Welding MAZAK

[AlanT]

Everyone knows that MAZAK is poor stuff and hard to fix.

 

Anyway I had this, it's a somewhat rare DR1 motor, from an early Jaguar. Didn't look like this when I got it of course.

 

 

I got it cheap because of this:

 

 

This is the result of using the MAZAK casting as a "spanner", when undoing the wire-rack nut.

WARNING, the TR motors will break just like this, if you do it to them.

 

Fixing this is way above my skill level and it's quite the most difficult weld repair I've ever considered.

There is a thick boss, where the screw goes, right next to the crack.

 

The wall thickness, where the nipple slides in is barely 3mm, and you must not weld through and mess up the slot. And then there is the tiny flange that retains the nipple. This must not vanish either.

 

Anyway, this is a case of I know a "man that can" and so now it's fixed, until somebody makes the same mistake again:

 

 

I'm actually amazed it was possible to do this. If it were steel, I'd have MIG-welded it. If it were Aluminium, a TIG guy would do it quite easily.

 

But with this stuff the temperature between a liquid weld-pool and a puff of white-smoke is very small.

 

So if you have a problem that requires a magic-touch then:

 

 

With this sort of thing, when a bloke gives you a brochure stamped with a greasy-thumb, then you know you are on a winner!

Edited July 11, 2017 by AlanT

[stillp]

That takes some skill!

 

Pete

[AlanT]

This was a real "punt".

 

I sent him the photo above. He said "no problem, I've done lots of this".

 

Lots of his business is Vintage motor-cycles, so I'm not really surprised.

[Peter Cobbold]

Did he use Technoweld?

Peter

[AlanT]

Don't think so.

 

I've done MAZAK repairs with this myself. You get a "bright" line between the two original metal areas.

 

I think this is a true weld and done by Gas not electricity, although I'm not really sure about this.

[RogerH]

Hi Alan,

lumiweld would probably do it fairly easily but you can;t beat experience.

 

Nice repair.

 

Roger

[AlanT]

I broke a piece out of the flange on a Dynamo by trying to straighten it. Was not too hard to but back by Lumiweld.

 

But this is so thin and awkward and needs to really work afterwards. Like the nipplw must go in!

[GT6M]

the rods ye get that melt at blow torch temps will doo it too

they really med for ally type stuff

butt, i found oot they work ok on the mazak stuff

{ door handles , an bits of castings of various bits an bobs }

 

M

[John Bracher]

Would these method work for filling the pits in mazak parts to be rechromed??

[RogerH]

Hi John,

could be very time consuming. The normal method is to copper plate and polish back until the pits are filled.

 

I have considered copper plate and then (for deep pits) fill with lead but the platers frown on this.

 

Roger

[MikeF]

I'm a bit rusty on this, but so far as I remember: Plating onto lead requires fluoroboric acid cleaning process to prevent poor adhesion from salt deposits left if using regular materials like Hydroelectric/sulphuric. They probably don't have this. May also be issues with this stuff and the mazak.

 

Mike

[stuart]

Hi John,

could be very time consuming. The normal method is to copper plate and polish back until the pits are filled.

 

I have considered copper plate and then (for deep pits) fill with lead but the platers frown on this.

 

Roger

Plating with copper is the normal way to fill these pits but its very time consuming as it has to be done several times to build it up enough and polished between each coat to get the surface layer back down. Most platers dont want to do this. Capital Chrome (formerly London Chroming ) will do this but at a price so only worth going for on unobtanium parts.

Stuart.

[Lebro]

S&T Plating in Bristol have done just that to my radiator surround on my old Hillman, many coats of copper were applied, then some lead filling, then more copper, then nickel, then chrome.

Bob.

 

 

 

[John Bracher]

Shame.......

[RogerH]

Colonnade in Wembley will also build up with copper.

 

Roger

[AlanT]

I tried Lumiweld on a 4A door-handle which had quite a big pit in it.

 

Filling the pit was not the problem. This was pretty easy.

 

The problem was the pit was located in quite a thick section. So I needed a fair amount of heat.

 

But MAZAK conduct heat quite well, so I overheated the thin sections around the button. They kind of sagged.

 

If I had made an ally block to support them, I may have got away with this. But it's not really on to try to "unsag" them.

 

This is why I did not try it on the DR1 motor.

 

I would guess you need a very tiny, but quite hot gas flame.

[RogerH]

Hi Alan,

would filling the corrosion pits using a mig welder be a practical solution.

I appreciate they are different materials - but that's just another challenge.

 

Roger

[stuart]

Hi Alan,

would filling the corrosion pits using a mig welder be a practical solution.

I appreciate they are different materials - but that's just another challenge.

 

Roger

No you would just blow even bigger holes!

Stuart.

[RogerH]

......I'll stick to aeroplanes.......

 

Roger

[RobH]

Just a thought - it is possible to plate plastics materials if they are first coated with a electroless-plated layer to make them conductive. Could the pitting be filled with epoxy and the part then plated using this technique?

[rcreweread]

I have been experimenting with this very problem for quite a while now - any sort of resin filler (eg JB Weld, Rectorseal etc ) or low melting point metal such as solder will not work because it cannot withstand the heat generated by the polishing required before chroming - it just gets pulled out - I have had limited success with higher melting point alloys such as Alu-Build 300 and HTS 2000 - the former is easier to use as it has a lower melting point than HTS2000 but that in itself has been a bit of a problem when it comes to polishing and I have not yet been able to get a perfect finish.

 

HTS 2000 has a higher melting point which is good on the one hand but bad news on the other because you have to be very very careful not to melt the Mazak at the same time - trying to get accurate and quick high heat into a small area is a challenge and I've tried a number of different gas powered bits of kit, but not found anything totally suitable.

 

Roger mentioned Lumiweld in one of his posts and I have to admit I haven't tried this yet, but will.

 

As I understand it, the pitting in Mazak often occurs from within the metal, due to impurities in it, and I've found that unless you remove all trace of the pitting/corrosion, it returns very quickly and/or you cant get a good finish - I therefore drill or grind out any corrosion, assuming you have enough metal to start with, before filling - as you can imagine, this is a time consuming operation and if you take something like a 4A rear light unit, often the pitting covers the majority of the surface, so you can end up with a lot of filling and then finishing to do - these materials ain't cheap either, so I suspect this is almost certainly why this is not a process readily available -it's not really cost effective

 

I'm convinced this is doable but I need to do a lot more practising first - at the moment, I'm concentrating on bigger things so this project is currently on the back burner, but hope this info helps - be delighted to hear of others and their experiences

 

Cheers

 

Rich

[AlanT]

Repairing a MAZAK part for which no repro equivalent exists, like a DR1 body, is one thing.

 

But you can get repro 4A rear-lights that are almost indistinguishable from original.

You can certainly fit original lenses with original screws.

 

You could easily recover a 4A rear-light full of pits. It would be cost effective and mainly DIY. Rub down, fill and Chrome paint.

 

Won't look perfect, will need re-doing after a while, but it's not bad.

 

Here are Cresta rear-lights done this way. No repros for these.