Woodworking/epoxy help please

[R Q]

I am building an outside bar on my deck. Using a cedar plank. I used this as my resin first coat and it feels like it has grit in it so I deduced that it was from the fans in my shop spreading dust but then realized it's air bubbles maybe...?

My final coat will be this

Which is supposed to shield it from UV rays and such.
This is the bar

But the resin didn't smooth out as I would have hoped and it's gritty and wavy as you can see in the reflection in this pic...

Now I still have the System Three Gloss coat to go on and I will sand with some 220 or 400 or these cool new steel wool pads I found before final application but I would like for this to be smooth as glass.
FYI this is the underside of the bar so it's kind of practice.
Thanks in advance.

 

[skyhighZJ]

@cgm147

 

[Falko]

If they are air bubbles, you can go over the surface quickly with a propane torch right after you lay it down. The heating of the air causes the bubbles to pop.

 

[Fabrik8]

What was the shop temperature? I'm guessing it was too hot or there was too much airflow (fans), either of which can cause the cure to be too fast before the resin has proper flow-out. The amount of flow-out that it needs achieve also depends on how you apply it, and at what thickness. If it's hot, and you're working it around a lot after applying it, and it's starting to cure, there's not much you can do. If you haven't already, you may try putting the epoxy in a shallow tray (paint tray liner, foil roasting pay, etc), instead of a deep cup. This will help dissipate any exotherm heat from the chemical reaction, which will slow down any curing that is happening before/during application. You want curing to occur on your piece, not in the cup before the epoxy is applied.

You should figure this out with test pieces under the same ambient conditions, else you could make a lot more work for yourself during finishing of the actual part. Depends on how much epoxy you want to level out with abrasives, etc. It's always a good idea to use the scrap resin on a test piece while you're doing the other piece as well, because then you have something to poke and prod while it cures instead of your important piece.

I don't know the chemical composition of that product, but if it's been really cold at some point (or is really old) it may have some amine precipitation, which could be the cause of the grittiness and the cure problems. Probably just dust though, from somewhere.

 

[R Q]

What was the shop temperature? I'm guessing it was too hot or there was too much airflow (fans), either of which can cause the cure to be too fast before the resin has proper flow-out. The amount of flow-out that it needs achieve also depends on how you apply it, and at what thickness. If it's hot, and you're working it around a lot after applying it, and it's starting to cure, there's not much you can do.

You should figure this out with test pieces under the same ambient conditions, else you could make a lot more work for yourself during finishing of the actual part. Depends on how much epoxy you want to level out with abrasives, etc. It's always a good idea to use the scrap resin on a test piece while you're doing the other piece as well, because then you have something to poke and prod while it cures instead of your important piece.

I don't know the chemical composition of that product, but if it's been really cold at some point (or is really old) it may have some amine precipitation, which could be the cause of the grittiness and the cure problems.

Shop temp was 80-88 during the process. I followed directions and painted the first coat hard into the grain at a thin coat. Then gave it time and added thicker coats to get...thickness... It didn't smooth out as it said it would.

 

[Fabrik8]

Shop temp was 80-88 during the process. I followed directions and painted the first coat hard into the grain at a thin coat. Then gave it time and added thicker coats to get...thickness... It didn't smooth out as it said it would.

Were the coats adequately cured before adding the subsequent coats, so you weren't mixing fresh resin with resin that was starting to crosslink?

That's a fairly high temperature, see my advice above for using a shallow pan. Mix the two parts thoroughly in whatever container, then pour into shallow pan to increase surface area and control the exotherm.

 

[Mac5005]

When I did our bathroom, the epoxy instructions were specific about the temp of the mixture before pouring. Also had temps not to exceed and to stay above while pouring.

Propane torch or heat gun to get the bubbles out.

 

[R Q]

Were the coats adequately cured before adding the subsequent coats, so you weren't mixing fresh resin with resin that was starting to crosslink?

That's a fairly high temperature, see my advice above for using a shallow pan. Mix the two parts thoroughly in whatever container, then pour into shallow pan to increase surface area and control the exotherm.

No the first coat wasn't cured before adding the second, that's probably where I messed up, also I did work out of the mixing cup. It says I have an hour working time and can recoat without sanding in a certain amount of time also. My resin in the cup never got tacky or thick so it wasn't trying to cure but I will try your suggestions. Thanks

 

[Mac5005]

No the first coat wasn't cured before adding the second, that's probably where I messed up, also I did work out of the mixing cup. It says I have an hour working time and can recoat without sanding in a certain amount of time also. My resin in the cup never got tacky or thick so it wasn't trying to cure but I will try your suggestions. Thanks

The epoxy I used gave a time window for adding the flood coat over the seal coat. I think it was like with 1.5 hr or after 24 hrs. Don’t quote that, but along that idea.

 

[R Q]

The epoxy I used gave a time window for adding the flood coat over the seal coat. I think it was like with 1.5 hr or after 24 hrs. Don’t quote that, but along that idea.

I looked thru the directions for that info but couldn't find it so after sanding it down, I'll be fine to redo the bottom and then move to the top with my newfound knowledge! I'm going to go to their site and see if I can find that info though before I move to the top.
Thanks for the help from all!

 

[McCracken]

I used Total Boat epoxy and mine came out very smooth. Also, did you use a heat gun or propane torch to pop all the bubbles as they rose to the surface? It looks to me that it cured fast (wavy). You sure you got the mix ratio right?

 

[R Q]

I used Total Boat epoxy and mine came out very smooth. Also, did you use a heat gun or propane torch to pop all the bubbles as they rose to the surface? It looks to me that it cured fast (wavy). You sure you got the mix ratio right?

Mix ratio was dead on, I got some of those measuring cans that have marks for all the different mixtures. I think I just added my second coat too soon. I didn't know the heat gun trick so will do that next time too.

 

[R Q]

I looked at the data sheets for the System Three epoxy resin that I used and there is no stated limit on application, only a minimum temp which is 50 degrees. Curing time, Gel time, and tack free time are all at 77 degrees F. It's 90 in my shop now so will do some sanding and wait until it cools to reapply.
Mix Ratio by Volume 100:50
Mix Ratio by Weight 100:43
Total Solids 100%
Mixed Viscosity 380 cps
Minimum Application Temperature 50°F (10°C)
Tensile Strength, psi 7,800
Tensile Elongation at Break 8%
Flexural Strength, psi 12,000
Flexural Modulus, psi 375,000
Compressive Strength, psi Yield 13,000
Failure 26,000
Coverage See Product Usage Estimations Chart
Gel Time @ 77°F (25°C) 60 Minutes (100g mixture)
Tack FreeTime Thin Film @ 77°F (25°C) 24 Hours
Full Cure @ 77°F (25°C) 72 Hours

 

[No fries]

RQ
Keith S. has been playing with resin for a few years now, not sure if he has all the technical knowledge but he has do e a few furniture pieces and his counter tops. If he isnt wiring the pumpkin or working i'm sure he'll give you some pointers in application and techniques. Let me know if you dont have his number. Live edge is going to look great.

Sent from my SM-G973U using Tapatalk

 

[Ibayne]

Like they’ve said propane torch or heat gun will pop them bubbles... stirring has a lot to do with it to. Try to stir slowly an not to agitate that stuff up. Just stir really slow. I’ve also found if I put the epoxy part in a cup of hot water to heat it up it helps with the bubbles too. Like put the jug it’s in in a bowl or cup of hot water an let it heat up a little. One mention Total Boat they make good stuff. I’ve used it with minimal bubbles. I paint my own fishing lures an top coat with epoxy. Very few bubbles... sometimes

 

[R Q]

Yesterday I sanded all my bad work down and am ready to apply resin again. I didn't start because it was so hot in my shop. I am moving it to a smaller building to finish. What I did find out is that it was not as many air bubbles as I thought. All of the fans in my big shop are moving dust and grit around in the air. I laid the completely sanded and smooth wood back to it's regular workspace and in an hour ran my hand over the smooth surface and it had grit all over it. SO that's where the roughness is coming from.

 

[Ibayne]

Yesterday I sanded all my bad work down and am ready to apply resin again. I didn't start because it was so hot in my shop. I am moving it to a smaller building to finish. What I did find out is that it was not as many air bubbles as I thought. All of the fans in my big shop are moving dust and grit around in the air. I laid the completely sanded and smooth wood back to it's regular workspace and in an hour ran my hand over the smooth surface and it had grit all over it. SO that's where the roughness is coming from.

You shouldn’t need the fans. Never used one on any epoxy work. As sticky as that stuff is I’m sure it’s grabbing everything that goes across it

 

[R Q]

You shouldn’t need the fans. Never used one on any epoxy work. As sticky as that stuff is I’m sure it’s grabbing everything that goes across it

Not using fans to dry the work, using them to try to not be miserably hot!

 

[WARRIORWELDING]

Epoxy equals paint and clean room pratices in my head.

I spent hours early early this morning watching concrete counter and epoxy work.

I plan to construct in the shop. Then move everything in a fairly large vacant bedroom in the house to pour. Set up a clean room. Did fairly well with that aproach on furniture pieces.

Im already dreaming of a dedicated shop addition when the lotto hits.

 

[R Q]

SO... I got my epoxy resin recoated several times and sanded down and ready for the clear Gloss UV stable poly coat. Applied the poly (From the pic above) and gave it the recommended drying time per the directions on the can and applied second coat. I could tell it wasn't going to be good but it was the bottom and I can live with some imperfections and learn from it so I can do the top better. Came out this morning to assess and found that the second coat wasn't even dried! Took to the other shop to wipe off and this stuff starts coming up like Saran Wrap!
So yesterday when I see that I'm going to have issues I came inside to get on the PC to look at SystemThree's website about troubleshooting and material data. I find two other sets of differing instructions on application and drying time and they are all markedly different. I originally followed the directions on the poly can, you would think that you're good there right? I sent a pretty scathing email to SystemThree tech people. This stuff is made for boats that sit in the water for extended periods of time and it has a great following and the products were highly recommended by the people at Woodcraft and the place I bought the slab from.
Here's how it's peeling, I don't know if this is the first or second coat that coming up but I suspect that it's the first since the second wasn't dry yet.