Mistakes were Made

We decided a while back that utility room floor would remain un-tiled but we’d add a coat of epoxy for protection and to make it easier to clean. This weekend we thought we’d tackle this project so Saturday was spent prepping, I went over the whole floor with a random orbital sander with a diamond pad to scuff up the surface and to remove any dirt, then swept and vacuumed a few times.

Sunday was the application of the epoxy and it didn’t go as well as I had wished. I’m hoping it’s not a disaster, but we’ll see. Main issue is that the epoxy still hadn’t cured after 24 hours and was sticky in parts. 48 hours later it did seem a little less sticky. This epoxy should have cured in about 6 hours.

So what went wrong, well lots of things really and in order of most severe to least:

• I usually weigh my resin and hardener on a gram scale^† to get the correct ratio, but this time I used the dispensing pumps which should supply the resin in the correct ratio. I’m using West Systems which has a resin to hardener ration of 5:1. One press of each pumps should deliver that ratio and to be fair the instructions do tell you to check this which I didn’t.
• Didn’t tighten the screw caps on the pumps and one of them came apart, fixable but I had to guess how much resin was dispensed whilst trying to fix it.
• I should have mixed the resins in larger batches, using a drill/paddle mixer. This would have helped in the color matching as I was tinting each batch.
• I probably should have used some sort of primer as the porous concrete produced loads of bubbles.
• I should have mixed downstairs so I didn’t have to carry everything down the ladder.
• I didn’t calculate the the correct amount of resin for the job so I had to leave it incomplete. I did manage at least to cover the whole floor but half of this was a very thin coat and you can see the concrete through it.

So what’s next? I’m hoping the epoxy will cure in time and if not the un-cured portions will have to be removed. If it does cure then I’ll go over it again with my diamond pad and knock down all the air bubbles and the re-coat and this time I will mix the whole gallon of resin in one go.

† I did have my scales at hand but they only go up to 500g and I was mixing more than that until the end when the resin was running low and then I used the scales, so at least some of it cured correctly.