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Bubbles in my top coat

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Forum topic by Jim posted 01-31-2011 03:01 PM 3535 views 0 times favorited 17 replies Add to Favorites Watch
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Jim

32 posts in 2347 days


01-31-2011 03:01 PM

Topic tags/keywords: question finishing traditional rustic pecky cypress

Good morning. I need a little help with a table I’m making. Because my workshop is under my house (on stilts) and usually below 50 degrees (I’m in the NC mountains), I’m using a satin lacquer as my topcoat. It’s Deft (no sanding between coats) and I’m using a good brush. I tried cutting with lacquer thinner and I still can’t seem to get a smooth finish. Any suggestions? Thanks

-- All who wander are not lost.


17 replies so far

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CharlesNeil

1610 posts in 3335 days


#1 posted 01-31-2011 03:59 PM

couple of questions, what is the wood, second, is it bubbles as in blisters or as in debris in the finish, deft usually levels pretty well, how ever, while its not needed, mid coat sanding is a good idea, i usually use some 320 between coats, since it is lacquer, one coat will bite into and adhere to the other,,, ( chemical bond) so midcoat sanding isnt required for adhesion, but it is for a nice level finish

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snowdog

1158 posts in 3447 days


#2 posted 01-31-2011 04:01 PM

I use a shop light (regular bulb) on a timer in my shop when it is cold. I point it directly at the work surface about 3 or 4 feet away. It works great and the finish cures in very little time with no problems that way. Prior to that I had a heck of a time with tacky cures.

I am not sure about this one but I have heard that a heat gun can remove air bubbles but test that and keep a fire extinguisher handy :)

-- "so much to learn and so little time"..

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ScottN

261 posts in 2144 days


#3 posted 01-31-2011 04:10 PM

My first bet would be that the stain hasn’t fully dried yet. You said your shop was around 50 deg so it would probably have to sit at least couple of days.

-- New Auburn,WI

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Jim

32 posts in 2347 days


#4 posted 01-31-2011 04:27 PM

Thanks, the wood is old pecky cypress. I used a natural danish oil for the stain. I let that dry for about a week before I put a couple of coats of General Finish gel poly. It took that so long to dry that I sanded and used the Deft. I really like the gel because it goes on so well, but I think it’s warm blooded…. I don’t think it’s debris, I wiped the wood with mineral sprits and compressed air to remove any dust.

-- All who wander are not lost.

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RBWoodworker

432 posts in 2816 days


#5 posted 01-31-2011 04:31 PM

This really isnt too hard to finish.. Charles Neil has guidid me thru some harrowing nightmares myself..hes correct..sand between the coats eventually you will seal the wood and no more air will escape to allow bubbles to form..

-- Randall Child http://www.racfurniture.com/

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CharlesNeil

1610 posts in 3335 days


#6 posted 01-31-2011 04:54 PM

I am wondering of we are gettin some lifting of the gel poly, meaning of any was left on the deft will krinkle it up, ( lifting), I would give it a good 320 sanding and try another coat… pay close attention when you sand it, are the bubbles breaking ( blister) or is something contaminating,,, as well deft is a brushing lacquer , has lots of retarder in it, to slow the dry, debris can land on it you have lumps and bumps,,, a picture would help alot

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Jim

32 posts in 2347 days


#7 posted 01-31-2011 05:38 PM

Thank for your help Charles! I just took a pic, hope you can see the problem.

-- All who wander are not lost.

View CharlesNeil's profile

CharlesNeil

1610 posts in 3335 days


#8 posted 01-31-2011 06:33 PM

ok try giving it that 32 scuff sand and lets go from there….it almost looks like its brush drag marks, which can happen with deft or any brushing lacquer, its a result of the bottom coat being redissolved by the next coat…My concern is if its contaminated with the poly , it could reoccur, so lets just scuff sand a small section with some 320 and apply a coat and see what happens…it it lays out, and is ok, then we may want to sand it with some 600 to a smooth surface, then using a rattle can of deft, spray a final coat rather than brushing, the spray can deft has better driers and dryes much faster…. but lays out very nice

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Jim

32 posts in 2347 days


#9 posted 01-31-2011 11:54 PM

Thanks again Charles. I think I’m going to sand it back to bare wood and start over. Question…. should I brush a couple of coats and then spray or just go staight to spray?

-- All who wander are not lost.

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CharlesNeil

1610 posts in 3335 days


#10 posted 02-01-2011 02:30 PM

well the spray cans are expensive. so brushing a coat or twofor build nad level would be much less expensive, and also will lay down a heavier coat, use the spray can for the final , but remember a spray can doesnt lay down a very thick coat, so sand it up to about 600, other wise the thin spray will not fill the 320 sand scratches, i often hit it with a spray can, let ti dry then do the 600 and a last final spray

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Jim

32 posts in 2347 days


#11 posted 02-01-2011 02:36 PM

I have also heard that a coat of shellac first to seal the wood works, what are your thoughts on that?

-- All who wander are not lost.

View CharlesNeil's profile

CharlesNeil

1610 posts in 3335 days


#12 posted 02-01-2011 03:30 PM

that works well, however lacquer is self sealing, unless you have contamination, if the contamination here is actually the poly , the shellac will react in the same manner, meaning the shellac can also lift the poly, its a case where the shellac or lacquer trys to redissolve the poly, lacquer is worse than shellac, however lacquer will also redissolve the shellac, so its a case of either/or the shellac certainly wouldnt hurt, but I would also use a spray can, and apply a couple light coats the spray can shellac is dewaxed .. do not use the orange or the yellow qts as they are not dewaxed , if you choose to brush use the seal coat or mix your own , a 2 lb cut would do fine,,the spray can is a 1lb , the seal coat is a 3 lb , which is fine as well

View sandhill's profile

sandhill

2128 posts in 3388 days


#13 posted 03-29-2011 09:26 PM

I have the same problem with cypress. Charles nailed it. I did find that Arm r seal poly/oil seems to do the best job for me but you have to apply a lot of coats.

View Jim's profile

Jim

32 posts in 2347 days


#14 posted 03-29-2011 10:16 PM

I ended up starting over…. I sanded back to raw wood and then I used the advise Charles gave me. I sealed it with un-waxed shellac (2 coats) then used the lacquer, I think I gave it about 10 thin coats. I used shop lights 2 feet above the tables to help with the drying. It turned out great. I think the most important leson I learned here was PATIENCE is very important when it comes to finishing. I have a lot more lesons to learn but I think I’ll enjoy learning them.

-- All who wander are not lost.

View fussy's profile

fussy

980 posts in 2515 days


#15 posted 03-31-2011 02:54 PM

Charles,

Let me add my 1.5 cents. In following this discussion I was feeling Jim’s pain and was trying to come up with a solution, but was unsure. You took time to walk us through it, we all learned a valuable lesson, and I just want to say “Thank you.”

Steve

-- Steve in KY. 44 years so far with my lovely bride. Think I'll keep her.

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