chops1983 Posted May 29, 2010 Report Posted May 29, 2010 Hey Guys, I'm having problems with shellac as a sealer coat, after spraying the stain burst im spraying the shellac to lock the colour in. Here's a pic I'm not sure why its doing it as i've been using 2 and a half year old shellac no prob's and then this morning i mixed some fresh stuff, the first time i sprayed this fresh shellac it was fine and now the last two times its done this . Yes i have sanded back and bursted 3 times today as i wasn't happy the first 2 times. Im at the end of my tether. Im thinking its moisture but im draining the regulator regularly and ive been using alchohol not water with the stain. Also why is it just in those spots? Guys if you can help me with info i would be very grateful, im not sure i want to rub it all back for this to happen again. Its 18 degrees celsius outside if that could be an issue. Thanks Chad. Quote
low end fuzz Posted May 29, 2010 Report Posted May 29, 2010 you said you sanded it back 3 times today; which means to me you have tried to stain and seal at least twice in one day? i would assume right there some kid of problem would be rushing it and your contamiating each process; it looks like where those marks are, are where moisture wouild harbour te longest; basically where the 'end grain' pops up, like the counter sinking of the knobs and routed areas; i give colour a couple of days just out of practice (whatever the carrier is, alcohol/water) even tho it may seem dry something might be lingering in the grain that bleeds out while the shellac is dying or that u pushed around while applying the shelac; so..... more time, best bet; and aplly the first coats of sealer really thin Quote
Woodenspoke Posted May 29, 2010 Report Posted May 29, 2010 Though I have never experienced it, looks like Blush to me. It may have to do more with your humidity than the product or your compressor. I have read that taking a heat gun to the shellac removes the problem. Gentle heat. http://www.woodweb.com/knowledge_base/Cont...llac_Blush.html Quote
Drak Posted May 29, 2010 Report Posted May 29, 2010 1. Let your stain dry for 24 hours. I know you're using alcohol as your solvent, but you're also using dye. Let it dry completely. 2. Add more alcohol into your shoot mix. Trust me here, I've been in your shoes before, thin it down more. 3. Tape up all those holes and slots from the backside. The air moving through those holes and slots makes your finish dry too quick, giving you blush. 4. Don't shoot if it's humid. You can't add lacquer retarder to alcohol, so you have no control over it's drying time except to add more alcohol (which is a moderate controller), so you have to wait for the weather to cooperate. Quote
avengers63 Posted May 29, 2010 Report Posted May 29, 2010 All I can add is that shellac takes forever to dry. When I'm brushing on mine, I wait at least a full day between coats. Quote
Drak Posted May 30, 2010 Report Posted May 30, 2010 True dat when brushing, but shooting it is a different set of circumstances. Brushing it typically involves much thicker coats, which of course take longer to cure. If it took so long to dry (which it doesn't when you're shooting it), moisture would have plenty of time to evaporate, which it looks like it certainly did not. Alcohol cools and evaporates rather rapidly in thinner coats especially when air is being passed over it (like through those holes when it's hanging to dry), which allows it to absorb then trap moisture as it rapidly cools and gasses off. Quote
chops1983 Posted May 30, 2010 Author Report Posted May 30, 2010 Hey Guys, Thanks for all the feedback. It is sorted now. I ended up wiping some shellac over the blushing which obviously blended the old coat in. I wasn't aware of leaving the colour for 24 hours to dry either which wouldn't of helped. I can understand if i was using water stains to let it dry, hence why i was using alchohol to help with the time period. But now i know and next time ill leave plenty of time between stages. I will also take your advice into account Drak when im shooting the clear and cover those holes. The finish isn't quite as nice as the first time i did it but its pretty close to where i want it. It may be a little on the dark side now but its not bad. Thanks again, especially from the more eperienced guys. Chad. Quote
chops1983 Posted May 30, 2010 Author Report Posted May 30, 2010 Just quickly on another note while i got you all here. The temp is 20 deg C or 68 deg F, What temp is to cold to spray clear coats? Quote
Drak Posted May 30, 2010 Report Posted May 30, 2010 You know, wiping a little over the blush was a damn fine idea in hindsight, wish I wudda thought of it! Just be careful if sanding it back smooth to where a shot finish would be, you're awfully close to your dye. Quote
Drak Posted May 30, 2010 Report Posted May 30, 2010 You can get a lot of answers like "I shoot in the damn SNOW and my finishes come out GREAT . I've read those before... But for me, it has to be sunny, minimum mid-70's, and fairly dry...common sense stuff, although the weather doesn't always cooperate willingly...I can deal with some humidity when shooting lac, I just add a little more retarder...just a tiny bit more. And I never shoot past about 7:00PM when the weather is cooling down in the evening, you will get blushing easier due to condensation trying to develop. Quote
chops1983 Posted May 30, 2010 Author Report Posted May 30, 2010 Hey your around? What time is it there? Im Just having some brekkie before work and hitting the forum as my regular routine. Yeah mate, i was desperate not to have to sandback again as it has been mentally draining on me. So i tried naptha first to see if that would help and then i thought to just wipe some shellac. I had nothing to lose as i was almost certain i would have rub back anyway. Before my eyes it disappeared! I will scuff the shellac before the clear goes on but as you say careful careful. Thanks for your help man. Chad. Quote
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