Replies

1. 
   SgianDubh | Mar 06, 2003 10:01pm | #1

   Dewaxed shellac is a good barrier and base coat underneath all film finishes as it's the most tolerant film finish over 'difficult' surfaces. Zinnser(sp?) now sell SealCoat, a thinned out (1 or 2lb. cut?) dewaxed shellac designed specifically for this purpose, although it can be used as a complete finish in its own right. One or two coats of this stuff should provide a seal or barrier, and a good base.

   As to your current problem, it sounds like you are polishing over an open grained timber. The fish eyes may not be caused by silicone, but it may be air bubbles trapped deep in the grain and in the pores of the wood that cause the polish to collapse after it's skinned off. I'm not saying that it's not silicone, but offer this cause of pinpricking and bubbles as another possibility.

   If bubbling is due to trapped air, for the future, an alternative to using dewaxed shellac as a first coat under a nitro-cellulose type lacquer, you can thin out the nitro-cellulose type polish about 50% and shoot on a light, thin sealing coat. Once the grain is physically sealed, the air bubble problem should be eliminated.

   You might have to strip off and start again, with the SealCoat, but you might (and I only say might on purpose) be able to rescue the job with some of the SealCoat over the top of what you've already got.

   Notice that at no point in these suggestions did I say anything will definitely work. I can't see what you've got from here. Use the suggestions I've given to help you decide what you've got, and plan your strategies from there. Slainte.

   Website    The poster formerly known as RichardJ-- now Sgian Dubh-- again.

1. 
   BrianF | Mar 06, 2003 11:13pm | #2

   Thanks Richard,

   It's definately not a bubble problem. The finish pulls back in spots all along the top. Kind of like oil and water. I'll try the dewaxed shellac and see what happens, maybe I can save what I got. Worst case I sand and start again. It always seems something like this happens when you try to help out a friend.

   Brian

1. 
   Splintie | Mar 06, 2003 11:41pm | #3

   I've had eventual success with numerous mist coats of lacquer in this situation. I'm talking perseverance here, like 10-15 mist coats before you lay down a "real" coat. I was cautioned not to use the fish eye eliminator bec i was told it would mess up my gun, that fish-eye eliminator was a hair of the dog that bit you...i've no clue if that is accurate, however. 

   Another option would be to dispense altogether with a film coat and see if the friend well accept a wipe-on finish for the table. 

1. 
   BrianF | Mar 07, 2003 01:33am | #4

   Thanks Splitie,

   I've got a coat on of the sealer that Richard suggested and it seems to have done the job. I'll try a few more and sand between to see if I can build up and level out the depressions with out sanding through. I'll take you advise and dump what I have in the cup with the eliminator in it, and clean the gun well. Better safe than sorry. No sense in making a bad situation worse. On the positive side the shellac is a much nicer smell than the conversion varnish.

   Thanks again, Brian

1. 
   SgianDubh | Mar 07, 2003 08:41am | #5

   Well, Brian, I hope you can rescue the job with the SealCoat. I have my doubts, and your later description of the finish crawling away from a spot of possible contamination rather than a pinprick hollow, or bubble leads me to think that you are correct.

   It's true that fish eye killer is a bit of bitch in the gun as that Splintie bird mentioned. The stuff is, uhm,.. it's late and I'm seeking the right term--- it reduces surface tension anyway, assisting levelling, and any residue of the stuff left in the gun can do nasty things to subsequent polish jobs. I'd definitely flush the gun out very thoroughly. I wouldn't consider a gallon of lacquer thinner flushed through as excessive. That's only seven or so dollarss for the materials, and a wee bit of time.

   Splinties telling of the need to gash on 'several' mist coats prior to a real polish coat seems a bit excessive to me. I'd expect to lightly spray on a nitrocellulose type polish thinned out about 30% to 50% just once prior to applying regular coat thicknesses of about 5 mils wet each--even on teak and other difficult oily woods. Some polishes of this type are very sensitive to a final dry coat thickness of ~5 mils max, e.g., pre-catalaysed lacquer, it tends to fail if applied too thickly, but nitrocellulose lacquer can be applied coat upon coat.

   Bear in mind that I'm poor at polishing, and polishing problems, so don't hang on my every word, ha, ha. There are people that drop in here that are much better at analysing(sp?) these sorts of problems than I am. Slainte.

   Website    The poster formerly known as RichardJ-- now Sgian Dubh-- again.

2. 
   BrianF | Mar 07, 2003 05:56pm | #6

   Richard,

   I think that you did better than you had hoped. I put two coats of the sealer that you had recommended. I figured the worst I could do was start over. I lightly sanded this morning and shot a coat of my conversion varnish. It laid down with no problem. It may take a few more coats and sanding to level out, but I think you helped me save it. Like I said that's what I get for trying to be helpfull. (Oh well) I should have tried talk them into a new on instead. Not quite the sentiment value of a 40yr old wedding gift though

   If you or Splintie ever get up to Green Bay I'll have a cold homebrew waiting for you.

   Thaks again, Brian

3. 
   SgianDubh | Mar 07, 2003 07:32pm | #7

   Well, Brian, that seems to be good news. Thanks for the feedback. Do bear in mind my earlier warning regarding final coat thickness. Check your product information sheet for recommendations. If you don't have such a sheet, contact the maker, or your local supplier for this information before you get all hairy chested slapping on numerous coats.

   Cracking and 'chinese writing' appearing 6 months or a year down the road because the final coat thickness is too great is, at a minimum, inconvenient. Slainte.Website    The poster formerly known as RichardJ-- now Sgian Dubh-- again.

4. 
   BrianF | Mar 07, 2003 11:15pm | #8

   Richard,

   A wise man once told me " If some one takes their time to give you advice take the time to listen". (of course no-one listens to their father until much later in life) I'll take what you've given me. I sanded and put on one more quick coat and I'll wait for it to cure and rub it out with some paste wax and call it good.

   Brian

5. 
   Splintie | Mar 08, 2003 05:01am | #10

   Thanks for the feedback about the good results. Keep one on ice for me, OK?

   Colleen

6. 
   SgianDubh | Mar 08, 2003 09:07am | #11

   It seems you might have dodged one Brian, and it makes my day a little better to think I might have helped a bit. Apart from telling lies, belching, farting, and being rude to women from time to time when the mood takes me, that's what these forums are best at.

    I know it's not in the nature of men to read directions--- Directions! Who needs no steenkin' directions? But if you can get hold of the company product information sheets, they can save a lot of heartache. I use ML Campbell products almost exclusively  in the pre-cat, nitro-cellulose type range, and I find their fat book of information useful. Slainte.Website    The poster formerly known as RichardJ-- now Sgian Dubh-- again.

7. 
   Splintie | Mar 08, 2003 04:59am | #9

   Splinties telling of the need to gash on 'several' mist coats prior to a real polish coat seems a bit excessive to me.

   Could be the lacquer i was using, but i've found that if i laid a wet coat down prematurely, the fisheyes would develop right down to the wood, effectively eliminating all the work i had done up to then to bridge them. I like your way better, though, and i'lll use it when one of those nightmares comes my way again. What was i thinking by putting my address on my products, telling people to have me refinish them if they ever needed it??? 

    

8. 
   SgianDubh | Mar 08, 2003 09:09am | #12

   Sounds like it might be worth experimenting a bit on some scrap anyway, Splintie. Slainte.Website    The poster formerly known as RichardJ-- now Sgian Dubh-- again.