Wiping wet glue

[shaneymack]

Interesting read. Chris Schwarz "debunks" the myth of wiping wet glue in a blog post from a few weeks ago. Good info here and I tend to agree with him.

http://www.popularwoodworking.com/woodworking-blogs/chris-schwarz-blog/the-myth-of-wiping-wet-glue

 

[Guest]

Yeah I do it all the time.  Never had a problem. 

[Just Bob]

Me too.

[Eric.]

But here's the rub for me though...

"Regular surface prep with sandpaper and/or handplanes will remove any glue-clogged fibers. In making many many panels since 1993, I’ve never once experienced glue size (or a joint failure)."

 

Totally agree, because it's easy to surface prep panels.  It's different when you're talking about joinery, and I'd much rather let the glue harden just a bit and scrape away the excess with chisels and scrapers than try to get into those corners with wet rags and then later, sandpaper.

So I get what he's saying but there are some caveats IMO.  And I'm too lazy to go into the house for water anyway, so I'll continue scraping.  I also don't like raising grain if I don't have to.

[Guest]

On my desk project I prefinished my sub assemblies before final assembly.  Makes glue clean up a breeze.   On my coffee table I did not prefinish and regretted it as soon as I started to finish.  Cleaning glue (dry or wet) from unsealed wood is a PITA.  Getting finish into corners is also a pain.  I will always prefinish going forward.  

[wdwerker]

I cut a drinking straw at a 45 degree angle and use it to pick up semi hardened glue from inside corners. When the tip of the straw fills up cut it off and go again.

They sell glue that shows up under a blacklight. You can wipe away any trace of wet glue and get visual confirmation that it's completely gone. I have tried the version that Wilsonart sells but Titebond offers one too. I put about 2" of clean water in a plastic gallon bucket with a clean cotton rag before I ever start a glue up. Straw and scissors completes my prep.

I agree with Eric for complex pre sanded glue ups that patience and some chisel work beats raising the grain and re sanding, but the straw trick takes a lot of work out of it.

[Robby W]

Interesting topic. I have used water and a rag for years without issues. Around here, especially in the dry summer, the transition from liquid to hard happens pretty quickly, so I gave up trying to catch it then. With red oak, you have to be careful to clean the pores properly or you will regret it later. I'll have to try the straw trick, especially on inside corners.

[Coop]

One of the comments to Chris's article was to use a couple of grains of salt in the joints to keep the boards from shifting. Has anyone ever tried that?

[..Kev]

40 minutes ago, K Cooper said:

One of the comments to Chris's article was to use a couple of grains of salt in the joints to keep the boards from shifting. Has anyone ever tried that?

I haven't tried salt but, I've tried pins that are cut off just proud and this works pretty well.

[wtnhighlander]

One of the podcasts I listen to recently had a discussion about the salted glue trick. Seems one of the hosts (or maybe a listener) had done it, and experienced a reaction between the glue and salt, resulting in a failed joint. I suspect inert sand might be a better choice than salt.

[pkinneb]

I did for years with no issues now I let it skim over and use the Benchcrafted small scraper.

[BobInAustin]

9 minutes ago, pkinneb said:

I did for years with no issues now I let it skim over and use the Benchcrafted small scraper.

Love that scraper.

[toddclippinger]

I noticed that the "salt in the glue joint" trick really started showing up in YouTube videos after a woodworker featured on "A Craftsman's Legacy" did it a couple of years ago on one of the first episodes.

I have never done it for a couple of reasons:

#1 A basic principle I hold to: mess with chemistry of the products as little as possible. I don't know if salt degrades the glue performance and I have not bothered testing to see if it does. Maybe there is a short term issue? If I did some testing and it did not seem to degrade the glue performance, maybe there is a longer term issue that would not be apparent until much later?

#2 I get good results by rubbing the joints together a bit which causes them to really stick where I want without salt. It is commonly referred to as a rub joint technique and it works pretty good.

My experience is pretty well in-line with the Chris Schwarz article. 

Early on in my career I did not trust glue at all. I started doing a lot of testing and began to understand the product and how to use it. Now I am a big fan of adhesives, they are a pretty amazing product of chemistry.  

 

19 hours ago, wtnhighlander said:

One of the podcasts I listen to recently had a discussion about the salted glue trick. Seems one of the hosts (or maybe a listener) had done it, and experienced a reaction between the glue and salt, resulting in a failed joint. I suspect inert sand might be a better choice than salt.

Just noticed your post after I made mine. This could confirm my suspicion and why I don't like to mess with product chemistry, it is a potential liability. 

[ChrisG-Canada]

If enough salt is used to cause any type of chemical reaction with the glue then far too much salt was probably used.  The technique of adding salt to a glue joint means adding a few grains to the glue joint - it's not like salting fries or popcorn!

I don't know for certain, but I suspect a few grains of salt would be far better than sand (as someone mentioned). Salt will crush easily and allow the pieces of wood to fully contact. I would be worried that in some cases grains of sand might keep the wood separated a little bit - especially with very hard woods.

[wtnhighlander]

2 hours ago, ChrisG-Canada said:

If enough salt is used to cause any type of chemical reaction with the glue then far too much salt was probably used.  The technique of adding salt to a glue joint means adding a few grains to the glue joint - it's not like salting fries or popcorn!

I don't know for certain, but I suspect a few grains of salt would be far better than sand (as someone mentioned). Salt will crush easily and allow the pieces of wood to fully contact. I would be worried that in some cases grains of sand might keep the wood separated a little bit - especially with very hard woods.

In this application, I would expect the sand grains to be pressed into the wood by clamping pressure, forming tiny little dominoes to hold it in alignment.

But I wouldn't bother with sand OR salt. If I can't keep the boards aligned with clamps & cauls, then some sort of spline or key is in order.

[Mark J]

Shane, thanks very much for sharing this tip.  I like the straw idea, too. 

I had this small bench I was putting together from a kit.  Five panels all butt jointed together (a butt joint, by the way, is really aptly named).  I knew I would need squeeze out, but having already sanded the be geebers out of it I did not want to raise the grain and I was afraid if I tried to scrape the glue off I would end up scratching the surface and making it even worse.

So not knowing any better I masked the joints.  I did some experiments with Post It Notes and 3M Blue painter's tape.  Both worked, but the painter's tape leaves a subtle adhesive residue (which comes off with light sanding).  The Post It Notes leave no residue and if a double layer is used there a minute or two before the glue seeps through and begins to bond the paper to the wood.  (Also I have a ton of Post It Notes left over form when we closed an office).

Here are some pictures with the making, glue and glue and making removed.

 

 

In one joint I was a little slow removing the Post It masking and some of the paper fibers were left behind.  These were easy to scrape off with a wooden shim.  

It's important to remove the making promptly so you want to do a dry fit and make sure you can remove the masking from around the clamps.  

I don't think this is an idea that would work for all joints all the time, but for a few small joints (as here) or a joint that would be difficult to get at this might have application.

[Tpt life]

Angle snipped micro pins or even 18 g. does not mess with chemistry and is simple. 

[toddclippinger]

3 minutes ago, C Shaffer said:

Angle snipped micro pins or even 18 g. does not mess with chemistry and is simple. 

Done that too on occasion and it works well while presenting no liability issues. 

 

[soonerdg]

Yep, I do this all the time when it's easy to get to the glue line.  When it's not I use another method.  There certainly is nothing wrong with wiping wet glue.  But, as with almost every woodworking technique there are some instances where another method works better or is just easier.