Pin holes/bubbles in NC lacquer

[John Samuel]

Herein a call for help from the brains trust.

Except for outdoor furniture I generally use NC lacquer on furniture and similar.

A problem I have occasionally is pin holes/bubbles in the finish, and I am looking for a solution. Right now I spray on 2-3 diluted coats of lacquer, sanding with wet and dry between coats. That usually does the trick, but it is time consuming.

Thinking about using something like a clear grain filler. I don't need a mirror finish, just to eliminate the pin holes and bubbles. If I want a mirror finish I use high gloss acid cure lacquer. I tried using a paste made from wet plastic wood. That helped, but too often I still got some pin holes and bubbles.

A web search found a lot of contradictory advice. Every technique has its supporters and detractors.

Any comments on the various grain fillers? Any other bright ideas to get rid of pin holes and bubbles gratefully accepted.

P.S. When I was a kid I watched a teacher French polish (I think that's the term) a jewellery box with shellac. He produced a beautiful finish, but it took 40 coats and a lot of sanding to achieve. Pass!

[rod1949]

I've noticed that when I stir/shake the pot excessively is produces bubbles and these translate to the item being sprayed. The pin holes can be form air escaping from the pores of the timber. I'm no expert.

[John Samuel]

I've noticed that when I stir/shake the pot excessively is produces bubbles and these translate to the item being sprayed. The pin holes can be form air escaping from the pores of the timber. I'm no expert.

My issue is definitely air escaping from the pores. I stand there, watch the pin hole bubbling air, and weep.

[tony_A]

My issue is definitely air escaping from the pores. I stand there, watch the pin hole bubbling air, and weep.

Ive had the same issue myself John. I think the problem is caused by the wood getting warmer after coating and "off gassing". I have seen specular bubbling when varnishing in direct sunlight. My approach is to apply the finish later in the day when the ambient temperature has cooled somewhat and the timber is starting to cool. More likely to be sucking the finish back into the pores rather than pushing bubbles out. Keep the wood out of direct sunlight before and after coating.

[John Samuel]

I may have found the solution, a product called Solarez Grain sealer.

To have a look, follow this link. It looks very good. The Best Wood Grain Filler I Have Come Across - YouTube (https://www.youtube.com/watch?v=405f5bAFVx0)

[John Samuel]

Ive had the same issue myself John. I think the problem is caused by the wood getting warmer after coating and "off gassing". I have seen specular bubbling when varnishing in direct sunlight. My approach is to apply the finish later in the day when the ambient temperature has cooled somewhat and the timber is starting to cool. More likely to be sucking the finish back into the pores rather than pushing bubbles out. Keep the wood out of direct sunlight before and after coating.

Tried that, Tony. Still sometimes getting bubbles from open grained timber. The current job, a jewellery box made from NG Rosewood nearly drove me to drink because of the pin holes and bubbles. I never lacquer in direct sunlight and the recent jobs have been done in quite cool weather. Morning or afternoon, I get bubbles and pin holes.

I will likely order some Solarez. If it's half as good as it looks in the video it will do just fine.

[rod1949]

nearly drove me to drink

:drink2: :rotfl:

[John Samuel]

Ordered the Solarez. I'll let you know how it performs.

[rod1949]

Ordered the Solarez. I'll let you know how it performs.

Where did you order it from John.

[homey]

John,

I use this: Aqua Coat | Eco-Friendly Water-Based Wood Finishes (https://aquacoat.com/)

It’s now the only sealer I use.

Regards,

Brian

[Mobyturns]

Tried that, Tony. Still sometimes getting bubbles from open grained timber. The current job, a jewellery box made from NG Rosewood nearly drove me to drink because of the pin holes and bubbles. I never lacquer in direct sunlight and the recent jobs have been done in quite cool weather. Morning or afternoon, I get bubbles and pin holes.

I will likely order some Solarez. If it's half as good as it looks in the video it will do just fine.

NG Rosewood is perhaps one of the most difficult woods to pore fill that I have encountered, though I haven't experienced the issues you mention. I've used both Mirotone and Stylwood NC fillers and have never really been happy with the excessive number of coats required, nor the sanding back to get a reasonable finish. I think the only way to deal with it is to use similar grain filling techniques to those that Luthiers use.

[John Samuel]

Where did you order it from John.

Ordered it from Amazon Aust, Rod.

There are at least two similar products produced by Solarez. One is a clear product (I think a sealer) and the one I ordered (I hope) is a white paste (sealer and filler). The white paste looks to easily be the superior product for difficult timbers like NG Rosewood, but I'll soon know.

[John Samuel]

NG Rosewood is perhaps one of the most difficult woods to pore fill that I have encountered, though I haven't experienced the issues you mention. I've used both Mirotone and Stylwood NC fillers and have never really been happy with the excessive number of coats required, nor the sanding back to get a reasonable finish. I think the only way to deal with it is to use similar grain filling techniques to those that Luthiers use.

That's exactly why I am trying the Solarez, Mobyturns. If is as good as it looks, I have solved the problem completely ... and it is a very fast solution. If it is not as good as it looks, but if it still successfully fills the big holes and prevents pin holes and bubbles with a single coat, I still have a winner. All will be revealed by Father Time.

[John Samuel]

John,

I use this: Aqua Coat | Eco-Friendly Water-Based Wood Finishes (https://aquacoat.com/)

It’s now the only sealer I use.

Regards,

Brian

Thanks, Brian. I looked at that product, but was seduced by the 3-5 minute cure time of the Solarez and by the fact that if I only wanted to fill the big holes to stop bubbles and pin holes a single coat should do the job. If the Solarez flops, I'll likely try the Aqua Coat.

When I am making furniture for kids (for example), I am happy for the grain to telegraph through the lacquer because putting a very smooth finish on kids furniture seems a bit like casting pearls before swine, especially after one of my grandsons decided to chew on the corner of the chest of drawers I made. In such a case, I only want to get rid of the pin holes and bubbles.

I refinished a 2400 X 1200 mm table for my daughter in law. It was finished in acid cure lacquer and hand rubbed to a mirror finish, and I was feeling well pleased with the result until I discovered that she hated it because it showed every speck of dust, every fingerprint and every kid mark. She asked me to cut it down to a 1650 X 1000 mm six seater, and specifically asked for a low sheen finish. Most women no longer want mirror finishes for the same reasons. In such a piece I don't care if the grain telegraphs through so long as the pin holes and bubbles don't appear.

In the rare cases when I want a mirror finish I use Mirotone's acid cure lacquer. It is high build, like poly, and a couple of coats usually does the job. Only used it a few times, but never have I had an issue with pinholes, perhaps because it is such a high build product. Mind you, I have never used it over NG Rosewood.

[rod1949]

Ordered it from Amazon Aust, Rod.

There are at least two similar products produced by Solarez. One is a clear product (I think a sealer) and the one I ordered (I hope) is a white paste (sealer and filler). The white paste looks to easily be the superior product for difficult timbers like NG Rosewood, but I'll soon know.

Thanks for that John. I have a lot of Jarrah timber that came out of my old 1957 built house. The timber has a lot of fine/small cracks in it and sometimes I can machine these out (depending on what I'm making) but the ones remaining I have been applying the lacquer and whilst its still wet applying the fine (like talcum powder) dust collected from the dust extractor and pressing in and scrapping over to fill. Its a long process.

Look forward to your opinion with Solarez.

[John Samuel]

Thanks for that John. I have a lot of Jarrah timber that came out of my old 1957 built house. The timber has a lot of fine/small cracks in it and sometimes I can machine these out (depending on what I'm making) but the ones remaining I have been applying the lacquer and whilst its still wet applying the fine (like talcum powder) dust collected from the dust extractor and pressing in and scrapping over to fill. Its a long process.

Look forward to your opinion with Solarez.

I had not thought of that application, Rod, because I seldom use reclaimed timber after buggering up the blades on my planer/thicknesser a couple of times. Nonetheless, I do have some reclaimed Douglas Fir with the same issue of fine cracks, so I'll try the Solarez on that once it arrives.

Thanks for the "heads up".

[John Samuel]

Rod,

A trick PJT taught me for filling cracks/voids in veneers might be of use to you.

I use a flour sieve to produce a reasonably fine sawdust product. This sawdust is rubbed/pressed into the imperfection and the excess blown away. Then, a little super glue is dripped onto the sawdust. (Use only the original thin product, not the rubberised, thicker product.) A minute later it can be sanded off. It occurred to me that if you used very fine sawdust the same technique might work with the fine cracks in your jarrah, providing you can press the sawdust into the cracks.

Many thanks to PJT. I have used this approach to successfully fill cracks, voids, knotholes in both veneers and solid timber.

[rod1949]

Rod,

A trick PJT taught me for filling cracks/voids in veneers might be of use to you.

I use a flour sieve to produce a reasonably fine sawdust product. This sawdust is rubbed/pressed into the imperfection and the excess blown away. Then, a little super glue is dripped onto the sawdust. (Use only the original thin product, not the rubberised, thicker product.) A minute later it can be sanded off. It occurred to me that if you used very fine sawdust the same technique might work with the fine cracks in your jarrah, providing you can press the sawdust into the cracks.

Many thanks to PJT. I have used this approach to successfully fill cracks, voids, knotholes in both veneers and solid timber.

Thanks for that John. This is the bag of Jarrah dust (like talc) that has been collected in the dust extraction unit over a long period of time and I'm surprised that it is all Jarrah coloured as other timbers have been machined as well. My process has been to mix it in with the lacquer or apply the lacquer to the item and then sprinkle the dust on and work in. It works but is a long slow process as the lacquer can take time to dry.

[John Samuel]

My Solarez arrived this morning. Because there are several Solarez products, here is a pic of the one I bought (about $55-60 for a pint, including shipping). It is a combined sealer/filler, but is a clear product. I was expecting a white product (as per the video), but heaven knows what new developments have occurred.

496190

Some testing notes follow. The tests were conducted with a piece of the same NG Rosewood board that gave me no end of troubles with bubbles and pinholes in the most recent job, a jewellery box, and a piece of Surian cedar.


FIRST TEST PIECE. NG Rosewood. Does the product eliminate pinholes and bubbles in a finish where the grain telegraphs through?
1. Wood was sanded with 120 grit on an orbital sander.
2. One coat only of Solarez was used. I wanted to see how easily the product defeated pinholes and bubbles.
3. Sanding done with 120 grit orbital (instructions say use 400 grit, but that was far too slow). I sanded it back until the wood started to show through, hoping the Solarez remained in the pores, but was concerned that 120 grit might scratch a lot of it out.
4. A full coat of NC lacquer was applied. At first there was a little "twinkling" on the surface, suggesting tiny pinholes or similar. I ignored this, sprayed on another coat whilst the first was still wet and waited to see the result. It worked. I could see no pinholes or bubbles. As expected, the grain did telegraph through the lacquer, and it is likely that some tiny pinholes were present in the deeper pores, but I could not see them and bubbles were non-existent.
5. The wood retained its rich red/brown colour. It looked the same as if sanding sealer and lacquer only had been applied. No opaqueness and no colour change. I got the same bright rich colour that is one of the key reasons we use lacquer.


SECOND TEST PIECE. NG Rosewood. Filling the grain entirely.
1. Wood was sanded with 120 grit on an orbital sander.
2. Three coats of Solarez were applied, sanding with 240 grit between coats.
4. A full coat of NC lacquer was applied. At first there was a little "twinkling" on the surface, again suggesting tiny pinholes or similar. I ignored this, sprayed on another coat whilst the first was still tacky. Once dry, I could see I had not quite filled all the pores with Solarez and some tiny imperfections remained. My guess was that one or two coats of sanding sealer would finish it nicely ... or another coat of Solarez ... so I brushed on a coat of sanding sealer, sanded that smooth and reapplied lacquer. The blemishes all but disappeared.


THIRD TEST PIECE. Surian Cedar. Fill the grain entirely.
1. Three coats of Solarez were used, sanded with 240 grit between coats.
2. Sanding sealer was applied with a brush because the gun was full of lacquer and I did not feel like changing it over.
3. Sanded with 240 grit and sprayed with NC lacquer.
4. Surian is notorious for producing a wooly finish when planing or sanding and for it's open pores which regularly produce bubbles or pinholes, especially on horizontal surfaces. However, one coat of the Solarez eliminated the wooliness completely. The lacquer finish, although only two coats, was free of bubbles and pinholes. I reckon that after a few more coats of lacquer this piece could be hand rubbed to a mirror finish.


CONCLUSION
This product will be a permanent feature in my shop until something better comes along. It takes only 15-30 minutes to apply three coats depending on sanding time. To prevent pinholes and bubbles, only one coat is necessary, but the grain will not be completely filled.

These are limited tests ... not at all comprehensive ... but the results suggest that one or two coats of sanding sealer over the Solarez is a good idea when a hand rubbed, mirror finish is sought ... but that might be due to the inexperienced operator.


I started with the objective of eliminating pinholes and bubbles. It did that well on all my tests. When the grain is not filled, I reckon there were some tiny pinholes still present, but they could not be seen in the completed finish. So far as I am concerned, this means that for practical purposes, they are not there.


A bonus is that with three coats it will fill the grain completely or almost completely, depending on one's skill and the size of the pores in the wood. This is not a magic bullet. For instance, if one runs the squeegee along the grain it can scoop the product out of the pores a bit ... a little skill and care is required ... but not a lot. I still got a few tiny bubbles on one section, but that is only an issue when hand rubbing a mirror finish (for which a couple of coats of sanding sealer is indicated). Doubtless I have more to learn about this product. Nonetheless, it seems to have solved a problem that has irritated me for a very long time.


One positive characteristic is that this product is 100% solids, and so does not shrink during cure. This is why it is so great at filling the grain with repeated coats. Another is that you can take as long as you like smoothing out the finish. It will not cure until you put it in the sun. Finally, being able to spray finish coats a few minutes after applying the Solarez and sanding it smooth is a real boon.


The first coat wets the wood surface completely. One should use less product for the second and subsequent coats because the squeegee removes most of the product sitting on the surface, which is now sealed, leaving only a very thin smear and the product that is sitting in the pores. Use sparingly. Also, get the surface as smooth as possible before exposing it to the sun. Any ridges left by the edges of the squeegee will cure as ridges and must then be sanded smooth.


At about $55-60 for a pint it is not cheap. However, if i use it only on the tops of my cabinets, which is the plan because that's where I get the bubbles and pinholes, a pint will last a long time because it is used so sparingly. By my reckoning it is excellent value for money. It reduces the number of coats of sanding sealer required (or eliminates them) and the elimination of bubbles and pinholes saves a lot of time and frustration. Even if 5 or 6 coats are needed to eliminate the grain/pores when desirable, it is still far quicker and easier than all the other methods I have tried. Although it will solve my initial problem, pinholes and bubbles, it will be a handy product when I want a hand polished mirror finish, such as jewellery boxes.


If you are guessing that I like this product ... quite a bit ... you are correct. It is not perfect, but it is a vast improvement on all my earlier approaches. At the very least it is well worth buying a pint and running your own tests. If after using it on real furniture rather than test pieces I make any new discoveries, I'll post them here.

[homey]

John,

Thanks for taking the time to write up your findings. Sounds like you’ve found a winner! I look forward to seeing some of your boxes finished using Solarez.

Regards,

Brian

[rod1949]

Thanks for the info John.

So where you are saying "solarez" and then further on a "sanding sealer" are you still referring to solarez or two different products?

[John Samuel]

Rod,

"Sanding sealer" is different to Solarez. It is the product I normally spray before applying lacquer. It seals off the timber and sands easily to a smooth finish but requires many coats to fill open pores and fill the grain.

Solarez can be used without any lacquer at all, in fact some luthiers do that. They apply 3 or 4 coats of Solarez. The last coat is sanded with 400, 600, 800, 1200 1500 and perhaps even 3000 grit. It is then polished with a cutting polish or similar to give a high gloss finish. You can do the same thing with lacquer to give a hand rubbed mirror finish.

I seldom want such a finish. Most of my furniture will get a single coat of the Solarez to the horizontal surface (to avoid pinholes and bubbles), followed by two or three full coats of lacquer which is sanded flat with 400 grit. Finally I apply a thin, fast drying coat of lacquer. The top of the cabinet is then sanded with 1200 grit and polished (to get rid of dust specks and the insects that may have landed on the wet lacquer).

When I want to fill the grain completely I'll likely use three coats of the Solarez followed by 1-2 coats of sanding sealer followed by lacquer. I like lacquer because it is very easy to repair and because it never leaves a witness line during the repair process.

[John Samuel]

John,

Thanks for taking the time to write up your findings. Sounds like you’ve found a winner! I look forward to seeing some of your boxes finished using Solarez.

Regards,

Brian

Thanks, Brian.

I seldom produce mirror finishes these days. Most women don't like them, except on things like jewellery boxes and I only make one or two of those a year.

However, I have been tormented by pinholes and bubbles, especially in cabinet tops made from timber like NG Rosewood and cedar, for a very long time. It was a breakthrough when the Solarez stopped those issues in today's trials. We can apply a coat of Solarez to a cabinet top and sand it flat in ten to fifteen minutes, maximum. In the past I have lost days fixing pinholes and bubbles on some jobs. If today's trials are any indication we can proceed with lacquer confident that we will not suffer pinholes and bubbles. I have half a cube of NG rosewood sitting in the racks. Until today, it was mocking me ... threatening to curse me with pinholes and bubbles. After today's trials I had a brief chat with that timber and made sure it knew who the boss was from now on.

[tony_A]

Sounds brilliant John. I have a couple of pieces of highly figured eucalypt with numerous natural defects (holes) and presume Solarez would be ideal for filling these.

[John Samuel]

Sounds brilliant John. I have a couple of pieces of highly figured eucalypt with numerous natural defects (holes) and presume Solarez would be ideal for filling these.

Tony,

I suspect that is a function of how big your holes are, but am sure you have several approaches to fill the larger holes. I think we need to bear in mind that if the sun's UV light can't reach the Solarez, it won't cure.

[rod1949]

I have some Salmon gum timber. It has lots of gum veins and also drying some cracks as per photos 1 and 2. Today I decided to use the solarez grain filler with two applications and sanding with 150 grit (no clogging) the results being as per photos 3 and 4. I'm very impressed, the crack on the end of the board is almost filled apart from where the solarez leaked on the edge. Previously I'd been resin filling as per photo 5 but its messy and time consuming and sanding will clog.

[John Samuel]

I have some Salmon gum timber. It has lots of gum veins and also drying some cracks as per photos 1 and 2. Today I decided to use the solarez grain filler with two applications and sanding with 150 grit (no clogging) the results being as per photos 3 and 4. I'm very impressed, the crack on the end of the board is almost filled apart from where the solarez leaked on the edge. Previously I'd been resin filling as per photo 5 but its messy and time consuming and sanding will clog.

Great work, Rod. You have filled bigger defects than I have attempted.

Usually, I fill the bigger defects with sawdust and then apply super glue. After sanding (only a few minutes later, especially if I have dampened the sawdust a tad) I apply the Solarez.

Sometimes, I still use resin where big defects are encountered and where strength is mission critical for the repaired piece.

Nevertheless, until something better comes along, Solarez will have a home in my shed. It is a very handy product.

[riverbuilder]

When you say “diluted”, I presume you mean thinned? With thinners?

[John Samuel]

When you say “diluted”, I presume you mean thinned? With thinners?

Mate,

I can't find the word "diluted" anywhere in this thread except for your post. Am I missing something?

[powderpost]

I had the problem of "pinholes" coming up in the finish. After much deliberation, I asked a local panel beater to have a look at my set up. He said the problem was water vapor, because the water/oil trap was to close to the compressor, and did not allow the air to cool enough to release the vapor. I added a second trap with a metre of hose between the second trap and the trap at the compressor and have not had a problem since. I release the water from the traps as further security.

Jim

[malb]

Mate,

I can't find the word "diluted" anywhere in this thread except for your post. Am I missing something?

Not trying to take sides in this, but thought I had seen it and went back to check. Third line in the first post "A problem I have occasionally is pin holes/bubbles in the finish, and I am looking for a solution. Right now I spray on 2-3 diluted coats of lacquer, sanding with wet and dry between coats. That usually does the trick, but it is time consuming."

Just hoping that this may produce a more fruitful answer for riverbuilder.

[John Samuel]

Not trying to take sides in this, but thought I had seen it and went back to check. Third line in the first post "A problem I have occasionally is pin holes/bubbles in the finish, and I am looking for a solution. Right now I spray on 2-3 diluted coats of lacquer, sanding with wet and dry between coats. That usually does the trick, but it is time consuming."

Just hoping that this may produce a more fruitful answer for riverbuilder.

Thanks, malb.

I did a search for the word, but did not think to go back to the first page.

Yes, I dilute lacquer with GP thinners.

[John Samuel]

Yesterday I had a chat with my Mirotone sales rep.

He confirmed NG Rosewood as one of the worst timbers for producing bubbles in lacquer. Apparently the stuff is notorious for this problem. He also mentioned cedar as a regular troublemaker, although my experience is that surian cedar is a breeze compared to NG Rosewood. Don't know about Red cedar.

His solution was to apply several very thin coats to begin with, in an attempt to seal up the holes that produce the bubbles. Given that the problem only occurs on horizontal surfaces, I think I'll keep using the Solarez to seal the surface before applying sanding sealer and lacquer.

It's nice to know that I'm not the problem ... that NG Rosewood does produce bubbles in lacquer.

[Mobyturns]

It's nice to know that I'm not the problem ... that NG Rosewood does produce bubbles in lacquer.

NG Rosewood can be difficult to get a satisfactory finish on due to its porosity. I make a lot of inlay banding to use in small turnings, mostly pens, and have issues with the "extractives" from NGR transferring across into almost all woods used in the banding. It seems that no matter what is used to pore fill / seal the NGR that subsequent coats of finish will draw the "extractives" out. Any wipe on finish and even some sprayed coats can be affected.

[John Samuel]

NG Rosewood can be difficult to get a satisfactory finish on due to its porosity. I make a lot of inlay banding to use in small turnings, mostly pens, and have issues with the "extractives" from NGR transferring across into almost all woods used in the banding. It seems that no matter what is used to pore fill / seal the NGR that subsequent coats of finish will draw the "extractives" out. Any wipe on finish and even some sprayed coats can be affected.

I think I'm beginning to understand why one can sometimes buy NG Rosewood "on special". It can be very difficult to maddening during finishing. My only real problems with this timber were pin holes and bubbling on horizontal surfaces. Thank goodness the Solarez seems to stop that.

[rustynail]

Silica and lacquer do not mix happily. Bubbles are the result. Many timbers have it naturally (NG rosewood being one.) Silica may also be introduced when using silicon based sprays and waxes as a lubricant on woodworking machine tables. Drying lacquer in direct sunlight can also exacerbate the problem.

[woodPixel]

Agh! Rustynail beat me to it.

Its silica.

Happens in car finishes. Fisheyes are the bane of car refinishers and introducing silica into a shop can result in someone being shot.

Simple solution is to wipe down with prepsol and a cloth. One can also put this goop in the NC/lacquer/poly: 804 ANTI SILICONE - Bodyshop Paint Supplies Bayswater (https://www.bodyshoppaintsuppliesbayswater.com.au/product/804-anti-silicone/)

[John Samuel]

Silica and lacquer do not mix happily. Bubbles are the result. Many timbers have it naturally (NG rosewood being one.) Silica may also be introduced when using silicon based sprays and waxes as a lubricant on woodworking machine tables. Drying lacquer in direct sunlight can also exacerbate the problem.

I have been careful not to get silicone in my shop. I only use lubricants declared safe with finishes like lacquer. The only timber used that routinely gives me bubbles is NG Rosewood, and even then only on horizontal surfaces ... not on vertical surfaces. The Mirotone rep said that was his experience, too.

[rustynail]

The NGR has silica in it naturally. I never lacquer it, I only use an oil. As for red cedar, I use a lot of it and have never had a problem with lacquer or any other polish for that matter.
I mill my own timber except for NGR, which I buy in against order. The big question is; What has the timber been exposed to prior?
Even if the timber is rough sawn when you get it, that is not to say silica has not been introduced. If the timber has been dressed, the possibility increases. Machine surfaces can become pretty bunged up with gum from milling green timber, a quick "fix" is a squirt of silicon between runs. Solves the problem for the machinist, makes a problem for the polisher.

[Mobyturns]

Just seeking a bit of clarification - are we talking silica as in the mineral in beach sand; or silicone used in some polishes, spray lubricants etc?

Silicone is one of the causes of "fish eye" in painted finishes. The fish eye is formed because the silicone modifies the surface tension f the paint.

"Popping" or "solvent popping" can be caused by a number of factors, but is basically the paint solvent; or moisture in the timber; or another solvent / thinner; moisture from the air line; or even the compressed air being trapped under the paint usually by the fast drying paint forming a skin.

PPG state this may be due to:



Poor quality or too fast thinner.
Excessive film thickness, or insufficient drying time between coats.
Compressed air pressure too low.
Drying temperature too high, heat source too close to the film, too hot, or applied too soon.


The bubbles structure will give some clues to identify "fish eye" or "solvent popping."

NGR has many quite large vessels and capillaries in its structure - and my theory for what causes them for me is moisture in those vessels mobilizes while spraying or the compressed air is trapped by a fast drying or heavy coat.

"Fish eye" is typically a shallow crater where as "solvent popping" is characterized by bubbles trapped in the finish as well as popped bubbles.

[John Samuel]

I am building a chest of drawers in NG rosewood.

Usually, I'd finish the top with Solarez before using sanding sealer and lacquer. This time I went directly to the sanding sealer.

I got heaps of bubbles ... but only on the top which was horizontal. No bubbles on the cedar drawers and no bubbles on the sides or the framework ... only on the horizontal top.

So, as an experiment I sanded it back with an orbital sander. Then I rolled it onto it's back, so that the top of the cabinet was now vertical, and I applied three coats of sanding sealer allowing it to flash off between coats.

No bubbles.

Once it had dried I rolled it back onto its feet, sanded it off again and applied another coat of sanding sealer to fill the wood grain.

I have used a wide variety of timber in my shop over 20 years. The only timber that gives me bubbles is NG Rosewood, and then only when the panel is sprayed in the horizontal position.

I guess I stop grizzling and roll cabinets onto their back to spray the top whilst it is in the vertical position, then roll it back onto its feet and spray the remainder of the cabinet.

[John Samuel]

This morning I put a thin coat of lacquer on the chest of drawers.

No bubbles.

So then I put on a very full coat of lacquer, On my return an hour later the top was full of bubbles. The heavy coat had melted through and opened up the pin holes so bubbles were created.

ENOUGH!

I used nuclear grade carcinogenic paint stripper to go back to bare wood. I'm going back to using Solarez as a sealer.

[woodPixel]

Maybe a swipe or two of Shellac first?

[John Samuel]

Maybe a swipe or two of Shellac first?
That's worth thinking about woodPixel.

What I still struggle with is the fact that I only get the problem with NG Rosewood (although my lacquer supplier did say bubbles were a common problem with this timber) and only when the panel is horizontal.

I stripped it yesterday, re-sanded and re-routed it and applied two coats of Solarez (to be sure ... to be sure ... like the Irishman who wore two condoms ... then two coats of sanding sealer followed by two coats of lacquer.

Once everything is dry and hard I'll rub it back with 400 grit wet and dry and apply a final, thin flash coat.

The Solarez works.

[rod1949]

I was using some Solarez today. I was filling/flooding some cracks. Put the timber in the sun to cure which is instant and I put a finger on the curing solarez to fine it gets extremely HOT whilst curing.

[John Samuel]

I was using some Solarez today. I was filling/flooding some cracks. Put the timber in the sun to cure which is instant and I put a finger on the curing solarez to fine it gets extremely HOT whilst curing.
Rod,

Are you getting the desired results with Solarez?

[rod1949]

Rod,

Are you getting the desired results with Solarez?

Yes I am John. Given its fluidness (compared resin) and instant drying filling the voids is very quick. A downside is, as I'm doing spot fills and not over the whole timber, I get spot stains that darkens the timber and thus this shows in the finish.

[John Samuel]

Just finished a bedside table in NGR.

Used two coats of Solarez to seal the top.

Works like magic. No bubbles or pinholes.

Solarez is great at eliminating pin holes and bubbles. It is also a first class grain filler. It will be a permanent feature in my workshop.