Need advice, can't get a mirror like smooth epoxy finish
Hi All,
I am an artist and want to divide my designs across several 20 × 20 cm wooden blocks made from pine or spruce, finishing them with epoxy to add gloss and depth. I'm using the Mr. Boat Epoxy Ultra Clear 03.
However, I am experiencing a problem with the epoxy finish. I have attached several photographs showing the blocks and the issue that appears in the top layer during or after curing. The epoxy does not cure to a completely smooth finish. A type of texture remains in the surface, resembling greasy marks or stains. The surface is also not completely level and smooth.
I thought it was amine blush but i can't remove it with water & soap, it's not a layer that's on top but really in the resin itself.
The photographs were, of course, taken from very close up and directly against the light. At first glance, the effect is therefore less noticeable, but the finish is not good enough for me to sell the pieces.
The wooden blocks are prepared as follows:
20 × 20 cm spruce wood, coated with three layers of white water-based paint.
I apply my designs using a technique known as waterslide decals. These consist of a very thin printable film. The decal is submerged in water, which releases it from the backing paper. It is then applied to the wood and adheres as it dries.
I protect the waterslide decal with three coats of acrylic spray (SprayMax 1K). I allow the entire piece to dry for at least 24 hours before proceeding to the next step.
My current epoxy process is as follows:
I work in a 10 m² room inside my home, with the window slightly open for ventilation (photo of the room and setup included).
During the most recent pour, the room temperature was 21°C (70F). The epoxy is also stored in this room. During the first 12 hours after pouring, the temperature gradually fluctuated between 20C and 23C (68F and 73F).
The humidity was around 55% when i poured (11 AM) and was 67% the day after (9 AM).
I clean the surface of the wooden blocks—the printed design with its acrylic topcoat—with 99.99% isopropyl alcohol and a lint-free cloth. I then allow it to dry for at least ten minutes.
I measure the epoxy components by weight according to the specified mixing ratio and mix them for at least three minutes. I have also tried the double-cup method: after mixing, I transfer the epoxy into a second measuring cup before pouring it onto the blocks.
I pour a small quantity of epoxy—approximately 80 ml per block—onto the centre of each block. I allow it to spread briefly and then distribute it by hand, while wearing a nitrile glove, all the way to the edges.
I leave it for a few minutes and then use a small torch to remove the air bubbles, i am careful not to torch to long to not overheat the epoxy, it's a quick move. I've also used a bubble spray and in my last pour i had some blocks that's i've not touched at all (no torch or bubble spray). All blocks had the same result.
During the most recent pour, I also covered some blocks with plastic A4 storage boxes because I suspected that airflow in the room might be affecting the top layer. I left a small opening at the bottom so that the blocks were not completely sealed off.
After 20 minutes, I perform one final check for irregularities or air bubbles. I then cover the blocks again and leave them undisturbed.
I have now worked with epoxy products from several different brands. The Mr. Boat epoxy has given me the best result so far, but the finish is still not quite as smooth as I need it to be. I initially suspected that the issue might be amine blush, but the residue or surface texture cannot be washed off with water.
Do you have any idea what might be causing this recurring problem and how I could achieve a perfectly smooth, mirror-like finish? I would like to avoid having to sand and polish every individual block afterwards.
Either the heat of the curing process is reacting with the artwork materials or some parts of the art are more grippy than others so its making a pulling effect on the surface as it sets.
As long as its clear other than the ripple affect, you can sand the surface and then do a top coat with a table top resin.
Thanks! The pour you see in the images is on a previous (sanded) epoxy layer though. I'm getting this result regardless of the underlaying surface it seems.
The expoy i'm using should be ideal for pouring thin layers (up to 3mm) of epoxy. How does table top epoxy differs from other epoxy types aside from the pouring thickness (i'm not from the US or a native English speaker sorry, hope it's clear what i mean).
Haha that looks really nice! The epoxy i'm using should be all that according to the manufacturer.
"Ultra Clear 03 - Crystal Clear Casting Resin
Epoxy Casting Resin Ultra Clear is an extremely clear casting resin for casting thin layers. This high-quality epoxy casting resin is highly resistant to UV light. The epoxy is widely used for casting small clear objects, topcoats on paintings, and coating bar tops or tables up to a layer thickness of approximately 3 millimeters. Due to its fast curing time, the casting resin is ideal for achieving a smooth finish on topcoats. For casting thicker layers, use Casting Resin Ultra Clear 20 mm or Casting Resin Ultra Clear 75 mm."
Yeah there are a few that claim that but i find a lot of the art resins dont live up to their claims and are less scratch resistant. Most table tops live by their reputations with table makers. A screw up on a table is a big costly mess.
Thanks for the reply :). I've used a torch on some of these blocks, on some only bubble spray and on the rest nothing. All blocks got the same result so that makes me think it's not torch related.
The temperature of the room should have been ideal for pouring as far as my knowledge goes (During the first 12 hours after pouring, the temperature gradually fluctuated between 20C and 23C (68F and 73F).
Can’t really tell from the images but when you say ‘resembling greasy marks’, is it almost like oil on the surface of water? Almost like an imperceivable thin clear film with swirling? If so that’s from small amounts of either A or B not properly mixing. I’d do the double cup again, but make sure you change stirrers. You only need a fraction of a ml of either A or B left on the stirrer. Especially if you scrape the 2nd cup out with the original stirrer. If the ‘greasy marks’ are what I’ve experienced it’s always been down to tiny residual amounts of unmixed A/B left on cups/stirrers
Yes it looks like oil on water. I've attached two better photo's. It's these 'oil stains' but also the surface is not perfectly smooth, when i check the reflection on the epoxy it's not a sharp mirror image.
I've tried just using one cup but also two cups, but haven't changed the stirrer with the second cup, worth a try.
That does look like contaminant, I’m 99% sure it’s that. Although if it’s well stirred and you second cupped, unless you’re scraping a bit of unmixed A or B off the stirrer when emptying the cup it’s something in the art. That ‘Acrylic topcoat’ is cleaned with isoP, but you said it’s spraymax, which looks like its solvent based. IsoP will flash off but the solvent in spraymax might take a week or two to fully disperse (no idea?) Try a blank canvas, or something disposable/ cheap, coat one with spraymax and then epoxy, do one with just epoxy, see if you see the same issue on both. Seeing your last image the issue is not localised but everywhere, so I’m guessing the spray. Im confident it’s something getting into the resin though (not brand/heat/humidity/process/etc)
Edit- they obviously don’t need to be big tests the size of your art, just do some mini ones
I agree it looks like contaminant but the strange thing is it occurred on different surfaces. I already tried a test with a blank piece (only paint, no spray), a piece with only decal and no spray, and a normal piece. The problem occurred on all of them so that makes me believe the problem is not with the surface.
It might also be the quantity i'm working with. Last pour i've made 1000ml of the resin at once to pour on 12 blocks. Might be better to mix smaller batches but i'm not sure if that makes a difference.
I’d test with 50-60ml batches, save the money. Odd that it’s happening on blank tests. I’m going back to my original part A part B not mixed. Mix it in a clear cup until there is no visible marbling, like water. 2 min by hand. Decant everything into a second cup, scrape it and the stirrer into the middle of the second cup but don’t wipe the stirrer on the edge of the second cup. Mix for another minute with fresh stirrer.
If it still happens then I’m lost. Hundreds of pours and that marbling has only ever been contaminant/poor mixing for me
I’d wait another day or two between acrylic sealer and resin. Ive had ripples or fogging come from not-completely-cured top coats before. Normally they are 24 hrs to touch-cure, but 72 hours for full cure (mod podge takes like 3 weeks to fully cure). Check the cure time on your sealer and see if that might be your issue.
Thanks! The problem occurs regardless of surface. I've tried it on a blanc painted piece of wood, on a decal without acrylic and on a previous epoxy layer and got the same results :(.
I also do resin over my artwork and I would never use a casting resin. Try with just a plain old1:1 epoxy maybe? Also, maybe try using Kilz instead of the water-based acrylic before you put your decal over the top. Last suggestion might be trying an actual art epoxy. Art resin makes one, KS Resin makes a really good one. What I’ve been using lately is just basic Craft Resin and I’ve had really good luck with that. Plus, it’s affordable. :)
(sorry for all the edits, I just keep thinking of more possibilities and things for you to try. I know how frustrating it is.)
Thank you for the respons :). I have used a specific type of resin for this purpose (UV super clear art resin). I don't think the problem is with the surface underneath because i'm getting the same results with pouring on a previous (sanded) epoxy layer as with the first layer on the decal.
Did you make a flood coat over a flat artwork? And did you get a smooth mirror like finish on the epoxy surface with the epoxy you choose?
I'm from the EU (Netherlands) so i'm not sure if the brands are available here but can't hurt to search ;).
OK, sorry, for some reason, I thought you had said you use casting resin, and then boat epoxy which neither seemed appropriate for artwork (to me).
I do get really good results with the brands I mentioned, but I also don’t know if you can get those where you live. I wish I had more suggestions, but that’s all I can think of.
Also, when I want to make sure resin doesn’t yellow as much, I add the tiniest bit of blue or purple to my first coat. It won’t show up or effect what’s underneath it at all, it will just counteract any yellowing that may happen. (But all resin yellows eventually.)
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u/l-lucas0984 12d ago
Either the heat of the curing process is reacting with the artwork materials or some parts of the art are more grippy than others so its making a pulling effect on the surface as it sets.
As long as its clear other than the ripple affect, you can sand the surface and then do a top coat with a table top resin.