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Can I stain over Thompson's Water Sealer, or must I strip it?

July 18, 2008

Greetings all,

I'm a newbie DIYer, so I'm not very knowledgeable.

Last year, I built a new PT deck with Doug Fir railings.

I left the PT untreated to let it weather for a year, but I made the HORRIBLE mistake of putting Thompson's Water Seal (the one with wax in it) on the Doug Fir railings.


I washed the railings and deck with Sherman Williams Deckscapes Deck Wash. The color came back nicely, but a white residue was evident here and there on the railings. I figure this must be some of the wax from the Thompson's.

Water is still beading up on the railings.

I tried Deckscapes Stain and Sealer Remover to strip out the wax. The application directions say to apply with a brush, rinse with water, and then apply a wood brightner to neutralize the stuff and lighten the color of the wood.

The Stripper was AWFUL stuff. Some of it dripped on my bare skin and burned it! Not badly, but it did sting.

I tried this on only a small section to see the results before doing all the railings.

The wood did get lighter after applying the Deck Wash after rinsing off the Stripper, but it wasn't that nice reddish Douglas Fir tone anymore, but rather a sickly green, like the old-style cuprous arsenide PT wood.


I'd like to apply One-Time or Ready-Seal to the railings, but I don't want to have to go through the ugly Stripping process if I don't have to, and I certainly don't want to ruin the beautiful color of the Doug Fir.

I already talked with One-Time and they said I would have to strip the Thompson's out.


1. Do you know if I'd be able to apply the Ready Seal without having to strip all the Thompson's out first?

2. If I have to strip, is there something better, less caustic, that I can use that will get the Thompson's wax out of my Doug Fir railings?

3. Is there a product that can restore the original color of the railing section that turned green?


Comments (11)

  • jsmith99702

    Have you tried sanding the railing? That would remove the layer with the wax on it; it would also not be as harmful as the striper, and the color you like will come back just like new. It is wood so you always have that as an option not like the composites out there.

  • john_hyatt

    Thompson product might be good for sealing a creet sidwalk but thats about it. In fact thats what it was made for but some bright market person started pitching it for wood and here we are. They havent been to class action court because they dont lie, all they say is it will bead water.

    Sanding will have little effect because of the penatrating nature of the product. MD 80 will get it off with a lot of work but that stuff is really hot and requires many saftey procedures as you use it.

  • oklahomagreg

    John, EFC-38?

  • john_hyatt

    Not strong enough. J

  • tunaman4u2

    Let us know how you go about this project. Sanding would stink but may be the best. Decks are such a pain.

    Clear sealers seem to be terrible and I've had awful luck with strippers too.

  • brickeyee

    Thompson's water seal is paraffin in a solvent.
    Sanding or replacement with new wood is about the only way to get rid of the stuff.
    You can try pressure washing, but it may not remove the wax enough to allow a stain to be used.
    A solvent based stain would have a better chance of cutting through the wax, but all the VOC regulations have run most of them off the market.

  • Faron79

    Brickeye speaks wisely...

    Sanding is non-toxic, AND you can stain THE SAME DAY...

    Not possible with any strippers....

    In a sense, stripping weakens wood-fibers. Sanding blasts all the degraded stuff away, leaving new, strong wood-fibers that will hold stain evenly.

    (I can't remember the last deck-stripper solution we've sold....!! The sanders roll out the door however. Mainly due to My prodding!)


  • Sonya Wells

    I am building a brand new house with beautiful new knotty alder french doors on the front. Someone said that we needed to seal the doors to protect during the building process with a clear Thompsons sealer. We did that, and now its an awful orange color! I am so frustrated! I wanted to keep them natural looking with the dusty weathered wood color (whitey-grayish). I am so upset that I could cry! What would you recommend?

  • Peter Rutkiewicz

    Tsk, tsk. Bogus advice, poor understanding of products and consumer confusion abound with regard to treating decks, Thompson's WATERPROOFER PLUS CLEAR WOOD PROTECTOR is a paraffin oil product with an effective fungicide antimildew component in an oil based petrochemical carrier that will penetrate wood and carry the paraffin and fungicide into the wood. Read the MSDS before you buy anything that applies with so much labor. There is NO NEED TO REMOVE THE THOMPSON'S TO STAIN OR PAINT THE DECK OR RAILINGS. Follow the directions, You must wait at least 30-45 days (I recommend 6-12 months) before applying another product. The waterproofing nature of Thompson's precludes using a water based product as a stain or paint. Water based deck stains do not hold up on horizontal surfaces with foot traffic and require stripping the deck before every recoating and should be avoided and rejected by the deck owning public. Do any of you have a latex paint on your indoor hardwood floors? Then what would possibly make you think that latex will work outdoors with the wide range of hot and cold, dry and wet, humidity, rain, snow, ice, and mechanical expansion and contraction of the deck boards? Recoat over the Thompson's Clear product the following season with a 100% oil and petrochemical based product, clear or stained, such as TWP, Armstrong-Clark, Penofin (Penetrating Oil Finish). Only use a product that requires a mineral spirit cleanup and NOT soap and water. Quality penetrating oil finishes will soak into the wood right past the Thompson's paraffin if you have waited until it is actually time to treat the surface again. DO NOT USE A WATER BASED STAIN. They are phony paint stains that leave pigments on the surface as a skin that must be removed before any recoat and the removal costs money for chemicals and lots of labor. Moreover, a water based semi-transparent stain will have an adhesion problem with Thompson's paraffin underneath it which a penetrating oil based true stain that does NOT sit on the surface will dissolve and soak past the paraffin, carrying it further into the wood along with the much higher quality truly dissolved wood stains of a quality product. In general, you will have trouble finding a really good deck product in the big box stores. The best products are carried by lumber, paint, fixture suppliers that deal with contractors and tradesmen, not DIY homeowners. Thompson's Clear Oil Based is a good product for initial protection and gives a DIY homeowner time to pick and choose a more permanent product with the color they are looking for. It is possible to make PT SYP, a yellow-green wood when constructed, look like mahogany, chestnut, western red cedar, rosewood, ebony or California Redwood in a single coating with a quality true oil based penetrating stain. You will still need to coat the horizontal surface every year but the vertical rails will last three (except the top surface). The difference in appearance is quite striking when you use a quality professional product. Beware of deck stains put out by a paint company, keep in mind that Cabot has NO MILDEWICIDE, and Consumer Reports rating system is at the DIY homeowner level, not Pro level and does not take into account abrasion on horizontal surfaces and over-emphasizes the "importance" of water based, non-VOC products that are environmentally friendly (and therefore mildew, fungus, reapplication and periodic stripping "friendly", if that's how you like to waste your time). Their rating system is super friendly to the big box stores which carry mostly inferior products and they completely exclude the professional leaders in the deck stain industry. Also, expect to use a quality brush. Rollers and paint pads don't work so well on seams and a sprayer wastes a lot of material and requires a brush or rag to spread out excess material or it will be very tacky and you won't be happy. Several of the best products recommend going over the project with a cloth rag every 20-30 minutes of stained area to get the best uniformity and avoid any sticky spots. Remember that deck product confusion means more gallons of chemicals sold so be a skeptic and "know" what works rather than "trust" advice from inexperienced clerks. Knowledge is power. Confusion is dollars and labor wasted. Good Luck to all.

  • Kimberly Wells

    Thank you, dear person. Thank you!

  • deouss13

    Does anyone know how to actually reach out and chat with people on this link.. I need to chat with Peter, but there doesn't seem to be a way.. My number is 716-307-3330 thanks. Doug

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