Thread: Huon Pine Reacting to Coating...Turns Pink?!?

something in the timber?

what epoxy are you using?

I'm using Megapoxy HX as the main casting resin.

But I also use Dalchem Crystal Clear as a finishing coating (basically liquid glass) and it has done the same thing too.

Its got me baffled because some areas of the timber do it worse than others.

Originally Posted by hardwood_tides

Its got me baffled because some areas of the timber do it worse than others.

Seems this is becoming more common, recently there was the thread about the ply on a rocking horse changing colour.

Is there any difference in the preparation of those areas? i.e. more sanding? or was there more material removed to level / thickness it? Could be that more effort / work, creating heat, in those areas is freeing up the natural oils in the huon pine.

Reviewing absolutely everything that you have done or subjected the timber to may offer some ideas on possible contamination from another source. Was it covered by another timber or material, iron sheet? Was steel wool used? Possible contamination from overspray from say another aerosol product? Partially covered & subjected to sunlight? Is it simply grain variation in those areas reacting differently to your finishing schedule? i.e. confused grain vs straight grain enabling "free movement" of the extractives / more volatile natural oils? Could even be something that may have happened well before it came into your possession, how it was stored, partially exposed to direct sunlight etc.

Some timbers such as WA Jarrah don't react very well to having "items" stored or being partially covered by another material, scrap, tools, etc even overnight and may / will finish with defined patches apparent where the covering was placed.

I have a possible explanation as to why there appears to be a colour change but its not chemistry related. Trees i.e. timbers do have some complex organic chemistry to deter critters from eating it.

My best advice if my suspicion below is incorrect would be to contact the manufacturers of the resin to make them aware of your experience and to ask if they have any explanation of what is most likely to be causing the colour change.

edit - on closer inspection of the first image it appears that the item has been thickness sanded and that the "colour changed" areas have not been sanded back to raw timber. The lighter areas are true exposed wood where as the "colour changed" areas still have a coating of the casting resin over them. The demarcation lines between the areas is ragged and consistent with sanding lines. In the top LH piece of huon pine there appears to be original milling saw lines still visible in the wood, therefore some wood, the far right end is exposed fresh raw wood, whereas the bulk is aged exposed to light and air wood.

My suspicion is that there is no chemistry related colour change at all, simply some areas of wood thicknessed / sanded back to fresh wood, with the bulk being aged wood that has been exposed to light and air and covered by an inconsistent thickness of epoxy. The bulk of the top LH piece of huon appears to be aged exposed wood with original milling marks still visible. Some resins may not be optically clear and will have some colour to them so the varying colour change is due to the varying film thickness of the resin. The lighter areas have a consistent film thickness so do not have any apparent colour gradation.

My advice is to pre-finish i.e. at least remove the aged surface from all pieces prior to casting.

It may be because of its naturally occurring methyl eugenol oil. A chemical reaction probably starts during the curing stage of your finish.
Read this.
Extract from Huon Pine timber | Huon Pine @ Tasmania's Special Timbers The timber contains quantities of a natural preserving oil called methyl eugenol which allows it to survive on or under the forest floor for centuries. A buried Huon pine log was documented by scientists to have been lying there for 38,000 years! As well as being a preservative, the methyl eugenol provides the timber with natural lubrication, so it can be bent, shaped or sculpted without splitting. It is also waterproof and insect resistant, making it prized as a boat building timber.

methyl eugenol is contained in the timber.

Methyl eugenol, and similar PHENOLIC chemicals are in this wood oil conferring the properties mentioned above AND likely interfering (chemically) with coatings adhesives and resins (some which use phenols.) Similar compounds are found in clove oil and other plants extracts and are powerful antiseptics/ preservative (eg creosote). The variations in affects could be a results of variations in surface wood oil content. Cant offer a solution except removal with solvent but the wood oil may still diffuse to the surface where ut may or may not interfere after curing / drying.

Euge (short for eugenol .... )

Thanks for all the help guys - looks like the general consensus is Methyl Eugenol.

I've just now done a test with some sealer on an offcut of the Huon and will sand slightly and then resin coat as a test and see if that is enough to relieve the issue.

If that fails I'll also try the wiping with metho trick before coating and see if that helps - can't make it any worse.

Having said all that I can't resist saying that one of the most desirable characteristics of anything made of Huon Pine (Lagarostrobos franklinii) is the scent of the timber itself which continues to "off-gas" for decades. In fact, you can still smell its scent on furniture well over a 100 years old. A light sand of exposed surfaces and a new waxing will let it all out. From my experience anyway. Apart from its beautiful work-ability that is.
So, I'm just wondering why you want to mask the fantastic scent by covering your object with resin, epoxy or any other synthetic coating for that matter.
If you're making a piece of furniture then I'd highly recommend that you simply apply a high quality furniture wax. Ubeaut has a nice one.
Visit some of the antique shops and check out the Huon Pine furniture - if they have any or if they do and some idiot hasn't painted it - and you'll find that wax is the only finish on it. a wax finish will continue to allow the scent to be released for ever just about.
Anyway good luck with the project.
Cheers

Originally Posted by Shedhand

Having said all that I can't resist saying that one of the most desirable characteristics of anything made of Huon Pine (Lagarostrobos franklinii) is the scent of the timber itself which continues to "off-gas" for decades. In fact, you can still smell its scent on furniture well over a 100 years old. A light sand of exposed surfaces and a new waxing will let it all out. From my experience anyway. Apart from its beautiful work-ability that is.
So, I'm just wondering why you want to mask the fantastic scent by covering your object with resin, epoxy or any other synthetic coating for that matter.
If you're making a piece of furniture then I'd highly recommend that you simply apply a high quality furniture wax. Ubeaut has a nice one.
Visit some of the antique shops and check out the Huon Pine furniture - if they have any or if they do and some idiot hasn't painted it - and you'll find that wax is the only finish on it. a wax finish will continue to allow the scent to be released for ever just about.
Anyway good luck with the project.
Cheers

Hi Shedhand,

Point taken, however the pieces I make are surfboards (art pieces not functional) and skateboard decks. Its very important to have the timber sealed for a few reasons, the main two being I export overseas (France & USA mainly) and the look my clients are going for are a high gloss finish.

Exposed timber is harder to export, sealed timber is not an issue.

Not to mention the resin 'skin' coated over them keeps them structurally stronger and also not prone to humidity or high moisture conditions which can cause them to warp over time.

I've been making these for over 3 years now so this isn't a stand alone project, just something I've noticed on some Huon Pine pieces lately.

The irony is that I've used Huon Pine alot and on almost all of my early pieces I didn't have this issue, its only more recently.

Thankfully now I'm confident with the help of forum members I've gotten to the source of the issue to hopefully avoid it moving forward.

Quick update for anyone following along...

I did a test over the weekend with a scrap piece of Huon that came from the same pieces I had the reaction with.

The test involved sealing the timber with Bondall Monocel Timber Sealer...I did a bit of research and could see any reason why this sealer would not work well.

So I sealed with it and the next day gave it a sand with 320G, dusted off and applied a finishing resin I use (Dalchem Crystal Clear) which I have had reactions with before on Huon.

Initial pouring and watching for 10-15 mins yielded good results so I left alone overnight to check this morning.

The good news is it worked a treat - because the sealer is water based 100% acrylic I was confident it would not react with the timber...tick.

And as a barrier it has subsequently stopped the resin from reacting anywhere the sealer is on the timber.

The proof is when you look at the photo you can see the resin has certainly reacted (turned pink) on any areas exposed...especially the side.

In the end good result and thanks for the assistance all.

IMG_2090.jpg