Removal of Epoxy Paint

How much area?

Inside a building?

Are chemicals an option?

Heating and mechanical removal may be the best way.

The best strippers have been banned by the EPA.

The paint to be removed is on the deck of a steel trawler yacht. Surface is of about 30 square meters. Chemicals are an option. Unfortunately I am not able to import these kind of strippers cause they are restricted by local customs. I have written to ICI Paints / Akzo Nobel Argentina (the company that manufactures this epoxy) some days ago, but still got no reply.

Read the instruction on label.

You could try this stuff, it softens it up and then you blast it off with a high pressure water sprayer.....

http://www.hydroclean.com/data_sheets/ht-350.htm

Have you used this gunk, or are you just doing a web search?

Gunk has a distributor down here, but they only sell products for car care like waxes, detergents, etc. I have been searching the local web and found some possible providers... but still got no replies. In the meantime the clock is ticking and the shipyards bill continues growing.... $$$$$

<...the shipyards bill continues growing.... $$$$$...>

That's not CR4's problem.

I'm not sure if I have used it or not.....I'm old.....but methylene chloride is well known as a paint stripper and solvent...and I've used my share...

https://www.osha.gov/SLTC/methylenechloride/

Oh, yes. Me too. Didn't recognize it.

Noxious stuff.

You may have done my day! I´m at my job now and we have some liters of this stuff here. This afternoon I will give it a try... and let you know!

Good epoxy is hard to deal with:

Have you considered to just leave it and build up from there?

Acids won't help. It will just discolor the epoxy in the best scenario.

High Temperatures can destroy the epoxy (flame) and will still leave you a messy cleanup. Depending on the epoxy, hammering with needles could work, but you mentioned that as not effective.

Sanding, grinding works but produces toxic dust and fumes. (also the fire option)

"Good epoxy is hard to deal with:" yes unfortunately, this one seems to be the good one ! The previous owner of my boat seemed to have considered leaving it a couple of times, cause in some places there are 6 mm thick crusts made of epoxy and quartz. I would be more than happy of leaving it, but it is almost impossible to know where adhesion to steel is good and where not: there where areas you almost had to remove it with dynamite, and spots were it fell off showing a big patch of rust!

You can try to knock. It will sound hollow and different where it is loose.

With a broad jackhammer bit (2") and sharp edged, you might be able to cut the bad parts out, considering you'll use new epoxy to fill the voids. Epoxy usually loses grip at the edges, where water seeps underneath. You can have rust there underneath.

Have you tried "dry ice", or even "liquid N2"?

Maybe the temperature differential expansion would shear the bond with the metal substrate and allow you to peel it off. (Or at least make it brittle enough to then use a pnuematic needle tool to shatter it.

Or else you could sail the yacht to the Bahama's or wherever the necessary chemicals are available. Legitimate bussiness expense??

Hi there! The problem is that the laborers who do this kind of jobs in the shipyard unfortunately are uneducated, careless people. Giving them liquid N2 is probably as dangerous as this: http://www.youtube.com/watch?v=Zi92pRbG8ms

I thought soap or more caustic stuff will get into Epoxy!

check this: http://www.polymericsystems.com/images/faq/Epoxies/EpoxyPuttyChemResist(4108-EM07).pdf

Not for Paint but close enough to get you an idea.

If the money clock is ticking proceed with sandblasting which at least gives you a nice finish for the subsequent coating.

Ideasmith, do you want to get me depressed? According to this sheet, Epoxy is immune to everything!!! I expect getting an answer before this weekend, if not I will instruct them to go on with the sandblasting. The problem it has is that, as the epoxy is so strongly bonded to the steel. Getting it off is quite tricky, cause if guys pay no attention, they will overexpose a lot of metal areas to sand or even perforate it!

I have just talked to an Epoxy Guru who locally produces epoxy putty, caulking materials, etc. He strongly recommended NOT to go the chemical way, as these diluents are potentially dangerous and of restricted sale. They seem to need a long contact with the substrate in order to properly work. He said an hot air gun is the best alternative. In his opinion hot air is even better than a propane torch cause it will not burn the paint, releasing toxic fumes. I´ll keep you posted on how it works!

I tend to agree with this approach.

Methylene chloride is readily absorbed through the skin and lungs and is very toxic.

Unfortunately Methylene Chloride has been now listed as a cancerous substance; use very appropriate PPE if you should try to use it. Also it isn't very effective and would be extremely expensive to use.

Try a hard wood floor sander with coarse aluminum oxide sanding disks/belts/pads on it. Use a low numbered paper (lower the number the coarser the paper). The coarsest, #16, #24 and #36 would probably be the best to try first. Use an open grade if there is any choice. Aluminum oxide is the hardest material commercially available for sanding. There are some exotics but very $. Zirconia alumina is also worth a try since it also is aggressive and extremely hard.

Flap sanding disks used with a 4-1/2" or 7" angle grinder would also be a productive and aggressive way to do it, perhaps the most aggressive.

Good Luck, Old Salt

Hi there! thanks a lot for your help! I eventually managed to solve this some minutes ago! (pls see next post).

IT WORKS! After exposing the epoxy to heat for some minutes it gets soft and can easily be removed with a scrape. Tomorrow I will use a butane torch to speed the process up, but well: the problem is solved!

So its all hot air, it is!?

Glad you found a solution!

So its all hot air, it is!? ... yes, it is astonishing! I have used hot air to strip other type of paints, but on epoxy it works even better!

If the paint doesn't want to come off, leave it be, patch it where necessary, and cover the substrate with fresh paint of appropriate type and colour.

What about water jet for paint removal?

OP has tried sand blasting, I doubt water jet would do it.

I do graffiti removal (I don't DO it, I have it done) and power washers are ineffective. Water jets are highly concentrated streams of water used to cut steel, etc. A wide stream would be 10 mm.

Check this out:

http://www.flowwaterjet.com/en/surface-preparation/products/accessories/hydrocat.aspx

That ought to take care of it.

OK, nice find. I wasn't aware of this.

I don't do bridges.

Use "Aquastrip ACB" to strip epoxy paint. Follow the instruction on the label. After stripping, try to wipe clean using Acetone. good luck.

Acetone? I think not.

Try "Aquastrip ACB " It is environmently friendly. Contact Hubbard Hall for the bulletin . Search on Google.

This is the best available method to loosen/ remove Epoxy powder coating and then use Acetone and not before.

There are other toxic materials but it is banned by EPA in USA.

Thanks and I do not have much time.

Dr. Navin PE, Ph.D., D.Sc., FASM

Water jet is used to remove paint from bridges. It's more powerful than sand blasting.

What is not mentioned , is where you are and the regulations you are under, and what you have available, resource wise. Go to the Epoxy links for the material you have, and check with the Military specs of application and removal.. Shot blasting is often used for aggressive material removal, with a high efficiency vacuum system for removal. Using chemicals is very effective, only if you will not face problems with Environmental restrictions. We have used regular industrial heat guns for removal for years, but Enviro regs are slowly moving in on Air Quality (AQMD) restrictions. Whatever you use, please research you material being removed, and use the proper mask materials and ventilation systems required.

I have used with great success"TS3 - STRIPPER ANY MEDIUM WITHOUT METHYLENE CHLORIDE" French products refer. http://www.decapex52.com/documentations-Decapex, for softening and removing stove cured epoxy paints

My option is a STEAM PAINT REMOVAL method, this is the best one to save the steel floor.

And this is the easy way to collect all removed paints.

I've done a project on this, and it has worked for me!

Sulphuric acid will decompose / de-adhere cured epoxy after a few hours. When getting the right dilution in water, be sure to add the acid to the water, or risk a thermal disaster.

Won't it also react with the steel deck underneath it? When the epoxy gets an opening through it the sulfuric will start eating the steel away. Compounding this is that as the acid gets under the epoxy it will be more aggressive towards the steel.

Good Luck, Old Salt

sulphuric acid is not very aggressive to steel in the time frame here

of course you want to use common sense as to where the effluent goes

cleanup neutralization with baking soda would work fine

Having been involved with several sulfuric acid reaction and storage systems, what you're advocating is neither safe nor effective for the removal of epoxy paint. In order to remove the paint the concentration has to be much higher than a weak solution. To be storable in steel the acid must react with the steel to form an iron sulfate layer on the steel. This will only happen at concentrations between 70% and 99.5%, much higher than can be safely handled for cleaning epoxy paint off of steel.

A weak solution is not strong enough to remove epoxy paint, corrodes steel and extensive PPE required. Strong solution will remove epoxy paint but will eat away underlayment steel, requires extensive PPE, high risk to personnel and difficulties with handling this concentration.

http://www.wisegeek.com/what-are-the-effects-of-sulfuric-acid-on-steel.htm

Sulfuric acid is a strong acid capable of responding in many different ways, and the reaction of sulfuric acid on steel can sometimes be contradictory. At certain concentrations, sulfuric acid will form a protective layer on steel and the steel will be fine. Other concentrations will yield corrosion and the steel will slowly deteriorate. With corroding steel, sulfuric acid often forms hydrogen gas, which furthers the corrosion. Low levels of hydrogen gas can cause the steel to groove or warp.

The best reaction of sulfuric acid on steel is that the acid begins to create an iron sulfate layer that protects the steel from the acid and causes no corrosion and little metal loss. This will only occur if the sulfuric acid's concentration is between 70 percent and 99.5 percent. At a concentration in this range, it can be stored in a non-protective and unlined steel case.

As with most substances, the more common reaction of sulfuric acid on steel is corrosion. Regardless of whether the concentration is lower or higher than the safe concentration range, sulfuric acid will begin corroding the steel. The corrosion typically is slow, but very high concentrations may quickly eat through the steel. To hold sulfuric acid at the safer concentrations, a steel case lined with iron sulfate should be used, and the lining should be replenished as needed, if possible.

The use of an aggressive acid on a reactive material is not a safe way to handle this situation.

Good Luck, Old Salt

duly noted

I wish to thank you all for your commitment in helping me figuring out the best method for removing the epoxy coating. Last evening I tried a small scale test using a hot air gun and it worked amazing and unexpectedly well. Today I will go on using a propane torch as it will do even better. Extra care will have to be taken to prevent overheating the paint as if it gets to ignite it will release a black, toxic smoke. Despite there are a lot of other alternatives for doing this job, you probably will agree with me in the sense that the best method or tool for doing it is (not necessarily in this order) the most affordable, easiest to use, cheapest, safest, environmental friendly... etc.

I would definitely not use a torch to remove epoxy (or lead) paint. This will not only release toxic fumes, but you run the risk of starting a fire (especially if the floor is raised and there is dust in the void). See if you can rent a waterjet if you can't afford to buy one. Cheap is not a good thing if the price you pay is with your health and/or your life!

Re: Removal of Epoxy Paint

Dry ice blasting would only be practical for this if you first do what Solar Eagle mentioned. I have tested dry ice blasting for removing Mil Spec paint for one of our contractors who works with the U.S. Navy. Without pretreatment you can only expect about 2 square inches per minute and that is with the most aggressive machine, 230 PSI.

Quick lesson on dry ice blasting:

The beauty of dry ice blasting is that the cleaning media sublimates upon contact and is a dry process, no water, chemicals or solvents. combine that with that it is non-abrasive with a wide range of cleaning aggressiveness and you can clean anything from PC boards and electrical control panels to heavy build up of all types of contaminants.

Dry ice blasting is more of a cleaning tool as it is non-abrasive. In the world of media blasting you have a scale of abrasiveness in regard to media's used. Aluminum oxide being perhaps the most abrasive, then maybe coal slag (or black beauty) with sand being not too far behind. Dry ice blasting is at the other end of the scale and is the least abrasive. In fact it is 100% non-abrasive towards metal.

I have a tentative opportunity to demo cleaning in a ship bilge in the near future. This will be for removal of grease and other contaminants, dirt, soot, etc.

In regard to Lyn's comment about graffiti, dry ice blasting can be a great tool for this however there is a challenge which will also help understand where dry ice blasting works and does not. My understanding is that most, if not all graffiti removal chemical offer limited success and pressure washing makes a mess. I have removed graffiti with dry ice blasting however it leaves a shadow where the graffiti absorbed into the substrate (brick, block, etc). If you apply the chemical (which draws it out of the substrate -typically leave it on for 24 hours) and then dry ice blasting I have been told this is the best practice for graffiti removal. If there is no need or concern about collecting the water (contaminated with graffiti paint) then pressure washing will be far more economical.

I'll be happy to help with any of your dry ice blasting questions or needs.