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

Posted by westbrooknh (My Page) on
Fri, Jul 18, 08 at 22:57

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?


Follow-Up Postings:

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

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.

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

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.

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

John, EFC-38?

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

Not strong enough. J

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

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.

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

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.

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

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!)


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