Never Again!!!!!

[Scott Dunsworth]

I am doing the miserable interior sanding. Around the stringers, bulkheads and every other this and that you can imagine. When I built my Penobscot 14 it was even worst because you could not get a sander in most places.

So the next time I build a boat whether or not it is stitch and glue or ply on frame every piece will be epoxied and sanded first before putting them togther.

If every piece is coated and sanded before assembly then there would be very little to do inside before finishing.

On my Belhaven if I would have coated and sanded all of the interior faces except 2 inchs along the main stitch and glue areas I would be only touching up the surface and it would be ready to finish.

The panels would have been coated laying flat, a nice even coat would have been easy to achieve.

I am going to do the rest of the boat this way. I still have the deck the cabin and cockpit tops to do.

I could have saved endless hours of sanding not counting sanding discs and such.

Just something to think about.

Scott

[Charlie Jones]

boy- you learn fast!!

It also uses a tad less epoxy that way too, since you can roll it on in thinner coats.

I precoat and sand EVERYTHING I possibly can before I install. I also PAINT what ever I can before I install.

[warthog5]

The school of had knocks is the Best teacher. You will never forget it. HeHe

[Klaus]

What also helps is to build the boat in the head, well in advance of the physical progress.

When I built my NIS26 I would first figure out the best sequence of putting it all together, right up to the final finish. Not all designers actually BUILD the boat, mine certainly did not as was obvious from the suggested building sequence.

Tinkering with a scale model quickly showed that access to various locations gets progressively more and more restricted, in lots of places it will be impossible to epoxy coat or paint, once the building had progressed beyond a certain point.

I also had the advantage of seeing a part finished boat where the builder did NOT foresee access restrictions, devaluing the whole project due to large uncoated areas in a plywood boat.

Sadly, a boat in progress nearby at present is also heading that way as the builder follows the plans from page 1 to the end in exact sequence without looking and thinking ahead frequently (and not willing to).

Klaus

[Scott Dunsworth]

Actually Charlie I am a slow learner. After building my first boat I was wishing I had took the advice in a clarkcraft cataloge that said that the best way was to coat all of the parts and then assemble. But I got to reading about chemical and mechanical bonds. So understanding that chemical bonds where stronger, I proceeded. And now I am paying the price.

All well after a week of sanding and a hundred discs or so all will be well .

I did get the V berth area sanded out today and ready for finish. Got the other berth done and painted inside.

Going to try to make small projects out of the rest of the work to be done.

Scott

[Frank Hagan]

But I got to reading about chemical and mechanical bonds. So understanding that chemical bonds where stronger' date=' I proceeded. And now I am paying the price.

[/quote']

Sometimes I think the advice we get is questionable, even if it is true. In this case, I think a chemical bond with epoxy being stronger than the mechanical bond is a "distinction without a difference." In both cases, the epoxy bond is much, much stronger than you actually need. So if both are strong enough, and someone had told you that, you could then go on to evaluate the other factors in the decision making process. Like how much easier it is to pre-coat and then rely on the more-than-adequate mechanical bond later on.

I was thinking about this after seeing that Charlie drills a hole, fills it with epoxy and sticks a bow eye's threads into the epoxy. "Strong enough to lift the boat", and here I was thinking I would make the bottom of the hole larger than the top to increase strength, etc.

[Charlie Jones]

Frank- If you REALLY want to make that eye in a hole "hell for stout" put a nut on the bolt, down towards the end of the threads , then shove THAT into the epoxied hole and fill it up with thickened epoxy!!

Ain't EVER coming out

[Designer]

I agree with most of what was said here and I will be doing my next boat as Scott described. As wonderful as epoxy is, you still have to be careful and prep the glueing surface carefully. I went to pick up a half finished Spindrift from a friend who was permanently posted overseas and as I roughly hoisted the boat up onto my roof racks, one gunwale de-bonded for half its length and the other for about a quarter of its length. The epoxy on the boat side was perfectly smooth and shiny and the epoxy on the gunwale side was a perfect mirror of the boat epoxy.

Coating the inside of the hull panels does not make the boat much harder to fold but I would not coat the out side as it does make the panels stiffer to bend.

[Tom Lathrop]

Graham's second sentence should be re-read several times until the meaning sinks in. Otherwise what happens in the next sentence is sure to occur.

Epoxy just not bond well with a cured epoxy coating that has been poorly prepared or, in this case, not treated at all. Pre coating panels is fine but later bonding joints MUST be agressively sanded to get decent strength.

[Charlie Jones]

I'll chime in with a resounding third on that. The surface HAS to be sanded or the secondary bond will not be good. BUT with a properly sanded and cleaned surface you'll get a very good join.

[JeffM]

Re: Graham's mention of difficulty of bending ply with exterior epoxied, that might explain why I broke so may wires and ended up needing one threaded rod to get the bow together, and another to get the bottom to conform its curve to the forward bulkhead. Took days to get most of the daylight out of the seams!