Thread: Tri-Sodium Phosphate, strip lathe

Dear members,

Following a lead supplied by our revered Grahame Collins, I'm trying to track down where tri-sodium phosphate can be purchased.

It's made by DAP in the States, and is a powder mixed in hot water that dissolves paint. Apparently you just emerse the part you wish to strip, and wallah, the paint falls off.

I have contacted DAP in the States, and I'm not getting any replies.

Have tried local hardware stores and supermarkets, just get a blank look.

Haven't tried Bunnies as yet.

Any clues?

Regards,

Ken

I seem to recall TSP being used as a disinfectant in plant propagation (orchids)
Not sure if that helps.

Hey Ken, in my previous life I used TSP all the time for cleaning and pre-painting prep on existing painted surfaces. It is sold at paint stores everywhere...kind of an all-purpose household cleaner. I have never seen it strip paint, so maybe Grahame was thinking of something else?

Like gregoryp, I have never seen TSP used as a paint stripper. It is used extensively as a surface cleaner, especially in the metal plating industry in dipping baths as a degreaser prior to plating.

The only effective chemical based paint stripper I am aware of is caustic soda, not the nicest chemical around, but effective in removing most oil-based paint films. It is not so effective on certain water-based finishes. We had a large tank with caustic soda solution (heated) where we dipped all our mixing vessels, used in our paint factory, regularly to remove dried paint.

This link will tell you some more about paint stripping.

BTW, if you decide to use caustic soda, be aware that it will burn your skin, so use long rubber gloves and goggles. Also be aware that you HAVE to add the caustic soda to the eater, NOT the other way around, just like preparing an acid solution for cleaning brickwork.

I'll try and find an MSDS for it.

Edit:

Found it here

Also be aware that it takes time to work, usually 24 hrs, then wash very thoroughly with water.

Further to my earlier post, I searched for a wikipedia listing of TSP which confirms my memory of it. Look up "sugar soap' as well-it is the commonwealth country broad equivalent.

On another note, I have used electrolysis before to remove rust, and this also will slowly loosen paint to the point that it scrubs off with a wire brush. The resultant goop of metal salts and paint residue will be a toxic waste though, especially if it contains any chromium caused by stainless electrodes.

It also destroyed my high quality eBay $39.00 battery charger (

The article re using tri-sodium phosphate to strip paint, kindly researched by Grahame, is here.

http://www.broncosaurus.net/sb10.html

It describes stripping an old South Bend lathe down to bare metal.

Ken

Originally Posted by neksmerj

The article re using tri-sodium phosphate to strip paint, kindly researched by Grahame, is here.

http://www.broncosaurus.net/sb10.html

It describes stripping an old South Bend lathe down to bare metal.

Ken

Ken, could I give you a tip? Don't buy too much of it until you have actually tried it.

I also note that he boils the unspecified strength mixture.

IMHO caustic soda will do a good job for you and is cheap and easy to obtain.

Hi Big Shed,

Thanks for your advice re caustic soda.

What does "IMHO" stand for?

Ken

Originally Posted by neksmerj

Hi Big Shed,

Thanks for your advice re caustic soda.

What does "IMHO" stand for?

Ken

In My Humble Opinion

Some input from my days in Auto industry.

TSP AFAIK will not strip paint. I suspect as mused above, that this was more likely caustic which had this effect.

Where the phosphate comes into play is:

After metal is degreased, (particularly with caustic), you are left with a very clean, and very reactive surface. On exposure to air, this will very quickly develop a thin Oxide (incipient rust) layer. Your subsequent painting goes on on top of this, and the bond to the steel is weak, and can result in poor adhesion, and rust creep in the future.

To prevent this, the clean metal is immediately immersed in a phosphate solution. This forms a very fine coating of iron phosphate on the steel surface. This "passivates" the reactive steel, and protects it from oxidation. It is also a strongly adhering crystal layer, and provides a very strong bond for the future primer and paint system.

regards

Originally Posted by Alastair

Some input from my days in Auto industry.

TSP AFAIK will not strip paint. I suspect as mused above, that this was more likely caustic which had this effect.

Where the phosphate comes into play is:

After metal is degreased, (particularly with caustic), you are left with a very clean, and very reactive surface. On exposure to air, this will very quickly develop a thin Oxide (incipient rust) layer. Your subsequent painting goes on on top of this, and the bond to the steel is weak, and can result in poor adhesion, and rust creep in the future.

To prevent this, the clean metal is immediately immersed in a phosphate solution. This forms a very fine coating of iron phosphate on the steel surface. This "passivates" the reactive steel, and protects it from oxidation. It is also a strongly adhering crystal layer, and provides a very strong bond for the future primer and paint system.

regards

Spot on

Den

Alistair,

Thanks for your advice. You mention that once the metal is cleaned, it is emersed in a phosphate solution. Can you suggest a brand name that I should purchase?

After emersion, is the part then rinsed in water, or will the primer go straight onto the phosphated part? If yes, do you let the phosphate go dry?

Does Prepsol have the same effect?

As you can tell, I still have a lot to learn about painting.

Ken

Phosphoric acid is what you're looking for here.
I have a brand of rust remover called Ferropro from Triton Paints. It's a 30% solution of phosphoric acid.
You might also do a search for Naval Jelly .

Correct, it is phosphoric acid that does that. TSP is a base like caustic soda.

Hi all
I was surfing and found this if it helps at all'
<If anyone ever needs to strip the paint from their HF lathe, acetone is
speedy quick. Just wet a paper towel, leave it on a painted surface a few
minutes, and the paint just lifts right off. The original Tap Magic comes in
a distant second, but it will do it also. Of course if you DON'T want to
remove the paint, acetone is maybe not such a good clean up solvent.
Grinding on the lathe does more (and different) damage than I expected. Now
where _did_ I leave that alcohol?>

HF is Harbor Freight,fellas not Hare & Forbes, as I found this some where on a yank board and its been in my screen tray for a day or two.Who knows maybe it will only work on HF paint.
Don't think I will be using Tap Magic any time soon either,not at $40 a tin.

have a good one
Grahame

Grahame