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Tips
Tips

TR2/3/3A Anyone got a TR2/3 Frame??

Excellent tips Al. I never thought about intentionally leaving a slight gap to keep the weld thin. Very good idea! Like you said, I have always used the low power on this kind of thin material, but will try some practice on high power...dragging the puddle may be the key to not burning through.

I picked up the metal yesterday, but have to spend the weekend at work. It'll be early next week when I get started. I'll be sure to post the progress...and really apprecieate any more tips as I go!
 
Its a pleasure to have something useful to pass on to someone else. I've been welding old cars for 30 years.

The welding schools used to start with butt joining two 1/8in plates. You made a V by bevelling the edges at 45. Then filled it with weld. The backing plate/gap trick is the same thing but quicker.

1.6mm metal I regard as THICK. I can do 0.8mm, 22AWG gauge probably. This I do with a Joddler, which leaves one thickness behind the other. But 1.6mm is too thick to Joddle. So I spot on a backing strip.

With the Mig-spots you need a lot of current to get into the layer behind. You should see the wire-end poking through. If you dont then you use two holes adjacent so they break into each other and run a small bead. Done right these can be quickly linished flat.

Have you got one of those sheet cutters that has two big wheels, one knurled on the edge? This can cut 1.6mm without much distortion and beats hand-sawing.

One thing to know is that there tends to be a thin layer, between the metal that stayed cold and the metal that was liquid, that is carbon rich and goes hard. This is where the weld will crack most easily. So I usually try to add some reinforcement to welds that see a lot of cyclic stress.

In some places on the chassis repair I deliberately left 1/2in gaps between the ends of weld beads rather than running continously. This stops a crack running right round.

I clean the welds almost at once using Phosporic acid metal prep. Otherwise in our climate they will rust up overnight.

REMEMBER HIGH CURRENT ON MY WELDER MAY BE MEDIUM ON YOURS. Everything in Europe is weedy compared the the US.

Al.
 
I had to look up what a joddler is. Really cool tool I have to put on my list!

When you are talking about the backing plate, are you talking about a steel backer that stays with the weld permanently, or a copper temporary backer?

The welder I am using is a 185 amp unit, and I have been using the smallest wire it will feed. I know the highest setting with this welder is too hot, but I will definitely try setting above the min to try your technique.

I'm glad you showed up, Al. Very good pointers!

Here are a couple pics. In general, all the rust through is on the bottom. I think the tires went flat and the frame settled into the mud. The top section is pitted where there was no floor to keep the rain off.

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I grew up in New Orleans, which has climate similar to England...always damp and frequent rain. Bare metal would rust overnight, even if kept dry. I am now spoiled here in the dry part of Texas. The bare frame as you see in the pictures will not rust at all unless I get water on it. It really makes it easy for long repairs like this frame. Here's the start of my new outrigger...


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Nice pictures John. Mine had much worse tin-worm in this area.

If I were doing yours I would cut the side walls on their centre-line and make a new U-shaped bottom. This would put the weld on the neutral bend-axis.

If you imaging a tube supported only at its ends, with a weight in the middle, all the metal above the centre-line in being compressed and all that below is being stretched. The centre does not carry much load.

This is why you see construction beams made with a solid top and bottom but just tie wires criss-cross joining them. Like the wings on a WW1 bi-plane.

I made the backing plates from 18 SWG steel about 1in wide and spot welded them to the edge of the new metal. Same shape as the joddler makes.
Then the plate just slips behind the old metal.

The backing gets trapped by the weld. Basically you weld from the new-metal into the backing and the pickup the old metal. You get off the old metal a bit quick and go back across the backing-plate and pick-up on the new metal again. You are making like quick U-turns picking up the old-metal at the bottom of the U.

By the way I got two types of Joddler. One is two wheels that make a continuous run. The other is like a pair of hand-grips that Joddles 1/2in at a go.

Ask me to photo anything that would be of help.

Your chassis frame looks an easy fix to me. Take a bit of time but it will hone up your skills.

Al.
 
A couple of other things:

Where the bumper irons are bolted to the frame I put a support across the frame made from 1in dia tube.
This means you can tighten the bolts without fexing the frame.

I reckon the frames fail at the end like this because they fill with water if you drive in the rain.
This just the lays for a while in the bottom of the tube.
We get some rain most days but there are not many days it rains ALL day.

This is another reason why I'd make the weld halfway up the side wall.
I also "capped" the ends.

Try the Metal Prep from Frost/Eastwood. It will get all the brown off your frame left by your blaster.
Its phosphoric based and is the ideal pep for painting with POR.

Al.
 
You can see one of these tubes in the photo actually. Its just that mine had gone and I had to re-invent them I realise now.

Anyway its important to ensure you have these and not just bolt-up across the frame faces. It won't go tight.

Al.
 
Yep JP, that's straight bare metal after sand blasting with the low-end Northern tool blaster. The parts with a lot of brown showing are the parts that will need to be replaced, as they pitted all the way through with rust.

Al, it gives me comfort to know you fixed a frame in worse shape. I understand what you are saying about moving the seams to the mid-line for strength. I'll try to work that into the heavily rusted sections.

Can't wait to get back to work this week!
 
Well, still not done, but got everything but the final weld beads to go. If I never touch another body grinder it will be too soon! I did discover some interesting facts about TR frames...

1. The frame was painted inside. It appears it was dipped after final welding at the factory. Surprised me!
2. Rust is not uniform, as I thought it would be. It attacks in pits, that invariably go deep either from the inside out, or vise versa, but never both.
3. My frame was damaged at the front, allowing water inside. Once in, the only way out was through a single hole in the back of the frame. The result is that an inch or so was puddled inside , likely for years, till it made its own hole out.

Anyway, I think the pics speak for themselves...hope somebody learns something from my pain!


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All the original metal was 16 gage, or .063", with the exception of the outrigger mounts, which was originally 14 gage, or .83".

I had a shop cut 14 gage strips that were 2-3/4" by 4', and I used these for all repairs. I don't have a sheer, so cutting was done with a body grinder using a cutoff disc. I don't have a break, so all bending was done using a 6" vise and a hammer.

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And this last one is a pic of how it looks after final welding and grinding the bead smooth. By using Al's technique of high heat and dragging the puddle, I was able to get the bead equally thick on both sides...in other words, I got the bead on the front side and back side with one pass. That ensures there is no unbonded metal, with the bonus of being able to take the bead down flush. Once painted the welds will be practically hidden.

For each patch the old gets ground off, the new is cut by grinding, and then the bead gets ground flush...lord I'm tired of grinding!!!

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Awesome work John!

Cheers
Dave
 
Nice fabrication, and welding work, keep it up.
 
Wow, wonderful work. What are you treating the inside with?

Scott
 
Thanks guys!

Good question Scott...everywhere I could access, I sprayed with black rustoleum. I sprayed the inside of the patches too.

I don't have a lot of confidence that it will help, though, since the welder heat will inevitably remove some of the paint. I am torn...on the one hand, I may see if it is cost feasible to have the whole frame dipped, like standard did originally. On the other hand, my TR3, finished 1-1/2 years ago has not seen a drop of water since it was finished (it gets wiped down instead of washed), so I doubt the TR2 will ever have a problem with rust! Even if it does get wet, the extra .020" in thickness for the patch steel should give it an extra decade before it rusts out.

I don't think this car would ever have had a corrosion issue in TX, except the bozo PO damaged the frame without plugging the hole, and then parked it for 24 years with flat tires in a mud puddle...uncovered. "whata maroon", to quote Bugs Bunny!
 
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