Ask your WELDING questions here.

Whatever needed cutting. Scarf teeth off a bucket? Pre-heat some aluminum? Pop some holes in sheet metal? Nip the corners off some 1/4" flat bar?

Grab a torch!

Thats ok, I don't work there anymore either.

Every time I turned the pressures down to spec one of the "Ive been doin' this for 30 years and you don't know shit" guys goes behind me and cranks em up.

Any thoughts on welding 12l14?

I am making pannier mounts for my ninja and the fronts shown are crs dom tubing which tig welds great. I machined threaded caps for the tubing and all was well.

The back studs which aren't shown, I mistakenly grabbed a piece of leaded steel because they were so short I decided to lathe it out of rod.



I only figured it out when it was not welding normally. But I did seem to get a decent weld. This part isn't critical as the front studs are are welded tubing and overkill as it is. Plus my wolfman bags have straps over the seats.

Does this weld stand a chance in the lightly loaded scenario or should I cut it off and start over? Any recommendations for steel that machines well on a home lathe setup and also welds well? 12l14 sure does turn nicely.

I'll toss up a pic of the actual welds when I get home. I was tig welding, red tungsten, pure argon, 100a 70s6 filler

Heres the actual stud from leaded steel I was welding.

Make up a test piece with the same stuff, take to it with hammer & you should get an idea

I've machined up a few small bushes & things out of 4140 bar then welded it to 4130 tube with good results. On my basic gear, Atlas 10F & hand ground HSS tool, it didn't seem wildly different to mild steel.

No doubt there are specialist grades that are optimised for machining+welding but they don't sell them by the metre at my local engineering supplies store like 4140

Cheers
Clint

I think your welds look good and will be fine. Leaded steel is to lubricate the tool when cutting it. It just turns nice.

I don't think you have a problem.

David

The welds shown are front the dom tubing. Although the leaded steel looks fine to me. I plan on grabbing hold of it and yanking and see what happens. Usually fun stuff I imagine.

In your pic it doesn't look like you are disconnecting the computer. That is #1 whenever I weld on a chassis.

The computer Cdi is under the seat bar, that's a triple set of relays encased in plastic. Right now everything wiring wise is basically disconnected, battery is out etc.

It's the added sulfur that causes problems. If lightly stressed you may get away with it.

Check out #4.

http://www.weldingtipsandtricks.com/welding-303-stainless.html

Free machining steels usually contain too much lead and sulphur to weld. The problem with them is that the lead and sulfur migrate to the grain boundaries of the matrix and freeze last. Since lead tends to be much lower strength than steel you get a weak line in your weld. If the sulfur does not crack the weld initially the lead will be where a crack will appear if put under force. So don't use free machining steels if you need to weld them. Max sulfur is .014% or .14% if I recall. Phosphorous and lead are similarly bad.

It sounds like you are having a wire feeling problem. Start by using a new tip. Your should be able to feed wire against your glove without the wire stopping. If it does check that your drive roll tension is set properly and the hub holding the reel of wire is not too tight as to cause too much drag on the drive rolls. Your gun liner is probably the culprit as they tend to load up with dirt and dust and hold the wire from feeding freely. The last recommendation is to buy good welding wire. I have seem a lot of off shore brands that have inconsistent diameters or have too much lube on them that makes feeding tough. I recommend Lincoln Electric L-56 for mild steel welding. It is make in the USA and it is a bit more expensive but if it tangles or gives you trouble which it won't you can take it back because they have a 100% satisfaction garantee.

I put a harder foam earplug on my wire before the feeder to keep dirt out. They sell felt and foam devices that do the same but earplugs are free. Some people oil the felt but to me that seems like asking for more dirt and troubles.

You can clean out the liner with an air nozzle.

If your problem isn't the contact tip you could possibly have your drive rolls set too loose.

If I'm making some gussets and brackets to weld to the subframe, how important is it to use the same grade steel as the subframe itself? Can you weld mild steel to chrome-moly and visa-versa?

This is for a BMW X-Country rear subframe, which I assume is made of mild steel like 1018? Or is it chrome-moly like 4130?

I'm going to make the brackets myself, but have a professional welder do the welding.

Doug

I don't know the BME X-Country, so I googled "BMW+X-Country+rear+subframe" images and every thing I see all looks like aluminum to me.

Unless you are going to heat treat the whole subframe when you are done, it really won't matter what you weld to it (alloy steel vs carbon steel). Just clean it good before painting it.

Just to clarify: Stock X-Challenge frame is aluminum, and that is the only subframe listed on BMW's parts fiche.

For the X-country, both aluminum and steel versions are available on the BMW parts fiche.

I have an X-Challenge with the stock aluminum subframe, but have purchased the X-country steel frame from BMW. For all practical purposes the geometry of the X-Country and X-Challenge subframes are the same. There are some difference with regard to passenger pegs, etc.

I have welded mild steel gussets to my 640's 4130 subframe with no issues. I would have used 4130 for the extra pieces but it wasn't available locally in the size I needed & the extra few % of strength wasn't critical.

Cheers
Clint

4130 will work just fine

The 4130 Chromoly steel is a higher tensile strength than 1018 but you can weld them together. Use an ER80S-D2 welding wire like Super Arc LA90 to match the 4130 or use a mild steel ER70S-6 it match the 1018. Either will work.