Ply Baseboards: Glue, Screw and/or Pin?

[5BarVT]

Morning All,

 

I’m building my baseboards from 6mm birch ply with 21mm square PSE strengthened in the corners.  Most are 100mm deep sides, some are 50mm and two are 36mm.  In the past I have glued and screwed all the joints, so far I have only glued the new boards.  Is glue alone likely to be sufficient, or should I add panel pins or screws for additional strength?

 

Views and comments please . . .

 

Paul.

[Hibelroad]

It depends what you want to do with the boards, will they stay at home or are they likely to be used on the (future) exhibition circuit? If they don’t get moved very much glue will be OK. For boards that get regular handling and are likely to be subject to stress a few screws will help. I’m not a fan of pins and nails so small thin screws would be my choice. 
 

[PMP]

Without knowing what the design looks like it’s difficult to answer. With the information supplied I’d say yes use screws and pins too, they’ll help with the assembly fixing, but not necessarily the rigidity.

[5BarVT]

Thanks for the quick replies,

 

You're right: just because I know what I intend to do doesn't mean that anyone else does!

It's a home layout on separable boards so that I can turn them on edge to work underneath.  Initially there will be a lot of handling as I wire up etc, thereafter only for fault finding /maintenance or when (if?) we move. 

 

This is one of the 36mm deep boards under construction - the diagonal bracing is just scraps placed in position to give the idea.  All rectangular boards will be similar in method.  The tops will be screwed down onto the PSE blocks, my current thoughts are to screw through the ends into the PSE to hold the ends (as the screws will not be seen) and pin through the sides to take any longitudinal forces from the bracing.

 

Paul.

[melmerby]

1 hour ago, 5BarVT said:

Morning All,

 

I’m building my baseboards from 6mm birch ply with 21mm square PSE strengthened in the corners.  Most are 100mm deep sides, some are 50mm and two are 36mm.  In the past I have glued and screwed all the joints, so far I have only glued the new boards.  Is glue alone likely to be sufficient, or should I add panel pins or screws for additional strength?

 

Views and comments please . . .

 

Paul.

I've made my baseboards out of 9 or 10mm ply (the batches varied)

They are 4' x 3' and 100mm deep, (yes mixed measuring systems!) all are pinned and glued but don't have corner blocks per se, but the legs are screwed into the corners, post assembly

Some have bracing down the centre to stop sag but were already pretty rigid without diagonal bracing and before the legs were fitted.

Edited February 15, 2021 by melmerby

[doilum]

Depends on the glue and how many clamps you have. 

One approach is to regard the screws as removable clamps. This will make it much easier to fill and smooth the outer facia.

A good eurathane ( sp?) foaming glue will achieve a good strength in ten minutes and full strength in half an hour. This does require fast accurate clamping which is why many stick to PVA and pins.

Perhaps one day I will get round to trying the 21st century approach with cynoaccrylates and accelerator spray.

 

[teaky]

I used wood glue and brad nails of appropriate lengths driven in using an electric stapler.  Boards were either clamped or weighted and generally left overnight to set.

 

What I actually used is as follows but there are plenty of alternatives.

https://www.toolstation.com/interior-exterior-pva-wood-glue/p31670

https://www.screwfix.com/p/titan-ttb516nal-25mm-second-fix-electric-nail-gun-240v/85214

https://www.toolstation.com/search?refinementList[brand][0]=Tacwise&q=brad nails

 

[Harlequin]

Glue alone using exterior grade PVA Wood Glue works fine for me. I started off pinning and gluing but realised that the pinning stage was a pain and pointless after I'd made a few units. (In fact, detrimental because half the time the pins would split the ply.)

 

After gluing a joint you want to cramp it up as quickly as possible. Faffing around with pins, usually right where you want to position the cramps, always worried me, especially if it causes the joint to move slightly while the glue is starting to go off.

 

Gluing alone relies on joints being clean, true and straight, of course - i.e. cut by machine not by hand (for most of us).

 

Edited February 15, 2021 by Harlequin

[ISW]

3 hours ago, 5BarVT said:

Is glue alone likely to be sufficient, or should I add panel pins or screws for additional strength?

 

Views and comments please . . .

 

Paul.

Paul,

 

I did the opposite, and used 4mm (No.8) screws of 30~50mm length and no glue. I thought about gluing as well, but the screws at ~200mm centres were already strong enough. All holes were pre-drilled and countersunk to avoid cracking. Top plywood and PSE sides, although plywood was used for some sides where the height was more than the PSE depth of 44mm. The link below goes into a little more detail:

The advantage of screws is that you hardly need any clamps, just one or two for the piece being assembled. Screws also make retrospective changes easier to accommodate. Make sure you have enough bracing - I worked to a spacing of ~300mm for mine, with holes drilled to save weight and provide routes for 'tidy' wiring.

 

Ian

[PMP]

 

I’d use more bracing along the lines above. Whilst you may only occasionally move it, the original design will likely have longitudinal flex particularly if heavy with scenery. As you’re using 6mm ply it’ll be lightweight so more bracing won’t significantly compromise the weight. You’ve also got the option of drilling lightening holes in the bracing, and those holes can assist with feeding a wiring loom around the board, preventing the loom from hanging and catching beneath the layout 

[melmerby]

2 hours ago, Harlequin said:

Glue alone with exterior grade PVA works fine for me. I started off pinning and gluing but realised that the pinning stage was a pain and pointless after I'd made a few units. (In fact, detrimental because half the time the pins would split the ply.)

 

 

 

Pins too fat or board too thin.

 

Never had a problem with mine.

I used to clamp the edges in a workmate and arrange some packing so that the main board was level when offered up

Run some PVA along the edge piece put main board on top and bang in pins every 150mm or so, hardly a PITA.

Repeat for other 3 sides including some glue & pins between the corners.

Never clamped any of mine and they are strong enough to support the full weight of my ample frame.

I used hardboard pins & Screwfix cheap PVA

 

[RobinofLoxley]

My boards are all 6mm ply as thats what i had lots of left over from the last layout, with edges 21x44pse. I have screwed and glued everything, the 21mm section is thick enough to take a woodscrew without splitting- the screws are there to hold the battens in place while the glue sets. What I realised this time around is that a glued joint is more rigid than screws alone because a screwed batten can flex between fixing points. If the glued joint is well made I can probably take the screws out after but so far I have left them in. All screws were countersunk and this time I managed to get them all inside the play without splitting it, although with the glue one or two casualities wouldnt have been a problem. If as above you have thin ply for the frame of the  baseboard I dont see how you can in or screw that without some risk of splitting, so the glueing needs enough clamps to provide pressure along the entire length of any joints.