Frequently Asked Questions epoxy

Below we answer frequently asked questions. Epoxy is a great material with great potential. Our customers have many questions though in daily practice. We try to give some more clarity here. Do you have a question that is not listed here? Please let us know.
Problems and solutions
Applications and processing
Tips & Trics

Repairing osmosis

Before you start repairing osmosis, make sure that the ship is not too moist. There are special hygrometers to test this on polyester.

There are 2 possibilities:

1. There are only a few local vesicles found:

Sand the vesicles open and rinse them well with sweet, clean water. Then let it dry well. The formed small hole can be filled with Mr.Boat epoxy putty. Then apply 4-5 layers of epoxy on the repaired spot.

2. Vesicles are found all over the ship:

When this is the case, you have to remove the gelcoat. This can be done with a special peeling machine or by sanding. Then the ship is thoroughly rinsed with sweet, clean water. Next the ship has to dry very well, otherwise there is a good chance the osmosis will recur.

A first layer of epoxy will be applied on the dry laminate (possibly injection epoxy when loose fibres are visual). Imperfections can be puttied. After that 4-5 layers epoxy are applied.

What is osmosis?

Osmosis is the symptom of arising vesicles on polyester boats which eventually can burst, with all consequenses. These symptoms usually occur on olders boats and often have to do with used materials and technics from that period.

You can recognize osmosis by sticking a hole in the vesicle. When damp comes out with a sour smell or feeling greasy, then it is osmosis. It is necessary to solvethis problem because it can aggravate quickly and it can even delaminate the polyester.

Further in these FAQ will be explained how te repair osmosis and how te prevent it.

I haven't used the epoxy for a while and it is hard now

This can happen when epoxy is stored for a longer period of time in a place with lower temperature. You can make the epoxy easily fluid again by putting the tank in warm water for some time. This has no effect on the quality of the epoxy.

Epoxy is thick and hard to process

Put the tank in some warm water for a while and it becomes fluid again.

A white, greasy layer forms on the epoxy after curing.

This is called "amine blush" and can arise when worked in a high humidity or when curing epoxy gets wet. Before any next layer is applied, remove the amine blush with water and a scouring pad, otherwise the next layer will not or badly stick.

Amine blush can arise too when epoxy is applied on a wet underlay. the recommended humidity percentage of wood is < 12%. To measure the humidity percentage accurately, you can use our handy hygrometer.

Amine blush can also be prevented by using peelply.

Epoxy on wood gets dim

When the epoxy layer on wood gets dim, the wood is very moist. The ideal humidity of wood is < 12%.

" Craters" arise in the epoxy

The cause of this is greasiness. Epoxy departs on some spots. Solution for this is sanding again and decrease the bad spots well. Then apply another layer of epoxy.

My skin is irritated from epoxy. Does it do any harm?

Most people have no problems when skin comes in contact with epoxy, but it can occur that an allergic reaction arises. This has no further consequences but is annoying.

When health problems do occur, please consult a doctor. Therefore always use face and skin protection.

Why doesn't my epoxy cure?

There is a big chance that you didn't use the right mixture (or maybe didn't mix at all?). Too little hardener results in not curing at all. The epoxy doesn't get hard.

Too much hardener doesn't cure the epoxy faster but provides a weaker result.

When you use epoxy at temperatures below 21 degrees Celsius, curing time can be longer. A big surface that is treated at a temperature of 15 degrees Celsius can take upto 1 or 2 days to cure. You can speed up the process by adding for example heat (stove or hair dryer).


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