Lumiweld.

Date: Sun, 3 Mar 1996 09:50:00 +0100
From: lopezba@atnet.at
Subject: Re: Lumiweld

I would like to thank Nick Fuller for his prompt reply. I am sure the following will be very interesting for many of us.

N J Fuller from the UK wrote: Having been a user of Lumiweld for some years in my home workshop I would thoroughly recommend it every time. Being a dabbler in many model engineering ventures, there have been numerous times that a repair or renovation is required on some aluminium component. Components that I have successfully worked on using Lumiweld include:
- Manufacturing model Glow engine silencers,
- Filling unwanted mounting holes in model Helicopter landing gear, - Reclaiming model Helicopter rotor blade holders,
- Rebuilding motor cycle cylinder head fins and filling stud holes drilled out due to broken studs,
- Repairing Alternator mounting lugs,
- Rectifying casting defects in model petrol engine cylinder head casting and many more that escape me at this moment.

When my last Lumiweld kit ran out I purchased a clone version called Techno Weld which for all intents and purposes, IMHO, does the same job with very similar packaging and instructions.

Although I have never seen a direct reference to its use with Birmabright, judging by what is mentioned there is no reason why it shouldn't be experimented with, obvious caution required if working on panels still fitted to one's vehicle.

Have attached a copy of one of the original reprints sent to me by Lumiweld many years ago. Other texts with pictures available but all show basically the same.

All The Best
Nick

Reproduced from a reprint sent by Lumiweld. "OLD BIKE MART" issue 16 - Oct 1986 -

Perhaps, like us, you have seen demonstrators at Classic Shows and Auto jumbles repairing broken aluminium components by the 'Lumiweld' process. With nothing more elaborate than a butane gas blow lamp, a seemingly magical repair is quickly effected and proves impossible to break when a 'Doubting Thomas' is asked to try his luck. We asked Bob Robinson of Grand Union Products, who import 'Lumiweld', if we could try out one of his Kits to see how practical the process is and, if it really does allow you to repair or join aluminium parts in your home workshop.

'Lumiweld' is brought in from U.S.A., where, we are told, millions of rods have been sold since 1979. It is claimed to provide a weld four times stronger than aluminium and harder than mild steel; it is non toxic, uses no flux and requires only a low working temperature and, as a bonus, it will also do its stuff on zinc based alloys including Mazak (Monkey Metal).

In a true welding process, the operator has to raise the temperature of the work pieces to melting point, then, using a flux to prevent oxidation, introduce a filler rod of similar material in order to fuse the metal together. Controlling the working temperature isn't easy with aluminium as it doesn't change colour on heating up and great skill is needed to avoid melting the parts.

With 'Lumiweld' however, the working temperature is far below the melting point of aluminium and indeed, at only 730`F, is very similar to soldering. Now, with soldering, you are joining two pieces of metal by introducing a dissimilar filler which has a lower melting point than the metals to be joined, in other words it doesn't fuse to become a part of the parent metal, as is the case with welding; it can't, as the filler isn't a similar material (usually a Lead/Tin composition). So how then does `Lurniweld' differ from soldering, well, the claim is that (although we aren't given the composition of the rod) in use the `Lumiweld' forms a 'molecular bond' with the parent metal and is therefore a true weld.

We gave our Kit to a hard-nosed, sceptical, engineering friend and asked him to try it out for us. His unshakeable view was that the process was soldering, not welding, but he did concede that `Lumiweld' could have a place in the home workshop; although in his engineering business he would always go for the `real' thing.

Is it as easy to use as watching the demonstrators suggests? if you follow the instructions included with each pack; then the process is quite simply within the grasp of anyone who can master soldering (that word again!); no flux is used, oxides are removed mechanically by agitating with a stainless steel rod (or stainless steel brush, available from the suppliers) through a pool of molten `Lumiweld' on the surface of the workpieces. The `Lumiweld' itself prevents the oxides reforming and a neat run or fillet can be made with the filler rod, which then forms the`Molecular bond'. You can make Lap, Butt or Joint welds and a butane canister type of blow lamp or even a gas cooker will suffice as the heat source. As the bond is only formed with aluminium or zinc alloys it can be effectively used to reclaim stripped threads in such materials by drilling out the offending hole and popping in a bolt of the correct thread form; `Lumiweld' run around the bolt then bonds to the aluminium but not the bolt, which can be unscrewed from the hole leaving a new thread behind it: Again, the low working temperature of the operation makes this an attractive alternative to other forms of repair, where a complete strip down might otherwise have to be contemplated.

An Amal carburettor Mixing Chamber in diecast alloy, with a broken mounting flange, was neatly repaired with `Lumiweld' making it fit for further service and, doubtless stripped threads in carb bodies could be dealt with in the manner described above. We did however find one product that defeated `Lumiweld', one of the dreaded Best & Lloyd Oil pump bodies; a familiar problem to Vintage restorers as they were fitted to so many bikes in the Twenties. These pumps are made from a zinc-like material and are invariably broken around the screwed oil pipe connections. Try as we might, we couldn't get `Lumiweld' to bond with the B&L body material and nor could Bob Robinson when we sent it to him. To his credit he returned the pump admitting defeat, but then there must be limits, even with `Lumiweld'!

Kirby Rowbotham, whose various engineering modifications and carburettor reclamation services are well known and respected in our field, is a recent convert to 'Lumiweld' and rang us to say just how impressed he was, after trying a sample following the Bristol Show earlier this year. Rebuilding chipped cylinder fins, broken lug bosses on chaincase and gearbox covers, or even cracked castings are all candidates for home repair with this process. A versatile product then and one which is a useful addition to the range of DIY materials available today, not a panacea for everything though, but we found the suppliers very helpful and ready to advise on a particular application; what's more, as we said at the beginning, they are at most of the major Shows and Auto jumbles so you have the chance to meet them in person.

End quote from 'OLD BIKE MART'.

Peter Hirsch,
SI 107in S/W,
Vienna, Austria (officially 1,000 years old this November 1) [3/'96]