Thread: To salt or not to salt, this is the question...........

Never heard of using salt for that, and with your glue likely being water based I’m not at all confident of its ability to a) stay solid, and b) not affect the glue’s adhesive properties once it had dissolved.

I have heard however of using SAND for this purpose; a very, very light sprinkle of coarse builders sand onto one edge of the joint will stop the joint moving as you clamp it up. Try to keep it in the centre of the joint.

You could also use dowels, biscuits or loose tenons; any of these would work and add strength to the joint.

salt is often used to give friction between two well prepared boards that you've just lathered with slippery glue. I have no idea if it has any longer term implications, but personally I would have no concerns using it for that if I felt I needed (use cauls across the lay up to help avoid issues in the first place would be my first port of call/caul )

In a chopping board, a well seasoned glue-up rather than a sandy glue-up would also seem preferable to me

I'd be inclined to do a test piece before committing to using salt. I don't know what they use to emulsify the PVA but any polar substance that would interfere with the surface active agent used may be affected by salt and "crack" or break down the emulsion into gooey globules. Extreme cold will do the same thing. Even so, it may still adhere but you'd have to experiment. Sand sounds a lot safer.

mick

Just found this

YouTube

test will be done today.

In my experience major slippage occurs when too much glue is used because the wood floats on the glue so to speak. I sometimes let the glue go off a bit as well, I certainly don't rush the job at all and if it gets a bit sticky all the better as then there is definitely no slippage. Get some off cuts and try using less glue or even slow things down so the glue is a bit tacky. If you get major squeeze out then you have used too much glue.

I've used salt before, and it works great. However, I don't use it every time. I'm not concerned about any issues with adhesion, but it's always in the back of my mind that I am impregnating the joint with crystals which will then be planed with either a hand plane or buzzer/thicky. The crystals may dissolve, maybe not. I don't know, and I'm not about to split a joint apart to find out. I only use salt when I am laminating shaped parts together and I can't drill a dowel through one piece and into the other, and I need the lamination to be pretty damn close to perfect because anything away from perfect means more unnecessary smoothing afterwards. Table legs, cutting boards, table tops are things I don't care much about because I can smooth them out quickly and I HAVE to do that work anyway.

Salt is one of the most bizarre additions to this gluing problem Ive heard of lately .

Salt attracts moisture so the glue may want to be water proof .. It would dissolve in a water based glue and could this lead to water being drawn in and causing problems later ?

The hydroplaning of wet surfaces coming together stops when they meet . Just starting clamping off with light pressure until they meet is one easy way of getting around it . Then crank up pressure later.

If its a job where it really must not move then nailing in the finest brads and clipping them off sharp , placing the part to be glued in position so it receives the brad holes then glueing works .

The worst situation is when there are large amounts of sections to be glued. The best thing is to separate it down into parts that can be glued up , then add them to each other later rather than try it all at once.

I don’t know about the whole salt thing, but I have just had a glue failure in one of my boards. It appears that I have over oiled it or squeezed the bejezzus out of it on glue up. Either way it failed and simply popped apart.

I have used salt in a few glue ups to reduce the sliding effect. I dont know exactly how much it affects the glue, but it does affect it. I did one and put WAY too much salt and knew it. Broke it apart later without too much effort. There were actually white spots in the joint from where the salt had dissolved. I have used it a few times since then, but VERY sparingly (like a couple dozen or so grains) with no noticable adverse effects.

I use different clamping method.. home made clamps.. basically 2 pieces of steel tubing 20 x 45 one end has been joined by steel strips having a block in the middle.. 10mm screw through it. other end using same type of join with a solid block in the middle.. that end can be moved along to cater for different widths of the work to be glued.. when assembled over the job.. the screw is pushing boards together while also compressing them down... the worse glue finish i had with them was less than a 0.5mm difference between boards.. easily sanded though.. no issue with allignment etc...
Carbatec sells basically same system as piano clamps or the double bar clamp set.. same principal.. mine ones are just a bit sturdier..

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Thanks for the pic.
I made an almost identical set out of wood

EB142B89-F6F8-4852-B5F5-3FEF54C1A357.jpeg

when using wood make sure you put a layer of plastic between the clamp and the work.. (glad wrap works a treat) also timber might bend a bit.. but for you needs it might be sufficient just be careful as they can apply a lot of pressure.
Also make sure you put a bit of sacrificial wood between the screw and work... (and also on the other end ) so you dont damage your work

I use Baking paper. I also have the timber chamfered from the middle to each end (cauls) so it clamps more evenly under pressure. Also use wooden blocks on the screws.
They have been working fine for some time and I get good results.