Need advice on refinishing 1940's vintage mahogony boat hull

[Dueller]

Wood is good but varnish has taken on a slightly clouded apperance. How do you refinish it where the grain shows through and eliminate cloudiness. Complete stripping? Sanding? Chemical removal of varnish? Don't want to damage or discolor wood.

[Joeaksa]

On airplanes we do a chem strip of the old varnish to get down to the bare wood. Assuming that this might be a way to go on a boat but its a bit larger than doing a wooden prop!

[Jim Bremner]

Man, I wish I had this problem!


I would assume sanding.

What engine does this boat have in it?

Pics?

[Tim Hancock]

Are you sure it is varnish that is cloudy and not epoxy? Alot of guys have gone to epoxy encapsulation with varnish on top for UV protection. There are pluses and minuses with all wood boat finishes.

[Dueller]

Originally Posted by Jim Bremner

Man, I wish I had this problem!


I would assume sanding.

What engine does this boat have in it?

Pics?

Its a 17ft ChrisCraft dual cockpit inboard 6 cyl flat head. Cool little boat

[Racerbvd]

Originally Posted by Dueller

Its a 17ft ChrisCraft dual cockpit inboard 6 cyl flat head. Cool little boat

Post pix, I have to restore my Lewis Craft, when It was stored at the farm, it was moved to the barn that had a bad roof and now needs a lot of work

[Dueller]

This model but not quite as nice as this one

[Dueller]

Originally Posted by Tim Hancock

Are you sure it is varnish that is cloudy and not epoxy? Alot of guys have gone to epoxy encapsulation with varnish on top for UV protection. There are pluses and minuses with all wood boat finishes.

OK, tim...gonna really show my ignorance. Its a friends boat..how do I determine if its epoxy? How to strip if it is? If is just varnish how do I strip?

TIA

[pwd72s]

Damn, that's gorgeous! Owning one would be fraught with financial peril, I'd think. Such is the case with many pretty things.

[VINMAN]

Jim,send into me. I,ll do it for ya. Might take me 30yrs or so,but I'll get it back to ya when I'm done.

[GWN7]

Sanding...if it's epoxy or varnish the safe way to remove without damaging other parts of the boat.

Cloudy parts can mean the varnish is breaking down. A light sanding with 400-600 grit and recoat with marine grade spar varnish should bring it back. It might need several coats. Follow the directions on the can.

[GWN7]

I used this to protect the new planks for my scafolding last year.

[intakexhaust]

Neat boat. Reminds me of a buddy who had one with a straight 8 Packard flat head motor. Fun summer water skiing behind that solid runabout. A labor of love and no doubt you've been on the old boat sites for expert opinions.

Is the cloudiness in spots or the entire hull? If its yellowing, thats varnish aged. If in spots or specific areas, the cloudiness appearance might be a telltale from water stain in the wood itself. I would think if thats the case, you would strip just that area down, re-stain and then varnish again.

Used both chemical and sanding, both will work but you probably will get into the wood. The chemical stuff is messy and don't like it. Prefer sanding in grit stages. Obviuosly you don't want blotchy or mis-matched tone so you have to keep the grain pores as even as possible.

Without knowing what condition the entire hull is in but if I was to redo one they have some terrific chemicals to consider, far exceeding varnish. Probably most owners stay with the old way but the latest two part urethane's and sprayed (lethal - so heed all pre-cautions) are excellent. The stuff sets up fast and hand touch within 20 minutes but let it sit an hour, scuff sand and re-coat. Repeat a third time and you have a beautiful depth to show off the grain.

[Tim Hancock]

Originally Posted by Dueller

OK, tim...gonna really show my ignorance. Its a friends boat..how do I determine if its epoxy? How to strip if it is? If is just varnish how do I strip?

TIA

FWIW, I have little experience in working on wood boats but I researched them extensively several years ago as I was looking to buy/restore or build a replica mahogany runabout. Originally these boats were simply varnished with multiple layers of spar varnish that every so often needed a good sanding then revarnishing.

For at least the last 10+ years, some folks have been epoxy encapsulating these boats after replanking them on both sides thus preventing water from soaking into the wood to prevent future rot and to eliminate the need for soaking the bottoms (to get the wood to seal back up after putting them in the water after they had been stored on trailers each winter). This epoxy encapsulation method only works well if the entirety of both inner and outer surfaces of the wood is well coated/sealed with epoxy. If water gets past the epoxy in places, it stays there and causes rot as the wood cannot breath. Epoxy is damaged by UV, so after epoxying, it still typically needs a spar varnish applied on the exterior surfaces that has UV protection in it.

Another popular refinishing technique involves coating/sealing only the bottom with a 3M product (I can't recall the multiple digit 3M product number) and then just refinishing the sides with old school varnish.

Your friend should really contact the PO and find out who refinished/restored the boat last to find out what technique/products were used.

These old boats are too nice IMO to risk botching up the finish with the wrong products.

[Rot 911]

Originally Posted by Dueller

OK, tim...gonna really show my ignorance. Its a friends boat..how do I determine if its epoxy? How to strip if it is? If is just varnish how do I strip?

TIA

Find a area that is not easy to see. Get some denatured alcohol on a rag. Rub it on the surface of the wood. If the stuff dissolves it is varnish.

[MT930]

Originally Posted by Tim Hancock

Are you sure it is varnish that is cloudy and not epoxy? Alot of guys have gone to epoxy encapsulation with varnish on top for UV protection. There are pluses and minuses with all wood boat finishes.

West System Marine Epoxy

I have repaired a few boats with this, I use it for many things around the house.
Friends who are boat builders turned me on to this stuff. It's amazing customer service / tech people are very helpful if you have questions boat applications are 90%of the business. The web site is outstanding Lots of boat porn.


Epoxy by the Leading Epoxy Manufacturer | WEST SYSTEM Epoxy

[Tim Hancock]

Originally Posted by MT930

West System Marine Epoxy

I have repaired a few boats with this, I use it for many things around the house.
Friends who are boat builders turned me on to this stuff. It's amazing customer service / tech people are very helpful if you have questions boat applications are 90%of the business. The web site is outstanding Lots of boat porn.

I have built two airplanes with it along with a plywood rowboat for the pond and many other smaller projects. It is the ONLY epoxy I ever use. That said, it does not fair well when exposed to direct sunlight hence the need to either paint over it or varnish it with UV blocking spar varnish.

Good spar varnish is tougher to find these days.... Hardware store varnish does not contain the good stuff any more and is lucky to last a year outdoors.

[intakexhaust]

Wood is always tempermental depending on its environment. Like someone mentioned above, if the wood can't breath and moisture sets in, it starts rotting. So many products are out there but who knows what the longevity is. Some of the early epoxies have ruined hulls from seperation and one could only imagine the extra work involved repairing or restoration. With an investment in one of these classics, I would certainly make a phone call to the pro's. These guys are local to me and interesting to visit.
Fox River Valley Boat Co.

[fritzgator]

if epoxy, chemical followed by sanding. Varnish, heat gun &scraper...followed by sanding. if you need inspiration, Vintage Race Boat Shop ,some tech articles and good links to other stuff. I frequent this place alot,just cool. The Vintage Hydroplanes. We used to race in the Ross B ,back in the day, Dueller. Vintage boats, talk about a slippery slope,darn near vertical! Good luck.

[Zeke]

Originally Posted by Rot 911

Find a area that is not easy to see. Get some denatured alcohol on a rag. Rub it on the surface of the wood. If the stuff dissolves it is varnish.

I think you're thinking of shellac. Varnish will get tacky with lacquer thinner. I use alcohol to clean it. If it's epoxy, hardly anything will soften it including MEK.