What happens when you cut epoxy 50 percent with acetone? 

25 years of wooden boat ownership, repair, and research here. Thinning epoxy with acetone has a few effects. 1 - It does not help with penetration. The acetone penetrates easily into the wood, but the larger epoxy molecules penetrate much less. If you want epoxy to penetrate wood, use a low viscosity or penetrating epoxy such as MAS. Another approach is to preheat the wood to the desired depth, but this will cause the epoxy to set much faster. 2 - The acetone as you noted will outgas through the epoxy leaving bubbles and porosity all the way through it. This makes it permeable to air and water. 3 - Any chemical, e.g. acetone, added to epoxy will change the chemistry. In this case, it retarded the resin/hardener curing reaction. It likely affected the strength as well. A side note: heat, such as a heat gun or a judiciously applied propane torch, will help the epoxy flow out and eliminate bubbles. This is a standard technique on epoxy countertops and floors.

Denatured Alcohol is recommended for thinning of epoxy. Acetone will interfere with polymer cross linking. That is why we use Acetone for Epoxy clean up.

42 years ago we also used the 50/50 process to put a finish on our wood race boats. We would sand the first coat after a few days and then apply a second coat. It made the boat look like a piece of furniture. Fast forward to today and the wood finish still looks good and the wood was protected from the water.

To remove the bubbles in the surface of the epoxy just lightly spray with alcohol. This removes the surface tension and allows the bubbles to escape.

After another week, the thinned epoxy was significantly harder, so it will cure eventually. Also, here's another experiment with different solvents: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-j93uNH8SLNU.html

1) Acetone is hygroscopic, e.g. it attracts water; 2) Acetone can also react with epoxy catalysts that are usually some kind of amine; You should try for instance, xylene or ethyl acetate that will dissolve similar things that acetone does but are way less reactive.

As a retired boat builder I used 10% MEK to mixed epoxy for the first coat over wood with fiberglass, or to bond 2 pieces of wood together. This allows the epoxy to soak deeper into the wood for adhesion. Then the next coats with fiberglass would be 100% epoxy. MEK evaporates faster then acetone, which allows for a faster cure.

I am a woodworker and wooden boat restorer. I start my outdoor and boat wood with Smith's Clear Penetrating Epoxy Sealer (CPES). This is "high octane" stuff--I wear an OGV-HEPA full face respirator when applying it, but it penetrates wood like no other thinned epoxy that I have used. In the world of composite hulls (wood and ply "sealed" with epoxy), boat builders rely on thicker and thicker epoxy to create ugly dense plastic boats that offend the wooden bones that lie underneath. My journey is not complete--more field tests will reveal more findings--but old boats will tell you a lot if you are listening.

A number of years ago, I was doing some laminating with epoxy. Yes, you can thin epoxies with Acetone. But very little is required. Also, there are many diff. kinds of epoxy. I preferred using some with sufficient pot life (45-90min) to tack. The trouble with mixing anything with epoxy is the act of trapping air into the mixture. So I used specially modified mixing machine to accomplish this. Worked very well. But I also added another aspect to the process using vacuum to remove unwanted air bubbles from the epoxy being poured. Acetone is generally used to flash air bubbles from a poured surface using spray bottle. When the exotherms kick in the cure progresses. But thinning the typical, 2-part epoxies affects both cure times and final results, as well as durability. Compounding anything into epoxy during mixing traps air. So the more mixing you do makes it worse. And thinning with any solvent only degrades the balance between the amines and hardener. As I recall, I used approx. 10% Acetone. Then I mixed my compound in a vacuum environment. I could tell you more. But am reluctant to do so on this platform.

I make wooden fishing lures and many people recommend using polyurethane or super glue to waterproof the lures before painting. My preferred form of waterproofing is mixing devcon 2 ton epoxy with a few drops of acetone to make it very thin, then painting the lure with it. It not only makes it waterproof but causes the outer layer to become much more durable. I've found the lures resist dents and abrasions better.

I use Acetone for thinning epoxy resin when have to brush it over non flat surface. Like round ones from wood lathe. But very little. maybe 1 to 15 proportion or maybe even less. Just eyeballing. It does takes longer to cure, but surface is thin, even and glass like. I also leave it in the lathe, slow spinning to keep it even spread until it starts hardening. It will cure faster, if heat it up a little, time to time with a heat gun. Don't overheat it.

Legend has it, the thinned down epoxy is still curing to this day..

Fascinating. Who would have thought diluted epoxy wouldn't be strong as that which was engineered for high impact resistance. I wonder what would happen if you made two batches of pancake mix under similar conditions? The possibility of various test subjects is limitless. Keep these tests coming. 👍👍👍

when laminating to wood, unhardened resin +25-30 acetone, cover with resin and hardener for full amount. Good adhesion.

When the epoxy has flowed out but still liquid, try a hair dryer, heat gun or propane torch with a fan nozzle to draw out the bubbles. Practice a little.

Awsome experiment - Totally explains why I found a completely cured but very flexible leftover in the bottom of my mixing cup that I must have put some acetone in after cleaning a brush maybe 😊

The container of acetone will tell you that thinning at over 10% will cause curing and strength issues. Using TWO coats of acetone-thinned epoxy (while running through a strainer to take out the bubbles) will give you a rock solid coating that looks like glass.

A four year old video but nothing has changed. I built model RC aircraft and used Glow engines/fuel. The fuel was a mixture of Alcohol, 15% Nitro Methane and 18% oil. There are a lot of different brews but this is what I used. The oil tends to get into the wood and soften it over time so I would mix up a batch of epoxy and 50% Acetone. That brew would be slathered on the firewall and anyplace the fuel would get deposited on. The thinned down epoxy would soak into the wood and repel the oil. The blend is still used today.

Acetone thinned epoxy worked for my shifty boot patenting in the 80s

Popular to mix alcohol with epoxy, in engine compartment of model airplanes. But it's brushed on and a couple coats. It allows epoxy to soak in and fill pores in wood.

Since acetone is used for cleaning up brushes and rollers after layups since it completely dissolves epoxy, I would imagine it significantly degrades epoxy in ANY dilution! I personally wouldn't put even 10% acetone to my epoxy. If all you want it to seal in wood just go with polyurethane.

The MEK comments are really good; it's about the chemistry..."You have to respect the chemistry, Jesse." The only other suggestion would be to make a ghetto vacuum chamber using one of the shop buckets from home Depot or Lowe's and then fit your Shop-Vac to it.

Methyl alcohol (methanol) is an excellent thinner for epoxy. Used as a fuel constituent for glow plug engines as used in model aircraft, cars and boats. When doing clean up I find methyl alcohol actually works better than acetone. Methylated spirits which is ~ 85% ethanol and 13% methanol may also work

Very good initial experiment. Now we need to determine the best ratio of epoxy and acetone! I'll be watching your channel with interest 😁

Acetone affects the cross-linking of the epoxy, that's why its soft. Try using Denatured alcohol as a thinner or penetrating epoxy

Thank you. I'm just getting into epoxy reason and I've been curious about the thinning of it. I'll stay with full strength.

I used mostly isopropyl (above 90%) and a little acetone and it helped my clear, aeromarine grade epoxy soak into my fiberglass stuffing in body work. Otherwise it would just run along the outside and down. Has lasted so far about 10 years.

WEST SYSTEM boatbuilding manual used to recommend against thinning their epoxy, on the grounds that it did not improve penetration and had a negative effect on strength.

I watched a guy use 50/50 to brush on a wood lathe turned hollowform that was super punky. I just picked up xylene and resin, going to give it a go with my spalting mapel... I let the fungus go wild, but now my pieces are exploding haha. Thanks for this

If you use acetone with epoxy, pre-wet the wood with acetone first ... Also, you used half the epoxy with the acetone. IMO, if you really want 50% acetone, you should coat twice to ensure a constant amount epoxy for your thickness measurement.

Thanks for the experiment.

I was curious about this, thank you for making this video

I love the empirical test. People and so called experts constantly spout out opinions without any side by side tests when it comes to paint, or just about anything. An interesting side tidbit : I ran into moisture bubbling in lacquer I was spraying on cabinet doors a year ago. I called all the help lines and experts. Only one guitar guy realized that it was moisture getting into my air, despite a recent upgrade to my moisture traps. I first solved the problem by adding acetone to mix. Then I re downgraded my moisture trap which made the acetone unnecessary.

So happy you did this test for us. Always wondered. Thanks a bunch

This is a good experiment! The acetone thinned epoxy resembles a soft vinyl. That alone allows for some creative uses. Since the acetone thinned epoxy is more flexible, maybe there should be a test of its elastic properties. You might have also opened a door to experiment with adding plasticizers to epoxy and noting its properties.

This is probably the plasticizing effect of acetone...These are very small molecules which comes in between the polymer chains and softens them. The polymer chains can then slide over each other...Nice experiment but when you use solvents you have to wait longer until it gets dry.

I added epoxy, acetone, white spirit and turpentine I grew a third arm.

good video. almost of there with the project farm guy!

Thank you for the experiment and for the great care of control factor and observations. It is a greatly appreciated contribution and share. Keep it up

Only use dilution on warm/hot days.. otherwise the mix may not fully harden (ie, stays gummy and weak). Open air (not in cavity repairs) give the best results.

if you are in the boat business and are building a wooden boat it's a good idea to use acetone with your epoxy but not as much as you used this will be a sort of your primer coat that you go over corners angles and curves and all joints the idea is to have the some of it seep into the wood grain joints extra and you let it dry for not 24 hours or 48 hours let it be sitting their for weeks o coem as you work your project they you light scuff or light sand when you are in the final stages in a lot of the project there maybe fiberglass cloth too and that will soak up better with solvents then you come back with the final coatings but we never use epoxy by itself unless we are just doing like tabletop extra all exterior stuf its best to use marine varnish because it moves with the weather epoxy doesn't

We need it to flow freely into v-carved wood so I will be trying this technique. Application will be via syringe.

Looks like a good way to inject resin in area where the fiberglass cloth has air pockets.

i wonder if the titan sub was had its epoxy thinned with acetone?

Ketones CAN be used to thin epoxy IF you are thinning a system with a long room temperature open time. Such systems typically require elevated temparature cure, In such a system all the ketone will have evaporated before cure. Instead of a ketone use a reactive modifier like Heloxy 61 or 68. (butylglycidyl ether family). West already has some modifier in it; it is not a "pure" resin system. Most systems for hand layup will already have some rective modifiers in the mix.

I would be interested to know whether the thinned epoxy eventually hardened after weeks or months.

wonder what would happen if you added superglue to the acetone one??

This was very helpful. Thank you.

Try lacquer thinner, that's what is used (brushed on to make the plywood waterproof and harder) on marine plywood in boat making in the Philippines.

I think the acetone-thinned epoxy sounds about ideal for paint-on/brush-on applications - less bubbles, more forgiving in application time due to the longer curing time window, and a thinner, more translucent finish.

TL;DR: try denatured alcohol We used EnviroTex (that tabletop epoxy from the 80s, you could buy it at the home centers) thinned with denatured alcohol to apply 3/4 oz glass cloth to wooden helicopter rotor blades. We tried several things to reduce the epoxy including acetone, the alcohol worked best. No idea if that holds true for other epoxies. It cured hard overnight and you could sand it the next day. We scuffed the bumps off and sprayed primer/surfacer, blocked and painted. This was in lieu of a traditional aircraft Ceconite/dope type finish the manufacturer originally used in the 50s. Kaman HH-43 Huskie, we remanufactured them from USAF surplus for logging/fire fighting in the early 90s. They were eventually replaced by the Kmax.

The facile delamination of the dilluted provides a noteable warning.

fascinating...it would be interesting to pre-treat the surface with acetone to a degree and then adding the epoxy while being subject to (audio) shaking....

Water affects the setting of epoxy and polyester resins. Gelcoat for example without a special additive will set sticky, but covered with cling-film will set tack-free.

Great Experiment!

To make the epoxy thinner, best to just put it out in the sunlight. Heat is what is needed.

the acetone acted as a contaminant or plasticizer.

Painters often heavily thin primers or other undercoating in order to increase penetration on first coats. Especially good on new wood.

It can keep it from curing properly. That's from someone who was in the Composite business for 30 years.

One comment mentions heat gun. Hopefully not one with acetone added, where the red hot element is exposed closely to the work. Another method for popping bubbles is a flame/torch, but probably would not want to attempt that in the epoxy/acetone method. At least not unless your head and eyebrows were already shaved.

I did a similar with mineral spirits. It made a flexible epoxy. I put some on paper and it became like leather when dried. I think the cosplay community could use it in costume making.

Good experiment👍...... Although, I think you've just recreated the Wally-World brand epoxy, I'm sure it produces the same result 😉

Very helpful!

Works great with denatured alachol

T-10 (xylene), or Napthalene are typically used to reduce epoxy.

Argh, just built a kit car and have the slightest water leak in the roof. I was hoping to thin the heck out of some epoxy and let it sit in the area and wick in ,I was just worried how thin I can go.

would be rather interested to see what would happen with vacuum chamber epoxy mixes poured over, and poured over then vacuum chamber, perhaps it would suck in and bond better and cleaner if after treating..... and perhaps less bubbles in the undiluted.... but still interesting, Thanks.

I did a similar test. The thinned epoxy never hardened to more than silicone like substance which is not satisfactory to me as I need all the rigidity, strength and hardness I can get from my epoxy finish. Deep penetrating sealer - Yes. Surface coating for hard wearing protection - No.

Acetone acts as a refrigerant, slowing cure. Does appear to be softer too.

As i understand it the sample on the left has twice as much epoxy as the one on the right

Have you tried thinning epoxy with ethanol? I heard that it works well and does modify as much the cured epoxy properties compared to acetone.

Interesting experiment

That would work well, with say, a worktop where you'd want some degree of flexibilty

does it matter what brand or type of epoxy with the acetone. also do you think if you had add less acetone, would it be a stronger expoxy?

I found this video very useful. Thanks!

Thank you for this very informative video

I was one of the first 3 people to get West system Meed shipped using 5 gallons in a metal can I have Built about 25 boats with West system Meed and Jan and I were good friends I took Meed to the first Port Townen Wooden Boat festival I am unfortunate to find out about there Passing I worked in a small production Powerboat Shop in Everett Washington back in the (90ty) we did one peace side and bottoms for 26"we took care of the bubbles with gas won and I have never thinned West system My Name is Del Saul and I had a boat Building Co named WOOD FEATHER BOATS Thank you for your youtube peace

I am curious if you happened to save that 50% reduced epoxy sample and check it for cure hardness after a few weeks time? I would like to know if additional cure time results in most of the hardness of an standard mix developing. thanks.

"I'm not going to touch it". Touches it.

Given that individually both epoxy fumes and acetone fumes can cause varying degrees of harm to the human body, what happens when the two are intermixed?

Excellent. Have you tested it on none porous serface

Prob wouldnt be a good idea to pop those bubbles with a torch on the 50/50 side lol

interesting, I would of expected the thinned epoxy to have penetrates much deeper

what about xylene? also if you are bored I cant do it right now but if you could experiment with flex seal and xylene I want to make a thinner for flex seal.. dont know if mineral spirits is good or what but I think they recommend spirits for cleaning and heard people say it's b.s. so any help would be great thanks and big thanks for the video...

It looks like maybe the acetone raised the grain on the wood? Did you try it with alcohol also?

It would be good to try the thinned epoxy over a piece of wood with various paints on it. Will it dissolve other paint products?

Did you do another video with less acetone? Was thinking about putting some in my epoxy to thin it out and help with a slab I'm working on so it will get in the micro holes.

I tried thinning Araldite with acetone and it took about 4 days for it to cure.

Maybe the acetone is still in it ? In case it doesn't shrink over time, could also be good for making gaskets ...

Could you determine penetration depth?

We all use iso-propyl, rubbing, alcohol. 99% works well to thin and evaporates out quickly.

would this be a good way to thin out epoxy for spraying?

Is there a difference in how it stick to that wood ?

What's the point of thinning epoxy. I've used hundreds of gallons of epoxy for various reasons/projects and never once needed to thin it.

if you were trying to be thrifty with epoxy, would you recommend thinning your epoxy this way to make it go farther? or perhaps about a 75:25 ratio? epoxy/to acetate? Great video.

I have to remove an epoxy liner from a fuel tank. Would you recommend acetone or thinner?? Thanks

Can u help me how to make epoxy Hardener Thicks???

what about mono styrene?

Doing an epoxy floor? NEVER thin. Sticky floor forever.

Kills dry rot and termites and leaves rotten wood stronger.