What next? Rain on fresh Poly

[Fred Woodward]

I rebuilt and added on to our old back porch/deck a few months ago. The deck is 5/4 x 6 Tigerwood with Ipe railing and a 2 x 6 Tigerwood cap on the top rail. I used "Ipe Oil" on the deck and railing initially. I think it is a BLO/Tung Oil mix from the smell. I do not like how the finish is wearing; seems to be fading pretty fast and is a bit muddy on the topcap though it was put on as a thin seal coat. Finished the deck in early November and knew I would have to apply new finish in the Spring.
The weather has been very nice and dry (Texas) lately so I decided to start working on the topcap today. I sanded down the top cap w 80 Abranet to remove old finish and machining marks; followed with 150 Abranet. Rinse and wipe down with mineral spirits followed by tack cloth. Applied a sealing coat of 40% mineral spirits 60% clear Poly (Minwax). Let it dry for about 6 hours and was in process of applying a second coat of the 40/60 mix and out of the blue, it started raining. Well, they did predict a 10% chance of rain. LOL
It wasn't a very heavy rain but now I have rain water on top of fresh poly on about 15' of on the top cap (total rail cap is about 70'). I know I won't be doing anything with it today, but, what is the prognosis?
Will I need to start over?

[Chris Fournier]

I have built several IPE outdoor projects for myself and clients, including decks over the last 15 years. I am also very fond of your home town and quite familiar with the incinerator that it can be in the summer. I would not recomend using any more than 25% varnish or "solid film" finish in anything that you put on IPE; it will crack and peel very quickly, especially in direct exposure to the sun. Regardless don't go for a build. Honestly the easiest and best looking finish is pretty much just double boiled linseed oil applied as needed. You can slap it on lickity split and the wood just soaks it up looking good as new.

A client of mine had a "finishing expert" refinish the IPE porch that I built for them and despite my advice he used a thick varnish finish. Uh oh it went to pot in months and he had to strip and redo the entire job. It was hard to feel sorry for him especially when he blamed the results on an inappropriate wood selection for the job! I guess that he was a wood working expert too!

[Fred Woodward]

Thanks Chris,
The Ipe on the deck is limited to 4X4 rail posts and upright posts on the covered portion of the deck and the 2X3 lower and upper railing. The rail then has a 5/4 x 3 Tigerwood top with the 2X6 Tigerwood cap on top. I will stay with the BLO on the Ipe. I was using the poly on the topcap, hoping it would get rid of the muddy on the Tigerwood. I'm not trying for a high gloss or thick film finish, just a clear finish with the natural color of the wood. What would you recommend for the deck finish itself on the TW?

[Chris Fournier]

"Tigerwood" is a pretty vague trade name that serves as a catch all for several species of timber that are grown from Brazil to Africa! For that matter, the Ipe we buy is upwards of 8 different species from Brazil.

If the Tigerwood that you have is Goncalo Alves then I would stick to my recommendation of less is more. Look for a good spar varnish locally and I think that this will likely serve you best. I bet that it looks stunning!

[Jim Becker]

Fred, unless the polyurethane varnish you used in your mixture is made for exterior use and has substantial UV inhibitors, you're not going to be pleased with how well it lasts. Further, a film finish isn't really the best choice for outdoor projects like this. A penetrating product made for the task, such as Pentofin or Sikkens will usually perform much better.

As to your specific question...depending on where the varnish was in it's curing cycle, the water could cause marking, etc.

[Fred Woodward]

Thanks again for the help. I purchased the TW from Advantage through the website tigerwooddecking.com; very pleased with the transaction and follow up from Advantage by the way. I have no idea what the exact species the wood is but it matches the flooring I put in our house 2 years ago very well, part of the reason I selected the TW for the deck project. The Ipe, I purchased locally but again, I do not know the specific species of the wood but it all seems to be the same and it is fairing very well with the "Ipe Oil" that was applied in November. Not sure how much actual penetration you get on the Ipe as it is so incredibly dense and tight grain structure but it is doing very well and has a dark chocolate color with no signs of oxidation or weathering. The Ipe Oil specs say it has 40% solids and high UV inhibitors and is a muddy light brown color in the can.
The poly that I used also has UV inhibitors but is a clear finish. I was using it for a sealer on the topcap and stair handrail and was planning to use a higher UV inhibitor content topcoat. The actual decking material will get a penetrating finish material for sure. I'm thinking the TW decking will take the finish better now that it has weathered for 4 months. I know it is a process and it will take some time before it is done.
And Yes Chris, the deck is quite stunning looking; we get lots of comments from our friends and guests about the deck. A lot of work went into it but we think it was all worth the outcome.

As for the damage done by the rain, I see some very small craters in the finish that look like little popped water blisters. There is no milky color or signs that there is moisture under the finish. The first coat was touch dry and I was applying a second coat when the rain started. I will try a light hand sanding to remove the damage and then continue with the topcoat finish.
Thanks again for the help.