Oily Wood

Hi Guys

After years of patching up the bottom of my boat I decided it was time to remove the bottom ply and redo it.

The bottom ply has rotted due to rain water but between the chine and the first bottom batten.

So I have cut out the ply almost down to the skeg where it is full thickness but there lies another problem.

Due to oil spillages and leaks from the engine, (inboard) the ply near the skeg has soaked up oil.

i doubt that any glue will stick to oily wood and I need advise as how to get the oil out. For example will a standard degreaser be suitable or is there a preferred glue for this application.

Or, will I never be able to obtain a good bond between the old ply and the new and will have to put up with the seepage.

Thanks for any help.

Poida

 

In my near vicinity are a number of weatherboard homes that don't hold paint very well at all. Reason being they were built following the war, in a time of acute material shortages, and the builder(s) decided to substitute sump oil for the red oxide pigmented linseed oil, which was a common coating of the day. If paint can't be persuaded to adhere, something that has to carry a mechanical load is less likely to. I'd be inclined to experiment with solvent and lots of rags to try and de-oil it, then test a small area with your glue, but you'd hardly be confident about it.

 

A solution of hot water and lye works.

 

NaOH ? Don't forget the gloves !

 

I agree, it is corrosive.

 

"Sugar soap" ( Trisodium Phosphate ?) is useful for cleaning greasy surfaces, I don't know how effective in this application though. But it does not affect adhesion of paint to surfaces it was used on, which may also apply to adhesives. Sugar soap is certainly a lot less alkaline than caustic soda, but in higher concentrations will attack skin. It is much more effective in hot water.

 

Thanks Gonzo

The lye had me stumped, so I had to google it, and it what we call caustic soda.
Certainly means gloves, a face shield and get the wife to do it.

Poida

 

If you do get lye on your skin, have some vinegar around to neutralize the very nasty effects. If there's one thing the movies taught me, it's this...

 

I would use carburetor cleaner spray on it, several applications. this is a solvent designed for petroleum products and will cut through the oil, and it is thin enough to soak into the wood. when you are done take a heat gun to it to soften the oil soaked deep in the wood, and than apply several more treatments of carb cleaner, wiping up with a white paper towel. keep doing this until the paper towel comes away clean.

Than I would apply dishwashing liquid and hot water. this has a very powerful grease cutting element to clean your greasy pots and pans. Powered laundry detergent and hot water also work well for cutting grease. this will also remove any residue of carb cleaner. rinse very well with very hot water.

allow the wood to dry out and it should be good to take paint or epoxy. simple and mostly non-toxic.

 

I am going to be the contrarian here and say that all of these methods will dilute and thin the motor oil and allow it penetrate deeper into the wood. They will remove a lot of it, but will it be enough for a truly good bond? I doubt it. If we were not talking about the hull I would say go for it, but what happens if the bond fails on a dark stormy night 25 miles offshore when you and your kids are on board? Is that a chance you want them to take? But it is your call all the way.

Why not contact System 3, West Epoxy, MAS or other epoxy manufacturers and see what they suggest?

 

I deal with oil soaked bilges frequently enough and what really works is to emulsify it, then draw it out. One of the best sequences I've found is to apply kitty litter all over the area first, which will draw out an amazing amount. Let this sit for a few days, then vacuum it up. Next is Tide laundry detergent (add a little water), scrubbed into the surface with a stiff brush, which will bust up the petroleum molecules pretty good. Suck this off with a shop vac, then heat the area with a heat gun, which brings more oil to the surface, where you repeat the process. I've found Tide seems to work best for some reason, maybe how alkaline it is. Once you've gone through a few cycles of this routine and the surface is dry, epoxy or epoxy primer will not have issue with it. Acrylics possibly, but not alkyds or epoxy, neither of which mind a little oil in their matrix.

 

I would be careful when considering some of the suggestions put forth when using a very strong liquid for getting rid of the oil. There is a chance that the solvent/diluent that you use could reach the first glued veneer interface and begin to affect the glue between the layers.

There are a couple of different avenues here and while there might be more than two, I have always went on the premise that there are diluents, which merely mix together and dilute the more viscous material (say an oil will mix with a thicker grease so you have thinner grease) and solvents that affect the chemical make up that will destroy the grease structure and make the surface almost grease free ( tricholorethaneIII, methanol, toluene etc)
methanol and toluene are used as the main components of a product called Brakekleen by CRC, which was designed to be sprayed on brake disc, drums to remove any grease from the friction areas. Highly volatile they can have some health issues when used in a non-adequately ventilated area, (like a boat bilge) these liquids kill oil and grease.
TricloroethaneIII is the best but you also have to be careful not to have any welding happening in the area as it can produce a lethal gas.

If you have an oily spot and spray it with Brakekleen the oil completely disappears.

But there is a good chance that using this type of solvent close to a glue interface might cause delamination.

I would also be concerned about providing heat close to the glue interface as was suggested

 

Part one of two part teak cleaner is good for oil removal. Best to use both parts of the cleaner. Soap residue from part one ,in the wood , promotes mold, rot. Part two of the cleaner is an acid and restores PH


Trichloroethylene is a very powerful grease, oil remover.

Be careful if you use it..

 

Brake cleaner might be worth a try. I frequently use it on rigging components to remove grease and assembly paste prior to inspection.

 

Rather than playing with Brakekleen, which I use frequently, I usually go for the actual chemicals. For the novice looking to remove some oil, I don't recommend they run down to the local Ace Hardware and grab a gallon toluene or xylene, both of which are easily obtainable, though some success can be had with these chemicals or the brake cleaner, as Barry points out you can also have other issues, not to mention to toxic nature of them.

The trick is to make the oil removable, then draw it out. It'll float on water, if you don't break the extremely long molecular chain down too much. This is the trick, then suck it out with absorbents, promoting movement with heat and wet/dry cycles.

Solvents seem the logical choice, until you've done this a few times and realize the issue is worse, not better. I've seen oil spots spread all over a bilge, just by the use of solvents, busting up the petroleum molecule so baddy it doesn't float and it just weeps further into the wooden substrate.

Get the area dry, really dry (kitty litter), then scrub with a particularly alkaline substance (Tide, trust me), suck this off and repeat the process. Light staining will be removed on one or two attempts. Heavy staining will leave the stain, but the wood will be clean enough for paint, heavily saturated areas will require a few days of this process, but eventually you'll get it enough oil out that the surface can dry for top coating.

I've opened up too may 60 year old powerboats, with oil soaks garboards, to try other methods. My usual course is to suggest the garboards are done, but some clients can be insistent, so you work with what you've got. For what it's worth, both toluene and xylene are compatible with epoxy in small amounts, but not so much the melamine or phenolic glues used in plywood.