New table varnishing tips.

[model 10]

I found for outside bright work, a thinned epoxy base coat is repairable. Unlike varnish that you need to remove, you can repair epoxy and re-varnish. But, if you need to remove the epoxy, wait till the UV kills it.
West Systems mentions how much thinner to use. I think it's only 10%.

[CassidyNZ]

Some very useful tips in this thread, some I knew, some I didn’t.

I’m busy restoring (trying to) a cockpit table. Made of teak, about 20 years old. Started with short cuts that never worked, ended up taking the whole table back to wood, thinking this will fix it.

Since then, three times back to wood, three different brands of varnish, two oil-based, one polyurethane. I’ve tried with quality brushes, I’ve tried spraying (which I’m good at, have done a lot of auto restoration), I’ve tried combinations. I’ve even tried some coats using an airbrush. But by the time I get to the 10th coat, even after flatting down with water paper between, things are getting worse, not better.

On a decent day my workshop is at about 20 degrees ambient. I’ve tried using heaters, dehumidifiers, you name it, still can’t get a decent finish.

Is it possible I have contaminated wood? But the restoration started because of dents and scratches, not because of poor varnish.

I’m nervous of the “epoxy first” approach in case it also doesn’t work because back-to-wood from there sounds nightmarish. I’m going to try a urethane floor sealer next which I’ve successfully used on staircases and if that doesn’t work I’ll maybe just make a new table.

[jacktheflyer]

I gave up on varnish. I use polyurethane clear (used on flooring) which gives me a great job and brushes wash up in water. Doesn't have that honey effect that varnish does but I think it looks better especially on dark wood brings out the grain.
Scrubby

[sand6000]

7 degs is marginal. I would wait for warmer weather.
Varnish mid morning and Never after 3pm in cooler temps.
Try and keep Both the timber and Definately the varnish warm overnight.
I prefer one of the older long oil varnishes (0ld fashioned). Slow drying but excellent flow properties. The new single pot urethanes can be tricky unless you get the thinners exactly right and the right type.

[s/v Jedi]

Cassidy, with teak you have to deal with it’s natural oil as well as with the old finish. When you are sure you’re really back to bare wood, sand it again, then vacuum, then just before the first coat goes on, wash it with acetone. Use two cloths, one in each hand: the first one wet with acetone, the other clean and dry. Wipe wet one stroke, wipe dry. When the dry cloth looks dirty, turn to clean part or replace.

I do think using epoxy at first leads to a better finish. I am experienced in using epoxy but did not use it under varnish yet. With your experience level, I recommend a different approach, which is a special epoxy sealer coat under Epifanes varnish.

The application of the epoxy sealer coat is crucial. Use West System 105 resin with 207 special clear hardener which cures very clear and has UV inhibitors. Here is hot to do that first coat; you need the 105 resin, 207 hardener, 2 new mixing pots, stir stick, small high density foam roller, throw-away brush, strong work light, rags, acetone, heat gun and propane torch. You really need all that. It also needs to be 16 degrees Celsius minimum, I recommend at least 20 degrees.

After the acetone wash I described above (wash oils off the teak), only touch with gloves. Heat everything with the heat gun, making sure to get it pretty hot but not scorching the wood. What we do here is heat the air in the wood pores so that it expands. This is the big trick. After that, mix the resin with special hardener which is a different mix ratio, I believe 3:1. When you buy their pump set, it comes with a special pump for 207 hardener. Use the two pot mixing technique: combine and mix resin with hardener in the first pot, making sure to first add resin, then hardener, then mix for one full minute while scraping bottom and sides. Then pour over in 2nd cup, scraping out the first cup and mix again for 30 seconds, then pour into a small roller tray.
Before rolling it on, use the heatgun on the wood again. I often use the heatgun in one hand and the roller with epoxy in the other. Work quick, with good light, making sure you have 100% coverage: keep roller wet, don’t stretch it out.

Next is the propane torch. Scan the surface for bubbles; if you did a real good job with the heat gun there are no bubbles, but often there are some. Hit them shortly with the flame and they will pop. Keep checking while the epoxy in the tray feels hot through the tray material. Curing epoxy is an exothermic process so it generates heat, which expands the air in the wood pores, which creates the bubbles. Once it stops heating, the bubbles stop forming. Hopefully they were all expanded even further with our heatgun so that the wood starts cooling straight after the roller coats it instead of heating up from the curing epoxy. As it cools down, the air bubbles in the wood pores shrinks again and draws the epoxy deep into the pores.

Let it cure overnight, then scrub with Scotchbrite sponge and warm water, rinse off and towel dry. It will probably feel rough as wood fibers were raised. Sand it nice and flat, removing epoxy where it float-coated (puddled) so that you are left with a hard, smooth, impregnated wood surface. Do the vacuum, acetone wash, heatgun and coating again which should give you a fully covered float coat.

Next day do the washing, scrubbing and rinsing again, then sand with 220 grit for the first coat of varnish. Use Epifanes gloss. Only thin it a little when the can is opened and old, use unthinned for a new can. After hand block-sanding with the grain only and 220 grit and coating 3 times, attempt a finish coat. If that 3rd coat comes out great that keep the finish coat the same except use 330 grit for hand sanding without a block and touch everything incl. low spots. If you’re not satisfied with the looks of the 3rd coat, then thin the finish coat with Epifanes brushing thinner 5%. If that still gives brush strokes, use a better brush and/or a little more thinner.

If the table is for outside, use the gloss varnish for topcoats. For inside I use their matte varnish. Always use gloss for the base coats; gloss is more durable.

Hope this helps Here is what it looks like on exotic cherry wood:

Originally Posted by CassidyNZ

Some very useful tips in this thread, some I knew, some I didn’t.

I’m busy restoring (trying to) a cockpit table. Made of teak, about 20 years old. Started with short cuts that never worked, ended up taking the whole table back to wood, thinking this will fix it.

Since then, three times back to wood, three different brands of varnish, two oil-based, one polyurethane. I’ve tried with quality brushes, I’ve tried spraying (which I’m good at, have done a lot of auto restoration), I’ve tried combinations. I’ve even tried some coats using an airbrush. But by the time I get to the 10th coat, even after flatting down with water paper between, things are getting worse, not better.

On a decent day my workshop is at about 20 degrees ambient. I’ve tried using heaters, dehumidifiers, you name it, still can’t get a decent finish.

Is it possible I have contaminated wood? But the restoration started because of dents and scratches, not because of poor varnish.

I’m nervous of the “epoxy first” approach in case it also doesn’t work because back-to-wood from there sounds nightmarish. I’m going to try a urethane floor sealer next which I’ve successfully used on staircases and if that doesn’t work I’ll maybe just make a new table.

[jlincoln04078]

"Brightwork, the art of finishing wood" by Rebecca J. Wittman is a wonderful resource with answers to all of your questions and lots more.

[Spot]

Jedi, thanks for the detailed write-up and pics.

In the epoxy resin surfboard world, acetone+epoxy is considered a recipe for accelerated exposure leading to contact dermatitis. It is also mentioned that epoxy should be cured as much as possible before sanding (same exposure reasons) and that freshly sanded epoxy, if handled with clean gloves, does not need wiping with any solvents. Secondary is that acetone destroys EPS foam which is often the core of epoxy and fiberglass laminated surfboards, windsurfers, and SUP's.

Confessional: I still have a quart of acetone and find myself using a little every time I fix/paint/seal/resin something on my old polyester resin fiberglass boat. If I could just teach myself to wear the proper gloves...I also find myself tack-ragging sanded epoxy projects with isopropyl alcohol (91% rubbing) if I feel the surface is too dusty to re-coat as-is.

I am not working with teak nor doing furniture grade work; however, some of the pictures on this thread are inspiring me to do better. My little sailing dinghy is worse for wear as it only got one coat of epoxy over plywood without varnish. The places with multiple coats and/or fiberglass reinforcements are doing fine.

[s/v Jedi]

Originally Posted by Spot

Jedi, thanks for the detailed write-up and pics.

In the epoxy resin surfboard world, acetone+epoxy is considered a recipe for accelerated exposure leading to contact dermatitis. It is also mentioned that epoxy should be cured as much as possible before sanding (same exposure reasons) and that freshly sanded epoxy, if handled with clean gloves, does not need wiping with any solvents. Secondary is that acetone destroys EPS foam which is often the core of epoxy and fiberglass laminated surfboards, windsurfers, and SUP's.

Confessional: I still have a quart of acetone and find myself using a little every time I fix/paint/seal/resin something on my old polyester resin fiberglass boat. If I could just teach myself to wear the proper gloves...I also find myself tack-ragging sanded epoxy projects with isopropyl alcohol (91% rubbing) if I feel the surface is too dusty to re-coat as-is.

I am not working with teak nor doing furniture grade work; however, some of the pictures on this thread are inspiring me to do better. My little sailing dinghy is worse for wear as it only got one coat of epoxy over plywood without varnish. The places with multiple coats and/or fiberglass reinforcements are doing fine.

The acetone is for removing the oils from teak wood. You don’t need to use it for other materials.
The washing/scrubbing is to remove amine blush from the curing process, as well as anything else that floated up from the wood.

[Hoohaa]

Thanks for all the posts guys and sorry. I have been missing in action for a couple of days but am back to it now. Strangely the site had stopped notifying me of new posts?
WOW, some of those finishes are amazing.
I have had some better success by using about 10% thinners and I am not starting until she warms up to around 20 deg.
I will post some more pics when Its near finished.
On another note. Has anyone got pics of nifty ways to hold the table leaf up? I have some ideas but am open to suggestions.

[capnigel]

So after many years as a pro yachtie doing this on classics

From bare wood

Seal with a good sealer or 50% epihanes
Then don’t sand next coat when it s touch dry
90-100 % epiphanies
Sand lightly 200 grit
Build up costs 6 coats using a compatible polyurethane ( fills the grain much better)
Between each coat sand 200 grit wet and dry and wash the dust off
Sand 400 grit and tack rag it off
Epiphanes gloss 1 coat not thin wed applied fast and don’t overbrush
Let it go dry and then hot coat after about 4 -6 hours in the tropics so you get a chemical bond with 100% epihanes

You should have a perfect finish

If not repeat the last two steps coat and hot coat until you do

If it’s cool warm your varnish up to 25 degrees in an oven before applying , if it’s damp or humid don’t do it!

[Cheechako]

Originally Posted by Hoohaa

I am having trouble getting the finish I want on my new table. I am at 6 coats and still getting what I call dry spots. Any Ideas??

I had another thought which I forgot to mention. I have had those type of spot reusing old pieces of furniture over the years.
Seal those "dry" looking spots with some shellac. There is something blushing through and it's often impossible to figure out what it is. That's what pro painters do to seal up issues on all kinds of things. Shellac seals it, and does not effect most finish products applied under or over it either. Here is the US it's Zinsser Shellac.

[Supers0nic]

I prefer to build up with epoxy then top coat with varnish

[Bloodhound]

I had the devil of a time getting a uniform finish on a 4' x 8' table last year in North Queensland. That is, until I thinned the varnish slightly and used Penetrol to slow the drying down. Otherwise almost impossible to keep a wet enough edge. A wet edge and slow even drying are sure to give success.

[Buzzman]

Not 100% relevant, but years abck I was helping a mate patch some dings on his car fenders. We colour-matched the factory paint at a mixing shop and used shop-filled rattle cans to spray it. First cuppla coats were fine, but the last one we did late in the day after the sun had gone it 'bloomed' and went really dull, and a different shade completely.
Droive the car ound to the paint guys to show them (it was $50 a can for the paint, so we wanted a free one) and they took the car into their warm shop and used the remainder of our can to go over it once warm and it came up heaps better.
They explained it is the cold that causes the dullness.
So this might be an issue with varnish as well....

And +1 the shellac to cover trick. Old french polisher taught me that trick when I was doing my time 40 years back (that's 'carpentry apprenticeship' for those of you with evil minds...)

[Rob seadog]

Another idea that might help is to warm the varnish after decanting some into a clean tin can. I have used a heat gun gently played over the underside of the can. Once it is heated slightly, stir in some thinners (10%) Apply this to lightly sanded surface after it has been dusted off and wiped with thinners using a clean, lint free cloth. Hope this helps.
Cheers, Rob.