Best Glue for Flatpack Furniture Assembly

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Peter67

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Hi there,

I have several pieces of flatpack bedroom furniture to assemble and want to glue all the butt joints to add some strength and hopefully see them last longer. They are made from narrow strips of softwood, glued together and finished with some kind of lacquer.

I don't think standard PVA wood glue will be much good, as it probably won't stick to the varnish/lacquer faces. I'm wondering about either Gorilla Glue Original or Everbuild Lumberjack 45 minute polyurethane. I've never used either before and I'm slightly put off after reading that after it has expanded, the excess glue is difficult to remove. (Or it would be in my case, as I'd have to be so careful not to damage the finished surface).

Just wondered if anyone has any advice or experience of gluing up this type of furniture and any glue recommendations.

Thanks

DSCF1488.JPG
 
Do they have dowels?

I can't make out from your pic what it is or how it's put together.
 
Avoid any expanding PU glue such as Gorilla or Lumberjack for this type of job (they are OK for carpentry but a nightmare for cabinetmaking), if only because any squeeze-out will be simply impossible to clean up completely.

Butt joints don't have much strength, per se, but if you really do want to glue them you could try the Everbuild 30 minute PU gel in a tube (designed for use in a caulking gun) - it has minimal expansion and can often (but not always) be removed after it is fully set using a sharp chisel. lt will adhere to smooth surfaces, but you will get better mechanical bond if you can scuff the hidden surfaces with some sandpaper before applying the glue. Use sparingly, though, and because it does expand although not very much

I'll ask the same a JohnD, namely are there any location dowels in the construction, but also why glue up?
 
Many thanks for the interesting replies.

Yes it is basically held together with dowels and those bolts/cam things. For example: on a wardrobe, where the sides join the top, there is a cam/bolt 35mm in from each edge and a dowel 70mm from edge. (Also a cam/bolt in the middle but no dowel). And on some of the smaller parts there is only one dowel and one cam. I will definitely glue the dowels in place, but I still think it will be a bit wobbly.

I'm wondering how I could sand the hidden surfaces without straying onto edges that will be seen? Where the sides join the top won't be so bad, but the bottom joins the sides about 2 feet up as there are draws underneath. I'd only have a maximum 15mm strip that would be hidden.
 
Peter67 said:
I'm wondering how I could sand the hidden surfaces without straying onto edges that will be seen?
Click to expand...
Carefully? :whistle:

Actually you make up a sanding board with a fence out if scrap. I'll do you a quick sketch and post it when I get home. Quite commonly used in shop fitting

Edit: Quick and Dirty Sanding Board - @Peter67 take an offcut of flat sheet material, in this case I'm imagining an end offcut of kitchen plinth about 250mm long x 150mm wide but the size isn't critical, all you need is something flat, ideally about 15 to 18mm thick an with one straight (factory) edge:

Sanding Board.jpg


Glue some sandpaper onto it. I use contact adhesive or spray adhesive because I always have them. In this case the (green) sandpaper is standard 114mm sheet width, but that isn't important. All that matters is that it goes to the straight edge:

Sanding Board 002.jpg


If your sandpaper laps over the edges just trim it back with a Stanley knife. Get another piece of straight material and screw, pin, nail, hot melt glue it onto the sandpaper about 13mm oin from the edge and parallel with it (in this case I'm imagining a piece of 2 x 1 PAR softwood battening, in reality anything with one straight (planed or factory) edge will do:

Sanding Board with Fence 002.jpg


Now you have a sanding board which will accurately sand a flat surface no more than 14mm in from the edge, hence "sanding carefully"

If you check that the 2 x 1 PAR softwood you put on top has a square edge (it isn't always) the same sort of jig can be use to flatten and keep square edges of MDF sheet (e.g. scratch built furniture, pipe boxing, etc). With a 44 x 44 piece of softwood as a fence it can be used to flatten the edges of doors after planing in, for example. A very handy home made tool from (mainly) scrap
 
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Thanks for the instructions how to make a sanding board.

If I've understood correctly, I can see how it will be very useful for doing the ends of the boards. In the diagram below, I can use it to sand down the top edges 1 & 2 for where they join onto 5.

Problem is, like where 1 & 2 join onto 6, the part that need sanding is through the middle of the 1 & 2 sides.
And the same where the divider joins in the middle of 5 & 6. (Arrowed).

Just wondered if you can think of an idiot proof way I can prepare these areas for gluing also?

IMG_20220313_211614 (2).jpg
 
TBH I think there is none. For those, where it looks like you have a dowel and a cam/peg (?) at the end of a narrow rail I'd just glue the dowel in the holes with a spot of PVA on each end. Don't over glue - believe it or not it is possible to split narrow chipboard components by hydraulic pressure if you use too much glue (don't ask how I know that)
 
JobAndKnock said:
Don't over glue - believe it or not it is possible to split narrow chipboard components by hydraulic pressure if you use too much glue
Click to expand...

There aren't any chipboard pieces, it's all made from narrow pieces of softwood glued together to make the wider panels. Does that make any difference?
 
Less likely to split - you need to be more careful with MDF and chipboard
 
JobAndKnock said:
TBH I think there is none. For those, where it looks like you have a dowel and a cam/peg (?) at the end of a narrow rail I'd just glue the dowel in the holes with a spot of PVA on each end. Don't over glue - believe it or not it is possible to split narrow chipboard components by hydraulic pressure if you use too much glue (don't ask how I know that)
Click to expand...

How do you know that? :LOL:
 
Because a very long time ago I made the mistake of assembling some IKEA (or more likely it was Habitat, it was that long ago) flatpack furniture where I insisted on glueing the dowels, and I put two lots of glue down some holes - so when I tapped the pieces together the chipboard shelf split from side to side and I had to do a repair. That's how I know. :oops: I have never repeated the error
 
JobAndKnock said:
Because a very long time ago I made the mistake of assembling some IKEA (or more likely it was Habitat, it was that long ago) flatpack furniture where I insisted on glueing the dowels, and I put two lots of glue down some holes - so when I tapped the pieces together the chipboard shelf split from side to side and I had to do a repair. That's how I know. :oops: I have never repeated the error
Click to expand...

Snap! Did just the same on a kitchen build - luckily it was the first cabinet I put together and could hide the mistake in a row of cabinets.
 
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