Replies

1. 
   SgianDubh | Jul 02, 2006 08:07am | #1

   What sort of conditions are you gluing up in? Are they hot and and humid, or perhaps humid in some other way, e.g., coastal location, for example? What's the MC content of your wood at glue-up? How long after glue-up are you waiting until you polish prep?

   You're describing one of the classic forms of creep, a characteristic of PVA glues. This form is where the wood shrinks after glue-up and the glue doesn't shrink with the wood. It remains as a raised line. Another way the raised lines can occur is if the wood is dry at glue-up, then its MC rises due to a change in relative humidity (RH) followed by shrinking again because of a drop in RH. This again can leave leave a raised glue line. You might possibly be leaving a thick glue line at glue-up time-- lack of cramping pressure for instance, or you might be trying to use the glue to make up for deficient or gappy joinery.

   I suspect you're suffering the former situation. In the hot humid climate I used to experience in Gulf coast Texas I pretty much gave up on PVA type glues and switched to non-creepers such as hide glue, hot and cold liquid forms. You could consider polyuerthane, epoxy, urea formaldehide and urea resorcinol. Also, if you continue to use PVA glue, you might try waiting longer between glue-up and prepping if you're working in a humid workshop. Slainte.

   Richard Jones Furniture

1. 
   gmoney | Jul 02, 2006 05:22pm | #2

   hmmm, i don't know the moisture content of the wood.  it is kiln dried.  i've had it for years and it is kept in the same environment as my shop.  i did do some straightening and it was planed slightly.  the time between working and finishing is typical, i believe.  maybe a day or so, not enough time for the wood to move much.  the glue line stands proud on both sides of the work after a day or two.

   perhaps i should try another glue, maybe polyurethane.  thank you for the input.

   my shop is ground floor on one end and basement on the other.  working conditions are humid here in connecticut in june.  the space is heated in the winter and therefore is somewhat less moist at that time.

   Edited 7/2/2006 10:27 am ET by gmoney

   Edited 7/2/2006 10:28 am ET by gmoney

1. 
   SgianDubh | Jul 02, 2006 07:13pm | #3

   It's hard to say how you eliminate the creep thing, gmoney, but there's definitely creep going on from what I can tell.

   If you persist with PVA glues and the atmosphere is humid I'd suggest leaving longer than two days between gluing up and polish prepping. A week might be better.

   Try and make a note of the atmospheric conditions you glue up in and the atmospheric conditions you prep and polish the wood in. Perhaps you can establish a pattern and in future work to reduce the chance of the problem recurring. Slainte.Richard Jones Furniture

2. 
   SARGEgrinder47 | Jul 02, 2006 07:31pm | #4

   Morning gm..

   "the time between working and finishing is typical, I believe.  maybe a day or so, not enough time for the wood to move much"... gmoney

   I use a moisture meter on lumber stored on my rack. You will always get more moisture in the middle of the stock than the end grain where it enters and exits at a more rapid rate. When I take that stock from the wood-rack to the jointer and planer, it will expose new wood. In summer humidity as we have here in Atlanta, it can move from night till the next morning. I call it "my summer problem".

   I have found the potential release of moisture from fresh jointing and planing coupled with the ever changing humidity in my local...  combined with slow glue as the yellow you mentioned can play a few tricks on you and creeping is numero uno on the list.

   How I deal with it is to let the moisture content re-orient after bringing the stock down to final dimensions. Once I get a 8%-12% reading over the entire stock (with 10% about perfect), glue up begins. As Sgain mentioned... get some faster drying glue and I give it ample time to dry. Any glue lines at that point, I remove with a card scraper or cabinet scraper. Then I'm ready for final prep and finish.

   Being a non-professional has it's advantages as dead-lines don't loom on the horizon. Time and patience are the key tools I have found for working summer humidity.

   Good luck... Luck = preparation meeting opportunity  :>)

   grinder47.. SARGE

    

1. 
   BG | Jul 02, 2006 09:21pm | #5

   gmoney,
   I called Franklin help line two weeks ago asking how long one should wait between glue up and final prep (Franklin makes the Titebond stuff, I, II, III, etc.)...they said without a mositure meter to actually measure he'd suggest two weeks. The wood will swell with the glue and eventually shrink back...after it's been preped if you did not wait.

1. 
   gmoney | Jul 03, 2006 04:42pm | #6

   ok guys, thank you.  now i'm thinking maybe i can still build away after glue up, but wait a couple of weeks before trying to sand and finish.  one note with woodworking:  it seems there's always more to learn and it's not always convenient to do so.  the difference between quality work and average work is in the thousands of details!

   thank you, greg

2. 
   dherzig | Jul 03, 2006 04:56pm | #7

   I agree it is the moisture in the glue that is swelling the wood. I have wondered if careful use of a heat gun after a couple of days will accelerate the drying. The same thing happens when using biscuits and then sanding too soon. Depressions are left where the wood swelled, was sanded flat and then contracted.

   Edited 7/3/2006 9:58 am ET by dherzig