Methyl Ethyl Ketone Peroxide - Revision history

Advance: /* The amount of catalyst used can vary depending on the 'thickness' of the Polyester resin mass */

2026-01-13T17:20:11Z

The amount of catalyst used can vary depending on the 'thickness' of the Polyester resin mass

Advance: /* Cleanup */

2026-01-13T17:17:34Z

Cleanup

Advance: /* Old Catalyst Pressure Hazard: Always Open Bottles Away from Face */

2026-01-13T17:16:39Z

Old Catalyst Pressure Hazard: Always Open Bottles Away from Face

Advance: /* Old Catalyst Pressure Hazard: Always Open Bottles Away from Face */

2026-01-13T17:16:01Z

Old Catalyst Pressure Hazard: Always Open Bottles Away from Face

Advance: /* Old Catalyst Pressure Hazard: Always Open Bottles Away from Face */

2026-01-13T17:15:39Z

Old Catalyst Pressure Hazard: Always Open Bottles Away from Face

Advance: /* Old Catalyst Pressure Hazard: Always Open Bottles Away from Face */

2026-01-13T17:14:59Z

Old Catalyst Pressure Hazard: Always Open Bottles Away from Face

Advance: /* Make sure to tighten the cap sufficiently */

2026-01-13T17:13:20Z

Make sure to tighten the cap sufficiently

Advance: /* Cleanup */

2025-09-18T02:36:00Z

Cleanup

Advance: /* Splashing */

2025-09-18T02:34:11Z

Splashing

Advance: /* Catalyst Measuring Syringes or Beaker */

2025-09-18T02:31:50Z

Catalyst Measuring Syringes or Beaker

@@ Line 25: / Line 25: @@
 ===The amount of catalyst used can vary depending on the 'thickness' of the Polyester resin mass===
-As an example, if you have 1/2 quart of resin in a 1 quart can, and you use 2ml of MEKP from a syringe, the resin will cure to a solid mass, although it may take overnight. This is a very small amount of MEKP. Because the resin is in a large mass, (i.e. you are curing the resin in the can itself) you are able to use a smaller amount of catalyst. On the other hand, if you try to brush or spray the same amount of resin & hardener to a thin film coating, it will not properly cure. In order to cure that same 1/2 quart of resin brushed to a thin coat, you must use 5ml of MEKP.
+As an example, if you have 1/2 quart of resin in a 1 quart can, and you use 2ml of MEKP from a syringe, the resin will cure to a solid mass, although it may take overnight. This is a very small amount of MEKP. Because the resin is in a large mass, (i.e. you are curing the resin in the can itself) you are able to use a smaller amount of catalyst. On the other hand, if you try to brush or spray the same amount of resin & hardener to a thin film coating, it will not properly cure. In order to cure that same 1/2 quart of resin brushed to a thin coat, you must use perhaps 5ml of MEKP.
 To put it simply, if you are curing a thick mass of Polyester resin, you are able to use less MEKP. Thin films will require more. In general, 1% is a recommended amount of MEKP. But, this nuance of resin is important to understand. You can use smaller amounts of MEKP in thicker masses of resin to get an equivalent cure. Be careful not to confuse this with the epoxy we sell where thick masses of epoxy resin are not possible to be cured (it will exothermically react, i.e. generate steam and overheat).

@@ Line 22: / Line 22: @@
 ===Cleanup===
-Of all the chemicals we use, the most unpleasant to cleanup is MEKP, so try to avoid spilling it. You can spill resin, or acetone and it will clean relatively easy, but MEKP is more corrosive to the environment. So please take extra care with MEKP. I use plastic totes to hold MEKP containers and beakers when working.
+Of all the chemicals we use, the most unpleasant to cleanup is MEKP, so try to avoid spilling it. You can spill resin, or acetone and it will clean relatively easy, but MEKP is more corrosive to the environment. So please take extra care. I use plastic totes to hold containers and beakers when working.
 ===The amount of catalyst used can vary depending on the 'thickness' of the Polyester resin mass===

@@ Line 36: / Line 36: @@
 In my case, I was using a brown glass bottle intended for chemical storage (which has a tighter seal), not one of the plastic bottles we sell.
-In general, always open bottles away from the face. This is a rule of all liquids, whether it is soda, milk, or catalyst.
+In general, always open bottles away from the face. This is a rule of all liquids, whether it is soda, milk, or catalyst. And always wear goggles.
 ==Images==

@@ Line 32: / Line 32: @@
 I have seen an MEKP bottle leak, if the cap is not 'fully tightened'. This is just something to be cautious of. By examining the inside of the cap, you will see it makes a plastic seal around the bottle. If the cap is slightly loose - you may get a leak - should the bottle be tipped on its side.
 ===Old Catalyst Pressure Hazard: Always Open Bottles Away from Face===
-There is a chance that the catalyst can generate pressure when stored over time. It may also be more likely when it is exposed to air, or recycled. In any case, when opening any bottle with an air tight seal, always open it away from your face. I had a bottle of catalyst pop, like a bottle of soda when I opened it the other day. I was only wearing glasses (not goggles) so this could've been dangerous, although it was not facing towards me. In my case, I was using a brown glass bottle intended for chemical storage (which has a tighter seal), not one of the plastic bottles we sell.
+There is a chance that the catalyst can generate pressure when stored over time. It may also be more likely when it is exposed to air, or recycled. In any case, when opening any bottle with an air tight seal, always open it away from your face. I had a bottle of catalyst pop, like a bottle of soda when I opened it the other day. I was only wearing glasses (not goggles) so this could've been dangerous, although it was not facing towards me.
 In general, always open bottles away from the face. This is a rule of all liquids, whether it is soda, milk, or catalyst.

@@ Line 32: / Line 32: @@
 I have seen an MEKP bottle leak, if the cap is not 'fully tightened'. This is just something to be cautious of. By examining the inside of the cap, you will see it makes a plastic seal around the bottle. If the cap is slightly loose - you may get a leak - should the bottle be tipped on its side.
 ===Old Catalyst Pressure Hazard: Always Open Bottles Away from Face===
-There is a chance that the catalyst can generate pressure when stored over time. It may also be more likely when it is exposed to air, or recycled. In any case, when opening any bottle with an air tight seal, always open it away from your face. I had a bottle of catalyst pop, like a bottle of soda when I opened it the other day. I was only wearing glasses (not goggles) so this could've been dangerous, although it was not facing towards me. To be clear, I was using a brown glass bottle intended for chemical storage (which has a tighter seal), not one of the plastic bottles we sell.
+There is a chance that the catalyst can generate pressure when stored over time. It may also be more likely when it is exposed to air, or recycled. In any case, when opening any bottle with an air tight seal, always open it away from your face. I had a bottle of catalyst pop, like a bottle of soda when I opened it the other day. I was only wearing glasses (not goggles) so this could've been dangerous, although it was not facing towards me. In my case, I was using a brown glass bottle intended for chemical storage (which has a tighter seal), not one of the plastic bottles we sell.
 In general, always open bottles away from the face. This is a rule of all liquids, whether it is soda, milk, or catalyst.

@@ Line 10: / Line 10: @@
 ===Splashing===
-What tends to happen to me, is that a syringe will splash when mixing small amounts of MEKP with resin. Any MEKP splashing on the skin should be rinsed off with water and soap. It will give you a light chemical burn (you will feel it after a moment), and that will go away after cleaning. Try to predict and avoid situations where it will splash around. Pure MEKP is reportedly more dangerous than the diluted one we sell.
+What tends to happen to me, is that a syringe will splash when mixing small amounts of MEKP with resin. Any MEKP splashing on the skin should be rinsed off with water and soap. It will give you a light chemical burn (you might notice it after a moment), and that will go away after cleaning. Try to predict and avoid situations where it will splash around. And absolutely avoid getting it in your eyes. Pure MEKP is reportedly more dangerous than the diluted one we sell. Ultimately, I find it's not so hazardous to the user, when I have goggles, but it can make a mess where you are working.
 ==Fire Hazard==

@@ Line 18: / Line 18: @@
 {{MixingTable}}
 ==Tips/Tricks==
-===Catalyst Measuring Syringes or Beaker===
+===Catalyst Measuring Syringes or Beakers===
 You may want to consider using [[Catalyst_Measuring_Syringes]] or beakers when dispensing MEKP. For a gallon, I tend to use a 100ml beaker. For a quart, I would use a 10 or 20ml syringe.