TSP - yes or no ???

[Ether Jones]

Why do some paint manufacturers recommend washing wood with TSP, and others explicitly say DO NOT use TSP?

[m Ransley]

who says dont use tsp

[Tom The Great]

Just a guess,

Many people don't want to use TSP, and don't use it correctly. So were ever you don't have to, I guess paint manufactures are willing to brag you shouldn't.

Just a guess, and TSP prep-hater. ;)

tom @

[Phisherman]

Some states (in the US) prohibit the sale of TSP due to environmental concerns. TSP is a very strong detergent and it is particularly effective in washing walls and outdoor things (furniture, siding, decks, etc.). in general wood should not be "washed" with a water-based detergent. It makes the fibers swell, and then when it dries you have a rough surface that needs sanding.

[George E. Cawthon]

Trying to be environmentally correct is one reason. Also TSP is supposed to be more difficult to wash off than the silicate washing products and if you don't wash thoroughly, the paint adherence is adversely affected. Not my experience, but maybe I use a lot less TSP than some people.

[George E. Cawthon]

UMM, don't you think the OP is talking about washing painted surfaces? Name a state that prohibits sale of TSP. Some may regulate the sale, but I doubt that any prohibit the sale.

[Ether Jones]

Shouldn't unpainted wood be washed before painting? How else are you going to remove the dust and dirt?

Every paint can label I've read says you should wash the wood to remove dirt and dust.

Some say even clean new wood must be washed to remove mill glaze.

But what to use? I've heard TSP will interfere with paint adhesion if not thoroughly rinsed off. But if the wood absorbs the TSP solution, how can you thoroughly rinse it off?

In such a case, would it be best to thoroughly soak the wood first with clear water, and only then apply the TSP (or other detergent solution)?

Are there any chemical rinses which could be used AFTER washing to help rinse away or neutralize any remaining detergent, so it doesn't interfere with paint adhesion? What about oxalic acid for example?

[Ether Jones]

I've seen at least one paint can label that explicity said NOT to use TSP. I'm quite sure of this, because it caught my attention. I didn't get the impression it was an environmental issue, but rather a product performance issue.

But I've looked at so many paint can labels lately I don't remember the brand or product name. If I come across it again I'll make a note next time.

[Ether Jones]

Why are you a TSP prep-hater? What are the issues that concern you? Any tips on how to do it correctly?

[zxcvbob]

BTW, you should look for "trisodium phosphate", not "TSP". Some unscrupulous company is selling... I think it's sodium carbonate; under then brand name "TSP".

Read the label. The fine print will tell you what's in there.

HTH, :-) Bob

[Ether Jones]

Why do all the paint can labels tell you to wash the wood, and many explicitly tell you to use TSP (which is obviously water-based) ?

If you don't wash the wood, how are you supposed to remove the dust and dirt and grease and wax (old wood) or mill glaze (clean new wood)?

[Ether Jones]

I think you're talking about "TSP substitute". I don't think TSP substitute is sodium carbonate (washing soda). I think it's sodium metasilicate. Big difference.

It is my understanding that sodium metasilicate is a slightly less effective cleaner, BUT it rinses off more easily leaving no residue to interfere with paint adhesion. Can anyone confirm/refute this?

[George E. Cawthon]

You are absolutely correct! Any real paint store will have both products and confirm what you said.

BTW, if you use TSP, you should not put it down your drain but poor it on your lawn or garden. Dilute it if the concentration bothers you. That way your lawn or garden benefits from the phosphorous and the stuff stays out of the sewer system and streams.

[George E. Cawthon]

Wood should not be washed if a smooth surface is wanted or you are not prepared to sand afterwards. In most cases a light sanding (no washing) is all that is needed.

[m Ransley]

I dought any manufacturer of regular paint says dont use Tsp, and you cant of course remember who said it. Tsp will only affect gloss if not thoroughly rinsed. Mill glase, now you worry to much. Dust, just dust it off. Not all wood should be washed, if you use Tsp just rinse well with very clean water. Tsp has been the norm for cleaning wood for 50-60? years.

[Tom The Great]

I long time ago, I learned about TSP's amazing powers. We would steal some off out ELT's to clean bilges. We had to add very little relative to the amount of water.

Well, because I know of TSP's powers, I tend to rinse extra hard. Causing me to wipe down walls over and over, since the littlest amount of TSP could interfere with paint adheasion.

So, I preferer not to use TSP, and use better paint, or sand down the surfaces to give the paint bite, and remove dirt.

later,

tom @

[Tom The Great]

Many I'm ruled by my parinoia's :)

I don't like washing wood, with water, but cleaning wood with items like vacuuming and tack clothes. Water can cause the grains to lift up uneven, and give the wood a 'bumpy' feeling. Also, not liking to use TSP, I have a hard time thinking I could remove 100% of TSP used on bare wood.

So I try to sand, vacuum, and tack cloth where needed.

later,

tom @

[Ether Jones]

course remember who said it.

No, I can't, but I've still got some more paint shopping to do, and I'll keep an eye out for it. I'll post the specific brand and product name if I come across it again.

I doubt the correctness of this statement. Everything else I have read indicates that TSP affects the paint's adhesion, and can result and premature paint failure and blistering.

Mill glaze apparently is a big issue for stains. Maybe not so much for paints?

[George E. Cawthon]

I presume you are talking about a house or wood construction outside. In cabinetry and furniture construction and new interior construction, there is no need to wash new wood. Woodworkers don't wash wood, or if they do they sand afterwards. Water on raw wood has undesirable effect including raising the grain and warping. If it is old construction is should have been painted or some type of finish applied, As a result, washing doesn't affect the wood (except in small spots where the paint has worn or flaked off, and those places should be scraped or sanded).

If there is grease on old wood, you might want to consider replacing the wood, but if you wash it, you need to let it dry thoroughly and then sand. If you have little spots that need washing, just wash those spots.

To be more definitive, we need to know what you are talking about washing. In general, dirt or dust is removed by wiping with a damp cloth. Washing wood to get rid of mill glaze is just plain stupid. The only reason to get rid of the glaze is to improve adhesion and you do that by lightly sanding with 220-400 grit paper for painting.

Yes you can neutralize TSP if you want. TSP is a base, that is why it is slippery (slippery is caused by dissolving the oils and your skin). So to neutralize it your guess about using an acid is correct. But, just use vinegar not oxalic acid.

Be careful what you read on the instructions of paint cans. The manufacture has reasons for what he puts on the can (mostly for adhesion purposes), but may not care about some things that are important to you. A good book on painting and other finishes is far more likely to provide useful information. For example, a good undercoat can be slapped on just about anything including your hands and it will stick. But you don't want to put it on globs of mud or something that will show through.

[Ether Jones]

It's an 8-year-old exterior wrap-around porch with white cedar decking and stairs, previously oil-primed and latex-topcoated.

There's a 200 square foot section (including stairs) that's in bad shape. Large areas (as big as a postcard in some cases, or bigger) are blistering (both paint and primer) revealing large patches of weathered wood beneath (light grayish-brown).

I don't mind paying top-dollar for a quality paint if I just knew what to buy and how to prepare the surface properly.

Sanding is out of the question; I don't want the mess, or the dust in my lungs.

I was leaning toward power-washing, but you (and others) have said don't wash bare wood, is that correct? (Or is this situation an exception?)

What options does that leave? Scraping? I could do that, but how effective would it be? (Should I use a heat gun or just try to get the stuff that comes off easily with just mechanical scraping?). And how do I get rid of the ground-in dirt, if I don't wash it? In your previous post, you mentioned wiping with a damp cloth; does that advice apply to the situation I described?

If I wash it, should I use just clear water, or TSP, or TSP substitute, or something else? If I use TSP, should I use an acid rinse to get rid of the residue?

Lots of questions I know, but that's what I'm trying to figure out.

I don't mind touching it up every spring. What I don't want is large areas of blistering that leave the wood unprotected.

Do you have a favorite book in mind which you have found to be well-written and accurate, that you could recommend?