Redo failed finish?

[russ57]

Looking for advice / opinions on refinishing a couple of table tops. These are used in a church Cafe. The tops are some hardwood. I suspect the finish has reacted with the cleaning product, 'lemonproof' which is an ammonia/detergent /lemon oil spray.
The finish has gone quite sticky/gummy.
We have removed it by scraping and sanding.
I suspect it was some sort of oil, tung / blo.
Is reaction with ammonia known?

We intend to refinish with a flooring type polyurethane.

Thoughts? Bad idea? Great idea? Need some sort of solvent before we refinish?

Tia
Russ

[russ57]

Some research has led me to understand that tung oil can indeed react with ammonia, so 8m still inclined to the view that the original finish is probably an oil based. Refinishing with a floor type pu seems to be working OK.

[ubeaut]

The most likely original finish was polyurethane. Same problem happens in cafe's all over Australia.

Next time you go for coffee and cake see if the surface of the table you sit at is sticky or feels soft if you put your thumbnail into it. This will be Polyurethane and a number of different cleaners over time reacting with the finish.

Back in 2005 a Melb shop fitter used our Hard Shellac on tables for one of the restaurants in the My Restaurant rules TV Show. I have been reliably told that the table tops are as good today (well late last year) as they were when first finishes 19 years ago. I believe they are no longer in the original restaurant which is now closed. No other info available. That same shopfitter still buys a 25litre container from us every month or so. He won't tell anyone what he uses, it's his big secret. His secret doesn't help with our commercial sales. However, we do sell it to a number of restorers and high-end cabinet makers in Melbourne.

I have a bell on a piece of meranti which was finished with 2 rough brush coats of Hard Shellac 7 years ago. It is on the wall outside our back door, exposed to the elements. This is also as good today as it was when I did it 7 years ago.

Not the best of photos but you will see what was a brand new bell then is now looking a bit worse for wear whilst the meranti shows no signs of wear. What looks like fading on the finish is in fact just early morning sunlight.

bell6.jpg bell.jpg bell 5.jpg
Hope this has been of some help albeit a bit late.

Cheers - Neil

[ubeaut]

For what it's worth I think the restaurant mentioned above may have been Pink Salt.

[auscab]

Is reaction with ammonia known?

Yes.
I knew two old antique dealer brothers who ran a shop and workshop from around 1940 to 1988 roughly . One of them told me once they used to use straight Ammonia to strip the finish from furniture! They did it outside of course because of the fumes.
I'm not sure if it was just the paint jobs over original finish on the antiques or the varnish / shellac finishes . The guy telling me was saying drums of stripper were not available like we could get it at that time the 1980s . Caustic soda would have been available but wrecked the timber. They were working with Mahogany and walnut furniture, not country kitchen tables and pine pieces. Caustic could be used on pine if painted and you could get a way with it. If the scrubbed pine look was what you were after. .

[Tonyz]

Mr Ubeaut sir,

I am lining the base of my uts with thick oregon 18mm x 149mm x 1800mm There is the plastic tub liner underneath. What would you suggest for protecting the timber.
There will also be strips of black metal 3mm x 35mm for stuff to slide on and protect the timber.

[aldav]

There is the plastic tub liner underneath. What would you suggest for protecting the timber.
There will also be strips of black metal 3mm x 35mm for stuff to slide on and protect the timber.

OMG! I'll be interested to see if there's any way this can be saved from an untimely demise.

[Tonyz]

whats the prob. Yourve seen early American pickup beds
lightshot

for something different Iam doing this to my Falcon ute. keeping the original tub underneath for extra protection

[aldav]

I'll bet they didn't use Oregon (Douglas Fir), Tony, especially sitting in a plastic tub. You need a timber with a high rot resistant rating to have any chance of surviving those conditions. Save your Oregon for something more appropriate and for your ute look at some of the Australian high durability hardwoods.

[ubeaut]

Mr Ubeaut sir,

I am lining the base of my uts with thick oregon 18mm x 149mm x 1800mm There is the plastic tub liner underneath. What would you suggest for protecting the timber.
There will also be strips of black metal 3mm x 35mm for stuff to slide on and protect the timber.

Hi Tonyz

Think I'd have to go with what aldav said about the hardness of the timber. Oregon would be a bit soft for mine. It will dent and scratch up pretty easily even with the metal strips to to protect the top. A harder timber would stand up to what it's probably going to have thrown at it over the years to come.

Oregon might be fine if the ute will be for show only, and not for work. Hard Shellac may do the job well but it isn't an exterior finish by an means so I have no idea how it will stand up to direct sunlight, rain, dust etc in that situation. I would imagine the yank tanks would have been finished with nitro or some other automotive lacquer, back in the day.

Had a friend who decked out his 1954 (or there about) flat bed F100 in the late 80's. The bed (from memory) was, grey or yellow box floor boards which he sprayed with the Hard Shellac. Which then, was in the early days of development and testing and long before it went on the market... Last time I saw it was around mid 1990's and it still looked reasonable (sort of) that was a few days after he totalled it when he hit a cow or bull and rolled it a couple of times down an embankment. It was on its way to F100 boot hill in Castlemaine. Haven't seen it or him since.

'twas a beautiful thing before he broke it.

Not sure if this is of any help Tony. But it's about the best I can offer.

[ian]

whats the prob. Yourve seen early American pickup beds
lightshot

for something different Iam doing this to my Falcon ute. keeping the original tub underneath for extra protection

Tony, I have to ask why are you keeping the rubber tray liner and decking your ute with real timber? If it were me, I'd just cut two sheets of OSB to fit the wheel arches, and replace the OSB (or construction ply) as it wears out. You should be able to buy the OSB or construction ply for a fraction of the cost of real timber.

Unless you are sliding heavy stuff in and out on a regular basis I wouldn't bother with metal strips.

[Tonyz]

Take your advice gents.

So as my ute is dark meteallic blue and Iam planning on Blue/dk gold overall outside finish what timbers would you suggest please