Frequently Asked Questions
Contents
- How safe is it to use epoxy resin?
- Is it true that the dust kicked up when sanding epoxy causes skin irritation?
- How much filleting blend should be added to the epoxy to make perfect fillets?
- Can I paint or varnish over PEC epoxy?
- Can I put another coat of epoxy over cured epoxy?
- Why does the epoxy go white when I spread it out?
- Can I use the epoxy in cold weather?
- Do I need to purchase some more epoxy if the resin has solidified?
- My final coat of epoxy has a texture like orange peel. What have I done wrong?
- What is amine blush, is it harmful and how can I get rid of it?
- When I moved my carefully assembled scarf joints the parts fell apart. How can I avoid this in the future?
- Why has my epoxy coated wood turned yellow?
- How do I repair cracks and scratches in epoxy?
If your question is not answered on this page, please contact us directly so we may answer it.
How safe is it to use epoxy resin?
Although the epoxy we supply is a modern solvent free epoxy it is still possible to become sensitised to the epoxy components. Sensitivity usually manifests itself as a type of dermatitis with red sores appearing on forearms, wrists and hands. To avoid sensitisation, we strongly recommend you take safety precautions when using epoxy. Please contact us if you require further advice or clarification.
Is it true that the dust kicked up when sanding epoxy causes skin irritation?
Most people do not have a problem but a few develop what looks like a sore rash. Rather than undertake sanding tests to see if you are one of these few it is highly recommended that, when sanding, you keep as much of the skin covered as possible. Always wear long sleeves and gloves. Incidentally, you should also wear a dust mask and eye protection as you do when sanding wood.
How much filleting blend should be added to the epoxy to make perfect fillets?
Mixing for fillets is almost an art rather than a science. The amount of fillers required depends upon the temperature and humidity. As a base mixture depress the pump on each bottle once and mix well then add a heaped teaspoon of silica powder and two heaped teaspoons of wood flour filleting blend into the mixture. From this base more wood flour should be added until the mixture is thick enough to stand up on the stick and, when applied as a fillet, not slide out of shape. In general, the wood flour will make the mixture thicker and silica powder will make it slide more.
Can I paint or varnish over PEC epoxy?
Yes providing the surface of the cured epoxy has been sanded to give a key for the mechanical bond which will form between the paint or varnish and the epoxy. The surface should be matt and dust free before painting or varnishing. Varnished epoxy shows the grain of the wood through a high shine.
A high (marine) quality varnish or paint finish over the epoxy is recommended since it protects the epoxy from UV light which can over several years turn the epoxy a yellow colour.
Can I put another coat of epoxy over cured epoxy?
Yes. Since the epoxy has cured a chemical bond is not possible so what is called a mechanical bond is needed. This simply means that the cured epoxy has to be lightly sanded before the next coat is applied: the first coat should have a matt, almost white, surface. Use glass paper of between 80 and 120 grade, no finer.
If the first coat has developed a blush or bloom this has to be removed before sanding and, in the case of this epoxy, it can be removed by washing the epoxy with warm water containing a few drops of washing-up liquid. Sugar soap solution is another fast way of removing it.
Why does the epoxy go white when I spread it out?
Air bubbles in the epoxy make it look white, but this is only temporary. The bubbles disappear as the epoxy cures. The main cause is working the epoxy too much, that is, spreading it backward and forward and then smoothing it out before having yet another go at spreading it. It is generally nothing to worry about.
Can I use the epoxy in cold weather?
Yes, as long as the epoxy is warm. Building in unheated sheds is not unusual but the epoxy should be kept off a cold concrete floor or, better still, be placed over a gentle heat. When the job is finished for the day the bottles should be put in a box and placed in a warm place such as a boiler room or an airing cupboard. If it is very cold, rather than heating the entire shed one should heat the wood with a gentle heat source.
If the epoxy resin gets cold it will become viscous and, eventually, crystallize. The problem with this is that it cannot easily be dispensed and is rather difficult to mix. The resin can be brought back to a usable state by warming the bottles and contents but this can take several hours which many will find frustrating if they have gone out to the shed to work for an hour. The best method of warming the epoxy components is by plunging the bottles into hot water.
Do I need to purchase some more epoxy if the resin has solidified?
Not usually. If the epoxy resin gets cold it will become viscous and, eventually, crystallize. The problem with this is that it cannot easily be dispensed and is rather difficult to mix. The resin can be brought back to a usable state by warming the bottles and contents but this can take several hours. The best method of warming the epoxy components is by plunging the bottles into hot water. Bottles can be placed on a heated tray or in an electric plant propagator. However, great care must be taken to ensure that the bottles are not melted.
My final coat of epoxy has a texture like orange peel. What have I done wrong?
The first coat of epoxy soaks into the wood and can be conveniently applied with a high quality roller. The second coat will not soak in and so will stay on the surface where it is put. If a roller is used and the roller is not evenly loaded with epoxy a pattern will be left on the surface. As it is so difficult to evenly load the roller it is best to apply the second coat using a hard plastic squeegee or an old credit card. If the surface is disfigured I am afraid that the only way around the problem is to sand the surface.
What is amine blush, is it harmful and how can I get rid of it?
This does not form very often and seems to occur in a peculiar combination of temperature and humidity that is not easy to isolate. If you are unlucky enough to have it, however, it is only a minor inconvenience that is easily removed from Professional Epoxy Coatings. It manifests itself as a waxy coating to the surface of the cured epoxy. Often users think that the epoxy has not cured thus the first check should be to see if a finger nail can be dug into the fillet or coating. If no depression is left the epoxy has cured and the bloom is on the surface. As a final test if you rub your fingers along the surface 'greasy' streaks will be left behind.
It is possible to remove the blush by sanding but this is hard work and expensive since the sand paper clogs up quickly and has to be replaced. The easy way is to wash the surface with warm water that contains a little washing-up liquid. If you use a green sauce pan scrubber to apply the water you are starting to prepare the surface for another coat at the same time. Do not try this with other epoxies. For rapid removal many use diluted sugar soap, as used to clean walls before painting, rather than water.
Tip: always wash the surfaces anyway whether or not there is a blush since wetting it shows what the finished surface will look like after varnish and imperfections and low spots are readily seen.
When I moved my carefully assembled scarf joints the parts fell apart. How can I avoid this in the future?
Epoxy is very strong and will stick two pieces of wood together, however, if there is a gap of even a tiny part of a millimetre it will be unable to bridge the gap and hold the parts together. To make scarf joints it is necessary to bridge the small gaps by thickening the epoxy. For a scarf joint thickening with silica powder is the best solution. After the epoxy has been mixed for about a minute paint both halves of the joint with the epoxy and then stir silica into the remaining epoxy mixture until the epoxy looks like slightly whipped cream. Apply this to one half of the joint and press the halves of the joint together.
Why has my epoxy coated wood turned yellow?
Over time ultra-violet (UV) light causes unprotected epoxy to turn a yellow colour and degrade. To avoid this the epoxied surface should be protected from UV light by coating it with either paint or varnish. As well as protecting the epoxy, varnish improves the look of the wooden surface.
How do I repair cracks and scratches in epoxy?
Cracks and scratches in the paint or varnish are unattractive but not usually harmful. If the damage has gone deeper than the epoxy layer then the wood is not being afforded any protection. To repair the damage remove the paint or varnish in the area of the crack and lightly sand the epoxy until it has a matt white surface. After removing the dust the area can be coated with epoxy and then painted or varnished.