Newbie question

[mattf]

I have been welding for a little while now( I have a HH 187). I have a question about penetration of the metal. I have been using 1/8" steel and practising welding pieces together. The pieces are butted. I am not sure how far the weld should penetrate. When I weld, should the steel pieces be butted tightly together? It seems to only go about 1/4 the way through. I have the settings correct as to the manual. I get a large bead on top. I am keeping the wire about 3/8" extended when I weld, about a 15 deg angle. I drag, not push.How deep should the penetration be? Should it be comletely through? What speed should I be moving at?(inches per minute).

[tsalagi]

put a 3/32 gap betwen the pieces. 1/8 is thin enough that this should work if you are running hot enough. if not, put a bevel on them.

[jamlit]

I Checked out the HH 187 rating and on the high setting you should be able to burn through 1/8 steel so I suggest beveling the edges of the steel a little and turning up the heat some so that the back side glows red while welding. Do a slight weave from side to side while welding. Sometimes the recommended setting don't always work so don't be affraid to turn up the heat when the penatration doesn't look right.

I play around allot turning the heat up and down on different welding project trying to get the best weld and penatration I can. Play with your welder and learn what it is capibable of have have some fun doing it.

[mattf]

So putting a gap between the pieces-is that called an open root?

[mattf]

I found this website. It answers most of my questions.

http://64.78.42.182/sweethaven/BldgConst/Welding/

Thanks for the info, Matt.

[Blondie_486]

mattf,

You never stated what wire diameter you're using or what shielding gas you're using. In our shop we generally use Co2 for a shielding gas and most times have decent penetration and will run all positions well. However there are times when we weld on heavier material or need better penetration and will use an Argon Co2 mix. I have a smaller MIG at home and I run an 80/20 (80% Argon 20% Co2) mix with it to compensate for it's lack of amperage and it works pretty well, I also run 80/20 on my larger MIG and love the results. They have another shielding gas that's supposed to work well with the smaller machines and is referred to as Stargon it has some oxygen mixed into it as well, it's actually a tri-mix and the Praxair dealer recommends it for all the welders 250 amps and under. I've never used it myself but I do know they sell a lot of it.

As far as your joints go anytime you need full penetration when welding MIG or SMAW (stick) it's always a good idea to have a gap between your parts uness it's some really thin guage sheet metal. On 1/8" material I don't know that you'd necessarily have to go with a 3/32 gap to get full penetration. I usually gap my parts the distance equal to the diameter of the rod/wire I will use to make the root pass with.

As with anything practice makes perfect so don't be afraid to experiment a bit. You should be able to pick up plenty of small pieces to practice on out of the scrap hopper at just about any fabricating shop for little to nothing (we give it away to guys like you), 2" x 4" coupons will make perfect practice pieces and shouldn't cost much.

Good luck
Blondie

[mattf]

Do I need full penetration to make the joint strong? I am using argon/co2 with .030 wire. I want to know how much penetration, let's say on 1/8", to have a strong piece.

[jamlit]

Full penetration is your strongest welds. I normally only bevel the edges to 45 degrees and butt the bottom of the bevel together on 1/8 steel. As the post above answered some good questions you should be able to play around and get what your are looking for. The welder you have is plenty big for 1/8, I think the specs showed 5/16 for its max thickness specs which can be increased with welding proceedure and practice. with your gas and 0.30 wire you should be set for 1/8.

Just crank up the heat a little and play with it. change the wire speed so that you get a good bead going at the heat setting you select. playing with the machine setting and seeing your results is half the fun when welding.

[mattf]

So even if I am welding a couple of 2' pieces together I should bevel them along the whole length? Or will a small gap do the same thing?

[Blondie_486]

So even if I am welding a couple of 2' pieces together I should bevel them along the whole length? Or will a small gap do the same thing?

If you can get enough heat to penetrate with a gap that should be fine, if not you'll have to bevel the entire length.

Welding isn't something you learn overnight, you'll have to experiment with your machine to get the right settings each machine will be different. You'll also have to experiment with your technique as well, try pushing the puddle rather than pulling it, play with travel speeds and circular motion and weave. You'll get the hang of it, just as no two welding machines are exactly the same neither are weldors, everyone develops his/her own technique. Be patient, don't give up and above all practice, practice, practice!

Good luck
Blondie

[Bmxin^Bjorn]

heyy matt .. is this regarding the trailer??.... if so all the welds on it are fillet and lap welds, no butt welds .. i have almost the same welder too and i just bevel the ends and put right together.. i've done this up to 3/8 thick tube witch needed to hold like 6000lbs with the little welder!.. that was before i got the 251 tho.. but it proves the little welders are a very good investment.. anyways if you have any questions about the trailer just e-mail me.

[tsalagi]

yes the gap makes it an open root joint. when done correctly, it will penitrate the back about a 1/16th. it should look like you ran a bead across the back side of the plate. when running mig, i knife the bevel. alot of guys put a small land because they run hotter than me. after i get the root and hot pass done i'll turn it up and go for broke. the root is the most important part.

[mattf]

Hey Bjorn, Not so much about the trailer. I just want to practise and do it right. But back to the trailer-I'm assuming the outside frame is mitered 45 deg. Would I also bevel the 2 pieces? It seems I may be getting in over my head a bit about this trailer. I think I will have to put it off for a few months until I am better at welding. I'm taking a class at the local college but they teach almost all oxy/act welding on thin metals(automotive). That's the only class offered in the state unfortunately. Iknow someone who has been welding for sometime, and when I build it, I'll have him over to supervise.