How do you apply epoxy resin and varnish to a boat?

Answer 1

Here's what DIY Wooden Boat website has to say:

Maintaining your Boat Varnish.

To keep boat varnish looking smart requires regular maintenance.

UV rays (sunlight), is the major cause of damage to a varnished finish.

All good quality marine varnishes contain UV blockers.

Unfortunately these do eventually break down allowing the UV light to penetrate to the base layers.

And when it does the base coat will begin to deteriorate and start to separate from the wood leaving you with those horrible opaque blisters.

Once the varnish has reached that stage the only option is to strip it all off and start again.

To avoid this happening you need to renew the UV protection by regularly sanding back and replacing the top coat.

How often this needs doing will depend on the amount of sun it is exposed to, generally once in the spring then again at the end of the season should be sufficient.

Not only will this top up the UV protection but it will fill up any scratches or cracks and your varnish will get better looking every year.

And filling those scratches will prevent moisture from getting underneath the base coat which will also damage the varnish to wood bond.

Here is a quick rough guide to when your varnish needs freshen up.

Give it a good wash, then when it is still wet the water should form beads on the surface.

If the water forms sheets or flattish streaks it's time to re-do that top coat.

Even where you are merely touching up sound boat varnish, the surface must be sanded to provide a key so the new varnish will adhere well.

Varnish should always be sanded with a fine grit, 150 or less, a course paper will leave scratches which will be impossible to hide.

For boat varnish work, always sand along the direction of the grain of the wood and not across it, so it really needs to be done by hand.

Where old varnish is lifting, blistered or has flaked it is better to take it all off and start again than to try to patch it up.

Start off with a long handled scraper, this is the type of job they are designed for.

If there is a lot of thick varnish to be removed you could resort to a hot air gun and a hook scraper or if you are feeling brave a blow torch.

I have found that chemical strippers are messy, hazardous to use and work out quite expensive, I'd rather take my chances with a blow torch.

Once you have got the old varnish off, or if you are starting from bare wood you then need to give the area a good sanding.