Thread: 1960's seacraft restoration

All the ply is in good condition except around the bow where it meets the keel. This is where a lot of the oil was concentrated, i've sweated most of it out with the heat gun and taken the bulk of the discolouration away. Its all still solid ply, hasn't gone soft or fallen apart. The timber strip that runs along the gunwhale and chines, what is this called? What type of timber can they be made from and what is the correct method to make/attach this strip? My plan now is to ascertain how to make new strips for the chines, remove the existing chine strips and sand back the surrounding areas. Then seal with epoxy from chine to chine, transom to bow, and lay a glass sheath over this area. Then fit the new chine strips and continue from there. Would this be an appropriate order of doing things? What type of finish does the ply have to be to get a good interface with the epoxy? I've just sanded with an orbital so far, with an 80 grit disc i think. I planned to hand sand with a finer paper before applying epoxy, but any advice on sanding methods and what grade paper etc would be greatly appreciated. Thanks!

Chris

Chris you seem to be doing well there, and the ply looks in good order. You ask a few good questions, and I'll leave some of them for 'them wot noes better', but since you're waiting for an answer or two, here goes. The strips on the chine (external chine logs?) are probably best replaced with hardwood ('KD'), or maybe oregon. It'll be interesting to see how the plywood edges look under the old strips. Attaching the new strips could be done with temporary screws, removed after the epoxy cures, and then the holes filled. That assumes that the log under the ply is good enough to hold the screws against the pull of the strip. You might want to leave a stainless 316 or silicone bronze screw at each end to help stop a split developing. Pre-drilling is essential at the ends.

Make sure that you really need to remove the old strips though...I guess you should, but if they are well-attached, and if removing them would cause damage to the ply , I wonder....
As to sanding, since you will be 'glassing you don't need to go very fine. Your 80 grit is terrific for what you've been doing, and 120-then (maybe)180 would be as fine as I'd go because it is crucial that you get good penetration and adhesion of the epoxy to the wood. On really oily wood, sandpaper may tear the fibres and it will all look woolly, so it may need to be sealed then sanded further.

Whether you glass before or after fitting the strips might be debated by others who know better than me...I'd be inclined to glass over the strip, even if it means joins, because the strip becomes part of the hull then and will not be tempted to invite moisture into nasty little unseen cracks. These joints then get faired into nice lines and every layer of epoxy or paint can be used to improve the contours as well as the impermeability of the hull.

One other thing, the oil residues might be worth attacking with a detergent, as long as it's rinsed and dried well, because the oil might stop the epoxy bonding with the ply.

Hope that's helpful
Rob

On oily or resinous wood, I seem to remember reading a recommendation that the area be
swabbed with a non-residual solvent like alcohol to remove any remaining surface oil,
allowed to flash off, then epoxied before more oil surfaces.

Expert comment please ? as I have no experience of doing this whatsoever.

cheers
AJ

Has Chris set some sort of record for the fastest growing thread? Particularly from a new member?

Richard

Thanks for the replies Rob, Aj + Richard! Is there normally a lot of activity on this forum? I am just greatful for all the help and interest. What kind of wood is KD? The chine strips are in good condition, but there are a few sections damaged by the trailer guides, moisture has entered and damaged the timber. They are glued, screwed and the holes covered with epoxy. Wooden moulding at bunnings has the same cross section, I'm not sure of what kind of wood it is. Would it need to be green or dried to fit the curve of the hull? I'd prefer to glass the hull then fit the chine strips, so they can be replaced without touching the glass. I like the idea of using alcohol to remove the surface oil, anyone have any opinions on this? I'll finish taking off the strips and use them as a template, then clean up and assess the chine ply etc. Then I will source a place in Perth to get bote cote epoxy, glass mat and ply. I'll seal with epoxy, lay a strip down the keel, then glass mat in 2 sections (port and stbd) from keel to chine, overlapping onto keel strip. Then I will start making the chine strips. Does this sound about right?

Chris

"You need to put something on it, that will draw up the oil . It can be sand, flour, cornmeal, powder,cat litter, paper, anything that draws the moisture in. Clay might be a good idea, or make a mixture of baking soda and cornstarch and water,and put it onto the spot. The more it dries,the more oil will dry up with it. Then wash the spot with some dawn dish soap,after the application of whatever you choose."

Martha Gardener ?????

Put your apron on and give it a go.

Nick

Nick sounds like someone who's done it

Chris KD is a generic name (stands for kiln dried) in Victoria at least for a number of native eucalypt hardwoods that might be Mountain Ash or other species (sometimes even called Tassie Oak but only some of this actually comes from Tasmania), milled and dried and sold machined into boards and moldings. Moldings in Vic can also be from pinus radiata (avoid this for boats I think), Meranti or a few other imported whitish hardwoods of unknown (to me) species. The KD is all durable, strong and good to work, but can be splintery if not handled with understanding. Some of it looks a bit like English Ash, but is more rot resistant than that, behaving more like oak in the presence of moisture. For bending just look for straight-grained stuff without much figure, ideally without much grain run-out too.

Your strips might be mendable by grinding, planing or routing off the damaged bits and grafting new wood into the gap (watch out for screws etc) and that's why I don't mind putting the glass over the top. Localized replacement is a lot quicker than replacing a whole length.

I reckon your glassing plan of operation looks great. Because you've got sealing issues and will be putting on the 'pox before glassing you'll have no worries about the wood starving the weave when putting the glass on a dry surface. The mat is a lot easier to lay without a sticky surface under it. (In my opinion)

Yes Richard..mmm maybe we've all caught a virus instead of a thread...

Thanks Utey and Rob! I'll see what suits me best to help draw out the oil. You may be on to something Rob, the chine strips as a whole are in good nick, and I can just remove the bad patches and graft some good timber in with epoxy. Will also help me when laying the glass, as a kind of border or boundary for the glass mat. I'll fully sand the chine strips and see what kind of material I have and decide from there. I will definitely need to replace the gunwhale strips though, as well as the framing around the transom. More sanding and I will post evidence of what I find over the weekend.

Chris

On another thread around here in recent months, I remember discussing removing oil from soaked planking. You may wish to do a search.

Kitty litter will pick up the bulk of pooled oil, but will not draw much out of the wood. Heat will force some out as it expands, which can be mopped up or drawn off with a vacuum. Alcohol will lift a little, but not much, acetone would be a more effective choice, mopping up as you work.

What works very well is steam. I have this handy, dandy portable steamer (Scunci Steamer) that was my other half's. She bought it to clean the grout lines in tile, but found it way too much effort. It makes steam in a few minutes and supplies it through a flexible wand with different tips. Man it works great at bending small pieces of wood, moldings trim pieces, lifting loose paint, etc. It also will dramatically raise the moisture content of the planking in your boat, which will cause the oil to literally float out of the wood (the oil floats on water thingie). This is then mopped up and other wise treated as surface contamination. Steam also leaves the wood sanitary, killing mold and rot spores. It's moisture content will return very quickly to previous levels, where you can apply epoxy or what ever to seal the area.

Don't use mat in your 'glassing efforts. You're going to use epoxy, which doesn't need nor is desirable to use mat.

If you have an inner chine log, the piece on the outside of the hull is just to protect the end grain of the planking and act as a splash rail. If this is the case, you can round over the planking along the bottom/side planking joint and apply cloth right over the joint, further sealing it from moisture. You can attach a new or repaired splash rail if you want, over this sheathing.

Gunwale (rub rail) lumber should be dense hardwood, preferably one that is known for toughness and rot resistance. The splash rail on the chine should also be fairly tough, though it will not see near the abuse the rub rail usually does. Transom framing is usually hardwood or especially dense softwood (like my exwife's head).

In all honesty, applying a cloth sheathing to this hull will jack up the effort and costs of it's repair a good bit. You may consider just applying three coats of epoxy, paying special attention to end grain areas then paint 'er up good. A thin, light weight cloth sheathing will offer some abrasion protect, but you're not going to be dragging this old gal over rocks or sand bars, just on and off the trailer. You may want to save the cash for a couple more carbs and just clean and seal her up, then paint.

Thanks for the reply PAR!

Firstly, I have made a decision on the order I will do things. I will finish sanding below the waterline, and remove any bad timber in the chine strips and ascertain if they are repairable. I'll also sand the transom and then hull from chine to gunwhale, back to bare ply. I'll then make some timber stands for the keel to rest on, and flip the hull the right way up. Then I will properly sand and clean up the interior of the hull and bilge as best as possible, taking my time to do a good job and remove any gunk, and also using the heat gun on the timber keel and bilge ply to remove any excess moisture and oil. Its going to be a time consuming job sanding in between all the frames (is that correct terminology?) but i need to open up both sides of the ply so that it can breathe and dry out properly. I don't want to epoxy the outside of the hull, only to find there is still excess oil soaked on the inside of the hull. I'm not doing this to a deadline, so i can take my time and the hull will benefit. Once this is done, i'll sprinkle saw dust through the bilge and let that sit for a while, help absorb anything else.

Once i'm happy that its as dry as practical, i'll flip it upside down again, use acetone on the oil affected areas and epoxy them. Follow that up with 3 coats of epoxy.

As for the glass- There are many small nails securing the plywood hull, and I see these as places where moisture can enter the ply, all it needs is a crack in the paint/epoxy. I want to lay a glass sheath for abrasion resistance, and also because it makes the hull below the waterline, one uniform surface. All that needs to happen is too much weight the wrong way when floating onto trailer, or to hit something in the water and it will breach the paint/epoxy coating. With the glass sheath, I have that extra added protection, and hope that the hull will go for longer before needing attention again. I'm not worried about the weight or cost, i'd rather spend another few hundred dollars in epoxy and glass for that extra confidence.

One question i have- what are the differences in using glass matt as opposed to woven fabric? And why should I use woven?

Thanks!

Chris

WELL!

The plot thickens. I've been busy sanding the hull all evening, and removing the strip screwed into the keel. I am indifferent about the condition of the ply. From the chine inwards about a foot is all good solid crisp ply. A foot on either side of the keel is still solid strong ply, but it is quite impregnated with engine oil, even though I have removed the bulk of it. It doesn't sand very well, not falling apart but has a very slight furry-ness to it. Even though it is not rotten and is still very solid, I can see issues with the epoxy not taking to the ply, and delamination later on. I got underneath the upside down hull and had a look at the bilge area, and the heat gun has not only brought oil to the surface on the outside of the hull, but also in the bilge area, and there is still a lot of oil inside, soaked into the ply. I think i would just be "band-aiding" if i tried any means of removing the oil from the outer ply veneer for application of epoxy. Just out of curiosity, plywood with oil trapped internally, and sealed on either side with epoxy- will this rot or soften or lose strength over time? How does the oil affect the plywood?

I am looking towards removing the ply from chine to chine so that I can take a better look at the keel and frames. If they are ok, then re-sheet the ply bottom and save a lot of hassles down the track. Any opinions? I am still deliberating. I assume i'd lay a single sheet of 4-6mm from transom to midships on either side of keel, then laminate 2 sheets of something thinner to compose the curve of the bow.

Chris

Before you start ripping out plywood, try the steam trick, it works very well.

There are some things I'd like to clear up. Plywood doesn't "breath" like regular solid lumber, nor does it "need" to breath like solid lumber. The outer layers of veneer, the parts of the plywood that you see, do breath to some degree, but very little as it's so thin and bound by a glue line on the opposite face. This same glue line also will prevent oil from getting to the internal veneers of the plywood. Of course end grain exposure, voids and other defects that provide a path for oil into the interior veneers is a real and likely possibility, given enough time.


You can apply epoxy over oil stains and oil soaked wood, if it's dry. Naturally you don't want to apply epoxy if you can wipe the surface with a clean paper towel and come away with oil, but if you can wipe the surface and not get oil on the towel, it's very probable that you're safe to coat with epoxy.

I'd also be hesitant about ripping up bottom planks wholesale to fix this problem. The framing on this boat looks fairly light and it a lot easier to install bottom planking when there isn't a deck and furnishings installed. Consider a scarffed in repair along the keel, before taking the bottom panels off. In a painted, 'glassed plywood boat, you'll never know this type of repair has been made under putty and paint. It's a lot easier to do and you will not opening another can of worms.

What kind of worms? Well, it would be nice if these sort of things came apart as easily as they went together, but they don't and most of the time you break things as you learn how to remove fasteners, remove planking, etc. and this can lead to a bottle of heart ache.

Thanks for all the help PAR. Whats worrying me is I will be applying glass and epoxy to the hull, which is only going to soak into the outer layer of veneer on the ply. This means I am relying upon the strength of that original glue line between the outer veneer and next ply down.



In this photo, you can see the transom area of the bilge. I am confident that I could get the outside of the hull in a good enough state for the epoxy to take, but not so confident about the inside of the hull. Even if i did try and sand every nook and cranny between frames inside the hull, i won't be able to get every last bit of gunk out, let alone oil. This leads me to think that I wouldn't successfully be able to seal the inside of the hull with epoxy? Will acetone attack the glue that is used in the plywood? If you think steam would be the best way to remove more oil from inside and out, i'll go see what I can find at the local hardware store. Eagerly waiting your reply PAR!

Chris

Oh hell man, that ain't so bad. I thought it was oil soaked, that's just a little staining. Granted the resolution isn't great, but I can see wood.

Steaming works wonders. Acetone can suck out oil too (actually it dissolves it and you mop it up). Given enough time, the oil will air dry enough to coat with epoxy.

I don't know where the little woman got her tile grout steamer thing, but it works great at jobs like this. It's pictured below.



The glue that holds the veneers together will hold on better then the fibers of the wood have strength, if it's good quality marine plywood. In other words, the wood will fail, not the glue that binds the veneers together, even oil soaked (okay, if you leave a piece of plywood in a barrel of oil for a few years don't hold me to it, all right)

The same is true of epoxy coating. Even though each has just a grip on the veneer face (actually epoxy soaks in, but the WBP plywood adhesives don't), they are so strong, that the wood fails before the glue gives up.

No, acetone will not attack the WBP glue used in the plywood (okay, again, if you soak it in a barrel of acetone for a year . . .) Barring any terrible industrial incidents involving acetone related disasters, you'll be in good shape. You could always light a match, which will rather quickly eliminate your concerns about acetone contamination, not to mention residual acetone (or eye brows for that matter).

Then again, do you really need to epoxy seal the inside of this boat? The epoxy will help seal the wood from moisture (and attack from acetone laden paper towels), but it will not improve the strength of anything nor offer much abrasion protection. Think of the money you'll save and the effort in applying the goo. A good alkyd (oil base) paint or a single part polyurethane (alkyd or acrylic) will be much less trouble, will offer pretty, easily maintained colors, good protection from flying drops of wayward water, though might not like acetone incidents as well as an epoxy coating, so avoid sailing near these industrial areas if you can.

You must remember this boat was designed for an alkyd paint system as it's surface protection and has faired pretty good, no small thanks to some of it's previous owners. Can it be made better with epoxy? Yep, sure it can. It'll cost more and will take more effort, but you'll get a noticeable return on the investment. Is it necessary? Nope, not at all. She'll be just fine without all the goo in a can stuff, given a reasonable amount of care. The boat will also be slightly lighter then an epoxy, sheathed version and by some folks way of thinking, better for it. These people would have you think of it as putting a bikini on a 300 pound woman (eeewwwww), but I don't take myself that seriously (I hope it doesn't show) and can find a happy place for a 300 pounder in a string bikini.

In other words, you can gussy her up as much as you like, but she is what she is and you shouldn't be ashamed to show it. Protecting the outside from abuse is a logical course (epoxy and cloth), but don't go nuts man, just get her squared away and splashing around in the wet stuff again, all the while remembering what she is, a plywood runabout with porch and patio enamel on her flanks.