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Discussion Starter #1
Gents, I'm trying to put Waterlox Gloss on Bubinga and Maple, and getting way too many bubbles when brushing on a coat on my test pieces. I think what's happening is the product is causing the wood to release air. I can dab and air bubble with a brush or foam applicator and the bubble dissappears then comes back in the same spot. My current plan is to do severaly wiped on coats in hopes of filling all of the places air is exiting. I did one coat 24 hours ago then just tried another one and the trouble continues.

I'm sanded to 220 Grit. I cleaned the surface with mineral spirits prior to the first coat. I've done some research and approached this methodically but no luck. The environment is around 70 degrees and lint and dust free. I tried brushes and foam applicators, the results are the same. I called Waterlox and they said just try a few things that the directions on the website are for wood floors. So they haven't been much help.

I'm not shaking or stirring the can. I pour the small amount I want to use in a clean coffee cup and let it sit to give any bubbles a chance to settle down. I let the brush absorb product up about an inch so no air is in the brush. I'm using a very light touch with the brushes, it makes no difference. I tried using a heat gun on a low setting from about 18 inches away and it makes only more bubbles and tends to blow the produce off the test pieces.

Based on the fact you can dot out the bubbles and the reappear in the same spot along the wood grain makes me lean toward the product is causing air to come out of the wood. That's where I'm hoping several wiped on coats will stop this behavior. Does anyone have any experieince or advice with this product and problem?

I like the amber color that the product turns the maple but I don't want any air bubbles.

Thank you, Mike
 

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In the past I've used waterlox I've had air bubble as well but they worked themselves out. Using the heat gun is probably not a good idea cause it will speed up the curing and give the air bubble less time to work out. Can you try adding a thinner coat, or are you already going pretty thin?
 

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In the book "understanding wood finishes", for varnish problems, they say...
Problem - air bubbles appear in the varnish as you apply it and don't pop out before the varnish cures - even after you have tipped off the varnish.
Cause - The bubbles are the result of turbulence caused by the brush gliding over the surface
Solution 1 - sand the surface smooth and add 5% to 10% mineral spirits to the next coat. The mineral spirits will produce a thinner coat and will slow the curing enough for the air bubbles to pop out.
Solution 2 - Sand the surface smooth and work in a cooler room. The bubbles will have more time to pop out on their own.
 

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I'm going on the assumption you are talking about Waterlox original. Which one are you using?

Usually with any finish including tung oil if you apply it too thick or don't have the finish thinned sufficiently it will cause bubbles. You can also generate bubbles by over-brushing the finish. Try applying it with a minimum of strokes. If it still bubbles then thin it a little with mineral spirits.

Despite what directions you may be reading about drying time, 24 hours between coats is probably too soon. Tung oil is a very slow drying finish that may take several days to a week to dry. The best way to tell if a coat is dry is to briskly rub the surface with a clean cloth and smell the rag. When there is no smell it is ready.

It's not a good idea to shake the tung oil but any finish should be stirred. A finish will tend to separate with the solids going to the bottom of the can and the lighter elements or solvents float to the top.
 

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Discussion Starter #5
In the past I've used waterlox I've had air bubble as well but they worked themselves out. Using the heat gun is probably not a good idea cause it will speed up the curing and give the air bubble less time to work out. Can you try adding a thinner coat, or are you already going pretty thin?
You are spot on the heat gun creates all sorts of havoc. One thing that was interesting is I took a test piece, put a coat on and let it sit for about 10 minutes, wiped off the excess, then waved the heat gun back and forth without getting it crazy hot. Air bubbles began popping up through the wood. So wiped them off, and tried a thick coat again. This time there were less air bubbles, but still too many. I did this several times and there were still too many. I put on my second rubbed on coat and let that sit for 24 hours. I will try again tonight.

I went about as thin as you can go with a brush or foam applicator. It seems like thinner actually gives you more bubbles. I have this theory that it may be humidity related. I've been doing the project in my garage and the temperatures have been swinging from 50 to 80 in the last few weeks. Plus being in Florida about 10 miles from the ocean it's always fairly humid. So I brought the project and my test pieces inside last night. I will try again tonight and see how it goes.

Thanks for the response. Mike
 

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Discussion Starter #6
In the book "understanding wood finishes", for varnish problems, they say...
Problem - air bubbles appear in the varnish as you apply it and don't pop out before the varnish cures - even after you have tipped off the varnish.
Cause - The bubbles are the result of turbulence caused by the brush gliding over the surface
Solution 1 - sand the surface smooth and add 5% to 10% mineral spirits to the next coat. The mineral spirits will produce a thinner coat and will slow the curing enough for the air bubbles to pop out.
Solution 2 - Sand the surface smooth and work in a cooler room. The bubbles will have more time to pop out on their own.
I'm with you turbulence creates more bubbles. I tried about a dozen times and went very slowly. What I see is the bubbles pop back up in the same places and in line with the dark grain in the Bubinga. So like a spot where air is trapped and getting out. Last night I moved the project to a less humid and temperature consistent environment but bringing it inside. I will see how it goes over the next few days.

Thank you for your response. Mike
 

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Discussion Starter #7
I'm going on the assumption you are talking about Waterlox original. Which one are you using?

Usually with any finish including tung oil if you apply it too thick or don't have the finish thinned sufficiently it will cause bubbles. You can also generate bubbles by over-brushing the finish. Try applying it with a minimum of strokes. If it still bubbles then thin it a little with mineral spirits.

Despite what directions you may be reading about drying time, 24 hours between coats is probably too soon. Tung oil is a very slow drying finish that may take several days to a week to dry. The best way to tell if a coat is dry is to briskly rub the surface with a clean cloth and smell the rag. When there is no smell it is ready.

It's not a good idea to shake the tung oil but any finish should be stirred. A finish will tend to separate with the solids going to the bottom of the can and the lighter elements or solvents float to the top.
It is the Waterlox High Gloss. On their website it says use the Original for the first few coats then use the Gloss if you want to. I phoned them and asked and they said that only matters for wood floors where high traffic is a factor. On a small project like mine the Gloss is fine to use they support guy said.

I tried adding about 10% mineral spirts to thin it with yesterday and it was better, but still an excessive amount of bubbles. I think the bubbles are coming up through the wood as they reappear in the same location. I'm speculating it's a humidity challenge that will either be overcome by bringing the project indoors out of the humidity or the wood will eventually be sealed by multiple wipe on coats. Worst case scenario I will wipe on all the coats. This just takes more time and the recipient of the gift will just have to understand it's gonna be a few more days. :)

I'm pretty much done other than the finish, the drawer knobs which are supposed to arrive tomorrow, and the velvet drawer liner and ring trays. Christmas is upon us! I feel like I'm on the Orange County Chopper show with a deadline looming. I'm sure a lot of woodworkers are in the same boat.

Understood stirred and not shaken. I will give that a try. I will also try the smell test to make sure it's dry.

Thank you for your response. Mike
 

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It is the Waterlox High Gloss. On their website it says use the Original for the first few coats then use the Gloss if you want to. I phoned them and asked and they said that only matters for wood floors where high traffic is a factor. On a small project like mine the Gloss is fine to use they support guy said.

I tried adding about 10% mineral spirts to thin it with yesterday and it was better, but still an excessive amount of bubbles. I think the bubbles are coming up through the wood as they reappear in the same location. I'm speculating it's a humidity challenge that will either be overcome by bringing the project indoors out of the humidity or the wood will eventually be sealed by multiple wipe on coats. Worst case scenario I will wipe on all the coats. This just takes more time and the recipient of the gift will just have to understand it's gonna be a few more days. :)

I'm pretty much done other than the finish, the drawer knobs which are supposed to arrive tomorrow, and the velvet drawer liner and ring trays. Christmas is upon us! I feel like I'm on the Orange County Chopper show with a deadline looming. I'm sure a lot of woodworkers are in the same boat.

Understood stirred and not shaken. I will give that a try. I will also try the smell test to make sure it's dry.

Thank you for your response. Mike
If you are finishing outdoors I would suspect it was direct sunlight making the finish bubble. Very few finishes would tolerate drying in the sun. It causes the finish to skim over the surface while wet underneath. Humidity wouldn't cause bubbles. It would just make the finish take longer to dry.
 

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If you are finishing outdoors I would suspect it was direct sunlight making the finish bubble. Very few finishes would tolerate drying in the sun. It causes the finish to skim over the surface while wet underneath. Humidity wouldn't cause bubbles. It would just make the finish take longer to dry.
+1 here
 

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Discussion Starter #10
Thanks Gents, I'm working on it in the garage so not directly outdoors in the sun, but not an AC enviroment where much of the humidity is taken out of the air. I moved it indoors about 48 hours ago now and it's pretty much the same amount of bubbles.

It's all good, I decided to stop fussing over the air bubbles and work around the problem by brushing on a thin coat and wiping it off. It will take longer to build up a thick coat but it will look good in the end. I started thinking about it and I can't brush on thick coats where the drawers and sides meet anyway because my tolerances are too tight. I built a lot of it to a two playing card separation, so to put a coat of finish on these spots as thick as one playing card is no good. So I will just do wipe on coats and work with the product.

I put the first coat on the whole box yesterday and it looks fantastic already. More coats will only get better. I'm up to 3 on my test board and it's beautiful. There is nothing like some real pretty wood. I like the way the product looks but I would be hesitant to buy it again. Maybe other people have had a different experience but this has been mine. Challenging to say the least.

This weekend I will do the velvet lining, ring trays, add the brass hardware, and of course a couple more coats of finish. I'll experiment with buffing the final coat and try to come up with something good. I'm hesitant to put wax on it in case it ever needed a touch up... but then again I probably won't have a can of this product around anyway so it may be the way to go. What do you all normally do for the final? Thank you for your advice.

Mike
 

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The only thing I could maybe suggest is perhaps there is something about the brush you are using. I have had problems with finishes making bubbles with a foam brush so now I only use them for stain. A brush for a finish should be silky smooth and soft. You might try to find a badger brush.

I would be apprehensive about putting wax on the finish too. A wax is difficult to get rid of clean enough to recoat. Then if the finish isn't fully cured it can penetrate into the finish damaging the finish. Usually if a wax is used on a finish, the finish should dry a month first.
 

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Thank you Steve. I bought a magnifying glass in the last few days and I'm convinced the air bubbles were coming out of the grains in the wood. Under the magnifying glass Bubinga has tiny black grains and you can see crevaces. No worries I'm just wiping on the coats. I'm up to 3 now and may do one more. When I first posted I was worried about using an unknown finish on an important project with the looming deadline. But after working with it a while I know it's turned out nice. I just finished lining all the trays with velvet and adding the brass knobs and necklace hangers.

Understood on the wax. I think I will skip it entirely. The piece looks glossy already so I believe i will skp it. I will post pictures either later today or tomorrow.

Thank you, Mike
 

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No matter what finish I'm using I like to seal the wood with a couple really thin coats first. (Like 50/50 with thinner) The finish penetrates into the wood better and seals off the pores so no solvent trapping occurs. Those first couple coats can be wiped off with a lint free rag and after those coats are dry you should be able to go back to a full coat with just enough thinner to let it flow out.
 

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Discussion Starter #14
Thanks Rick, that is good advice. I did do the thin coats and wiped them off but not with a 50/50 thinner. That was probably what it needed to get down in those tiny crevices and seal the wood. Is Mineral Spirits good for that type of thinning?

Thank you, Mike
 
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