Desperately Need Help: Varnish On Veneer Problem

[EagerBeaver71]

Hi,

I can't figure out whats going on here. I've applied one coat of oil based gloss varnish to this piece of red oak veneered plywood. As you can see it looks like the varnish is sinking in on the raised gran but not on the lower?. Please please can someone give some advice?

506637

[EagerBeaver71]

The only thing I can think of which I didn't do is use a wood conditioner, but I thought wood conditioners were only used when staining wood?.

[Skew ChiDAMN!!]

I haven't done much with Red Oak 'in the flat' as I've mainly turned it.

As I understand it, Red Oak is particularly porous (really not a good choice for casks or boats) and in my turnings it has been the end-grain which wicks up nearly everything I can throw at it. Mind you, in turnings almost all of the surface is end-grain to one degree or another. :rolleyes:

Anyways, I digress.

When finishing it I found I needed to apply multiple light 'sealing coats' of whatever my finish of choice was, giving looong curing times between coats to ensure the prior coat is fully cured so I'm not removing any with the next. The idea being to block the open ends of the pores without actually filling the rest of the 'straw' as it were.

Once coats start going on without looking patchy, then I applied proper finishing coats.

This could take anything up to a dozen sealing coats, depending on what I was applying. FWIW, I've also found a coat of thick blond shellac as a first sealing coat helps considerably. (By thick I mean fairly viscous... not a heavy coat!) But as you've already applied a coat of varnish, I don't know that I'd try this.

It's just the nature of Red Oak.

[EagerBeaver71]

I haven't done much with Red Oak 'in the flat' as I've mainly turned it.

As I understand it, Red Oak is particularly porous (really not a good choice for casks or boats) and in my turnings it has been the end-grain which wicks up nearly everything I can throw at it. Mind you, in turnings almost all of the surface is end-grain to one degree or another. :rolleyes:

Anyways, I digress.

When finishing it I found I needed to apply multiple light 'sealing coats' of whatever my finish of choice was, giving looong curing times between coats to ensure the prior coat is fully cured so I'm not removing any with the next. The idea being to block the open ends of the pores without actually filling the rest of the 'straw' as it were.

Once coats start going on without looking patchy, then I applied proper finishing coats.

This could take anything up to a dozen sealing coats, depending on what I was applying. FWIW, I've also found a coat of thick blond shellac as a first sealing coat helps considerably. (By thick I mean fairly viscous... not a heavy coat!) But as you've already applied a coat of varnish, I don't know that I'd try this.

It's just the nature of Red Oak.

Would this apply to plywood boards even though they're only veneered red oak?.

[Skew ChiDAMN!!]

Would this apply to plywood boards even though they're only veneered red oak?.

I'd imagine so. Being a much thinner layer it shouldn't soak up as much finish before becoming saturated, but the veneer is still red oak.

You've only applied the one coat? Perhaps that's enough to act as a sealer in this case and a second coat would be less patchy. I sincerely doubt you'll be able to sufficiently remove the varnish that's already been applied, short of replacing the veneer. so perhaps the way through is to bite the bullet and keep applying coats?

[EagerBeaver71]

I'd imagine so. Being a much thinner layer it shouldn't soak up as much finish before becoming saturated, but the veneer is still red oak.

You've only applied the one coat? Perhaps that's enough to act as a sealer in this case and a second coat would be less patchy. I sincerely doubt you'll be able to sufficiently remove the varnish that's already been applied, short of replacing the veneer. so perhaps the way through is to bite the bullet and keep applying coats?


Hi Andy,

Fortunately I've only used cut offs from the main board to experiment with a few finishes. Having experimented further I've posted another photo
with my findings.

506643


Both boards have been sanded to 600 grit, one on the left I used undiluted Feast & Watson clear varnish (only because I have it knocking around), as you can see its not sunk into the full grain correctly and looks dreadful. One on the left I diluted with 75% Turps and applied two coats and looks better.


I think I will be going the shellac route as you suggested. I'll get some dewaxed ubeaut White Shellac, how much should I dilute it?.

[EagerBeaver71]

Hi Andy,

Fortunately I've only used cut offs from the main board to experiment with a few finishes. Having experimented further I've posted another photo
with my findings.

506643


Both boards have been sanded to 600 grit, one on the left I used undiluted Feast & Watson clear varnish (only because I have it knocking around), as you can see its not sunk into the full grain correctly and looks dreadful. One on the left I diluted with 75% Turps and applied two coats and looks better.


I think I will be going the shellac route as you suggested. I'll get some dewaxed ubeaut White Shellac, how much should I dilute it?.


I should have mentioned this before. I applied the varnish using a rag, left it on the board for a minute then wiped it off. I figured that the veneer would suck some of the varnish in and I'd wipe the excess off, it leaves a very smooth finish but as you can see from the first photo, the look isn't so nice. This was done with both test pieces.

[auscab]

Hi,

I can't figure out whats going on here. I've applied one coat of oil based gloss varnish to this piece of red oak veneered plywood. As you can see it looks like the varnish is sinking in on the raised gran but not on the lower?. Please please can someone give some advice?

506637

Hi Sam .

You have applied a gloss Varnish and it would have soaked and dried in both the grain types I can see there, the flat closed grain parts and the open grain parts. So the flat glassy parts show a little shine and the the open grain parts don't look good. Their rough and open. Gloss varnish is usually left for the end stages of an oil based finish like that.

The normal way of going about sealing and putting a shine on is to do something about the open grain first. Either partly like 80% full or fully filled in . Grain fillers , sanding sealers and knowing how to use them is whats done . And then if your using matching sanding sealers an oil based gloss can go on top.

Staining or changing colours gets a little more complex and Im not talking about that at the moment . Just sticking with natural colour and getting a body , grain fill and shine . Which is what you need to improve that look .

If you get some oil based sanding sealer. Maybe this below or ask what matches your Varnish type as a sanding sealer where you bought it .

Wattyl Est Sanding Sealer - Strathalbyn H Hardware (https://hhardwarestrathalbyn.com.au/wattyl-est-sanding-sealer/)

and go through the process of brush coating, 2 coats first , letting dry between each one , then give a good hard rub back with 320 grit sand paper, do the same again . Then do a couple of coats thinning it each time and being more careful with the rub back using finer paper. Then try the top coat of gloss. You will see an improvement . That's the basics of it using sanding sealers .

[EagerBeaver71]

Hi Sam .

You have applied a gloss Varnish and it would have soaked and dried in both the grain types I can see there, the flat closed grain parts and the open grain parts. So the flat glassy parts show a little shine and the the open grain parts don't look good. Their rough and open. Gloss varnish is usually left for the end stages of an oil based finish like that.

The normal way of going about sealing and putting a shine on is to do something about the open grain first. Either partly like 80% full or fully filled in . Grain fillers , sanding sealers and knowing how to use them is whats done . And then if your using matching sanding sealers an oil based gloss can go on top.

Staining or changing colours gets a little more complex and Im not talking about that at the moment . Just sticking with natural colour and getting a body , grain fill and shine . Which is what you need to improve that look .

If you get some oil based sanding sealer. Maybe this below or ask what matches your Varnish type as a sanding sealer where you bought it .

Wattyl Est Sanding Sealer - Strathalbyn H Hardware (https://hhardwarestrathalbyn.com.au/wattyl-est-sanding-sealer/)

and go through the process of brush coating, 2 coats first , letting dry between each one , then give a good hard rub back with 320 grit sand paper, do the same again . Then do a couple of coats thinning it each time and being more careful with the rub back using finer paper. Then try the top coat of gloss. You will see an improvement . That's the basics of it using sanding sealers .

Thanks so much for your reply Rob. Do you think the grade of veneer is poor on this plywood based on the fact it varnishes up like this. I bought about a dozen of these boards to make some workshop cabinets. Fortunely I've only cut two of them so I do have the option opf returning the rest....

[auscab]

Thanks so much for your reply Rob. Do you think the grade of veneer is poor on this plywood based on the fact it varnishes up like this. I bought about a dozen of these boards to make some workshop cabinets. Fortunely I've only cut two of them so I do have the option opf returning the rest....

No its fine . Its just typical Red Oak. White Oak is pretty open grain stuff as well but not as open as Red Oak and Ive seen the same effect many times when starting out on it or playing around testing things out .

Years ago we used to use Grain filler that was like Mud in a Bucket . 4 lt tins from Haymes. Came in red Oxide and Brown umber colours . It would have been good for such a job as this . The best way to use it was to seal the piece first with a couple of brush coats of shellac . That way the Mud wouldn't stain the flat smooth parts badly but it would fill the grain . We had to throw it on and spread the Mud around across the grain in circles or figure eights , filling and taking off the excess. Then wipe it off straight with a lighter touch to try not to pull it out of the grain. It was oil based filler as well . It would go off and be hard the next day . It was a bit like a mix of window putty thinned down . It smelt the same , silica , you could feel the fine gritty sand in it , and oxide colours .

These days I do similar things using sanding sealer unless its Antique restoration . I don't think the old grain fillers are available any more. Pity . It was good stuff.

[EagerBeaver71]

No its fine . Its just typical Red Oak. White Oak is pretty open grain stuff as well but not as open as Red Oak and Ive seen the same effect many times when starting out on it or playing around testing things out .

Years ago we used to use Grain filler that was like Mud in a Bucket . 4 lt tins from Haymes. Came in red Oxide and Brown umber colours . It would have been good for such a job as this . The best way to use it was to seal the piece first with a couple of brush coats of shellac . That way the Mud wouldn't stain the flat smooth parts badly but it would fill the grain . We had to throw it on and spread the Mud around across the grain in circles or figure eights , filling and taking off the excess. Then wipe it off straight with a lighter touch to try not to pull it out of the grain. It was oil based filler as well . It would go off and be hard the next day . It was a bit like a mix of window putty thinned down . It smelt the same , silica , you could feel the fine gritty sand in it , and oxide colours .

These days I do similar things using sanding sealer unless its Antique restoration . I don't think the old grain fillers are available any more. Pity . It was good stuff.

Thanks again for your wisdom Rob. I'll get some same brand sanding sealer tomorrow and have a crack at it, should I use a thin coat of shellac first or just slap the sanding sealer on and finish it with the varnish?.

[Skew ChiDAMN!!]

I missed that you were using a gloss... in which case, yeah, you want to not only seal the grain but fill any open pores.

While a sanding sealer should do both jobs alright, I find that first applying a coat of shellac to seal normally gives me better results.

I generally mix my own from flakes (also sourced thru U-beaut) but from memory you'll want to dilute the dewaxed shellac about 4 or 5:1 for use as a sealer.

There have also been times I've followed up with a non-diluted coat as a grain filler instead of using a commercial filler, but that's 'cos I'm happy with the surface I get that way and I already have the Shellac out. I'm inherently lazy. ;)

[EagerBeaver71]

Sadly I'm still having the same problem even after 3 coats of sanding sealer and 1 coat of varnish. Heres a video I did to show the problem hopefully more clearly:

Bunnings Red Oak Plywood Problems - YouTube (http://youtu.be/Ym2ajN9WEIA)

[auscab]

3 coats of sanding sealer in one day ? Are you drying it in the sun ? Thats good if you are .

Are you coating it on straight out of the can ? No thinning ? Brushing it on ?
If yes to all that then keep going . It may be thin SS if 3 brush coats only does that .

[auscab]

If it stays to light looking in the open grain you may need to fill the open grain with a darker or a matching grain filler.

[EagerBeaver71]

3 coats of sanding sealer in one day ? Are you drying it in the sun ? Thats good if you are .

Are you coating it on straight out of the can ? No thinning ? Brushing it on ?
If yes to all that then keep going . It may be thin SS if 3 brush coats only does that .

Hi Rob,

The garage is very hot at the moment so they dried pretty quickly. The sanding sealer was laid on with a brush quite liberally.

Could it be that the veneer is so thin that the underlying ordinary ply is showing through?.

[EagerBeaver71]

If it stays to light looking in the open grain you may need to fill the open grain with a darker or a matching grain filler.


There isn't much open grain left to be honest. I think I might leave it and take all the boards back, I've had a sheet of American Oak which only required a couple of coats of varnish and it came up beautiful.

[EagerBeaver71]

I think the veneer is so thin that the underlying ply and glue is showing through and contrasting with the red oak.

[EagerBeaver71]

Just an update and to close off this thread.

Not one to be defeated I did a little testing of my own using the "wet finger" technique taught to me by Rob. Instead I used white spirit. I found that from the dozen boards I brought, there were 3 where the white spirit didn't sink into the grain so I concluded that
there must be some sort of manufacturing defect. It just so happens that the board I choose to start putting finish on was one of bad oens!(my luck!).

From what I have gathered the defect is one of two things. Either the glue used has bled through to the top of the veneer or the veneer itself has a problem like not drying out properly and/or tannin issue.

Forest1 who supply the boards to Bunnings are investigating (hopefully). The only way around this, and like Rob said I would have to fill the open grain with a darker or a matching grain filler. This would have been alot of faffing about so I took the boards back, some were cut (ooops!) and got a refund and went to another bunnings and got another batch.


Here is the result of 3 coats of Bleached Shellac / 2 coat of gloss varnish:

506923 506924

I'm sure you'll agree its a stark difference!.