design burned platter nearly bleached by poly

[Jeremy Patrick]

Hoping for some saving words of wisdom. Wife and I had taken part in a wood burning class for fun, made two platters meant as serving trays. Not sure of the actual wood composition of the platters, definitely soft like pine.
Anyway, we had stained them a few months ago and I finally got around to putting a coat of poly on them this morning. Within 2 hours the wood burned portion and the general color of the stained wood was nearly neutralized. can barely see any wood burned areas now and it's like it was never stained. Only area that seems to have kept it's color is the endgrain.
Nothing terribly special about the poly, some minwax fast drying. Maybe it was a bad batch?
Trying to figure out what in the world may have happened and what the best course of action would be to restore these so we can actually see the burned design.
Only one coat on so far, so if sanding it down is the first step at least I won't be trying to undo a bunch of layers.

Thanks

[Edward Dyas]

Hoping for some saving words of wisdom. Wife and I had taken part in a wood burning class for fun, made two platters meant as serving trays. Not sure of the actual wood composition of the platters, definitely soft like pine.
Anyway, we had stained them a few months ago and I finally got around to putting a coat of poly on them this morning. Within 2 hours the wood burned portion and the general color of the stained wood was nearly neutralized. can barely see any wood burned areas now and it's like it was never stained. Only area that seems to have kept it's color is the endgrain.
Nothing terribly special about the poly, some minwax fast drying. Maybe it was a bad batch?
Trying to figure out what in the world may have happened and what the best course of action would be to restore these so we can actually see the burned design.
Only one coat on so far, so if sanding it down is the first step at least I won't be trying to undo a bunch of layers.

Thanks

Does it kind of have a milky appearance to the finish? The only thing I can think of that went wrong is the finish blushed. It means in humid conditions water literally gets in the finish and turns it cloudy. If that is what it is then with polyurethane stripping it off is the only solution. By the time you sand it a little afterwards you will probably have to touch up the wood burning.

It's best not to do any finishing work with any film finish when the humidity gets up around 70%. Even the slow drying poly isn't exempt from blush.

[Jeremy Patrick]

I'm in mid WI and we're sitting in the 10-20 degree mark, humidity should be quite low and on top of it I have a forced air furnace heating up my shop. So it should be quite dry overall.
But in terms of the appearance, it didn't appear to have any abnormal look to it, other than the bleached effect. No milky appearance or anything else that would strike me as abnormal looking.
I was going to spray finish these but the stupid needle spring flew off and it's probably long lost. waiting on a replacement but I need to get these done this weekend.
Unless you know of any cheaper gun replacements that would work with an earlex 5500 and could be purchased at harbor freight...
Would still obviously need to fix the burning beforehand though.

[Jim Becker]

What species is the wood? Many will get darker when you add an oil based product to them which would get the "regular" surface a lot closer to the typical brown that results from pyrography...IE, the contrast is greatly reduced. A water borne finish would likely have less of this effect, but you may be stuck with the result on the existing workpiece at this point.

[Jeremy Patrick]

I'm not sure of the wood make up for these platters. felt and smelled like Pine but they were included in the class so I don't know where they were bought from or any other details.
I'll pick up another can of poly and see what I can do with a bit of sanding, burning and re-coating.

[Jim Becker]

If what you used first was oil based, try a water borne product for your second go and see what the difference might be. As I mentioned, oil based products tend to darken many wood species almost immediately. Try both on sample workpieces and go from there.

[Jeremy Patrick]

i have some garnet flakes i could use to get a darkened look but ill certainly test it out.
picked up a few alternate guns today so maybe i can do a weekend recovery.

any chance you have seen what em6000 or 9300 is rated for in terms of food contact once fully cured?
doubt there will be much food in contact but mostly platters or plates but just curious overall.

[Edward Dyas]

i have some garnet flakes i could use to get a darkened look but ill certainly test it out.
picked up a few alternate guns today so maybe i can do a weekend recovery.

any chance you have seen what em6000 or 9300 is rated for in terms of food contact once fully cured?
doubt there will be much food in contact but mostly platters or plates but just curious overall.

Can you post a picture of the finish you are having trouble with. Sometimes finishes have problems with compatibility with stains or other products you used but having the stain dry for months eliminates that possibility. You should not have had any problems. A mystery for sure.

When you come down to it any finish made after the 1970's is considered food safe when cured. The em9300 would be better for that purpose. It would be more water resistant.

[Jeremy Patrick]

It ended up being the poly. I have pictures but the iPhone page doesn’t give me the option to include them.
Took some mineral spirits and did a number of applications and scrubbing with steel wool and it started coming off.
I’m guessing the can I had was a bad batch or something else wrong with it.

[Jim Becker]

I have pictures but the iPhone page doesn’t give me the option to include them.

Posting and seeing photos requires being a Contributor which is a whole $6 a year. Click on the "Donate" button on the top to do that. For posting photos from a mobile, you'll have to switch your view to the "full", regular browser view as the mobile view doesn't support that on this particular forum software.

'Glad you got it figured out!

[Jeremy Patrick]

I saw the option to switch to full mode but for the quick reply I didn't want to mess with it.
I must have already donated if that is the only way to submit pictures. I can see the option to do it via the page in a normal PC browser.

Now the question is after putting stain back on these, is there any particular sequence before the 9300 is sprayed? spray a sealer coat of shellac before?
The projects I have been doing so far hadn't involved a stain, so this is a small loop I'm trying to figure out.

[Jim Becker]

Yes, my eyes were playing tricks and I missed that you were already a contributor. My apologies.

If the stain is oil based, you'll need to either let if fully cure (can take a long time) or use a thin barrier coat of de-waxed shellac before applying the water borne finish to insure proper adhesion. For small things, the spray-bomb Zinsser shellac is very easy to use for that and it's wax-free.

[Jeremy Patrick]

no worries. glad to support!

Given the stench from it and not remembering the exact label I'm pretty sure it's oil based.

I'm using a super blonde shellac for my other projects and I do have to touch up a few areas of that. I'm tempted to spray the super blonde on these with just a light coat. I'm kind of doubting the slight tint to this will make much difference on a dark oil based stain.
Think that is too much of a gamble and just stick with the spray-bomb?

[Edward Dyas]

I saw the option to switch to full mode but for the quick reply I didn't want to mess with it.
I must have already donated if that is the only way to submit pictures. I can see the option to do it via the page in a normal PC browser.

Now the question is after putting stain back on these, is there any particular sequence before the 9300 is sprayed? spray a sealer coat of shellac before?
The projects I have been doing so far hadn't involved a stain, so this is a small loop I'm trying to figure out.

You could use a sealer if you wanted to but not standard shellac. Standard shellac has a natural wax which is incompatible with waterborne finishes. You could use a de-waxed shellac such as sealcoat but in my opinion the 9300 alone would be the best bet. Use a light coat at first and let that dry and then finish as normal.

[Jeremy Patrick]

Ah, I should have specified. All the shellac I use is dewaxed.
Main concern I have is how long the strain will take to fully cure. But if I could sealcoat it then I would speed up the process.