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| Lacquer problem http://mowrystrings.luthiersforum.com/forum/viewtopic.php?f=10101&t=50329 |
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| Author: | Roy [ Tue Feb 20, 2018 11:21 am ] |
| Post subject: | Lacquer problem |
I used Cardinal Lacquer for two ukes I finished last year. One went to a family friend and one for myself. Now after only 7 months the lacquer on the uke's neck I'm using is wearing through. This is my tenth instrument and I've never had a problem with the others but these two are the only two I've used Cardinal lacquer. Also there was an 9 year gap between uke number 8 and these two. Unfortunately I don't remember what lacquer I was using back then. Questions: 1. Has anybody else had this problem with Cardinal lacquer? When I was searching for a lacquer this seemed to be well liked here. 2. If it's not the lacquer than any thoughts on what I may have done wrong? I sprayed 15 coats but all in the same day and with no leveling in between. Any thoughts, suggestions? Thank you, Roy |
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| Author: | AndyB [ Tue Feb 20, 2018 12:37 pm ] |
| Post subject: | Re: Lacquer problem |
15 coats with an HVLP gun? That's a lot of lacquer, especially with no leveling. Is it wearing through or is it chemical reaction to perspiration (being eaten away versus worn through?) A decade ago, a good chance you were spraying Behlen or McFadden (the latter no longer produced). Andy |
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| Author: | Barry Daniels [ Tue Feb 20, 2018 1:14 pm ] |
| Post subject: | Re: Lacquer problem |
Too fast on the application. Need to spray no more than 3 to 4 coats in a day. Take the next day off and then start again. The 15 coats in one day traps solvents in the lower layers keeping the entire finish soft for months. |
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| Author: | Roy [ Tue Feb 20, 2018 7:49 pm ] |
| Post subject: | Re: Lacquer problem |
@Andy, I too was wondering whether it's wearing through or breaking down from perspiration. I've looked on this site and found no other mentions of this when using Cardinal Lacquer so I really think it's more my process than the product. @ Barry, Thanks, I'll follow your schedule on my next spray (and level) and see how that works for me. |
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| Author: | B. Howard [ Wed Feb 21, 2018 9:38 am ] |
| Post subject: | Re: Lacquer problem |
Hmmm.....to thick, but wearing through? Let's see ... As to spraying all coats in one session with no leveling between and minimal flash time is known in the industry as "wet stacking". Something I have done and recommended over the years. At the end it will out-gass just the same, 90% solvents gone in 30 days. Just more solvent to start with than if you put down 5 coats every 5 days but it will still take 30 days to reach 90% or better solvent evap after the last coats. That is chemistry. Number of coats seems to get people all worked up, but it is rather meaningless! it says nothing of the actual weight of the coatings applied or what the actual solids content was off the gun (ie, how much reducer etc was used). So I have my doubts that this falls into the so thick it has to fail category. Wearing through? a pic may be helpful here. How is it leaving the wood (any crystals or dust coming up)? Can you feel the edges of where the finish is "worn" away or is the transition from finish to bare wood not felt at all? There are a lot of potential causes, not enough film build, wrong reducers, incompatible sealers, poor prep work to name the biggies. |
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| Author: | Mike OMelia [ Thu Feb 22, 2018 5:43 am ] |
| Post subject: | Re: Lacquer problem |
With no leveling in between, it would seem to me you would have to do a LOT of leveling at the end. Maybe your final thickness was dangerously thin? I wet stack like Brian said. I may do it over two days. But I level every 4-5 coats. Not sure why it works, but leveling leads to less roughness at the end. The amount of level sanding on final coat is very little. After 4-6 coats, I feel safer in applying heavier, wetter coats. |
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| Author: | Barry Daniels [ Thu Feb 22, 2018 9:09 am ] |
| Post subject: | Re: Lacquer problem |
Leveling between coats also helps curing of the finish before more wet stacking. That is why I wait one day after each leveling. The way this works is that the sanding scratches dramatically increases surface area so you get more evaporation of solvents. |
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| Author: | B. Howard [ Thu Feb 22, 2018 10:22 am ] |
| Post subject: | Re: Lacquer problem |
Mike OMelia wrote: With no leveling in between, it would seem to me you would have to do a LOT of leveling at the end. Maybe your final thickness was dangerously thin? I wet stack like Brian said. I may do it over two days. But I level every 4-5 coats. Not sure why it works, but leveling leads to less roughness at the end. The amount of level sanding on final coat is very little. After 4-6 coats, I feel safer in applying heavier, wetter coats. If you wet stack without leveling you need to wait longer before level sanding but in the end you will spend less time sanding overall and use 75% less abrasives. I ran the cost studies when I ran a large woodworking shop..... |
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| Author: | Barry Daniels [ Thu Feb 22, 2018 10:53 am ] |
| Post subject: | Re: Lacquer problem |
Brian, no argument there. But many individual builders are mostly concerned about wait time. And those are the folks that I address my comments to. An additional sheet of sandpaper and an extra hour of sand time is not their real issue. |
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| Author: | bluescreek [ Fri Feb 23, 2018 6:42 am ] |
| Post subject: | Re: Lacquer problem |
I shoot a coat an hour for 8 hrs but like Brian stated isn't so much how much you shoot but what your shooting. Thinner , retarder and then the blend and mix adjustments on the gun , you may be straying coats but not getting the coverage. I use a satin finish on necks a catalized product , the same that martin uses called chemsheen. Wears very well and is very tough. |
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| Author: | Roy [ Sun Feb 25, 2018 8:48 am ] |
| Post subject: | Re: Lacquer problem |
Lot's of good information here. Thank you everyone for chiming in. The edges are not rough, it feels like it wore through as opposed to flaking off from not sticking. I used Z-poxy as a pore filler. I waited 3 weeks before leveling. There was a lot of solids on the neck when I started the leveling but I'm thinking I just sanded too thin. |
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