Wet sanding without darkening the wood too much....what finish?

[John Keeton]

Roger, that shellac will clog fine grit sandpaper quickly and I don't think I would apply walnut oil over it unless you sand it heavily to remove the shellac. If the shellac went on without any runs or lap marks, I think I would spin it with some 0000 and apply a surface finish that would cure quicker.

[Roger Chandler]

Roger, that shellac will clog fine grit sandpaper quickly and I don't think I would apply walnut oil over it unless you sand it heavily to remove the shellac. If the shellac went on without any runs or lap marks, I think I would spin it with some 0000 and apply a surface finish that would cure quicker.

Yeah.....I posted that in a hurry, while busy doing something else, without thinking that comment through. I just had in my mind what I have on hand........I will put more thought into it. When I left it earlier this afternoon, I was thinking let dry thoroughly, and resand. I have some steel wool and synthetic pads......I think it will look good when I finish it up. Not sure what final finish will be yet........got any suggestions you would use in this, John? I'm all ears!

[robert baccus]

Sanding with soapy water is a standard here when working down a lacquer finish. Wet sanding on bare wood seems counterproductive except on very hard oily tropicals. This is for sanding. Finishing with wet sanding oil seems to produce a fine finish but the color change must be allowed for. All the oils used as a final finish seem to darken and dull for me except tungoil. I have old pieces finished with watco and watco under lacquer and there is a significant difference after 5-10 years.

[Roger Chandler]

Sanding with soapy water is a standard here when working down a lacquer finish. Wet sanding on bare wood seems counterproductive except on very hard oily tropicals. This is for sanding. Finishing with wet sanding oil seems to produce a fine finish but the color change must be allowed for. All the oils used as a final finish seem to darken and dull for me except tungoil. I have old pieces finished with watco and watco under lacquer and there is a significant difference after 5-10 years.

Thanks Robert. Last evening, I was looking at finishes online, and WC has raw ting oil by the quart or gallon. The info on it stated they do not remove the fatty acids, and could give variations in color and appearance. I also wonder if it polymerizes without being processed to take out the fatty acids?

[James Conrad]

Thanks Robert. Last evening, I was looking at finishes online, and WC has raw ting oil by the quart or gallon. The info on it stated they do not remove the fatty acids, and could give variations in color and appearance. I also wonder if it polymerizes without being processed to take out the fatty acids?

I don't know what WC is trying to claim with that comment. Pure tung oil is a natural combination of fatty acids primarily eleostearic acid. Perhaps they are trying to say it hasn't been heated to aid in quicker polymerization, or its part of their bit for marketing, but without the natural fatty acids you don't have pure tung oil. Just like polymerized tung oil, pure tung oil will harden it just takes longer, similar to pure linseed. Most tung oils sold as polymerized have been heated and driers have been added to speed up the curing process. And, many branded tung oil finshes contain very little tung oil. For finishing the primary differences between the two is the speed in cure time, a day vs. up to a week, polymerized tung alters the wood color less and finish texture for the same is more smooth. Asking for a copy of their MSDS sheet can also help in knowing what is in it, or not in it.

Finishing with pure tung oil can be done in several ways. I like to start with it thinned down with mineral spirits 70% and work up to final coats of pure undiluted tung oil. Lightly sanded between coats and careful not to sand through the layers. As you work up to your pure coats, cure time will increase.

[Faust M. Ruggiero]

Roger, I'm not sure you ever mentioned if this bowl is a once turned project or if you are finishing it from a dried rough out.
faust

[Roger Chandler]

Roger, I'm not sure you ever mentioned if this bowl is a once turned project or if you are finishing it from a dried rough out.
faust

Sort of a hybrid, Faust. Started with a large maple blank tbat had been sealed about 18 months ago.....stored inside my back shed, out of the weather, and got the summer heat and winter cold. I have turned this in stages, over a period of a week. Little at a time, keeping it on the lathe......let it do its movement, go back, turn some more, true it up.....repeat process, etc.

I am now in the final sanding phase.......I am trying to reach a flawless finish, so this process is a bit protracted, with my limited time, start and stop, catch an hour here or there in between other duties for my work. Not a process that is efficient, but allows me to turn something amongst a very busy schedule.

I am going to sand back the shellac sanding sealer, and then decide what finish to use. I went to my local hardware this morning and purchased fresh cans of WOP and antique oil. I have some Minwax tung oil on hand and Mahoney's......

Depending on the sanding results and how much of the shellac coats I have to take off, that will determine which finish I use. This bowl will be suited for a centerpiece on a large table.......or one could decide to fill it with a mountain of buscuits or rolls, if so inclined!

I think this approach has allowed stabilization to a great degree.......the last three days it has run true. If it does oval a little, that will be okay........I do not believe it is going to crack. Not the most efficient process, but under my unique circumstances, it should produce nice results, I think!

[Hayes Rutherford]

Roger, sometimes I will take straight alcohol on a rag and wipe off shellac if there is any build. As John mentioned it will plug sandpaper in a hurry. Sanding in brief intervals then use an ice pick or wire brush to pick off the clusters as they form. I bend the sandpaper over the tool rest and pop off any small bits of build up as frequently as needed. Kind of a pain but after a little persistence, it no longer builds and thats an indicator that you have completed the process.

[Lloyd Butler]

Also watch out that you if you are going to apply a penetrating oil finish, after sanding back the shellac you want a solid surface of shellac. If you sand back through the shellac in spots, then the oil will penetrate more than in others and you may get darker blotches on the light maple.

I ran into this issue with sanding sealer and then oil. I sanded through the sanding sealer in spots and could not really see, but once the oil was applied it took the liberty of showing me my mistake. The areas where the sanding sealer were still present on the surface stayed much lighter as the oil could not penetrate. I ended up needing to really sand everything back and go with the penetrating oil as I could not get it all out to do a solid coat of sanding sealer.

[John Keeton]

Generally speaking, shellac, lacquer and/or sanding sealers used prior to an oil finish is not very successful. They are sort of mutually exclusive. If you want an oil finish (not to be confused with a varnish blend such as wipe on poly), then the wood should not be sealed with anything as it prevents absorption - the whole idea with oil finishes. Likewise, it is counterproductive to apply an oil and follow with shellac, unless it is a prelude to a film finish. In those instances, the oil should be permitted to cure somewhat, and the dewaxed shellac then will act as a sealer for a film finish.

[Wally Dickerman]

Wet or oil sanding is very effective but should be done after you've done your best to get a good surface on the wood using tools. A much better surface can be had by carefully shear scraping with the grain. Apply Johnsons paste wax first. It does a good of lubricating without much darkening of the wood. Also use it for sanding with the coarsest grit you'll use. Then dry sand.

[Faust M. Ruggiero]

Wally, I am delighted to see you posting. I hope that means you are feeling great. I am curious about using a wax as a lubricant. If you choose that method, I assume you are then committed to an oil finish? Also, when you recommend shear scraping with the grain does that refer to working from the widest diameter toward the smaller diameter of a side grain bowl? Thanks for the tips.
faust

[Roger Chandler]

Generally speaking, shellac, lacquer and/or sanding sealers used prior to an oil finish is not very successful. They are sort of mutually exclusive. If you want an oil finish (not to be confused with a varnish blend such as wipe on poly), then the wood should not be sealed with anything as it prevents absorption - the whole idea with oil finishes. Likewise, it is counterproductive to apply an oil and follow with shellac, unless it is a prelude to a film finish. In those instances, the oil should be permitted to cure somewhat, and the dewaxed shellac then will act as a sealer for a film finish.

Precisely! Using an oil finish is for penetration of the wood.........sanding sealer prevents this for the most part. I am going with a WOP finish on this bowl........put a coat on already, and found a little area of end grain that needs some more attention, and since I am trying to achieve a perfect finish on this, it is back to another sanding sequence.

Some woods are just more stubborn than others! This piece of maple was slick as glass when I put that first coat of WOP on it.......and I inspected it carefully.........I saw this little area, but thought it would be okay with the finish......wrong! So another sanding sequence should take care of that, and then perhaps it is on to the final finish.

This thread is becoming very educational and should help a lot of newer turners with all the wonderful tips each poster has offered up.........thanks everybody!

[Roger Chandler]

Wet or oil sanding is very effective but should be done after you've done your best to get a good surface on the wood using tools. A much better surface can be had by carefully shear scraping with the grain. Apply Johnsons paste wax first. It does a good of lubricating without much darkening of the wood. Also use it for sanding with the coarsest grit you'll use. Then dry sand.

Wally........it is indeed nice to see you post! Hope you are doing well as you recover! I used the technique of shear cutting and shear scraping on this bowl.........as you mention, it really does help give a great surface with which to start the sanding! That wax as a lubricant is something I will have to give a try the next project I have with end grain issues! Thanks!

[Wally Dickerman]

Wally, I am delighted to see you posting. I hope that means you are feeling great. I am curious about using a wax as a lubricant. If you choose that method, I assume you are then committed to an oil finish? Also, when you recommend shear scraping with the grain does that refer to working from the widest diameter toward the smaller diameter of a side grain bowl? Thanks for the tips.
faust

Faust....I am feeling better but not great. I just got home yesterday from an 8-day session in the hospital and 8 days in a rehab. I'm not going to be in my shop for a while.

The wax penetrates very little so if it's used while shear scraping and with only the heavy grits it'll be sanded away and will have no effect on a finish. If I'm going to use an oil finish I use my finishing oil as a lubricant.

I've been using Johnsons wax for years to protect my roughed out pieces. Works very well even here in hot dry Arizona.