Thread: Epoxy Selection

Hi Darren,

What construction method is the boat.

If traditionally planked of real wood then epoxy may not be the right way to go. But if it is plywood or has been fibreglassed then the method below will work fine.

Resin and Hardener
Pumps to suit the size containers of the above (hint keep the resin warm)
DADDLES - what's the link to our discussion about light boxes?

That's the obvious bit.

Now as far as the filler powders.
High strength gluing filler - gives a structural bond but hard to sand
Lightweight filler powder - sands easily but not very strong.

You definitely need the high strength one for the gaps in the transom. If you work neatly the sanding won't be too bad - but if you have a lot of little bits to fill in a non structural way - then it might be worth getting the lightweight filler as well.

As far as filling the cracks goes. Mix up resin and hardener - mix well scraping the sides and bottoms of the container. Brush the unthickened mix well into the cracks. A good tool to do it with is a 1" disposable brush with the bristles cut down to a length of about 3/4".

Dip the brush into the epoxy one last time.

Then add the thickening powder to the container mix it in well - probably need a peanut butter consistency unless working horizontally (you can use a honey consistency if horizontal.

Use the epoxy on the brush to get one more coat into the cracks and then fill with the thickened resin.

Hope this helps

MIK

Here's the link to the light box selection. You'll notice that only Mik and I took it seriously
http://www.woodworkforums.ubeaut.com...ad.php?t=34266

Don't forget, if you want to colour the poxy the same as the timber, you can use fine sawdust ... just a pinch will do.

Sand the stuff while it's still green ie, within a day or two. You'll be amazed at the difference. Fresh paper is a good move too, and some suction on your sander makes the whole job less intolerable (don't be fooled into thinking that anything to do with boats is easy, especially when you combine epoxy and sandpaper )

The other thing is, although poxy isn't supposed to shrink as it sets, it flamin' well does. Like using ordinary putties, leave the fill slightly proud and then sand back. The beauty of poxy is there's no problem with gouging a bit out and having another go if you make a mess of it

And a Bote Cote supplier 10 mins from work? Such luxury.

Richard

Originally Posted by Daddles

Here's the link to the light box selection. You'll notice that only Mik and I took it seriously
http://www.woodworkforums.ubeaut.com...ad.php?t=34266

Don't forget, if you want to colour the poxy the same as the timber, you can use fine sawdust ... just a pinch will do.

Sand the stuff while it's still green ie, within a day or two. You'll be amazed at the difference. Fresh paper is a good move too, and some suction on your sander makes the whole job less intolerable (don't be fooled into thinking that anything to do with boats is easy, especially when you combine epoxy and sandpaper )

The other thing is, although poxy isn't supposed to shrink as it sets, it flamin' well does. Like using ordinary putties, leave the fill slightly proud and then sand back. The beauty of poxy is there's no problem with gouging a bit out and having another go if you make a mess of it

And a Bote Cote supplier 10 mins from work? Such luxury.

Richard

Thanks fellas! I will take a pic on Saturday when I am there and post to show what I want to do. The Bote Cote supplier is Trend Timbers near Windsor NSW. They have marine ply as well for sale. What's the difference between gabon plywood and pacific maple marine plywood?

Gaboon (Gabon, okoume) is lighter which is really nice - but it is more expensive

the quality has been really variable over recent years. Look for good faces and few voids along the edges of the ply - voids shouldn't be any wider than a mm or two and maybe one or two a sheet.

Michael

Originally Posted by Daddles

Here's the link to the light box selection. You'll notice that only Mik and I took it seriously

How rude !! I took it seriously..... eventually

Originally Posted by meerkat

How rude !! I took it seriously..... eventually

Someones got to maintain the standards of this forum ... ie, down in the bilge :eek:

Richard

Originally Posted by Boatmik

Gaboon (Gabon, okoume) is lighter which is really nice - but it is more expensive

the quality has been really variable over recent years. Look for good faces and few voids along the edges of the ply - voids shouldn't be any wider than a mm or two and maybe one or two a sheet.

Michael

If you are going to get the gaboon, (from experience) pick the sheets yourself.

Not sure how to find the voids, in one of the sheets I recently got I found a void that was up to 3 mm wide and a couple of cm long. Fortuneately for me where it was didn't impact the end result too much.

Andrew

Originally Posted by meerkat

If you are going to get the gaboon, (from experience) pick the sheets yourself.

Not sure how to find the voids, in one of the sheets I recently got I found a void that was up to 3 mm wide and a couple of cm long. Fortuneately for me where it was didn't impact the end result too much.

Andrew

Good advice if possible. If you can't choose - ask about the quality of ply and make a bit of a fuss (nicely please) asking about voids to the person on the phone.

Then be prepared to (also nicely) ring them back if there are problems - it is possible that they may not have known about them.

Generally if the edges look OK then the rest will be fine too.

If you find a big area of delamination or a big void that was concealed (not that common if the edges are OK) then the supplier won't have known about it either and will be more or less happy to replace the sheet.

MIK

Is anyone familiar with the Epoxy Resin system produced by International (www.yachtpaint.com)? How does it rate against Bote Cote? Seems a hell of a lot dearer.

Are there any issues with using a 2 pack paints over the top of epoxies like Bote Cote? Do I need to utilise an undercoat if the wood is epoxied?

Hi Danny,

In tests years ago now (so may not be true anymore) Bote Cote and WEST were much better able to resist fracture than anything else on the market.

System 3 was a little behind - then everything else was a long, long way back.

If you use one of those three you won't go far wrong.

Regarding undercoats. There is generally no adhesion requirement to use undercoats for 2 pots

(STRONGLY RECOMMEND USING THEM FOR SINGLE POTS - SOMETIMES IF ENAMEL IS APPLIED DIRECTLY OVER SANDED EPOXY IT JUST SITS THERE WITHOUT HARDENING UP MUCH - COATS OF UNDERCOAT PREVENT THIS PROBLEM)

But even with two pots there are very good reasons to use undercoats.

1/ Topcoats are generally quite transparent - so you would need lots more coats of expensive top coat to block the view of the timber grain and any filling/filleting/patching you have done. Much faster and simpler to use coats of undercoat to make the surface an even white (though you can tint the undercoat to get a head start if you want). Undercoat is a little bit cheaper.

2/ Undercoats give you a chance to do a lot of sanding to get rid of imperfections in the hull such as orbital sander scratch marks, the last 5% of epoxy texture/dimpling etc etc etc.

3/ Putting undercoat on a hull allows you to see a lot of gouge and scratch marks you would never see otherwise. Also shows up imperfections on edges if not rounded evenly.

Best Regards
Michael

All,
Finally remembered to take a photograph of the cracks I want to fill. These are in starboard side of the transom. At the widest point maybe 2-3mm apart. From the inside you can see light. I was told just to fill them and repaint the transom. Sikaflesk was suggested however so was Epoxy. I would appreciate suggestions about how to go about doing it.

Darren

Originally Posted by darrenyorston

Finally remembered to take a photograph of the cracks I want to fill. These are in starboard side of the transom. At the widest point maybe 2-3mm apart. From the inside you can see light.

Woudn't you want to know exactly what was going on underneath before deciding how to deal with it?

From the little experience I have had with Sikaflex it would be a mistake to use it to fill cracks like that. It seems to me that Sikaflex is more suited as a flexible sealant under deck fittings, laid decks etc.

More likely that you would -
a) Clean out the gaps and fill with epoxy, plus filler.
or
b) Widen the gaps with a small router and insert this wooden splines, plus epoxy, plus filler.

But I wouldn't be doing anything without a good understanding of how the gaps are forming.

Originally Posted by onthebeachalone

Woudn't you want to know exactly what was going on underneath before deciding how to deal with it?

From the little experience I have had with Sikaflex it would be a mistake to use it to fill cracks like that. It seems to me that Sikaflex is more suited as a flexible sealant under deck fittings, laid decks etc.

More likely that you would -
a) Clean out the gaps and fill with epoxy, plus filler.
or
b) Widen the gaps with a small router and insert this wooden splines, plus epoxy, plus filler.

But I wouldn't be doing anything without a good understanding of how the gaps are forming.

I have been told the cracks are normal movement between planks on a vessel 46 years old in area that's not surmerged. From the inside they are not cracks just gaps towards one end of the plank. The outside looks the way it does as the paint has pulled apart.

Originally Posted by darrenyorston

From the inside they are not cracks just gaps towards one end of the plank.

Are there some framing timbers holding them together inside? What sort of fastenings are holding the planks together? What sort of fastenings are holding the transom planks to the side planks?