Replies

1. 
   saschafer | Mar 12, 2008 02:02am | #1

   That's a pretty common instruction for lots of spray finishes. If you recoat within the shorter time, the partly-cured finish is still wet enough that the new coat will "bite" into it and bond. But wait longer than that, and you need to scuff up the surface to ensure a good bond. The reason you have to wait 72 hours is that the finish isn't hard enough to sand until then.

   -Steve

    

2. 
   webby | Mar 13, 2008 09:07pm | #2

   I have found that while it is a time committment I can acheive a nice sprayed on finish with out epensive spray gear. It does take some luck/ability to be able to tell if the finish is dry enough to recoat. It needs to be a little tacky with no visible wet areas. It is also more difficult to recoat without bubbling in the humid months.

   Here is what I have found.

   I think the key is to apply very thin coats. covering the surface but just barely. That aids in drying time.

   I generally plan a whole day, here is how it goes.

   I have my piece all prepped that morning. I shoot on a thin coat, really thin but covering end grain and the surface in general. Then I take note of the time and that is my day. every two hours I shoot on another coat a little heavier with succeeding coats, but overall still light coats.

   Spraying reslts in a thinner coat so I shoot for six to seven coats on the peice which is usaually late in the evening. I let the peice dry for a couple days or the required 72 hours. then I go back and scuff it up and knock down dust nibs then shoot another coat on. Lightly buff that and I am done.

   Also I try not to take it too seriously, If for example my hand slips on the can or I shoot a big glob for some other reason I don't panic, I just wipe the run off with a cloth and the next coat will get it.

   Also I turn a fan on lightly to move air around the piece to aid in drying time. I don't have a fancy shop just a garage. Humidity still messes with me on occasion but I try to limit it when I have to finish. I leave the g. doors down. and keep the fan on.

   It gets to be pretty routine. I turn the fan off, shake the can of poly while the fan spins down. when the blades stop I start shooting and am done in ten or twenty minutes. Clear the poly tip and turn the fan back on. 

   Try not to miss the two hour mark. I have and have shot at even 1/2 hour past that but it isn't as smooth.

   For me the part I hate the most is waiting for the piece to dry between coats and sanding. I will give up a day to get a nice sprayed on finish and 6 or 7 coats to boot. After spraying, I also cringe at the thought of brushing poly, the mess, the bubbles, the brush marks, the runs etc. Without expensive spray gear, this works for me.

   It may not be fine woodworking but it works for me. Also it is just one stop on my learning journey. In the future I hope to have the ability to use more and finer finishes, but for now I have finished keepsake boxes a mantle an endtable, a bed step, and a walking stick this way.

   When I work my way up to larger pieces, I will do something else.

   Hope this helps.

    

   Webby 

    

   
   

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   Edited 3/13/2008 2:13 pm ET by webby