Welding Tips and Tricks

Hi I am doing some Aluminum work on an Aircooled VW cylinder head, its a brand new casting, so nice and clean.

Have a lincoln 175 Square wave transformer machine. with Aircooled torch. straight argon.

The location I am trying to build up is about 2 " into a recess ( need to build it up prior to porting )

It would probably be easier to do the building up with a spool gun on a Mig setup but I don't have one so the Tig is going be the weapon of choice.

On to my questions.

Because of the mass Im thinking preheating it on a hot plate would be a great idea, how hot should I pre heat to? 300f? ( the head is a bare casting to no worries about seats and guides coming loose )

to reach the location I was thinking of using a 3/8 diamater xxl alumina cup ( long ) on a gas lens with a 1/8 or my usual 3/16 tungsten. is it OK to use a large diameter tungsten with a small diameter cup? I was thinking the small diameter long cup so that I can reach down in there.
My biggest worry is the amount of heat there will be down in the area I am trying to fill, I fear my filler rod is going to just melt before I even get it into the puddle .....

Or is It better to try to extend the tungsten way out of a normal cup.

Here is a picture of a Welded head prior to porting. this is someoene else's work. Im am attemting something along these lines.

What do you guys think of Zirconiated tungstens on a tranformer machine ( for Aluminum ) I have nevert tried them but someone told me thay were the best ....... I have always used Lanthanated. It's probably not worth changing what you know works....

There are lots of great instuctional videos on the site for welding T's flats, butts, etc.. but not much on the hard to reach spots..

Any ideas or suggestions greatly appreciated.
Thanks a lot.

Long stickout, smaller tungsten, up your CFH. I'd probably use a #5 and a 3/32" tungsten. If the hole/area is blind, the flow of Argon will "fill" the cavity and help with your shielding. If the area is open on the backside, dam it up or close it off. It really does help make a difference. Also, if you can, fasten the head to a work surface during welding and while cooling. It helps too, despite the mass of the part.

I've done something "similar" and only had good results by layering the weld up. I had to drill out a sheared screw that some dolt tried to EZ-Out of his motorcycle case. Hole was 6mmx30mm. In that situation, I had to ream the hole larger, fill it, then drill and tap it again.

A small amount of filler jammed in quickly to prevent balling up. Peen the surface, repeat. I loiter over the welded layer to help float the impurities up (from the filler rod angle) before adding wire. I have preheated the specific area with Propane to help with getting a puddle quickly. I also set my balance to 75% to help with penetration.

My 2 cts....they make super long and thin alumina cups just for things like this. I am thinking in a recess your arc may wander all over if you just extend your tungsten and give you grief but I havent seen the part and that would be your call but it's a consideration. I also think pre-heating is a good idea. I would find out from the manufacturer what would be a safe temp so there is no danger of warping though. Send in pics please. I know the guys around here would love to see how this turns out. Good luck.

VWRacer wrote: ...to reach the location I was thinking of using a 3/8 diamater xxl alumina cup ( long ) on a gas lens with a 1/8 or my usual 3/16 tungsten. is it OK to use a large diameter tungsten with a small diameter cup?

I've used 3/8 long cups with gas lens quite a bit on steel, with both 1/8" and 3/16" tungsten, and didn't have problems with heat buildup, but it wasn't a confined area like you have. I would use the long cup, and do everything you can to trap argon in the work area. Argon's heavier than air, so if you can orient the head so the argon lays in that depression, that might help. I would bump your pedal first without striking an arc and hold the torch head in that area to fill it with argon, then start welding. If you can't dam up the area to trap argon, I'd setup a purge from behind the area with a second argon line.
I'd practice on some scrap with a long cup first, I found it harder to keep the tungsten steady because of the longer lever arm from the torch to the tip of the tungsten.

There's a lot of good points to why use a longer cup, but the issue I've had with them in this type of weld, is you can't see diddly squat past the cup. That's why I use a #5 Pyrex and extend the tungsten to get the right arc length. I find the longer alumina cups works really well on notches and tight corners, but not so well in a blind hole, especially with aluminum.

My $0.0187 (my opinion is worth today's rate).

cj737 wrote:There's a lot of good points to why use a longer cup, but the issue I've had with them in this type of weld, is you can't see diddly squat past the cup. That's why I use a #5 Pyrex and extend the tungsten to get the right arc length. I find the longer alumina cups works really well on notches and tight corners, but not so well in a blind hole, especially with aluminum.

My $0.0187 (my opinion is worth today's rate).

The whole deal sounds like a challenge but you know what a pain in the ass just a plug weld can be sometimes with the arc all over the place. I agree that long cups are hard to see past in tight spots but he can still extend his tungsten a bit to get in there. I actually used a cup made from duct tape once for one tiny little weld that I couldn't get to without dismantling a bunch of stuff in the way. Luckily the weld was only a tack and the "cup" melted almost immediately but it worked and gave me an appreciation for some of the oddball stuff we need to use sometimes. There have been plenty of times I wished I would have bought that spool gun.

Another option: a micro TIG torch. I recently referred another member with some automotive head repair to a guy (Jim French) who does this work. His is awfully fancy, but the micro torches (if you have recurring need) can be pretty useful too.

Thanks to all of you for some great advice.
I will attempt this evening with the long cup and
A back purge, as being an aircooled head it with lots of air passages
Will be difficult to block off all the fins to trap the
Gas.
I will post a picture if my results ( good or bad )

Cheers.

So After Pre heating to 300 F I went at it using the cup pictured. My biggest problem was lack of space to dip the rod into the puddle at the start, ( down deep in the hole ) the rod would start to melt and turn black as it dropped down in, so I would hit the pedal hard and melt it in an pull the black stuff up, once the puddle cleaned up I would add some more filler ....
Once things were built up it wasnt too bad.
Here are a few pictures. The pic with the scribe lines is how much porting I will be doing once I install the new larger seats.
This is what we do to get 200 HP out of these little VW engines.

VW engines where popular in the midgets several years ago there is a few still running. They where heavily modified and was over 200hp running manuel fuel injection with methanol. Due to head modifications a lot of them where water cooled too. Also Ron Hottels the designer of sesco engines built his version of a VW with custom block and heads. Most early Sesco's where V8's cut in half. Either cut left or right bank off or cut it down middle to make V4. It didn't take long before these became custom all aluminium blocks. Here is some pics of some VW midgets Grabbed off one of our midget Facebook pages and a Sesco style based off VW that is up for sale. I ran a Sesco Variant called a Canaday Four with Dart Buick style heads and also Gearte engines with different heads on it threw out years all custom blocks. Never ran the VW stuff
These are of Sesco style VW believe this one still for sale