• January Turning Challenge: Thin-Stemmed Something! (click here for details)
  • Conversations are now Direct Messages (click here for details)
  • Congratulations to John Lucas for "Lost and Found" being selected as Turning of the Week for January 13, 2025 (click here for details)
  • Welcome new registering member. Your username must be your real First and Last name (for example: John Doe). "Screen names" and "handles" are not allowed and your registration will be deleted if you don't use your real name. Also, do not use all caps nor all lower case.

Vessel finish question

D

Dan Mosley

Joined
Jan 31, 2009
Messages
137
Likes
0
Below is one of several vessels i finished the other day and in the finish there are small needle like dots on the finish.
I sanded them down to 220 - two coats of shellac - knocked down with OOOO steel wool - then 6 or more coats of Deft spray on Laquer.
No matter if i knock it down again or add more coats the needle dots still show up.............wondering why ? any ideas on fixing ?

Thanks Dan
 

Attachments

  • Green .jpg
    Green .jpg
    31.2 KB · Views: 135
Can you get a close up shot that shows what you are referring to? Are they holes or points sticking up?

Since you used shellac, a good way to apply it and get a smooth finish is to apply it when the piece is still on the lathe and the lathe is running. A shellac friction finish will be very smooth and should fill in the small pin holes and not have any "stick-ups".
 
I tried to take a closer up view of the vessel but it comes out to blurry to see - and its a dark green vessel which makes the needle points harder to see but they stick up slightly i think....I ran my finger over it to see if i could feel the bumps but im not totally sure........
Can you explain the friction polish method on the lathe you are talking about? ...........thanks Dan
 
For one thing, I wouldn't stop sanding at 220 - I'd go to 600. And make sure you don't have any dots/depressions/whatever at that point. If you do, then go back down to 220 or 180 and sand through the grits to 600 again.
 
I agree - 600 or 800. Further burnishing with kraft paper (e.g. grocery bags) is practically equivalent to 1200.

Pin holes are usually from popping of entrapped air bubbles. Bumps most likely dust particles. I suggest wiping the work after sanding each grit, and doing the finishing in a more protected environment. A tack cloth is also useful for removing the last remnants of sanding.

For close-up photography, I use a jeweller's loupe as an auxiliary lens; 2x, 5x, and 10x. 5 and 10 may produce some vignetting - so what?
 
It could simply be raised grain. Although I don't remember if you said you sanded after the first coat. Finish if very thin and if there are any wood fibers standing up the finish won't cover them. They need to be sanded off. I've also had steel wool catch in the wood pores and then the steel actually sticks up but I don't think you used any steel wool.
Sand the top coat lightly until you have taken off all the little points. I would use 400 or 600 grit. Then try another coat. It's not dust is it. Although shellac dries faster than most finishes you could still get dust trapped in it.
 
finish

I understand the use of shellac as a sealer, a 50/50 spit coat has been used for decades as a sealer. The problem may be that he pushed the finish to fast. To many coats without adequate drying time. I've had this happen a few times.
Jim
 
As mentioned, kind of sounds like tiny bubbles. For a lacquer finish I always start with a wipe-on coat of lacquer sanding sealer, sometimes two coats. Follow with multiple coats of lacquer, thin coats at 1/2 hour or longer intervals. Even with rattle can lac. there is a bit of technique as far as thickness of coats, distance from nozzle to the object, etc. If the finish is not satisfactory wait a few days, sand lightly with 400 or 600 and try again.
 
As long as everyone is speculating without visual data, what about this? When you apply a solvent finish, the solvent which evaporates inside a pore will blow a bit of a bubble if the vessel involved is closed off on the other end. Also if you bring the piece in from cooler to warmer circumstances. If the pressure exceeds the cohesion of the finish, the bubble will pop, leaving a bump. You cut the crater walls off with a leveling sanding, and if the pore is closed enough, coat two will bridge but not trap enough air under to bubble, and leaves a surface with a dip. Coat three bridges flat.

Sealing with a 1# cut, it's a wipe, a dry and a rewipe. Might be enough to bridge so that the follow-on finish can span it.

I wouldn't bother being anal about surface prep on the wood. If the scenario I present is valid, coarse sandings will merely remove any incipient bridging. The finish, as above will bridge and fill just fine if you apply in a way that allows a partial dry and restick. If you really want fun, French polish it.
 
Dan Mosley said:
Below is one of several vessels i finished the other day and in the finish there are small needle like dots on the finish.
I sanded them down to 220 - two coats of shellac - knocked down with OOOO steel wool - then 6 or more coats of Deft spray on Laquer.
No matter if i knock it down again or add more coats the needle dots still show up.............wondering why ? any ideas on fixing ?

Thanks Dan
Click to expand...


What type of shellac did you use, Does it have wax in it? If you are using a sprayer, you might be getting contaminants in the lacquer. I had that happen before, I had to sand it down to bare wood and start over. Do you sand it past the dimple when you are sanding?
 
Dan Mosley said:
Below is one of several vessels i finished the other day and in the finish there are small needle like dots on the finish.
I sanded them down to 220 - two coats of shellac - knocked down with OOOO steel wool - then 6 or more coats of Deft spray on Laquer.
No matter if i knock it down again or add more coats the needle dots still show up.............wondering why ? any ideas on fixing ?

Thanks Dan
Click to expand...

Hi Dan,

It's hard to say when you have no geographical location. For all I can tell, you could be a pirate on the Indian Ocean with a sat phone and a Oneway on the mother ship. If you fill out your profile, you might receive real answers. I don't need your GPS coordinates, just the state if U.S. or country. At least you have a real name.

I have some questions:

What kind of shellac? How much time between coats? Is the shellac old? Did it fully harden before wooling it? Could a lot of dust have settled on the lacquer before it set? Can you observe the finish with a magnifying glass? Is the sandpaper stearated?
 
Robert and everybody.....

I will update my profile as soon as i can but I live in southern Calif....

The wood ? - Mesquite

What kind of shellac? Amber, Zinsser and wiped on two coats with 0000 knock down between them. The amber adds a nice warmth to the mesquite and also acts as a sealer

How much time between coats? 30min or more and then a few hours before applying the laquer

Is the shellac old? NO....can is 2 weeks old

Did it fully harden before wooling it? Yes

Could a lot of dust have settled on the lacquer before it set? No its not dust it is more like you took a needle and dotted it here and there....some areas have no needle dots at all

Can you observe the finish with a magnifying glass? yes it looks great when you first spray it on but in the next 15 mins or more the dots appear

Is the sandpaper stearated? I use the gold hook and loop discs sold on woodturnersresource...........never had a problem before and i have used a mixture of liquid soap and water 50/50 in a spray bottle before to spray the "dry" mesquite to make clean finish cuts with min tearout and havent had this problem (still sanded thru the grits after the finsh cuts usually starting at 150 or so)..........

The other day i tried a experiment and made a finial for a vessel I made and sanded to 320 - applied danish oil to it and let it dry for 24hrs and then applied Deft spray laquer.......still got the needle dots
On the vessel i made i have applied 2 coats of Danish oil sanding with 500 and 600 grit.....im going to let it dry and spray it to with the Deft.
However now that im reading this I am thinking I should use a couple coats of sanding sealer first before i part it off and 0000 between the coats as a precaution and see if that works..........
 
Dan,

Zinsser's amber shellac has wax in it. This may be your problem. Let the wax settle out for a couple days and then siphon off the shellac from the top of the can into a clean glass jar. This way you can see if any more wax settles out. It's also a good idea to strain it.

The following product would be a better choice and is supposedly de-waxed, but you can never be 100% sure:

http://www.zinsser.com/product_detail.asp?ProductID=72

I prefer to mix my own from fresh de-waxed shellac flake. If you need the warmth you can get flake in many shades.


Edit: You may be going a little too fast with the coats. The solvents need plenty of time to escape before re-coating.
 
Last edited:
Robert Manning said:
...You may be going a little too fast with the coats. The solvents need plenty of time to escape before re-coating.
Click to expand...

My thoughts as well. Even though shellac is dry to the touch in minutes, I'd give it at least a day (preferably more) before hitting it with lacquer. I also agree that the waxed shellac is another likely gotcha. I've had decent success using Zinsser spray shellac as a seal coat. It's dewaxed.
 
agree and ill try what you are mentioning and see if it helps............but remember the finial did not have any shellac on it......but ill try your suggestions.......thanks
 
Dan, given your location, have you checked to see if the Deft formula has been modified toward a water base compliant finish. You might call the manufacturer. Finishes are constantly in flux where you live and they change the formula without changing the label. Some finishes transition from easy to apply to impossibly difficult with the same labeling.

On my last post I changed the link to Zinnser's seal coat. They call this a sanding sealer, but it is simply a 2lb. cut of de-waxed shellac marketed as a sanding sealer. Zinsser sells virtually all prepared shellac.

For many years, there's been a lot of misinformation from companies that sell finishes. Whenever anyone asks me about finishing, I recommend Bob Flexner's book Understanding Wood Finishing as a reference to demystify this misinformation.
 
Robert...........I am sure your right about the water base formula - everything around here from what i hear is now water based.
The shellac i used was just amber colored shellac and not a actual sanding sealer - I just used it that way - the other method i use for sanding sealer is to use 50/50 laquer and laquer thinner (which works very well).

Flexner's book Understanding Wood Finishing - Ill look into that
 
There are alot of things that can cause issues in finishes.
You can have pinholes, craters, bubbles and fisheyes, all mean different things depending on the finish.
In you case, assuming the wood is dry, a pinhole, where there is a little tunnel between layers, usually means the products are incompatible or not enough time to flash off, solvent pop. In the case of the shellac, it could be that it isn't completely dry yet. Dry to touch doesn't mean all the solvents that are trapped between layers have has sufficient time to come up to the surface and degas.

If it is a pinhole all the way through to the mesquite (not likely) it would be oils in the wood coming through and causing pockets where the shellac won't bond because the oils are a contaminant. More likely to happen in a tropical wood like cocobollo.

Craters and fisheyes are usually some contaminant in the air you are spraying, or on the wood. A neighbor spraying armor all next door can cause this as can dirty air from the compressor, silicone in a 5 mile radius (exaggeration) old hoses, dirty guns, contamination induced in your process, etc.
 
Steve.............I think i have found where the problem is........yesterday i turned several finials and finished them this way........first applied 50/50 laquer/laquer thinner to them with 0000 between coats.....i used 2-3 coats and never saw the "needle dots" i mentioned (Behlens laquer-can)......then when dry after about 30min plus i parted them off the lathe and used Deft spray laquer as my finish coat (coats) and this is where the problem came back again.....
its not the same can of spray laquer either so im wondering if i am spraying to thick or wrong.........

I have other finishes ive tried -
- Seal a Cell and Armor Seal - very nice finish but takes along time if you do several coats
- I have used just DO seveal coats and let dry for a week or more and buff with the 3 wheel system - its ok finish but my laquer pc's sell faster
- Alot of times i used DO 2-3 coats - let sit for a week and apply Laquer which is the way I finish most of my projects
- Shellac 2-3 coats - let sit for a week and laquer over also

I like using laquer because it dries fast and lets me keep working with the pc....analine dyes dry fast also.....shellac also but use it less frequently.......The reason for using laquer so much besides the fast drying is i can decide from a satin to semi to gloss just by grabbing a different rattle can and applying it. I will usually knock down the second to the last coat and apply the final coat without doing anything else to it.....I have a 3 wheel buffing system but never seem to be able to get that finish to look like it does by just leaving the laquer alone.........

- but im open to other ways of doing my finishes and I would like to find a way to put a finish on that is not a struggle to obtain a nice finish......if you have any ideas let me know or post them i would appreciate it............thanks
 
Last edited:
Despite it's popularity, I hate Deft. I've had trouble with it for years, and I first used it in Junior High School in 1965. Back then with put it on with a rag. Oh the fumes!!!! A friend of mine did a walnut desk, finished with Deft. It reacted with the desk protector he put on it and it bascially melted it to the desk. I suggest getting a touch-up gun and use some professional grade lacquer. Rattle cans barely atomize the finish, and will always require more work after dry to get the high gloss. Even a really cheap Chinese touch-up gun is better than a rattle can.
 
Let's go back to your last message.

Do I understand that you are using two different lacquers, one brushed on and one in a spray can? That can be a problem if the brushed-on isn't thoroughly dry before the spraying because the thinners in the spray can aren't always compatible with those in the paint can. You said 30 minutes between coats. That isn't enough time. Give it a day or two before using the spray, and it may solve the problem.
 
Last edited:
You must log in or register to reply here.
Back
Top