Woodworking/epoxy help please

Discussion in 'General Chit Chat' started by R Q, Aug 1, 2020 at 7:52 PM.

  1. R Q

    R Q Well-Known Member

    Joined:
    Apr 4, 2005
    Location:
    Charlotte
    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...? [​IMG]
    My final coat will be this [​IMG]
    Which is supposed to shield it from UV rays and such.
    This is the bar [​IMG]
    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... [​IMG]
    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.
     
  2. skyhighZJ

    skyhighZJ Thanks for your taxes

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  3. Falko

    Falko Well-Known Member

    Joined:
    Mar 20, 2005
    Location:
    Winston-Salem
    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.
     
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  4. Fabrik8

    Fabrik8 Overcomplicator

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    Location:
    Huntersville
    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.
     
    Last edited: Aug 1, 2020 at 10:43 PM
  5. R Q

    R Q Well-Known Member

    Joined:
    Apr 4, 2005
    Location:
    Charlotte
    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.
     
  6. Fabrik8

    Fabrik8 Overcomplicator

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    Huntersville
    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.
     
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  7. Mac5005

    Mac5005 Welding Instructor

    Joined:
    Oct 19, 2005
    Location:
    Rocky Mount
    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.
     
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  8. R Q

    R Q Well-Known Member

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    Apr 4, 2005
    Location:
    Charlotte
    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
     
  9. Mac5005

    Mac5005 Welding Instructor

    Joined:
    Oct 19, 2005
    Location:
    Rocky Mount
    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.
     
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  10. R Q

    R Q Well-Known Member

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    Apr 4, 2005
    Location:
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    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!
     
  11. McCracken

    McCracken Logan Can't See This

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    With your mom at a nice seafood dinner
    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?
     
  12. R Q

    R Q Well-Known Member

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    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.
     
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  13. R Q

    R Q Well-Known Member

    Joined:
    Apr 4, 2005
    Location:
    Charlotte
    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
     
  14. No fries

    No fries Well-Known Member

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    Location:
    Charlotte
    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
     
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  15. Ibayne

    Ibayne Well-Known Member

    Joined:
    Jan 5, 2016
    Location:
    Fletcher
    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
     

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  16. R Q

    R Q Well-Known Member

    Joined:
    Apr 4, 2005
    Location:
    Charlotte
    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.
     
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  17. Ibayne

    Ibayne Well-Known Member

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    Jan 5, 2016
    Location:
    Fletcher
    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
     
  18. R Q

    R Q Well-Known Member

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    Apr 4, 2005
    Location:
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    :D Not using fans to dry the work, using them to try to not be miserably hot!
     
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  19. WARRIORWELDING

    WARRIORWELDING Owner opperator Of WarriorWelding LLC.

    Joined:
    Jan 6, 2008
    Location:
    Chillin, Hwy 64 Mocksville NC
    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.
     

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