Having TIG Trouble???

[Hunter]

****, welding a repositioned bolt handle on a old M98 Mauser bolt. The puddle looks as if bubbles are forming at the edges and as the puddle cools -- porosity. 2% thor, DC, Argon, SP, Miller Maxstar 200. 3/32 elec. Flow @15. Any help?

Hunter

[Hobart Expert Rock]

HUNTER...........AH THE OLD MAUSER YOU MOVING THE BOLT TO CLEAR A SCOPE???????????.... I DID LEAVE A MESSAGE WITH TODD AT WWW.RAPIDFIRE.COM MY GUN SMITH. HOWEVER HE IS OUT TO LUNCH...........MY FIRST QUESTION IS IT POROUS THE BOLT. WAS IT SCREWED IN, OR PRESSED IN............GUN OIL IS VERY GOOD QUALITY AND VERY THIN........THE PIECES ARE VERY CLEAN IS THAT CORRECT...............PERHAPS TRY CLEANING THEM WITH BRAKE CLEAN BEFORE TIGGING...........ROCK........... SSCOTT@MILLERWELDS.COM

[Hunter]

Rock: Yea its to clear a scope. This is turning into "how not to weld a bolt". First, most gunsmiths use oxy-gas and either forge the handle over or cut and reweld to a new position. I do not like either of these methods as they put too much heat into the bolt/locking lugs. TIG seem a better choice for those of us who have it. I cleaned it real well. Cut to bolt handle off and repositioned. Used a fairly high Amperage and focused arc (200 hz). Did not use any filler. It looked real good. Then, I gave it the plastic hammer test -- it failed! Back to the drawing board. Reground mating surfaces and tacked with no filler. Rewelded, this time with a mild steel .40 tig rod. Started to see the bubbles. ****, I can weld rebar better than this? I'm starting to think that the problems with the filler - but now its in the base metal. I'm open to all suggestions that don't specify a part of my anatomy. Hunter

[Hobart Expert Rock]

AH NOT THIS GUN SMITH.............I HELPED LINE HIM UP WITH A TIG MACHINE........AND A GOOD ONE I MIGHT ADD...............ANY WAY HE AIN'T IN HOUSE RIGHT NOW.........HOWEVER I DID TALK TO GALEN ONE OF OUR WELDING ENGINEERS AND HE SAID MAKE SURE YOU REMOVED THE BLUEING AND HE USES STAINLESS FILLER.........???????????....... I WILL E-MAIL GALEN THIS LINK AND LET HIM ANSWER........................ANY IDEA HOW OLD THIS GUN IS.........?......ROCK.......

SSCOTT@MILLERWELDS.COM

[Hunter]

Rock, there is no real value as a collector. This was a Styer mfg. around 1917. It was a NATO backup and rebarrled from 7X57 or 8x57 at some point to 7.62 NATO (308). It lost all collector value when rebarreled. Hum, stainless filler? Hunter

[Mike Sherman]

The nickel in the stainless will help with the porosity issue. Try welding with the stainless electrode, going very slow, even though this will put more heat into it, you will be able to work the contamination out. Drop your Hz back down to a more reasonable level and don't use a pulse. You will need steady heat to work the nitrides out while the puddle is fluid.

[Hobart Expert Rock]

MIKE..............THANKS.............WHERE YOU BEEN HIDEING AT OR SHOULD I SAY WHERE HAVE YOU BEEN "HD" ING AT........... PLEASE DON'T TELL ME IT IS TO COLD.............. .... YOU SHOULD OF WENT TO DAYTONA I HAD SOME FRIENDS GO AND THEY SAID WHAT FUN..................THANKS AGAIN..........HUNTER MIKE SHERMAN IS ANOTHER EXCELLENT RESOURCE AS WOULD BE DAN OR ROCKYD OR A MULTITUDE OF OTHERS ON THIS FORUM..... ANYONE ELSE WANT TO HELP................. .........ROCK....... SSCOTT@MILLERWELDS.COM

[Hunter]

Mike/Rock thanks for the help. I'll have to order some stainless filler. Any ideas on a inexpensive heat sink for the bolt??

Hunter

[Scott V]

Hunter,you said you focused the arc?Do you mean the pulse HZ?I have pulse on my inverter,and didn't know it would narrow the arc on dc.I know it will on ac.

[Hunter]

Scott yea its in pulse mode the higher the freq. the more focused/narrow the bead. This is a Miller inverter.

Hunter

[Scott V]

Thanks,Hunter I will have to give it a try.Mine will pulse at 0.5 to 500 pps.It kind of funny that my mig can pulse faster at 2000 pps.

[Rocky D]

Hunter, on the stainless...use 308 or 309, or as we say in the aircraft industry....if you don't know what it is...use hastelloy W. Never try to weld steel without a filler...you saw what happens.

[Pin Head]

Mauser bolts are case hardened and the thickness of the case is quite variable in the pre-1930s models. The outgassing of the carbon from the case is probably the source of the bubbles. Sometimes they fizz like a can of soda. This should only be a cosmetic problem at the edge of the weld as the case is only .010 max. I never have had any strength or porosity problem TIG welding them with mild steel fill rod. Are you sure that you have enough argon flow?

[Hunter]

Yea, the argon is flowing. I've found some 3.5% nickle filler that's "recommended" by a gunsmith supply house. I'll order some and see if that makes a difference. I'm also going to scrap the old bolt handle and replace it with a less troublesome aftermarket design. A few more dollars but I supose that's how we learn.

Hunter