can you pour an epoxy resin over a table top that already ha...

can you pour an epoxy resin over a table top that already has been varnished?

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CrankyBadger avatar
6 years ago #2
CrankyBadger
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Yes, but it's kind of backwards to do it that way.

If you do, you'll have a secondary bond between the epoxy and the varnish. One of epoxy's strengths is its ability to penetrate wood and form a matrix with the wood fibers. It also provides a waterproof "hard candy shell" to normally soft and porous wood.

Unfortunately, epoxy has virtually no UV resistance.

Putting epoxy on top of the varnish means that you will need to replace it once it turns milky and starts to come off from UV exposure.

In boatbuilding, the epoxy seals the wood, then the varnish goes on over top to give the epoxy the UV protection it needs. Epoxy also provides a much more stable base for the varnish than the wood - it takes fewer coats of varnish to get that deep-looking 'glassy' finish that varnish is specifically used for.

It's not what you want to hear, but I would NOT put epoxy over varnish. I suggest it as is for now then, when the varnish needs to be redone (it's a temporary coating), sand it down and start again with epoxy. That way you aren't sanding off all the hard work you've already put in. Plus, if the varnish is still 'green' (soft), it'll be tough to get off cleanly anyway.

Also, one needs to be a bit careful with pouring epoxy: most formulations generate quite a bit of exotherm as compared to other thermosetting resins. This will cause gassing (bubbles) or worse: I've watched as a 1/2 liter of epoxy kicked off and melted the container it was in.

To protect a table (from bare wood), the 'best' method would be to cover the wood with 6oz glass cloth and then epoxy it. Once it's wetted, the glass becomes clear, just like a stripper canoe.
Then apply a few more coats of epoxy to finish filling the weave. After it's had time to get good and hard, sand it down with 150grit to knock down any high spots, then prep it for varnish with 220grit.

Now, a few coats of varnish will look like 20 coats.

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lily694 avatar
6 years ago #3
lily694
Fresh Member
Blogs: 0
Forum: 10
Votes: -1
CrankyBadger wrote:
Yes, but it's kind of backwards to do it that way.

If you do, you'll have a secondary bond between the epoxy and the varnish. One of epoxy's strengths is its ability to penetrate wood and form a matrix with the wood fibers. It also provides a waterproof "hard candy shell" to normally soft and porous wood.

Unfortunately, epoxy has virtually no UV resistance.

Putting epoxy on top of the varnish means that you will need to replace it once it turns milky and starts to come off from UV exposure.

In boatbuilding, the epoxy seals the wood, then the varnish goes on over top to give the epoxy the UV protection it needs. Epoxy also provides a much more stable base for the varnish than the wood - it takes fewer coats of varnish to get that deep-looking 'glassy' finish that varnish is specifically used for.

It's not what you want to hear, but I would NOT put epoxy over varnish. I suggest it as is for now then, when the varnish needs to be redone (it's a temporary coating), sand it down and start again with epoxy. That way you aren't sanding off all the hard work you've already put in. Plus, if the varnish is still 'green' (soft), it'll be tough to get off cleanly anyway.

Also, one needs to be a bit careful with pouring epoxy: most formulations generate quite a bit of exotherm as compared to other thermosetting resins. This will cause gassing (bubbles) or worse: I've watched as a 1/2 layer of epoxy kicked of and melted the container it was in.

To protect a table (from bare wood), the 'best' method would be to cover the wood with 6oz glass cloth and then epoxy it. Once it's wetted, the glass becomes clear, just like a stripper canoe.
Then apply a few more coats of epoxy to finish filling the weave. After it's had time to get good and hard, sand it down with 150grit to knock down any high spots, then prep it for varnish with 220grit.

Now, a few coats of varnish will look like 20 coats.


his solution sounds like it is effective
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2 years ago #4
bob everyman
Guest

I think for something like that u want polyurethane which is what restaurants use to put things into the table top like coins or notes or company logos. I believe its more robust BC a lot of the tiki bars here in FL have that style table outside and its clear like epoxy and you only do it once instead of sanding and reapplying. U can make it an inch thick if u want. I plan to do this and submerge seashells to make them a permanent fixture to my coffee table

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2 months ago #5
Rex
Guest

Will it work on red cedar?

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CrankyBadger avatar
2 months ago #6
CrankyBadger
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Yes, either epoxy or PU will work well on red cedar.
Both will darken the wood a little. Because it's such a porous wood, you'll probably want to thin the first coat as a flood coat/sealer.

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