Thread: Repel spots in water based lacquer?

I've never heard of CA lacquer before. Can you tell me what it is?

Originally Posted by Kaisergrendel

I've never heard of CA lacquer before. Can you tell me what it is?

Meant NC. Stupid brain.

Thanks for that Kaiser, but I'm still confused as to what you're trying to do with the filler.

I think of Timbermate as a filler for nail and screw holes and other blemishes, not as a grain filler where you want to fill the surface but not obscure the grain.

Even though the Wattyl stuff is oil based, a coat of shelac will seal the surface allowing the use of water based top coats.

Originally Posted by tea lady

Meant NC. Stupid brain.

Hahah ok. I have to at least try everything to make it work with WB lacquer, otherwise I'll be wasting a whole gallon can of very expensive stuff. Will keep the club in mind.

Originally Posted by ian

Thanks for that Kaiser, but I'm still confused as to what you're trying to do with the filler.

I think of Timbermate as a filler for nail and screw holes and other blemishes, not as a grain filler where you want to fill the surface but not obscure the grain.

Even though the Wattyl stuff is oil based, a coat of shelac will seal the surface allowing the use of water based top coats.

I bought a can of the Wattyl stuff from my local Bunnings Warehouse and found a thick layer of dried varnish/goop sitting on top of the filler. After I removed this it took me a good bit of elbow grease to whip the stuff back into an even emulsion. Not sure if this means it was expired, but I'm not keen on using it again just yet. After trying to sand off the excess I was met with open grain again, either from over-sanding or the filler not working properly, so I followed up with Timbermate.

Actually Timbermate can be used as a grain filler - you just mix it with water to the consistency of thick cream then wipe it on as you would a "true" grain filler. This is what I did and It works for me, and it's virtually guaranteed not to cause problems with WB topcoats.

Update: Just sprayed another 3 coats today, taking care to flush the metho from the gun with distilled water before each coat. The repel spots are *still* coming back.

Diagnosed a problem with the gun; the nozzle cap was backfiring air. It could be the reason my gun's been sputtering lately. I patched the thread up with some sealing tape, and it seems to be spraying water smoothly now, though I haven't tested it with lacquer. Also cleaned every part of the gun's material channel. The diminished flow could account for residual metho being left inside the chamber and sputtering out with the lacquer, causing a regular, random pattern.

Might try wiping down the board and soaking the gun's parts in MEK next time. Currently I always wipe down the board with a 50/50 mixture of water and metho before starting the day's coats, but it doesn't seem to help.

Still sounds like silicon contamination; and I'd be pretty doubtful it's the metho causing the problem. If you've got greasy water trapping in the filter/regulator, I wouldn't be certain it is catching it all. Also, how often do you drain your receiver tank? You should be doing it daily, before you start up the compressor.

Re prepsol versus petrol. Ordinary unleaded, not 10% ethanol, shouldn't cause you any problems. It is horrible to work with though - prepsol is stinky but better than petrol. Prepsol is readily available from autopaint suppliers - google lists 9 in Melbourne.You should also be able to get fish eye remover from them.

Or try this mob in Glenroy:

AALL-PAINTS

But check first with the WB finish manufacturer whether adding fish eye remover is not going to cause more problems - some WBs are modified urethanes and they require a particular solvent mix to get around this problem. Or complete removal and refinishing - if it comes to that, I'd be giving all surfaces a couple of sealer coats of dewaxed bleached shellac.

I drain it nearly every day and never get more than 3-5ml of condensation.

Surprise! Sprayed a coat just now and there wasn't a single repel spot in sight. I went back to using a specially formulated retarder that I bought with the lacquer. Thought it might help level and flow the lacquer better, which it did! Will spray the rest of the day's coats and see if the effect holds. If it does, it saves me the trouble of getting prepsol and all manner of additional solvents.

One thing I overlooked was that I used the retarder on my second sample board (I'm working on the third one now) and never had the sputtering or repelling problems as I am now.

Spoke too soon, the repel spots came back with a vengeance on the second coat and then even more on the third coat.

This is a consistent pattern now. The day's first coat is always relatively even, with repel spots appearing with greater frequency with every coat I apply. Is this consistent with silicone contamination, or oil?

Edit: A thought just occured to me - I used baking paper to protect the iron as it went over the veneer as per its instructions. Could this cause any problems?

Originally Posted by Kaisergrendel

Edit: A thought just occured to me - I used baking paper to product the iron as it went over the veneer as per its instructions. Could this cause any problems?

Maybe. You could try aluminum foil on the iron instead. But if more and more spots are coming with each layer it is prolly something to do with the spray gun.

Originally Posted by tea lady

Maybe. You could try aluminum foil on the iron instead. But if more and more spots are coming with each layer it is prolly something to do with the spray gun.

That's exactly what I thought, I'm just wondering if silicone contamination works in a counter-intuitive way eg. it continuously floats up to the surface with every coat sprayed.

Originally Posted by Kaisergrendel

That's exactly what I thought, I'm just wondering if silicone contamination works in a counter-intuitive way eg. it continuously floats up to the surface with every coat sprayed.

Dunno! If it is resisting I guess it just keeps resisting. Wonder if a bit of detergent would break the surface tension enough to make it flow out?

It'll probably come out of my spray gun in a foam to begin with!

Originally Posted by Kaisergrendel

It'll probably come out of my spray gun in a foam to begin with!

Oh yeah! What about glyserine then!

Rather stupid question I guess, but what are you wiping the piece down with after sanding, but before spraying? Old t-shirts from the wife's chest of draws? (What is in fabric softener? or the soap powder? )

Disposable dry wipes from a sealed pack, soaked in 50/50 solution of metho and distilled water.I highly doubt there'd be a problem here.