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Scale Modelling and Your Health

Rob Plas

 

Without trying to scare modellers away from their hobby, this article tries to tell a little about some of the health risks that occur when building scale models.

As most of you will probably know well, the hobby of building scale models from trucks, tanks, airplanes and ships has taken a enormous jump forward the last 10 years.  New techniques as well as new materials have created a whole new era in making replicas of the subjects we admire for one reason or another.  With all those new materials new chemicals were also introduced to the hobby.  Think about glues, paints and plastics. Some of these materials can form a risk for your health.

For me the reason to write about these risks is twosome:

1st:   I work in a chemical plant and have recieved a lot of training about the dangers of certain chemicals like solvents, I feel that I should share this information with other modellers.

2nd: In our Club "TWENOT"  some time ago a member was hospitalised for about 10 days after working with resin casted parts. He suffered from severe respiration problems and nose bleeds.

The dangers involved with modelling can be divided in 2 kinds of risks: the immediate, short term risks and the long term risks.

Short term risks:

●Injuries to hands and eyes from cutting, grinding and other mechanical methods

● Eye injuries through chemicals

● Fire 

Long term risks:

●Allergic reactions to certain chemicals

● Problems to the respiratory system due to over exposure to chemicals.

● Brain damage caused by over exposure to solvents

Short Term risks

Injuries to hands and eyes

When working with sharp knives it is obviously that you will cut your fingers once in a while. Usually these are tiny cuts with razor sharp knives so this wonít be a very big problem. But every now and then on the ML newsgroups messages appear about some serious wounds people get from accidents with X-Acto blades or other sharp tools.

There are some basic rules to prevent yourself from cutting really bad: never work towards yourself, always cut away from yourself. If the knife slips away you won't cut yourself badly in your hand or fingers.

What is a bigger problem is the fact that splinters, sawdust and other tiny bits can come into your eye. Also electrical tools can let drill bit "shrapnel" fly all around your workbench. Avoid injuries by wearing safety glasses and if this occurs: Do Not rub your eyes! - ask help to rinse your eyes with some clean water and see a doctor if your eyes keep hurting.

Eye injuries through chemicals

With this I mean contamination of your eyes with fumes from superglue, thinners, solvents and paints.

Donít rub your eyes, rinse with water and see a doctor.

When you have got Superglue, or AcrylCyanoate Glue in your eyes go directly to a doctor, donít attempt to open the hurted eye yourself as you might damage the lense of your eye.  Damage to your lenses is irreversable!

Fire

Some of the practices in the hobby involves heating plastics on an open flame, soldering-irons and heat treating PE sets.  Often this is done on a workbench loaded with other hobby gear.

Take a look around, what do you see? A bottle of Thinner? Some turpentine and alcohol based thinners too? Perhaps an open jar with thinner for cleaning brushes? Polystyrene glue? All these chemicals are highly flammable.

In short: Be very careful with heat and open flames. An accident can occur before you even realise it.

And be honest, do you have a fire extinguisher at hand on your workbench?

Long term risks

Most of the long term risks are more dangerous than the list above because these risks are not always very clear: 

Allergic reactions to certain chemicals and problems to the respitory system due to over exposure to chemicals.

To realise what dangers we are talking about here you first need to know some basic information:

Allergic reactions occur when we come in contact with materials our body cannot really cope with. Allergic reactions can display itself at the skin, like red spots and even wounds in the long term and as problems with the respiratory system.  We are all know people being allergic to cats and dogs while Hayfever is also a typical allergic reaction.

It is a fact that you can usually withstand a lot of contact with a material youíre in fact allergic to, without having any trouble at all. But when you finally reached the point where your body starts "over-reacting" to contact with a chemical it will hardly ever go away.

You can develop an allergie for solvents and thinners and also resin, more precise PolyUrethane Resin is a chemical that can give very strong allergic attacks.

As mentioned before a dutch modeller was hospitalised for about 10 days with severe nose bleeds, and big problems to his respiratory system.  He was working with PolyUrethane Resin when the problems started. The dust from sanding some parts did the job. Therefore it is essential that you try to minimize the amount of dust you inhale when sanding, sawing and cutting plastics. The easiest way is to wear a safety mask, use wet sandpaper and clean up the workbench as often as possible. Also be sure not to eat, drink or smoke while working with these plastics.

Brain damage caused by over exposure to solvents

This may sound very dramatic but it doesnít have to be.

More and more literature is being published about a disease called OPS is now available and it is now clear that this disease is caused by minute braindamage due to years and years of working with solvents.  In Holland the disease is called "Painters Disease" because this is one of the labourgroups that frequently show the effects of this disease. These effects are: sudden moodchanges, loss of concentration and feeling tired and numb.  Altough most modellers donít use large amounts of the thinners and solvents that may inflict injury upon people, they do often work in ill ventilated areas and very close to their faces, in fact usually they are sitting right above the fumes and vapours.  These sovents are to be found in many paints, thinners, glues and puttys.

Some solvents are also possible carcinogens which means they may increase the risk for developping cancer. I will give you a short list of chemicals commonly used by many modellers with their risks for your healt.

Acetone: Used for glueing and cleaning airbrushes and brushes: Solvent, danger for OPS

AcrylCyanoate or Super glue: Suspected fumes and also dangerous for the eyes, it glues flesh together

Acrylic Paints: safest paint to use, low in fumes and solvents, often alcohol based

Benzene: Used for cleaning airbrushes, colvent, risk for OPS and a carcinogen.  Not normally available in hobby stores, but sometimes it is "found" with people who work in Industries

Caustic Soda: sometimes used for stripping paint of models, can give you severe burns and can cause blindness when the solution is too strong

Enamel Paints: paints based on oils, their thinners are the most risky components.

Epoxy Puttys like Zimm-it-rite and Miliput: Can cause skin and eye iritation, harmfull when swallowed

MEK: Solvent used for cleaning airbrushes and gluing plastics: OPS and suspected carcinogenous

Pigments in paint: Some of the pigments in paints are based on oxidised metals like Cadmium and Titanium. A dutch beer brewery (Heineken) had to destroy all of their yellow crates a few years back because of the Cadmium Yellow pigments in the plastics. As this cost them millions you can understand they didn't do this voluntarily. The good news is that most of these pigments are now no longer used.

Polystyrene glue: Often Toluene based, solvent with OPS risk and suspected of being a carcinogen

PolyUrethane Resin: plastic, the dust is the most dangerous, because it can enter your respitory system.

Polyester: very harmful vapours will occur during the curing process

Primer paints: Often from a spray can, lots of unhealty vapours and pigments.

Silicone Rubber Compounds: Can cause skin and eye iritation

Soldering lead: The fumes are not very healty, lead is very poisonous.

Protection

Before you decide to stop modelling and get another hobby: Protecting your self from these risks is quite easy and not really expensive too:

For most solvents and fumes a respitory mask will do. Get a type with changable filters so that you will be cheaper of in the long term. A good mask will cost you about 30 US Dollars and it will last for ages.

- Ventilate the room when working

- Donít lick your brushes.

- Wash your hands after finishing the job, donít eat, drink or smoke during the job.

- Use a dust mask when sanding plastics and always try to use wet paper. Apart from the healt advantages you will get a smoother finish to.

- When working with resin: Donít use your Proxxon, Dremel or other elecrical tool, the dust generated by these tools is enormous.

- Work in good light conditions so that you wonít accidentally cut your fingers.

- Try to wear safety glasses when working with your dremel tool

- Be very carefull when building your own compressor, a friend of mine build a compressor from an old refrigerator compressor and an old gastank. He blew up his shed because he forgot to turn the thing of and it had no pressure safety devices.

- Be very carefull with pressurised gas containers, I have seen postings of people wanting to use Nitrogen gas, Carbondioxide and other industrial gasses as a repellant for their airbrush jobs. DONíT do this, a (silent) compressor is still the best option.

After reading this article when it was published in the MIP, the magazine of the Dutch chapter of IPMS Ruud Pronk, produck Manager Filters and Masks at Dršger Nederland wrote a sequel, containing the know how he proffesionally has about protecting devices. It is well worth reading!

General:

When looking at our hobby with my proffesional background Iím sorry that I have to state that while modelling people use many potential dangerous chemicals that can harm ones health.

Many of these chemicals are used in Industry. There the people that need to deal with these substances have the right and the duty to use protective clothing and devices, something that is regulated by the Arbo wet. (This is a law that specifies all the rights and duties of people at work, and those who employ them {transl})

In this situation the employer is responsible for providing the best possible solutions to prevent health hazards to the people that work for him.

But working with these chemicals as a hobbÔist these laws will not protect you and it is of great importance that we understand the risks and concequences.

Hazardous Chemicals 

When we talk about dangerous substances we are talking about the following risks:

Flammable and combustious substances

Poisonous and/or harmfull substances

Agresive and/or irritating substances

Substances that are harmfull to the environment.

When dealing with poisonous chemicals you have to consider that there are 3 ways to get infected:

1)     Swallowing

2)     Absorbtion trough the skin

3)     Inhalation trough breathing

Swallowing is in many cases a simple matter of hygiene. At locations where is dealt with poisons you need to wash your hands, face and arms from time to time. Eating, drinking and/or smoking is a welknow contamination source so thatís a NO GO!

Swallowing poisons is normally a matter of personal disciple, and the willingness to follow that discipline is often a matter of knowledge about the chemicals we work with.

 Many dangerous substances are absorbed trough the human skin. This can become a critical situation when a large amount of it is spilled when accidentally turning a bottle over at the worktop.

Instant poisoning needs immediate action: do you know which actions to start with the different chemicals you work with?

For every dangerous substance you can find a safety sheet (Material Safety and Data Sheet or MSDS) that contains the most important data about the chemical it concerns. In Dutch and other European laws a compact version of this sheet is obliged on the packaging of the chemical. On the internet you can also find these sheets, just type the name of the chemical of simply MSDS in the search engine of your browser and normally you will find what you are looking for. Be aware that many companies use commercial names for their products, but by checking the labels you must be able to find the substances used in their product.

 A different kind of poisoning is the repeated contamination with small doses that are not a danger at itself. But many of these chemicals tend to build up in the body and will display their harmfull effects only after years have passed by. An extra problem is that due to this it is often very hard to find the cause of an illness that might occur. These problems are often summarised as ďProffesional DiseasesĒ in Europe

 Poisoning trough the respiration system is the most common and best known cause, and will be recognised as the primary cause of poisoning by many.

The effects of this type of exposure are often:

- Head aches

- Nausea

- Skin rash

-Affection of internal organs like kidneys and liver

-Affection of the nervesystem, brains and reproducing organs

-congenital defects

-Orientation problems

-Moodchanges

-Allergic reactions

-Digestionproblems

We can find these substances in the following ways:

-Gas

-Vapours (This is a gas that can condensate into small droplets)

-Liquids

-Solids

-Fog/Mist: A combination of gas with small droplets of a liquid, also know as aerosols.

Protecting your respitory system

First Iíd like to state that facial hair like moustaches and beards influence the effectiveness of all types of protecting devices in a negative way.

Everything that sits between the bare skin and the edges of a mask causes leaks. And thus by-passing the filters that are used to absorb the dangerous substances.

It helps to read the manual that usualy is upplied ith the filter of your choice, it normally describes how to check for leaks.

Breathing protection is roughly divided in 2 clases:

 -Depending and non depending

Independent protection means you can breathe independent from the surrounding environment, most often we are talking about scuba gear or the pressurised air tanks and masks used in industry and/or the fire department.

Depending means you breathe the surrounding air but filter the dangerous gasses and vapours from it. This is most often used.

2 types of protection are:

1)     Holding ones breath

2)     Filter masks

Different types of masks:

A mask that covers the face partially, with an exchangable filter cartridge with different types of

FILTERS:

1)     Dust filter: Itís all in the name: This type of cartridge only filters uot dust from the air you breath. They will not protect you from gasses and/or vapours.

2)     Gas filters: These filters will protect you from harmfull chemical vapours and gasses.

3)     Combined filters, simply a combination of the 2 filters mentioned above.

There are different types of masks:

Full face masks: that also protect the eyes and skin of the face

Half face masks: that are intented for the breathing only.

These masks can also be diveded in different types:

Durable, re-usable masks

Masks for one time use only, they must be disposed after use.

Disposable masks are not as effective as the masks that can be re-used. The main problem is often to get a good tight fit on the face. Often these masks leak air between the edges and the skin so even if the mask itslf is made of quality materials the air will by-pass the mask and you will still breathe in harmfull substances.

These disposable masks are only usable when the exposere to dust is little and not for too long a time.

They are not really suitable as personal protection for most of the chemicals allready named here.

A good quality disposable mask can be recognised by its classification marks:

These masks follow the EN143 classification:

FFP1: This has the lowest filtering capability and will only stop particles with a value of 10mg/M3 (Think about sand grains here)

FFP2: This mask will filter any medium sized dust with a value of 0,1 to 10 mg/3

FFP3: These are the masks with the highest classification and they will filter particles that are smaller then 0,1 mg/M3 like asbestos and quartz.

Other markings that you can find according these NE norms are

S= Solid, or solid particles

L=Liquid, suitable for filtering droplets and mists

V=Valve, a valve for the outgoing air is added (This prevents the air from going trough the filtering layers twice, so the filter will last longer.)

When using a filter you will feel a resistance in the airflow. This is quite normal, and the better the filters the highr the resistance will b. Specially when using a very fine FFP3 filter we advice you to use one with a valve, thus reducing the resistance when breathing out. You wonít find these filters in a DIY shop very often, they are a lot more expensive then masks without a valve. 

For modelling we advise you to use at least a FFP2 mask

Now the question arises: how long will my mask last?

This depends on a number of factors:

-         How much pollution is on the mask after use?

-         Blockage of the airflow due to saturation of the filtermedium

-         Moisture from exhaling will cause the particles to stick to the mask

-         By handling the mask with dirty hands it will get dirty very easy

-         Trough air leaks the edges tend to get very dirty very easy

 Also leaving the mask at the workdesk will cause it to get dirty very easy.

Gasfilters

Gasfilters do their work by binding gasses and vapours by active carbon. This can work in 2 ways, dpending on the chemicals used:

Molecules bind fysically to the carbon (Adsobtion) or it can be binded chemically. (Chemosorbtion) Depending on the filter and chemicals one of both processes take place and the choice of filter should always be made with the pollutionlevel taken in consideration. 

Always use a certified filter (EN141)

You can recognise it by itís markings:

A=     Browne strip, usable for organic vapours with a boiling temperature >65 degrees Celcius.

B=     Grey strip, usable for acid gasses, formaldehyde

E=     Yellow strip, for Sulferdioxide

K=     Green strip for Ammonia

AX=   (Letters)  Organic vapours with a boiling temperature < 65 degrees Celcius.

P=     White strip for dust, because a good one also filters out dust particles.

 On each filter that is made following official standards there is also an indication for itís capacity, devided in 3 classes: Class 3 has the highest capacity, class 1 and 2 normally are used with masks that only cover the mouth and nose.

A warning is in itís place here: In many DIY shops you can buy 1 or 2 kinds of carbon filed masks but these are not made according to official, industrial standards. They will function in one way or another, but if they are the best possible solution??

How long will a filter last? 

How long a filter will last depends on several different matters.

- The nature of the gasses and vapours: some chemicals do not bind so easy to the active carbon

- A combination of different chemicals: due to differences in reactioncapacity some chemicals tend to slip through the filter because others bind much quicker to the carbon. This can even result is exchanging chemicals that were allready bonded by the carbon to let go again, in favour of the new chemical.

- Temperature and humidity, as a rule you can say the higher they get the worse they effect the capacity of he filter used.

- The amount of air and the concentration of the pollution in that airflow.

- A filter that is used before will contain chemicals that can be released during the next use.

- When a filter is stored between use it will continue to absorb humid and chemicals from the surrounding air, so lock it tight in a plastic bag or something similar.

- If the air contains droplets or a mist of chemicals (Airbrushing!) it will result in a very high contamination rate. Using a P-filter will prevent this for a good deal, thus keeping the filter in better shape.

- Mechanical blockage of the filter by high concentrations of dust particals.

To help people and give some directions the industrial researchers have come up with the following guidelines:

Maximum time for using a filter is 8 hours total, over a 3 month period, providing that the filter is stored in an airtight seal in between use.

If you smell the chemical trough the mask itís a clear sign that the filter is saturated and needs to be replaced immediatly.

On a good quality mask you will be able to find a production date and when stored in the approperiate way it can be used for 4 years after production. A good way to store your mask is: In a dry, sealed bag under room temperature.

These figures are made following standard safety rules, but you will probarly find out that your filtermask will last a little longer, due to the low exposure rates normally involved with the smaller amounts used in our hobby. It makes a big difference if you are working with a small bottle of a thinner compared with a truckload if it.

To summarise a long story in a few sentences you can follow these guidelines to work in a safe way with the chemicals in our hobby:

Use at least a filtermask that covers your breathing organs (Nose, Mouth) to keep safe and healthy.

After studying the different chemicals used in our hobby I came to the conclusion that a A2-P2 mask is the best  and safest possible solution with the best cost/effect ratio.

There are special filters for working with chemicals like Aceton, with a bigger absorbing capacity. The filter I advice will provide you the same absorbing quality, but will last a little shorter. Even when taking this in consideration the A2-P2 filter is still the best and cheapest possible solution, even though itís shorter lifetime.

Ruud pronk,

Dršger, The Netherlands 

Iíd like to finish this article with stating that I donít want to tel you how to do your modelling, this article is purely intended to make people aware of some of the risks involved with working with the things we use. Maybe some newcomers in the hobby are not aware of these risks and will be more carefull now

Iíd also like to thank Ruud pronk for his excelent article and the pictures he provided.

Finally I want to give you the following advice: A good source for good quality masks are shops where they sell car paints and specialised safety articles shops

With no doubt you will be able to find one or two near you in the yellow pages.

Happy and safe Modelling,

©Rob Plas 2002