Thread: Which glue?

Originally Posted by silentC

I typically use shellac on my stuff and have used both yellow glue and hide glue without any apparent problems with the finish. So far

You must be a careful worker, & diligent with your clean-up, Silent, 'cos PVAs are notorious for showing under all sorts of finishes. I can vouch that they will show under shellac. A couple of times I have been a bit careless or in too much of a hurry wiping off squeeze-out & didn't wipe enough, 'cos it showed on the mop-coat, immediately! Why is it always in the most visible places? Hide glue is a lot more forgiving, and accepts many stains and finishes (but not all!) without showing through.

The Wisdom of the Elders says not to wipe excess PVA with a wet rag, because that's highly likely to send glue residue deep into porous woods, & it may take a good deal of scraping & sanding to get rid of it. The standard advice is to let it cure to rubbery consistency, then pare it off with a sharp chisel. This is ok where you can get at it, but a PITA in tight spots. Another drawback with using wet rags along joints is that you are adding yet more water to the vicinity of the joint. If you happen to be joining boards for a table top or any application where you want a dead-flat joint, make sure you let the joint cure thoroughly before sanding off, or you'll end up with a slight depression along the joint. Also been there, done that!

A common trick for dealing with squeeze-out is to wax the edges where you don't want the glue to stick, then you can usually flick the ooze-out off easily once it's cured . It's a useful technique for some jobs, but take care, the last thing you want is wax on the surfaces to be glued! Traces of wax can also be incompatible with some stains & finishes, but so far, touch wood, I haven't encountered any problems from that source.....

Cheers,

Well perhaps I need glasses

I don't use French polish, I do a wax over shellac finish on most of my stuff.

Generally my approach is to finish everything I can before assembly. Then I mask it off wherever squeeze out might occur. I allow the glue to go rubbery and then remove the masking tape. Then I finish the extremities, which I leave bare to avoid damage whilst clamping, then buff and wax the lot.

Typically the only place where glue might be present under the finish is in panels. These I glue up and then remove the squeeze out with a card scraper after they have dried. I've yet to get a panel joint perfect so that it doesn't need some scraping or planing afterwards.

But having said that, I think traditional methods call for hide glue and shellac. I'm making a kitchen at the moment and so I'm using Titebond II and a poly/oil blend.

Originally Posted by silentC

Well perhaps I need glasses ...

Hmm, I don't think so....

Originally Posted by silentC

... my approach is to finish everything I can before assembly. Then I mask it off wherever squeeze out might occur. I allow the glue to go rubbery and then remove the masking tape. Then I finish the extremities, which I leave bare to avoid damage whilst clamping, then buff and wax the lot....

I think that's the mark of a careful man!

Glue doesn't stick well to many finishes, & in any case, the finish blocks pores, so you are unlikely to get the soaked-in glue problem I was talking about - essentially, that's only going to happen with raw wood. If it ever happens to you, I don't think you'll be unaware of it! I always finish panels before assembly, too, & apply a little paste-wax at the corners, partly to ensure I don't get unsightly bare edges when the panel shrinks in dry periods, & partly to avoid glue sticking to the corners when the door is assembled.

Originally Posted by silentC

..... I think traditional methods call for hide glue and shellac. I'm making a kitchen at the moment and so I'm using Titebond II and a poly/oil blend.....

Agreed. There are places where synthetic glues make obvious sense to me, & places where hide glue and French polish are my preferred options. One of the better things about living in our time is we have a wide choice, & can match glues & finishes to the job in hand very nicely....

Cheers,