Thread: What Glue ?

Richard,
The auto filler is probably used to fill to the odd ding but I agree to fill a seam, split or gaps that may work and need sealing it would be a bad choice. They may also being using a two part epoxy based product so it may not sound so silly.

Looking at the pics the transom (can't see any planking problems) seems to have a split board opening up and the hull planking to transom area is a bit dodgy are there doublers behind that the planking is fixed to. If so for a quick sealing job I would use a 3M or Sikaflex sealer such as 4200 or 291 especially around that tansom there are less adhesive types as well. I think one of your problems may be getting the joints dry and a specific primer may be wise, check the instructions.

I don't understand why you are against epoxy for the repairs, how does the polyurathane paint /varnish make a difference. I don't know casamite but I would be surprised if it was as forgiving as epoxy.

Hopefully the suggestion is appropriate for the job.

Originally Posted by m2c1Iw

Richard,


I don't understand why you are against epoxy for the repairs, how does the polyurathane paint /varnish make a difference.

Hopefully the suggestion is appropriate for the job.

the two paint systems don't mix you can't use two part paints over polyurethane plus i have found when useing polyurethane over epoxy coated ply the paint does't harden properly.

plus the use of epoxy with my illness scares me

the split in the joint of that plank is less than 1mm it just looks worse because the paint has curled back above and below the split. it's not a problem i just want to use the right stuff for the job.

For the record, Sixpence is painted with 2 pack poly over epoxy and I had no problems.

Having said that, I can understand your wariness Richard. I'd go down to the local boat yards and use whatever they're using. If it seems an odd product, ask. The bloke who gives you full and honest answers (as opposed to the one who gives you ######## or ignores you), is the bloke to listen to. Get a good boat yard and whatever they're using will be right for your region - you may find there are climactic or other regional reasons for using a product.

Besides, get a local boat yard interested in your project and you might get all sorts of advice

Richard

Mmm gotcha think I should leave this one to the experts.

The purists will probably come back with a lead based oil putty.

i wasn't clear enough with my reply above regarding the paint

you can't use 2 pack over one part paint systems so i'd rather stick to what alreadys there.

my Yellowtail was done in 2 pack on the hull but i used international toplac over a 2 pack primer/undercoat on the intrior and still now it has not fully hardened.

Originally Posted by honkongphoie

my Yellowtail was done in 2 pack on the hull but i used international toplac over a 2 pack primer/undercoat on the intrior and still now it has not fully hardened.

That's coz you're so close to France and everyone knows that the French stop anything that wasn't made there from working properly

Richard

Generally you don't use fillers on planks except fairing compounds to smooth the surfaces and cover fastener heads. These often are polyester based, though in better yards they'll use rosin and beeswax instead.

If a major divot needs to be filled it's usually filled with wood and then faired. These types of repairs are very common at the hood ends, rub rails, impact sites, etc. They're non-structural, cosmetic affairs that restore the surface of the wood with wood, which is glued in place, then the seam is filled and faired.

A structural repair generally requires a different approach, though wood is again returned to the damage site, typically with a scarf repair. These may be simply fastened or both glued and fastened, before fairing the seam.

So, to answer your question about the gaps you see at the transom, possibly the stem, etc., no, you do not smash goo into these areas and smooth it over. You remove the damaged wood, typically cutting back to known good wood and then "splice" in a scab, Dutchman or other type repair to return firm wood to the area.

Plank seams on a carvel are an altogether different story and these do not get putty either, though the seam is covered with a sealing/fairing compound, to finish it off and protect the caulking, it's not intended to cover big gaps or surface imperfections. In short, if plank seams are narrow enough then they receive caulk. If they are too wide or damaged, they are repaired in one of a few ways, all place good wood in the seam to restore it's width, then it's caulked normally or wedged closed with, you guessed it, more wood.

Primers and bonding agents will solve any paint on paint issues you may have. The best approach is to contact the manufacture of the brand you want to use and ask them about it's capability over what you have. Naturally, they'll recommend their best primer, but if you have some experience with modern paint systems, the reply from the manufacture will tell you what type of system you need to use and you can go about your business.

My understanding of cascamite/polymite is it's use in powdered plastic resin adhesives. This may just be a translation issue as our puddle can get pretty wide at times.

Originally Posted by PAR

If a major divot needs to be filled it's usually filled with wood and then faired. These types of repairs are very common at the hood ends, rub rails, impact sites, etc. They're non-structural, cosmetic affairs that restore the surface of the wood with wood, which is glued in place, then the seam is filled and faired.

A structural repair generally requires a different approach, though wood is again returned to the damage site, typically with a scarf repair. These may be simply fastened or both glued and fastened, before fairing the seam.

So, to answer your question about the gaps you see at the transom, possibly the stem, etc., no, you do not smash goo into these areas and smooth it over. You remove the damaged wood, typically cutting back to known good wood and then "splice" in a scab, Dutchman or other type repair to return firm wood to the area.

Plank seams on a carvel are an altogether different story and these do not get putty either, though the seam is covered with a sealing/fairing compound, to finish it off and protect the caulking, it's not intended to cover big gaps or surface imperfections. In short, if plank seams are narrow enough then they receive caulk. If they are too wide or damaged, they are repaired in one of a few ways, all place good wood in the seam to restore it's width, then it's caulked normally or wedged closed with, you guessed it, more wood.

Thanks Par

i was hoping to get away with just filling and fairing but i want to do it properly so it looks like wood fillets between the planking are the way to go.

can i to save me time jut run my router along the seam with a 9mm bit approx 9mm deep into the plank and fix the new bit in with epoxy goop.
(i know i don't want to use the stuff but in small amounts and as long as i use over the top safty equipment, i now have a full face respirator mask with external air supply, i should be ok)

i'll have enough spare teak to do the above when i remove the sink and cooking area from the cabin and replace that with the helm, unfortunately all in plywood (as i have 18 sheets of the stuff scalfed for the scoter i need to use it)

I'm not sure what you're describing, but it sounds like wedging the seams. This can be done, but you'll need a custom bit or blade and the same material that the planking is made from as the wedges.

A V shaped grove is cut over the seam and a piece of planking stock is milled to the same V shape. The seam coated with adhesive and the wedge pounded into place.

I wouldn't recommend this for a trailered boat as the wet/dry cycling will spit out the wedges in time.

Some planking woods, don't like this treatment as well as others. Generally, the harder the planking wood, the more it will not like being wedged.

If you're referring to repairing the seams, then this is a different process, which can be done with a flat bottom bit or blade.

The seam is reefed out then usually dressed with a hand reamer, but if they're really bad, then milled out with a saw or router. Pieces are milled to fit the plank and provide a tapered seam face. Once they are glued in (on one edge only of course), the boat is caulked as usual.

The usual determining factor is the condition and width of the seams, the age and condition of the planking and the fasteners. For either method to work, the planking has to be solid and well fastened to equally solid and fastened frames.

All this sounds awfully complicated.

Why treat the gaps between carvel planks any different from the gaps between two sheets of ply in a "stitch & glue" new construction?

If epoxy +/- wood flour is good enough for that, why not for carvel?

I thought two pack PU had been used for years over epoxy with no problems, as long as the epoxy has set OK. If you're worried about 2 pack over 1 pack, why not strip the 1 pack off and start fresh? Either that, or use 1 pack again.

Am I missing something here?

Why treat the gaps between carvel planks any different from the gaps between two sheets of ply in a "stitch & glue" new construction?

Plywood is dimensionally stable, carvel planking (solid wood) is not. If the wood isn't stabilized (one of the main reasons we use encapsulation) the movement has to be minimized with thin laminations.

Without encapsulation, the use of epoxy is restricted to glue only and in this role movement can easily tear it (wood fibers attached of course) from a neighboring piece. This becomes an issue once the thickness of laminations get over 18 mm or so. With most carvel builds having relatively thick planks, you'll run the risk of moisture gain ripping out the glue lines.

I will not comment on the 2 part, one part polyurethane or single part over epoxy, as I think a little research will solve the seemly misunderstood aspects of the questions.