, the steel yards in our area only carry it in cold rolled, at twice the price of hot rolled---- so if I want any of that for S-hooks and for nails, etc., I'm stuck with the higher priced stuff--- unless I want to order a ton or two to get it in hot rolled form!

[knucklesplitter]

In general for weldments I use hot-rolled because it's cheaper and more available. Once it is primed and painted it looks fine for most mechanical applications.

I use cold-rolled for general mechanical pieces and some welded parts when I want it to have a decent surface finish (like mounting faces, sliding surfaces, shafts, etc.) without having to machine the whole face. The surface of cold-rolled cleans up nicely with just emery cloth or scotchbrite (or nothing really), whereas the hot-rolled has a rough dark gray crust that requires machining or quite a bit or grinding/sanding to "clean up". The cold-rolled also has pretty good tolerances of flatness, thickness, width, etc. so it can often be used as is without machining even on parts that need some reasonable precision.

It is tough to machine the whole face of cold-rolled because the residual stresses for the cold rolling will cause the piece to warp when you machine just one side of it. Machinists usually have to machine both sides (maybe more than once) to get a piece straight/flat again. If something is going to get a lot of surface machining (not just boring, drilling, and tapping) then start with hot-rolled.

[knucklesplitter]

Originally Posted by sperry

http://www.spaco.org/hrvscr.htm

This article is more related to actual "blacksmithing", but most of it applies to welding. Welders don't generally hammer and forge things though.

[knucklesplitter]

Scott, did you find the material you were looking for?

[sperry]

Originally Posted by knucklesplitter

Scott, did you find the material you were looking for?

With river rafting and the PDX last weekend, I simply haven't had time to work on anything. I'm hoping this weekend I might be able to get around to it, in which case I should hit up ProtoFab on Friday... but my folks are coming up for the air-races, and there's that autocross at Fernley... both of which I'd rather be at than in my garage welding.

[sperry]

I *finally* went by ProtoFab at lunch today. $100 bought me 6 2"x1/8"x6' flat bar, 6 1"x1"x1/8"x6' angle iron, and 4 1/2"x1/2"x.065x4' square tube. That's about 10 times cheaper than Home Depot. Now I've got enough stock to build those seat rails and a welder cart.

Looks like I'm welding this weekend!

[100_Percent_Juice]

Weld up a frame for your gaming chair while your at it.

[sperry]

Originally Posted by 100_Percent_Juice

Weld up a frame for your gaming chair while your at it.

I think I'll probably want to do that out of 1" square tube... which I didn't buy.

[Dean]

Originally Posted by sperry

I think I'll probably want to do that out of 1" square tube... which I didn't buy.

The 1" angle iron might be good for that. Easier to drill holes in and you still have the 1" flat to distribute weight. Just a thought if you have enough.