Picked up a tig recently and have been playing around a bit trying to get the hang of it. One of my RC cars needed a stainless exhaust so...



Tried to butt weld it first. First time lucky right?



On the underside is a hole where the tubes melted away from eachother. Got lucky and the pools joined on one edge. Didn't like the hole so I cut it apart and tried again without such luck, and again and again. Had two diameters to work with so I went with the slightly larger size and lapped it. Ended up using filler on the rear joint. Was managing to get by with out filler up front until I tagged the work with the electrode. It was already late so I called it without finishing the joint.





.0625 308 filler, no idea what the tube is, ceriated ground to a tip, argon, 30A.



I have a bunch of tube in boxes and in the mail for my van in the driveway. With any luck that'll turn out better. Hopefully one of these days I'll be able to post up work that'll look close to what everyone else posts up.

 

no expansion chamber?

i never thought of building crap for my R/C stuff really. btw get some small tungsten for that stuff and it will be way easier for you. I think i'm going to build a crazy dual system for my 2.5 maxx now

 

I could be wrong but that doesn't look like a two stroke.

 

looks like an OS 4 stroke. I'd be curious how it sounds.

 

yeah I wouldnt be able to tell 4 from two on an r/c... I buy RTR stuff lol...

now that you said something though and i looked again, i see whats going on there, cool. now I want a 4 stroke 4wd 1/8 scale buggy.

 

Hah that thing is probably loud as ****.

Neat project

 

It is a 4 stroke, OS FS26S-C. You'd be suprised, its a tad louder without a muffler than a two stroke with a muffler. I'll have to get some video when the weather clears up.

Down to proper business. Welded up a couple pieces of pipe for the van's exhaust and I'm not entirely sure what I'm doing (or not doing). Some beads almost look like I know what I'm doing. I understand that the welds are supposed to be shiny and have some color. I did back purge and maintained about 7cfm. Used .125 thoriated, a gas lens and 1" cup @30cfm. Paused over the bead to maintain gas coverage til it wasn't cherry. Tube is 16 gauge 304. Used .0625 308 filler. Have a pedal and set the machine to 80A.





















Whats the deal with the color on half the bead? Tips and advice would be greatly appreciated!

 

I'm nowhere near as good as some people on this site but I will add a few points that helped me improve:

1. Learning on a flexpipe isn't the easiest method as there are 2 edges that you are probably melting away (hard to concentrate)

2. You can drop down to a 1/16" tungsten and use lower amperage. I prefer to add quite a bit of filler on flexpipes to leave as much of the flexpipe intact without burning it away. I use .045 filler or even .030/.035 mig wire will do. .0625 will work but I find it to be too large. 30cfh is too much IMO. You could probably cut that in half.

3. When I was first learning I always wanted to see how far I could go in one pass. Don't worry about that, just concentrate on small sections and relax.

4. Get comfortable. This is one of the most important things when starting to keep steady.

5. Concentrate on keeping a tight arc length, this made things much easier for me but you need to be comfortable or you will just dip your tungsten.

6. Get some demos from somebody nearby. 5 minutes of watching somebody weld can save you hours and hours of frustration.

7. I personally found aluminum much easier to learn on and still find it easier to this day. It seems much more forgiving and heat input isn't as critical as with stainless. Aluminum will really help you get the technique down. I recommend getting a small scrap sheet of aluminum sheared or cut some on a table saw into strips/coupons and just practice getting consistant.

8. Search search search

 

Dont learn on a flex pipe. Use 1/16" tungsten. Less heat and move faster for stainless. Rest your palm or something, you are moving all over the place.

 

Thanks guys! I'll have to stop and pick up some 1/16" tungsten on the way home tomorrow.

 

Why is everyone recommending 1/16" tungsten over 1/8"? Being smaller I assume its easier to break and grind, but are there other benefits?

 

i use 3/32" for everything. 1/16" isn't useful at higher amps imo.

 

You will have a smaller arc, which will be a bit more precise in where you put your heat.

 

i like 3/32 too
i almost never use smaller

 

3/32 for about everything, 1/8th is a hoss.

 

Not to threadjack, but how the hell have I not seen your car on SpecialStage? That is an AWESOME build, and possibly the smallest rallycar i've ever seen lol.

<--- Sits in the right seat of an Evo8.

 

Ok, here we go again. 3/32 tungsten, 12-15 cfm, #8 cup w/ gas lens, no flex pipe, tighter arc, moving faster trying to keep the heat down...

First stab was at the existing cat from the van. Its mild steel, but in good condition otherwise.







Next was the down pipe. So the story here is that my van drones horribly between 55 and 65mph. The loop back is an attempt to remedy this by making the exhaust longer. Sadly the mandrel bends weren't as round as I would have hoped and didn't fit the V band flanges very well, I didn't think to use a tailpipe expander to fix that until after I started filling the gap.























Last weekend's adventure: something to hang this off of. Probably should have used something a bit thicker than 16 gauge to step the V band flange off the face to clear the waste gate service plate. Preheated to 500-ish, NiCrMo-3 filler, slow cooled. I wouldn't be surprised if it cracked.






@ScrapinSi
Thanks! I've been trying to keep the car under the rally radar until I could get it log booked, which showed up in the mail last weekend. I don't know who is nuttier, me for building a tiny car to rally or you for riding in the silly seat...

*edit*
Lookin' around at the pics in this section makes me think I'm trying to lay too much bead in one shot and that I'm not waiting long enough between beads to let the part cool? How much bead do you guys lay at a time and how long do you wait between beads?

 

In for practice, not for fancy show piece (not that it would or could have been). Didn't drop low enough after the flex pipe so I threw some mild at it to finish the job.



I <3 fusion welds, however they do nothing to help my filler/torch coordination.





Getting lazy, didn't feel like pulling the back half of the exhaust off again to weld it up at the muffler and the MIG was looking lonely.



Job almost done. Need to put together a hanger or two to support the loop.



Gotta start somewhere right? Tips? Tricks? Advice?

Thanks!