Silicon curse

[John Samuel]

There is no shortage of horror stories about silicon (and similar) contaminants on wood that ruins finishes. This weekend I had my own initial experience.

Was repairing and refinishing a desk top that came out of my ex's studio. Repairs went well, but as soon as I sprayed the top there were obvious spots where the finish was being repulsed by silicon or similar. I have no idea what the contaminant is, but it is highly repulsive of Nitro cellulose products. Having heard so many horror stories, I feared the worst.

I don't allow silicone lubricants or Mr Sheen type products in the house, and can't imagine what the contaminant is. The desk used to belong to my ex. What may have been placed on the top to contaminate it is anyone's guess. It remains an unsolved mystery.

I read through this site and did some research online, and decided to try something I had not seen before. I left the coat of sanding sealer in place and scrubbed the ugly spots with orange oil and a scourer pad, and then sprayed them with orange oil again. This was repeated until the orange oil was not repulsed, and took about an hour. Then the surface was cleaned down with metho.

In 1974 I was in the Construction Troop of 18 Field Squadron. This troop contained mostly building tradesmen. I remember a bloke who was a painter and decorator who swore by shellac as a sealant and binder, and shellac got several recommendations elsewhere, including this site. Bunnings supplied some shellac, which I have never used before. I mixed it with metho, waited a few hours, and applied three coats to the desk top. It looked good ... like it was sealing and covering.

This morning I sanded it back with 400 grit and put on a coat of sanding sealer. The silicone spots have gone. I got a nice even finish.

I can't guarantee that this approach will work for anyone else, because I don't know what the contaminant was, but it might be worth a shot if you strike similar problems.

I think part of the magik was scrubbing a single spot until that spot no longer repulsed freshly sprayed orange oil.



PS: First coat of lacquer is on. Lovely finish. Not a trace of those ugly silicone spots.

[ubeaut]

Bit of silicon trivia from my experience:

Many, many years ago I had the job of spraying a container load of bunk beds brought in from Taiwan for a furniture shop. That were put in sin storage for wa number of years where faded and aged dramatically due to poor storage.

All were silicon affected when the warehouse people tried to repair them with dozens of cans of Mr Sheen. I sprayed them all with a coat of shellac and then a brown 60% Nitrocellulose lacquer without a problem. The brown covered a multitude of horrible colours below.

As for other contaminants I was spraying a repaired bank counter (with nitro) outside whilst there was some welding being done in the council dept behind my workshop, about 100 mt away. 1st goat was fine, 2nd coat was covered in fisheye. WHAT THE!!! :C Turns out that welding (arc) produces silicone which can carry for a very long way in a light breeze. Took a long time to figure that out but switched from Nitro to Shellac and then back to Nitro again and all was fine. Cured me of outside spraying when the council depo was being used for welding.

Why Shellac Works: From my experience over the years shellac has the amazing ability to be able to stick like s&*t to a blanket on almost anything it is applied to and create a safe barrier for most other surface coatings as well as being a brilliant finish itself.

I have had success with shellac where fisheye drops (anti silicon additive) didn't work. However the fisheye drops (eliminator) is basically for auto finishes and using shellac would be no good on an auto finish. Although I did have a friend who used shellac as a primer on an old Plymouth guard that refused to accept auto primer due to silicon and as far as I know he never had a problem with it for a number of years, until some idiot in a truck couldn't judge the distance between a tram and the parked Plymouth and wiped out the whole right side of the beautiful (from memory 1936) plymouth.:C

Cheers :U

[John Samuel]

Thanks, benevolent dictator.

That's pretty much what my painter and decorator told me in 1974. He reckoned being alcohol based was part of the magik ... but that's something I can't confirm.

Any way we look at it, shellac seems to be a good option for getting rid of silicone problems.

[John Samuel]

Bugger! And double Bugger!

I was scratching through a cardboard box in the broom closet that had been untouched for years when I found a bottle of Mr Sheen and a bottle of Pledge. They are now in the bin.

I explained to my ex why these products were banned from the house, but clearly she decided she knew better than me. At least now I know the likely source of the silicone on the desk I was refinishing.

[EagerBeaver71]

Bugger! And double Bugger!

I was scratching through a cardboard box in the broom closet that had been untouched for years when I found a bottle of Mr Sheen and a bottle of Pledge. They are now in the bin.

I explained to my ex why these products were banned from the house, but clearly she decided she knew better than me. At least now I know the likely source of the silicone on the desk I was refinishing.

After reading this John I'm so glad I got rid of mine.

The wife that is not the Mr Sheen.