Dry-Ice cleaning

[RichardP]

Hi, I have posted only a couple of times but been reading the forum for some time. I have an old house with loads of oak (door, paneling in rooms etc). most of it has not been well looked after and is very dirty (especially from the knee down on the panelling) and the previous owner put a good thick layer of varnish over the whole lot.

I am looking to clean up the oak paneling etc and have tried using varnish stripper and wire wool. The varnish comes off reasonable well but it is a very very slow job and I have room after room of it to do.

I was looking over the weekend at alternative methods and one I came up with was DryIce cleaning. This looks to be a similar process to say media blasting, however it is used in industry to clean things like plastic moldings and electrical components because it is not abrasive (working by the dry ice some how fracturing the surface layer through contractions from what I can see.

Just wondered if anyone had any experience in this method of cleaning (either on wood or in its industrial purpose) as on the face of it, it look non abrasive and may be transferable from industry to home use.

PS - anyone in the South East nr Tunbridge Wells know of any good joiners to make bespoke windows (all joiners I talk to just want to sell what they already make..)?

thanks

 

[chuckey]

Can't help you with the dry ice. have you tried using a wood chisel as a scraper for flat panels? I use a sharp chisel, held at 60 degrees to the surface and drag it across the surface, while putting pressure on it. This method works well on brittle paints/varnishes. After about 10 minutes, rub the chisel on a smooth stone to touch up the edge and repeat! Finish of with 120 grade aluminium oxide paper. Its much better then chemicals -no staining or residues.
Just remembered, I got this method from my father except that he used broken bits of glass and dumped them when their edges went!!!
Frank

 

[Penners]

I have no experience of dry-ice paint removal, but I do remember its being mentioned in a previous thread as being effective at removing paint without abrading the wood substrate.

However, I would urge caution. Even if the dry ice has the capacity to break up the paint into flakes, the force that lifts those flakes off the substrate will still need to be considerable. If I were considering the the treatment - particularly on the scale that you appear to be talking about - I would demand a demonstration on a small area of my timber before I gave the go-ahead.

I also remember the previous thread saying that it's a costly process.

As regards Franks's suggestion of scraping, I feel I must add that this should be approached with caution for two reasons. Firstly, on smooth-sanded panelling it may be effective, but considerable practice and skill is required in this old cabinet-making technique to be able to remove the finish without taking off any wood whatsoever. On adze-shaped oak beams, it's not really suitable at all. The surface of the substrate simply isn't smooth enough. Scraping is also very tiring and hard on the hands.

If for any reason you decide that the dry ice process is not for you, have you tried Klingstrip? It's been my preferred oak-stripper for many years (and this isn't a commercial, because I have no interest whatsoever in the company!). Have a look at http://www.stripperspaintremovers.com/index.htm

 

[Penners]

Frank - if you're really getting into scraping as a cabinet-making technique, why not get yourself a proper scraper, rather than improvising with a chisel? You'll find it much more controllable and quick. Have a look at: http://www.axminster.co.uk/user_sea...ct-Lie-Nielsen-Cabinet-Scraper-Set-460356.htm

To learn how to sharpen a scraper, this is a good website: http://www.cabinetmaking.co.uk/scraper1of2.htm

 

[chuckey]

I have tried a "Sandvik" scraper. Its very difficult to resharpen. I have also ground up a traditional scraper with a curl that does the business this again works well until its time to re-sharpen it. I have come to the conclusion that the tool re-sharpening time is a considerable fraction of the total scraping time time, hence I use "glass hard" metal files ground to a chisel blade as the re-sharpening time is very short.
Yes, this won't work on rough textured wood, though nosing and curves can be tackled, albeit with care. I have a 1/4" wide radiused nosed chisel for internal curves.
Again (funny story), my old mans broken glass method:- Years ago(1961?) He bought a dark stained and heavily carved drop front bureau, which he started to scrape using glass fragments. My English Grandfather turned up and yes, he would help. As things would be, my German grandfather was staying with us on holiday and, not to be out done he would try his hand at it . Well it ended up with these two old buffers, scraping away and conversing in first world war soldiers french. We young'uns just left them to it. My sister still has the bureau, replendent in its light oak state.
Frank

 

[Penners]

it ended up with these two old buffers, scraping away and conversing in first world war soldiers french.

Nice story. If they'd been together on Christmas Day, they'd probably have played football!

Yes, broken glass is often used for scraping - the trick is to get a piece with a nice straight edge.

 

[Carol]

Forgive my ignorance, but what sort of broken glass would you use and how would you hold it.

(I think every time I've handled broken glass I've cut myself )

 

[Penners]

Forgive my ignorance, but what sort of broken glass would you use and how would you hold it.

Any sort, with a nice, clean, sharp edge, and very, very carefully!

I've never scraped with glass, but I think I would probably wrap some clingfilm around the top half or three-quarters for grip, then plenty of fabric on top of the clingfilm.

 

[chuckey]

Get hold of you shard of glass, a piece with say a straight edge 1/2" wide, this is often the end of a triangle, say 3" long. Grasp the FLAT surface of the glass about an inch up from the edge to use. From memory, each thumb on your side of the glass and your other fingers on the far side. Drag it towards you at an angle of 60 degrees. You would have to be pretty cackhanded to cut your self. The biggest danger is the glass snapping in half, horizontaly. The danger though apparent, never actually materialized, i.e. I probabley cut myself twice in 20+ hours and not severely, just a enough to restore concentration. :roll:
Frank

 

[rogerh]

I saw dry ice being used on TV to remove mould from the plywood sheeting lining the inside of a roof. I think it was on Holmes on Homes which is a Canadian building series on Discovery Real. (Great programme, by the way.) Seemed very effective and without damaging the wood.

 

[rogerh]

Here it is:

http://www.wickensdryiceblasting.com

 

[Flyfisher]

I am looking to clean up the oak paneling etc and have tried using varnish stripper and wire wool. The varnish comes off reasonable well but it is a very very slow job and I have room after room of it to do.

I've not done this myself, but I've read that wire wool is not a good idea when stripping oak as bits of the wire (steel) wool can become embedded in the wood and later rust, thus staining the wood. Can anyone confirm/deny this from direct experience?

 

[chuckey]

Yes you are right, oak contains tannic acid that rusts steel easily, I have also found that EVA wood glue goes black when gluing oak . You should be OK with stainless steel pot cleaning scourers on the staining front. I can't vouch for their effectivness though.
Frank