Welding Tips and Tricks

I had a friend who does a lot of tig welding for a machine shop weld some mounting spacers for an electric fan on to my aluminum radiator. He's really a machine shop guy--not a welder, but since I had only Tig welded steel before I asked him to do it. Bottom line--he welded each spacer enough to secure, but not completely around and somewhere on 3 of 4 spacers he managed to melt thru the radiator. When I put it back in now I have slight leaks. I don't want to take it back to him and say "you screwed it up," and since I just got a new Miller synchrowave 210 w/Zoro hot deal in Jan, I decided I needed to learn how to weld aluminum. I've been practicing quite a bit on 1/8 plate per Jody's recco's, including welding some round spacers as well. Not quite there, but I think I'll be ready to give it a try over Easter weekend.

So, looking at his welds, what would you do to prep prior to welding? Any grinding off of the old material (one picture he kind of has a balled piece)? Obviously SS brush and acetone. I planned on preheating each spacer with my MAP gas setup. I will target the existing weld and spacer with the arc b/c the spacer is thicker.

Thoughts/reccos? I'd really like this to work!

Really just like you said is the correct way, I'd lightly hit it with a flap wheel to knock any oxidation off of your cutting the spacers all the way OFF and starting over. Otherwise a brush and some acetone will do the trick. Keep the torch pointed at the spacer and gently point it at the rad side and when you see shiny material dab. Preheating the spacers will help.

I'm assuming the rad has been used so if you blow through you'll be fighting contamination from the backside.

What filler do you have?

My 2 cts....If it was me, not having alot of experience with aluminum, I would take it to a weldshop. Welding thick to thin ANYTHING is challenging enough much less aluminum. No disrespect to Rick but for guys with tons of experience this doesn't seem like a big deal at all but when things go south with aluminum, they go south fast. At least if a weldshop screws it up, you get a free radiator. Again, that is my opinion. I wish I was good enough to tackle a job like that but I know my limitations.

Oh man, that's too bad.

If it were brought to me, I'd cut it off, re-prep the area and start again.

It's a little difficult to weld thick to thin - I've done 1/4" to 1/16" before - best advice is to make dang sure you get the filler in there to chill the puddle at the right times and keep moving.

If you dwell on an area, filler won't chill it enough to save you.
Be precise with where you point your torch.
The tack is the hardest part to nail - once joined, then just work that puddle around.

Good luck and practice up right before doing it to "get in the zone"

Good advice above on the practice bit. Try to get some material that matches the sizes you are dealing with, and practice on that. Don't sit the thin material on any flat metal surface that can act as a heat-sink, as the radiator tank won't have that ability either. Definitely focus your heat on the boss.

Do you have a foot pedal? That would help keep things under control. Be prepared to have your skates on once you get the bead flowing.

Dry runs for position technique will be your friend too.

Best
Trevor

The guys are right, unless your practice is going very well this can be a hard project to learn on. You'll be the best judge since were not there.

The issue with aluminum is if it gets messy, its gets messy quick and then the repair will come major. I fab my own air to air and air to water intercoolers when new they weld like butter, when used or the need to repair arises it can be tricky.

I've done a couple of oil coolers & intercoolers that looked like this - don't see many aluminum rads here except with plastic tanks - there are several ways that will work - first being if your careful you can "bump" weld around what is already there using the same method as doing anodized - you could saw off the spacers & clean up whats left underneath then either make new spacers & back bore say 1/2 > 3/4" depth leaving around 1/8" wall thickness & re-weld - they will weld much easier than solid ones or the most likely to work if you have limited experience is after removing old spacers clean the area & puddle over the whole area with HTS2000 & use this to stick the spacers on with - there is no danger of melting the radiator material or melting the core to tank joint & it's not badly effected by contamination plus it will stick to any alloy - best of luck however you attempt it.

Just an idea. What about cutting the blocks off and padding the area. Maybe less risk welding the blocks back on afterwards.

Not to knock anyones welds, but take them things off & start over. If I was you I would do it like this, remove the thick pieces and clean them so you can weld them off the radiator to some thinner material that you will in turn weld onto the radiator. As some have mentioned welding thick to thin can be challenging, so by welding your plates to the thicker pieces while off the radiator it should prove easier and less risky. Once you have those welded on you can then weld those plates which would be similar thickness to your radiator on with a lot less frustration. Should leave you with some relatively straightforward lap joints to perform.

As with many things we do there is more than one way to get to the finish line.

My thoughts
Jeff

run a mill end or a drill bit into the end of the bung you plan
on welding to the radiator so the material is close
to the same thickness. weld fast.
if there is any antifreeze on the surface
or a hole to let it bleed out you are
fighting a tuff battle
craig

I have to agree with Damark here, I would remove the old ones and repair the leaks, followed by welding the bosses to a doubler plate and weld the doubler to the repaired radiator. My $.02

Len

Goldhawg,

Where are you located?

Perhaps another member is nearby, and can guide you through the first one?

I know it's a longshot, but aluminum welding of heavy to almost nothing is very hard to explain.

Steve S

Otto Nobedder wrote:Goldhawg,

Where are you located?

Perhaps another member is nearby, and can guide you through the first one?

I know it's a longshot, but aluminum welding of heavy to almost nothing is very hard to explain.

Steve S

Located near Dayton OH. Majority thinks I should start over. I was thinking of trying this first, and then if I failed to cut it out and do as you all say. Long story but I have the same radiator that failed at tubes so I have nice tanks that I could cut a section out and weld if necessary.

If I cut the spacers off and start over, what would you use to cut it loose? Would a 3" air cutoff tool be best? I suppose it doesn't matter much; I'll need to flap disc everything completely clean. Just wondering.

Braehill wrote:I have to agree with Damark here, I would remove the old ones and repair the leaks, followed by welding the bosses to a doubler plate and weld the doubler to the repaired radiator. My $.02

Len

Len's and Danmark's suggestion gets my vote.

If you remove the existing bosses and grind back say with a flap wheel, be careful to not take out any material from the radiator tank itself - it's already thin. Nice and easy does it.

I, too, like Damark's suggestion. Welding the heavy stuff to oversize patches of thin stuff on the bench, where mistakes are cheap, then trim to fit and welding a thin-to-thin lap joint to install would be relatively easy for someone not highly confident yet with aluminum.

Steve S

Gonna offer a totally different suggestion. This comes from Past experiences with aluminum radiators in race cars. If we hard mounted radiators into cars using tabs for mounting, the vibrations and bouncing of cars would always crack the tabs causing leaks. Best way us and others solved this was we had an aluminum box for the radiator to slide into.(radiator box) I used rubber stripping to make it fit more securely in box and limit rubbing and movement of it. I could picture your fan mounts having same problem as our mounting tabs. Eventually vibrations and movement gonna cause cracks in the thin wall aluminum radiator. So I would suggest mounting fan to radiator box if you have one or mounting it to another more ridge structure that you could weld mounts onto instead of directly on radiator. I tend to look for problems down the line or items that are gonna fail and try to avoid the hassle. Not sure how much abuse your vehicle has to take. If vibrations are not that bad obviously it will last longer but still eventually will prolly fail at mounts.

Just my 2 cents and observations