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Glue Line exposed - woodsman83192 - 11-06-2015
Might not be the right topic for Finishing, but I've has some issues with finished cabinet and coffee table tops. At the glue joints I can feel a seam sticking proud of the surface. All the tops are perfectly smooth and flat after I sand and finish them. Over time when rubbing my hand over the top it's as if the glue joint pushes up above the surface.
Why does this happen?! More importantly, how can this be prevented. Seems to be on a couple pieces I've built in the spring and fall, if that matters. Thinking about it just now, they have oil based finish on the top and waterborne on the bottom. Just because of drawers or carcasses. Could that be it??
Jake
Re: Glue Line exposed - fredhargis - 11-06-2015
You are experiencing glue creep, I would bet. PVA will do that. I've switched (after Howard suggested it) to using plastic resin glue (the powdered stuff) for table tops to avoid having glue creep. I recently built a new top for my workbench and used the plastic resin glue on it to avoid the "creeps". Has nothing to do with the finish.
Re: Glue Line exposed - Joel H. - 11-06-2015
Thanks Fred for that suggestion. I've never used the plastic resin glue. Any tips on mixing & storage? How long is it useable after mixing?
To Jake, does the glueline problem exist before applying the finish? I would guess not, or you'd sand/scrape it out. I use Tightbond now, but used to use the normal yellow glue before and have not experienced this problem.
Sorry I can't offer any help on this one, just questions.
Joel
Re: Glue Line exposed - fredhargis - 11-06-2015
Joel, the only suggestion I have on mixing is to follow the package directions. It will state the ratio of glue to water in both weight and volume measures, and the Dap I usually use suggests using weight. I use a HF scale and weigh it out. The pot life is temperature sensitive, but at 70º it's about 4 hours. Any clean up must be done when the glue is still soft, with water...after it dries it's almost impossible to get out of your clothes, etc. But once fry one the wood it's easily sandable, so squeeze out is a little less of a problem. It does a brown color, and on light woods a thick glue seam can be seen. You can get lightning agents to tone it a little more white, but they usually are at specialty places like Veneer Supplies. I love it, and if it wasn't such a pain in the arse to prepare I'd use it all the time.
Re: Glue Line exposed - Joel H. - 11-06-2015
I'm building a Kitchen Island and the top is going to be Hard Maple 62" X 40" X 1". Since I'll be staining it with a brownish cherry stain, the darker glue line shouldn't be a problem.
At roughly $10 for a tub, no reason not to give it a go. The only drawback I see is the pot life of about 4 hrs. It'll take several mixes to complete the glue-up. The top will have 5 boards, so 4 glue-ups to go through. I like to leave my important glue-ups a couple of hours each before unclamping. Just some smaller batches I guess.
Thanks,
Joel
Re: Glue Line exposed - fredhargis - 11-06-2015
I should have mentioned: this stuff has a longer clamp time. At 70º the package (Dap) lists it at 14 hours, it decreases with higher temps. That another disadvantage of using it. You also want to make sure the stuff you buy is fresh, Even dry it has a limited shelf life. I buy it from Amazon since the stuff at my local hardware has about 1/4" of dust on top of it.
Re: Glue Line exposed - jasfrank - 11-06-2015
Joel, there shouldn't be any problem clamping up 5 boards totaling 40" at the same time. Just be sure you have the joints prepared properly, meaning they come together properly while the boards lay flat. Easily done even if your jointer fence isn't 100% square. Just alternate face and back against the fence when jointing.
Re: Glue Line exposed - woodsman83192 - 11-06-2015
All;
Glue creep. That's interesting. I suppose I forgot the important part, I'm using Elmer's Wood Glue Max. Thought it was comparable to TBIII. I've a gallon pushing 2yrs old. Will be going back to TBIII shortly.
Those who say TB has not given them an issue with creep, is that with I, II, or III? Did not know a month after finishing a project it would 'creep', had not had that with TB. But I've not used the volume and variety everyone else has here.
Thanks!
Jake
Re: Glue Line exposed - fredhargis - 11-06-2015
Any of the PVA glues (like TB 1,2 and 3) will creep, some may be worse than others but they all will do it. If you search that phrase you will find a ton of info, a lot of it contradictory (go figure) so I've not tried to form an opinion as to the how/why/when stuff...it's likely to be different for every species of wood and set of environmental conditions. Best to just try and avoid it.
Re: Glue Line exposed - Bill Wilson - 11-06-2015
LIL,
What about liquid hide glue? Are they less prone to creep?