I get some questions from subscribers and a regular basis, so for these, I like to answer by video so that everyone can benefit from my answers rather than me having to email or text individuals one at a time ... 

Watch it on Youtube: https://youtu.be/ODWzUi2Zv3k

To start off with, let's have a look at "woodwork sizing" in terms of finishing and other related issues as it pertains to water down PVA glue.

As some of you may recall, a few months ago I made the statement that "there is no reason to water down PVA glue", that is the yellow carpenter's glue that many of us use on a regular basis. What I should have said was ... "there are ALMOST no reasons to water down PVA glue".
I did get a few responses on that statement and I thought the best was from someone in Idaho who was finding that when he was making glue-ups, the glue he was using was "skinning" over even before he could get the 2 pieces of wood together because his humidity level is so very low. To resolve this he adds 8 percent water to his glue, and he found that it slowed the drying out process just enough to finish applying his glue and clamping the wood together before the glue started to skin up. I also had a couple of people who suggested watering down PVA glue for end grain gluing was another application, but as we saw in last week's video where I used straight PVA glue to pre-treat end grain before clamping, watering down the glue was not necessary.

"Sizing" Wood before Finishing to Balance Absorption of Finish and Match Wood Colors Better
And finally, another very nice person actually sent me a copy of an older woodworking magazine article where they are using watered down glue as "sizing" on wood and MDF, to help prevent the absorption of finishing materials to avoid color changes. One of the best examples they used was to apply their "sizing" on end grain wood so it did not absorb so much finish, and therefore the end grain would more match the surface color of the wood. The "sizing" they used was one part PVA glue to 10 parts water. 

I wanted to see what affect both a water-based and an oil-based finish would have by "sizing" the wood in advance.

 Woodworking GLues

I have never used "sizing" and was anxious to see just how well it would work.  And now that I took a video of the process and we can all see, to be honest, I was quite disappointed with the results which were all but negligible. Almost no difference between the "sized" wood and the raw wood.

You can see from the 2 samples above there is almost no difference between the side that was "sized" and the side that was not.

Glue on MDF

Again, almost no difference in either the top or the bottom pictures 

Wood glue on hardwood

I was reluctant to start a big experiment on this process because the more glue we add to the water, the less chance we get that any finish will penetrate. The same issue we have when we have a bit of glue on our fingers and accidentally touch one of the surfaces during a glue-up, that is not even noticeable, until it comes to putting a finish on, then it stands out so bad we need to sand it all of and re-finish. 

I am still looking for anyone who has actual experience with this and can show us some real results that we can all use. 

My Wood Router Table has a Dip in it!
I get this question on an ongoing basis ... "Why does my router table top have a dip in it?". This frequently happens to router tops that are made from MDF material, which as we all know is ground up and processed wood. MDF is not waterproof, it still has the ability to absorb moisture from the air if the MDF is drier than that air. Because of its make-up and finish it takes longer, but it still absorbs the water. The reason for the warping of the top is because they are often topped with a plastic laminate that is glued on the top, and once in a while the sides but almost never of the underside. Sometimes the underside is coated with something to help reduce the speed of moisture absorption. The other issue is the hole that is cut away for the router insert plate that is almost never sealed and can be the biggest factor in the top absorbing moisture.

Router Table Fence Gap

In any case, the tops always will absorb moisture in damper areas, usually place with an average humidity above 40% (it sounds like Idaho might have actual flat router tables) The reason that the tabletops warp is because the MDF has no place to expand to because the tops are sealed with a plastic laminate so can't move, which means the only way the wood can move is to arch on the ends to relieve that expansion pressure.  

router table feather board

There is not a lot anyone can do, but the easiest is to use feather boards if you can and if the wood is pliable enough to bend along with the wood router top.

Can You Use a Kerf Maker on a Bandsaw?
I received an email from John-Eric from Sweden who asked if the Kerf Maker could be used on a bandsaw, I initially said no, then the next day emailed him back and said yes it was possible by using a "stop" on the bandsaw, which has led me to this part of the video. I'm not sure where you would use this application, but obviously someone needs it so perhaps others can use it as well.

Kerf Maker 

Below is a close up of what the Kerf Maker looks like

The set-up on the bandsaw is quite complex, with 2 stops for the woodside to side and another stop to prevent the wood from going all the way through the bandsaw.

Incra MITER gauge on a bandsaw

As you can see from the video as long as you take away the width of the blade from the kerf maker adjustment, yes you can make perfect notches. Bandsaw blades are very thin and were hard for me to set accurately but after one missed sizing, the second one turned out fine as you can see on the video. 

Thanks again to everyone who sends me interesting info ... tips and jig ideas, I love to see these.

Copyright Colin Knecht


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