Belzona Repair Compounds

An extra toolkit in the professional locksmith’s armoury

By John Harding


The name Belzona has become a well known name in the professional engineer’s vocabulary over the last 7 decades. In much the same way as cleaning staff refer to their vacuum cleaner as ‘the Hoover’ engineers around the world frequently refer to their solution to worn & damaged & broken components as ‘let’s Belzona it.’

Shipping Lines, Engineering workshops, MOD workshops, Transport Companies, Heavy Industry, Chemical Works, Mining, Building, Agricultural, Quarries, and many other industries have used Belzona Repair Compounds for decades and are viewed by top class engineers the world over as ‘The Best there is’



After the 2nd World War a Scandinavian, Dr. Jorgen Svendsen, understanding the properties of zinc to protect steel from corrosion through the process known as galvanising, developed a 2 part epoxy paint system that had a high percentage of finely powdered zinc incorporated in it. This was incredibly successful and steel structures were soon being treated all over the planet. Steel that was badly corroded already was able to be saved providing it could be shown that structural strength had not been compromised beyond safe limits and Dr Svendsen then concentrated on developing epoxy metal fillers to restore corroded steel cosmetically, before coating with the special paint called ‘Liquid Anode’. In the early years the company was called ‘Metalife’, then, following a serious car accident in which Mrs Svendsen’s life was saved because of the seat belt she was wearing (not a legal requirement then). Dr Svendsen changed the company name to Belzona which (I am told) is Swedish for ‘safety belt’ – an ironically appropriate name for the aims of his company. In the 1980s the company name was Belzona Molecular Ltd but today it is Belzona Polymerics Ltd and is still based in Claro Road, Harrogate, North Yorks.


Knock-on effect

Following the development of the early metal filler products, engineers then began to do what often happens – they began using these fillers for other purposes. One that stands out particularly to this writer, having worked in the motor trade for a number of years was, following the introduction of the Austin Mini in 1969, a common failure was the transverse engine aluminium transmission crankcase, which all too frequently developed leaks because the castings often had porous areas that allowed oil to seep through. This was common to all the British Leyland transverse engine vehicles but the solution was found in the Belzona Super Metal which effectively sealed the transmission cases saving the massive expense in replacements and consequential ‘down time’.

Dr Svendsen set up a laboratory in Harrogate to develop other compounds and the research & development went apace over the decades to produce hundreds of different compounds for use across a very wide spectrum of industrial applications: these included coatings for walls, floors ceilings, roofs: grip systems for safety flooring, chemical barriers for some of the harshest environments, sealants, concrete & stone repair compounds, elastomeric (rubber like) compounds, to name but a few, and there are very many more. In addition to manufacturing the products, Belzona also built a library of ways in which their products were being used and the techniques that engineers and specialists were developing to get the very best use from them, gaining constant feedback from their own network of field engineers and distributors across the world.


The Locksmiths Friend

The two Belzona products I personally find the most useful and am never without are Mouldable Wood and Super Metal 1111.

Mouldable Wood comes in 2kg units and Belzona Product code 416 contains 2 x2kg units in an outer cardboard container.

Super Metal 1111 is available in a variety of sizes 1kg; 1.6kg (in 4 x 400gm units); 2kg; and 5kg packs: the size I personally prefer is the 2kg pack as gm for gm it is cheaper apart from the 5kg pack which, where small quantities are being used at any one time is too bulky and eventually can be wasteful.


Mouldable Wood Applications

This product is very versatile and can be used as a filler to repair damaged or rotting timber, infill holes, and even be mixed to a semi-fluid consistency and cast in a mould to produce items otherwise unavailable. A classic example of this is the clamp nut on my HPC 1200 (Blitz) machine which was made of plastic and after 3 replacements because the plastic kept shattering I decided to make my own which has now been in regular use for over 12 years (see photo)

This was made by filling a 35mm polythene film container with Mouldable Wood and then suspending a long steel nut (with appropriate bolt with same thread as the clamp spindle screwed fully through the nut to protect the thread from the resin) supported with a large washer and centred in the resin & left to cure. This was then shaped using a stud in the clamp nut and an electric drill, using a chisel and wet & dry paper to contour for clearance in the clamp recess, then drilled through the top and a 4mm steel bar driven through for tightening grip.

There are literally a host of ways in which Mouldable Wood can be used successfully in our industry, limited only by the individual’s imagination. On a late night call out say to replace a nightlatch that has been destroyed: you arrive and discover the existing lock is an old 50mm backset and all you have is 40mm and 60mm on the van. Opening the hole for the cylinder left or right by 10mm is awkward and will not be accurate nor leave a professional finish as a gap will almost certainly be visible – so fill the existing hole with Belzona Mouldable Wood to flush and leave to harden, then re-mark & drill the hole for 40mm or 60mm using a hole saw (not a flat or auger bit as the differing densities of timber and filler will cause the drill to wander) and fit the new lock.

Door frames that have been split because someone has kicked the door in and the frame has given way can be repaired quickly and effectively saving the cost of ripping out an entire frame or splicing in a new piece of timber, (which in my view is never really satisfactory).

3G114E Breakout                                       

Yale 88 Breakout


Cut out the split timber back to sound material, refit the box receiver (I coat this with Belzona release agent and wrap some pvc insulating tape around the box to prevent resin from locking it into the frame), screw a few screws into the damaged frame to below final surface to act as a locking key for the resin, (sometimes you may need to fit a couple of screws behind the receiver plate for it to sit on and align it), then, using a former (say a length of 1.1/2” x 1/8” aluminium ‘T’ bar) that has been coated with release agent to prevent it bonding, mix and apply the resin to the former and to fill the timber area that has been removed, press the two together and clamp or screw to the frame to create original contours for the frame & leave to cure. When the resin has set, remove the former and pare off any excess material with a chisel or plane & sand smooth. This can then be painted to match the existing frame – an acrylic primer dries quickly and the client can then finish with a gloss to their own preference.


3G114E Jamb Repair


Yale N/latch jamb repair

Mistakes can also be rectified quickly and easily: suppose you are fitting a Chubb Viper deadlock and have marked & cut for the receiver box upside down (they are offset), simply re-cut the housing for the box the right way up, wrap some pvc insulating tape around the box of the receiver to prevent resin from entering the box and locking it in, apply some release agent to the rest of the box receiver, mix some resin and fill the excess hole, fit the receiver into position and leave to cure. The receiver can then be removed from the frame and pvc tape removed and a perfect cut-out has been created with the filler, the pvc tape having created just enough clearance fir easy removal & replacement.

Fitting a lock into an existing hole previously cut for a much larger lock can be done with Mouldable Wood. 1st put the new lock into the locked position so that the extended bolt will give a purchase point to remove it afterwards. Cover the body of the lock with polythene sheet or similar to prevent any resin entering any part of the lock body; coat the faceplate of the lock with release agent and allow to dry; mix Mouldable Wood to a heavy paste consistency and partially fill the hole in the door so that when the new lock is inserted just a small amount will extrude out. Press the new lock into the hole and screed off the excess and make sure the existing keyhole is filled flush to the door if it is not in the same position as the original. Leave to set, then remove the lock, re-cut the keyholes, remove the polythene and refit the lock & escutcheons – job done!

Some other photographic examples follow, not necessarily locksmithing but they are some things I have done with the product that has saved me a lot of time and money.

My daughter’s picnic bench was falling apart: repaired & repainted on a Sat. morning.

Garage door frame rotted: replacement would mean major disassembly & expense. Centre picture shows use of formers to maintain contours

Repair to a doorframe with electric release: kicked in by burglars this was repaired and photo was taken at a later date after client had done a ‘not very good job’ with the paint brush! – Note the Baddeley/Rose adjustable keep bar reinforcing the release as ‘belt & braces’ 3rd picture is of a different door release in the same complex

PVCu repairs: unsightly holes can be repaired in PVCu doors and frames using Mouldable Wood. The following is an example: the Mouldable Wood is very tough and pilot holes need to be drilled to accommodate fixing screws or the screws are liable to snapping off.

Super Metal Repairs

Belzona Super Metal 1111 is just 1 of a range of different metals but in my view is probably the most versatile. It is a 2 part epoxy resin product but unlike the Mouldable Wood it does have a fairly precise mix ratio of 3 parts base to 1 part solidifier (by volume) and is quite different to many other epoxy products in that it does not shrink as or after it cures out. It has a high percentage of ceramic steel encapsulated in the base product.

A couple of years ago an MLA member was called to a shop unit to repair the damage done to an aluminium door frame by a bailiff who decided to do the opening work himself and chain-drilled the aluminium frame until he could just pull the door open, then had no idea how to repair the damage. The following photos show how this sort of repair can be achieved. Two plates of aluminium were used approx 4 in. wide x ¼ in. thick, chain drilled and then filled with Super Metal 1111, filed flat after cure & then one side of the filled piece has been spray painted with Hammerite Smooth Silver  (Now scratched after rattling around with my tools for a year or so!)



It is preferable to pop rivet a backing piece of aluminium to add strength to the frame (drill a few small holes in it to give a key and if possible use a piece of aluminium angle if a box section to support the mixed product).  Mix the Super Metal 3:1 mix thoroughly until the product is an even colour throughout, then apply to the repair area (that has been cleaned with Belzona Cleaner [this is important to create a firm bond]), screed off to approx. level with the spatula (comes with each pack) leaving very slightly proud. Product will take about 2 hours to be firm enough to file flat at 20C (68F) – warmer will take less time, cooler will take longer – final finish will depend on your finesse with the file – then paint the repair to preferred finish.

There are many other applications for Super Metal 1111 but space does not permit inclusion here in detail: very briefly it can be used to finish holes drilled in safe doors after correct repair procedures have been done, stripped threads in metal components can be restored, components can be bonded to glass (I have used it to bond Chubb 8K100 locks to glass cabinet doors (though Belzona std ‘E’ Metal makes a better bond to glass and has a very fast cure time)

Super Metal 1111 has a number of amazing properties, most of which may be irrelevant to our industry but mixed product will cure at 0C (32F) and will withstand temperatures of 250C all day every day without softening, distorting or sagging.

Belzona supply COSSH and operational data/instructions sheets with every pack


BELZONA Contact details: http//

Belzona Polymerics Ltd, Claro Road, Harrogate, North Yorkshire, HG1 4AY.



Leave a Comment

You must be logged in to post a comment.