Multipass??

[Grampa]

I have noticed that a lot of people..like me have a small 110/115 welder..real fine for most of the things we do..

How about some tips on multipass welds...sometimes we need to make a jig or tool that requires some heavier steel than we noramlly use and it woudl be convenient to use the machine we have rather than having to have a larger machine on hand for a very seldom needed use..

I know the pipeliners..structural steel guys and shipyard folks weld materials way beyond any machines single pass capability..Using the tack, root pass, fill and cover technique..any tips on doing this with a small wire feeder..??

Thanks
Grampa

[Paul Seaman]

Grampa: on ebay there is a book by larry jeffus the lot # is 2595586358 it gives great step by step and the book is cheap it is an older edition I think a 2nd edition and I have the 4th but the basic book is the same. This guy is a welder and knows his stuff.

V-groove-
For the multi pass in mig you do the same as with stick burn in on the sides and fast across the middle. then tie in 1/2 the 2nd pass to the first and 1/2 to the side then cover the 1st by tying the 2nd to the opposite side and continue to build what looks like an inverted christmas tree. There are 5 joints and each is slightly different version of this same pattern. If you find a book look at the doint design section it will help with this more than just words on a page.

[ASKANDY]

MILLER also has a book called GMAW (gas metal arc welding) that covers multipass along with alot of other usefull info. I'll try to scan and post those pages.

A-

[Grampa]

Book

Andy,
If you can come up with the book title and ordering info can just buy one for reference..might be somethng your webmaster could do is gather that info on books and training dvd' together somewhere where folks could just order that sort of thing..Been a while for me so I am badly in need of "refresher"..

thanks
Grampa

[ASKANDY]

Grampa,

see this link. It has order info on most of the books we offer.

http://www.millerwelds.com/education/tools/index.html#books

Hope this helps.

Andy

[Grampa]

Thank you sir

And you are a gentleman and a scholar..grinnn..

Grampa

[Blondie_486]

Grampa,

I have a little machine at home and I do heavier work with it and I do my multipass the same as if I were stick welding. It differs with each joint so it would take tons of space to try to describe in detail how I do it but basically with a lap or "t" joint burn in a root pass where the two materials meet then work from the bottom and lay a bead just to the outside of your root pass then weld on top of the second bead and keep repeating this process until you have the amount of weld you need. It isn't hard just get some scrap and practice. Basically it's like welding stringer beads with a low hydrogen rod.

An important thing to keep in mind when using the smaller machines is the duty cycle. Be careful not to go over the duty cycle and burn the machine up. On the smaller welders they usually have a 20% duty cycle when turned up where you'd be welding the heavier materials at. In simple terms a 20% duty cycle means for every 10 minutes you can weld for 2 minutes the other 8 minutes is for the machine to cool down. If you lean too heavy on it the insulation on the transformer windings will melt and short the transformer out if it doesn't cook a diode in the rectifier first.

So take your time when welding your fixtures and jigs and you should be OK using the little machine. If you get into too much fixtures and jigs you may want to consider a bigger machine or an inexpensive "buzz box" and stick weld the fixtures and jigs and save the MIG for sheetmetal.

Good luck

Blondie_486

[Grampa]

thanks

Blondie_486
Thanks for the input..I believe this will get me by until I can get the Dynasty 200 I am drooling over..then it will be on to learn TIG..

I orginally bought this little guy specially for those little oddball repairs one runs into in commercial maintenance..thos jobs where someorun backed into a handrail and bent it...sooooo cut it loose pull it straight and reweld it..The short duty cycle did not seem to be a problem in that service..I think the current SP135 is about as eqivalent as it gets to the one I have..

This is a great forum with lots of good ideas..hope I can contribute a little bit at times...BTW I have made a little holder for the machine which has a loop on top..I now use my engine hoist as a welding cart which works very well as it allows me to position the welder conveniently to the work..Just thought I would passs that one on..

Thanks
Grampa

[ASKANDY]

Love the hoist idea. I kind of did something similar with my Bobcat skid steer. I modified a quick disconnect fork so it would bolt on to the base of my Trailblazer. Now when I'm off and running through rough territory, the welder won't slide off. Before I was always having trouble trying to get it into the bucket cause it didn't fit well and had to chain it on. (not good for the paint job by the way)

Have fun!

A-

[Grampa]

Good ideas

Andy,
Sometimes I wish the guys in the design shop could spend a day or two out in the field..they woudl come home with a whole new concept of what is needed...Oh well..

Grampa's next tip..If you need to punch some nice round holes in sheet metal..say for an instrument panel..or making provision for a wiring harness..Look into the punches made by Greenlee Tool..they come in a lot of different sizes and they work well..The Electricians use them in their work and some versions will punch up to 10 gauge Stainless..

Some of the guys might like to know that..

Grampa

[Blondie_486]

Grampa

I've used the Greenlee punches myself before and they do work great. Greenlee makes a great terminal crimper too, it double crimps and you don't have to worry about your connection coming undone unless you didn't use the proper size terminal for the job or the proper dies. Their conduit benders work well too and they have a slick tool for cutting the flexible shield on flexible conduit.

Blondie_486