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Bakelite and Plastic Restoration

Started by Bob Angel, November 17, 2015, 04:47:08 PM

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Bob Angel

Article Written by Bob Angel
Date: 17-11-2015

Telephone Restoration
This article relates to the repair and restoration of telephones that use Bakelite and other plastic materials in their production.
May I just start by saying that I certainly don't consider the repair process I use to be "the be all and end all" of repair procedures.
All variations of repair processes, methods and techniques have their place in the world of restoration. There are restorers out there with their own procedures utilising their own skills, knowledge and experience and who are doing a fantastic job.

The purpose of this article cannot be to pass on every detail and aspect in the process of Bakelite and other plastics restoration which I have built up over 25 years.  Hopefully it will give you an overview on the complexity of the process and an understanding of the method that I follow and that works for me.

If it prompts you to research and experiment, that's great. If your experiments succeed that's good but don't get put off by failed experiments, you can learn a lot from failure.
Results and Expectation
Many repair procedures can produce differing results and the required results and expectations of any restoration are subjective.
Ultimately it is the client who owns the affected telephone that decides which is the appropriate direction for them to take down the route of selecting the restoration procedure they think would be best for them.

The Repair Process
The process of repairing Bakelite and other plastic material telephones has always been a difficult area as there is no comprehensive "written manual" out there that I or anyone else can refer to for guidance.
The processes we all use are generally created and developed by ourselves as an extension of our hobby and the process I use has been developed by me over the past 25 years and continues to develop day by day.

The process, has been described by others as bordering on the level of "museum conservation" and by its very nature is very time consuming. Each repair is different due the wide variations of damage, fractures and the colour hue of those damaged items.
As in all processes the final cost of the restoration is related to time, therefore the value of the item in currency, emotion and self-attachment must always be taken into consideration before embarking on any restoration project. 

The aim of the process is to improve upon the "aggressive" look of the damaged area and thereby diverting the observer's eye line away from that area.
The process does not include repainting the affected area, it is carried out using pigmented resins and adhesives in an attempt to minimise the area of repair and maximise the amount of the phones surface originality.
The process will not be suitable for all aspects and levels of damage and there are situations where certain levels of damage may require a different approach and a different process.

Due to the nature of the work the repair can never be considered as an invisible restoration and the repair cannot be expected to recover an item to its condition prior to any damage.
The intention of the repair is to retrieve broken parts that would normally be considered as scrap and bring them to an improved level that's is pleasing to the owner of that item.
The repair is not the intended to fool anyone into thinking that the item had never been damaged.
Additionally, results can never be guaranteed, as no matter how much skill, knowledge and expertise is put into a repair, sometimes the materials used seem to have a life of their own and will not follow the science of the process.

An alternative opinion is that the use of a procedure that involves painting the item can sometimes create an invisible repair, and I agree with that comment in principal. However, we go back to "results and expectation", if the repairs are to be filled and painted over, a beautiful coloured phone could be covered in so much paint that its surface coating originality will be lost to the owner of the item and to any observer.
If a coloured phone is just covered in coloured paint it may just as well have been a black telephone underneath the paint.

The Process 
a) The process starts with identifying the colour that the affected area will end up after restoration. This is carried before we actually repair any fractures or damage.

b) As the restoration will include some degree of re-finishing, the colour of the affected area it will generally change during this process depending on the degree of any fading or colour change since manufacture. So we have to identify the final colour of the surrounding area before we can mix the required pigments for the resin.

c) The refinishing of the affected area may need to be extensive and it must be remembered that the rest of a faded telephone may need a "matching refinish" so that everything blends. Also be aware that any refinishing can sometimes reveal faults and blemishes which may have been present underneath the surface but not previously visible.
Extreme care must also be taken as refinishing can compromise the shape of the design lines and contours of the telephone.     

d) Once the final colour of the area is established the pigment can be created.

e) The creation of a pigment colour mix is a very difficult area. The pigments commercially available that can blend well with a low viscosity resin and some adhesives can be limited in their colour range. So mixing different pigments is required to suit the infinite colour and shade requirements of the affected areas.

f) As the repaired area will sit alongside the original surface colour of the item the slightest colour difference can be picked up by the naked eye. Also the colour pigment used in original manufacture will be different from the repair pigment and there is a possibility that these two may vary when viewed in certain light.       

g) As the pigmented resin can cure slightly off-colour, a variation of pigment is produced and around 5 samples are tested by pre-casting to select the best one before any before restoration is carried out.

h) Damage to the material. There are many types of damage, these can range from missing areas to "closed" and "open" mouth fractures. Each type of damage can require a different resin, pigment and repair process depending on the nature of the damage. For example; the repair process for a "one moment in time" sudden fracture may be completely different to a fracture that has occurred over a long period of time.     

i) All damaged and fracture surfaces have to be thoroughly cleaned by removing dirt, oxidisation, previous repair mediums etc. Any mating surfaces must mate and blend to the best possible degree.

j) If it is a missing area to be recreated, a mould has to be produced to create that area and the mould attached to the item. Sometimes due to the structural demands on the repaired area, additional strengthening has to be included into the resin and mould.

k) The selected pigment is mixed to the selected resin and is poured into the mould. Once the resin has cured the mould is removed and the area refinished and polished.

All the above is just a basic overview to indicate the process and its many levels.

I have attached some photos of previous restorations.

I hope it has been informative and of some use.

Bob Angel

Bob Angel

Article by Bob Angel
Date: 18-11-2015.

Following on from my article above I have been asked a number of questions and one is, how I did I get interested in restoring Bakelite and other plastics.
When I started restoring Bakelite it was to complete phones in my collection that had missing or damaged parts. Obtaining good replacement parts was almost impossible so I started repairing them.
It didn't matter if I spent many hours restoring something as it was for my own phones, but when people saw my work they asked if I could repair their items.
This can be done, but then of course time, cost and item value come in to the equation.

As the cost of collectable phones goes up and down the current value of the item will dictate if restoration work is financially feasible.
As we all know, most times it is cheaper in the long run to buy the best quality you can, as rectifying a lower quality item will probably be as expensive, if not more than a high quality item.
You only have to look at the classic car and bike market to see how many restored vehicles sell well below their restoration cost, the buyer gets a bargain and the seller incurs a loss.
I have also been asked by a number of people if I use an electric motor to buff the items for preparation or to finish the repaired items. I have put together some comments on this issue but please forgive me if you are a professional polisher, my comments are only based on my experience and you will be able to give far more guidance than me.

a) Motor buffing certainly has a place in restoration but if you do refinish with an electric motor do be careful on some of the softer materials. With extensive buffing you can lose or alter some of the original design profiles, lines and sharp edges that make a phone look good.

b) Too much generated heat can also cause a wealth of problems and can make the surface look "over polished" and unnatural.

c) You really have to be selective with the motor, HP rating, rpm, mops and polishing compound you use. (again, forgive me if polishing is your trade, as you will know all about this)

d) For me I always initially hand cut-back to prepare or finish the surface using a selection and variation of pre made shaped blocks and Micro-Mesh wet & dry cloth, this is used with loads of water as a lubricant for the wet & dry.
The Micro-Mesh is available in grades up to 12,000, very, very fine and this comes with its own polishing cream.

e) This process helps to keep all the profiles, lines and sharp edges in check and the part can be finished with a hand polish or a very light motor buff.

I have also been asked by a number of people about the pigments I use, I have put together some comments on this issue related to my own experience.
a) Over many years I have used and have experimented with liquid, cream, paste and powder pigments, plus a vast range of inks, dyes.

b) My main usage is with a cream type pigment, but that can change depending on the resin or adhesives required to repair a particular damage or fracture.

c) Some pigments will not work well with certain types of resins and adhesives and some resin and adhesive are not suitable for some damage. 

d) It really is a minefield of information as there is no "one" resin, adhesive or pigment that can be recommended as each repair, fracture, missing area is different and may require different products and processes.

e) One example;
1. You may have a part that has two issues, a missing area and an open mouth hairline fracture.

2. The colour of the damaged part is the same, rich, deep and uniform.

3. You will need a pigment for the repairs.

4.However, although the "colour" of the pigment will need to be the same for both repairs you will need a completely different depth and translucency to the pigment for the fracture than for the missing area.

5. If that depth and translucency is not spot on you will either get a strong colour line or a "greyish" dark line in the restored fracture.

6. That's why many, many test samples are produced and carried out before you go ahead with the repair.

7. Even after all the tests are done and the selection is made, sometimes the results haven't followed the science of the process and the repair is not as you would have expected. 

f) That's just one very small example for a multitude of problems you will come up against when restoring Bakelite and plastics.

g) Many people have suggested using "ground-up" Bakelite and plastic to use as a pigment and I have experimented with this and these are some of the issues I have experienced.
1. Grinding Bakelite and plastic to a dust is risky and you need to wear the correct mask and have a good dust extraction system around the grinder if you want to do it.

2. Generally, it will be difficult to find some "donor" Bakelite or plastic that is the exact same colour of the part you are repairing.

3. Ground-up Bakelite will not completely dissolve into the resin product you are using and generally the ground-up particles just stay in suspension within the resin.

4. Liquide, cream and powder pigments dissolve better into the resin and you have a greater control over colour, depth and translucency. 

As always my comments are from my own experience and are not definitive.
Generally, there is no one "definitive" answer in the selection of materials and processes used in restoration. Everyone has their own methods and materials they like to use and that works for them.

Restored Series 200 Body
I have attached some photos of an Ivory Body that has been restored.

My kind regards

Bob Angel

Article Written by Bob Angel
Date: 18-11-2015

Telephone Restoration
This article relates to one aspect of the repair and restoration of a 1932 Siemens Mottled Burgundy telephone.

The telephone had significant damage, fractures and missing areas to restore.

The mottle was very fine and a new restoration process needed to be developed in order to carry out the repairs.

It took around 150 hours to develop and test a repeatable procedure.

It took a further 200 hours to actually restore the many affected areas of the telephone.

This article relates to just one of those repairs.

Restoration of one "Open Mouthed" Fracture.
a) The fracture in question was approximately 400mm in length and ran from its closed end to the open mouth at edge of the body.

b) At the open mouth of the fracture there was an area of Bakelite missing and this was approximately 200mm by 100mm.

c) The affected area was photographed.

d) The plan was to restore the fracture line first and then once stabilised and secure the missing area could be in-filled.

e) The problem with bonding a fracture line in this mottled telephone is that within the length of the fracture there were 2 variations of the base colour and numerous mottle infills of various shapes and colours.

f) If you bonded the fracture line with a single colour pigment adhesive this would show as very thin single colour line against the mottled surrounding.

g) A large blow-up photo of this area was produced and notes were made of all the colour variations and mottles along the fracture path.

h) The plan was to produce a different pigmented adhesive for every colour variation along the fracture path.

i) The different pigmented adhesives would then be laid matching each colour variation along the fracture path.

j) To test this process, the pigmented variations were laid on the large photograph just to see if the process would be effective.

k) It was, so the next step was to try it out on a test piece. I fractured a spare piece of mottled Bakelite and physically practised the procedure on this piece, this worked well after a few practise runs.
This testing was vital and had to be carried out before any work could progress on the actual telephone.

l) The next problem to solve was that the fracture on the phone was an open mouthed fracture. It would open at one end but was closed at the other end of the fracture. The two fracture surfaces had to be kept apart while the pigmented adhesives were placed in the fracture, it would then be clamped while the adhesive was curing.

m) The was achieved by making a "mechanical spreader" that could be placed in the body of the phone to mechanically open the fracture to required amount and keep it there until the fracture required closing.

n) The fracture surfaces were cleaned and prepared for bonding.

o) With the spreader in place all the necessary pigmented adhesives were prepared.

p) The fracture path was in-filled with the varying colours of pigmented adhesive. In order to stop the different pigmented adhesives from running into one "muddy" colour they were left to a point of semi-setting so that the viscosity was still good enough to be an effective adhesive but not thin enough to run into each other.

q) The mechanical spreader was released and the fracture closed and clamped.

r) Once cured, the area was carefully re-finished and polished.

I have included two photos of the body.

Kind regards

Bob Angel


Excellent! Thanks for sharing all this great info with us. Can you provide specifics? Such as brands or types of different pigments, fillers etc. Pictures of the work in process would also be enlightening, such as the mechanical spreader separator used? I hope I am not asking too much but I am very interested in learning this process and I am eager to finish my current projects and attempt a repair using this method.
Harry Smith
ATCA 4434

"There is no try,
there is only
do or do not"

Bob Angel

Hi Harry,
Many thanks for your comments.

The Mechanical Spreader
I will sort out some photos of the mechanical spreader for you, it's a simple design nothing elaborate.

Specific Information on Materials
This is the tricky area;
a) I don't think the resins, pigments and adhesives that I use, and that are available in the UK, are going to be all that different from those available to you in the USA or other countries.

b) I can certainly pass on the name of the company I use in the UK; it is;
East Coast Fibreglass Supplies ltd, their website address is;

c) Have a look at their website and go through their product range of resins and pigments. I use both their polyester and polyurethane casting and pigment products but as mentioned in my article there is no "one" product that I could recommend as "the one that works". It really is a matter of trial and error and searching for "what works for you" and I don't think that is going to be different from the products already available to you.

d) I have put some photos on the forum of one of my projects during work in progress but there is nothing ground-breaking in the photos, it is just mould making.   

e) As with all restorations the successful results achieved will be down to a split of materials against technique and the skill and experience of what to do with those materials and how to implement that technique. Everyone's idea of that actual percentage split will be different but I have it at around 20% material and 80% on technique, skill and experience.

f) The information on material can be easily advised, even the technique can be described but that percentage of skill and experience is the area that is so difficult to put into words but is the key to the results we are all trying to achieve.

Project Photos

Bob Angel

Hi Harry,

Some photos of the spreader and how it fits in a phone body.

Mechanical Spreader
The spreader is just made up from steel tube, nuts, bolts and soft tips.

I have also made some different length variations on the movable bolts to give a choice on overall length of the spreader.   

Kind regards



Thanks again. Very helpful. I wasn't asking for the particular products you use, as I realize things across the pone are quite different, just info on the materials. I will peruse the website to try and gather some ideas. I have a few damaged cases to practice on, I realize it will take much trial and error to achieve results like yours!
Harry Smith
ATCA 4434

"There is no try,
there is only
do or do not"