nooooooooooooo!!!!!!!! unlucky there -i had the same problem with mine lives and learns though!

Now you know why plywood is recomended.

Now you know why plywood is recomended.

Yes, now that I will have to buy a new sheet of wood to start again I'll probably go for a quality piece of Scandinavian marine ply or the like. I don't think this problem was the fault of the MDF though, I've not had this problem before and I used enough of the stuff building cupboards and partitions when I did my own loft conversion. I just forgot to acclimatise the wood first. I bet if I put the baseboard back in the workshop for a few days it'll straighten back out again... especially as it's about -6°C and under a foot of snow at the moment!

That's a shame! MDF is terrible for warping though from my experience. At least it wasn't a few hours work!

I wonder if the PVA applied to glue the paper down was a contributing factor?

... I wonder if the PVA applied to glue the paper down was a contributing factor?

I wondered if that was a possibility too. My suspicions lie more with the spruce though rather than the MDF. From experience I suspect that it is the spruce that has expanded more than the MDF due to warming rather than the MDF shrinking due to drying out. Yes, it's cold and cool in my workshop but it's not wet. Unfortunately it looks as though progress will be halted at least until the weekend because the chances of me getting to the timber merchants in the next few days are looking very remote!

Why not use the "strips of ply screwed and glued to spacers" method as the supports, and mdf as the base again?

The method has been well documented in the modelling press.

Is it possible to dissassemble the thing, and then reassemble with the two convex components facing each other?

Why not use the "strips of ply screwed and glued to spacers" method as the supports, and mdf as the base again?

Mmm... interesting idea. I guess now that I'll most likely be starting from scratch I can do it however I like instead of being constrained by what I happened to have.

Is it possible to dissassemble the thing, and then reassemble with the two convex components facing each other?

I could give it a go, nothing to lose I suppose. Parting the MDF from the frame could be tricky though. I did use plenty of PVA and it's unbelievably tough stuff. Most likely a layer of the MDF will give way rather than the glue breaking.

Hi Peter

This might help, plywood baseboard construction.

Cheers

Jim

Not sure if using ply is the answer, either, as I had a banana baseboard made of this material a while back.

Wood of whatever variety seems to be inherently unstable, so I suspect we need to deal with our boards in a different fashion with more bracing. Diagonal bracing either of conventional 2" x 1" softwood or ply strips might be more effective.

I'm not a scientist, but I suspect the real problem is the amount of moisture content in the wood, both the board and the bracing. Given the amounts of liquid we slosh on our layouts (plaster, dilute PVA etc), its a wonder any of the baseboards stay flat. In an attempt to avoid future problems with my current layout, I splathered the ends of each baseboard where the tracks cross with wood hardener and then painted the whole lot with a couple of coats of white primer. The two scenic boards incidentally have 6mm ply tops supported by 2" x 1" softwood braced diagonally.

Until we moved last May, the boards were kept in the house. Now, they are in the garage - which is very cold at the moment. So far, so good with no sign of any "banana-ing"!

If the boards do "banana", I may look for alternatives in the future. Dense foam maybe one answer .....

David C

The oth

I recommend sealing the wood (all sides) with Yacht varnish. (I use Silkens)

HTH

Jim

That's a shame! MDF is terrible for warping though from my experience. At least it wasn't a few hours work!

I wonder if the PVA applied to glue the paper down was a contributing factor?

Depends how thick the MDF is - I have 3/4" MDF for the garage layout - no problems and its -1 degrees at the moment.... What I have trouble with is bloody backscenes - tried alsorts of adhesives - VERY prone to damp and bubbling.

For that thickness of recalcitrant MDF, I'm not convinced any 2" batten will be strong enough to counter the warping.

jim s-w's method is the one I mean. If you make the bearers and cross members from two strips of decent ply, screwed and glued to spacers, which can be thicker ply, blockboard, softwood, or even hardwood if available, and use plenty of diagonal cross-bracing, I can't see it warping far.

Then do as Jim says, yacht varnish, first coat thinned, sprayed/painted all over it.

For that thickness of recalcitrant MDF, I'm not convinced any 2" batten will be strong enough to counter the warping.

It's not the MDF that's warping it's the 2 x 1. It's about time this 50's throw back way of making baseboards was consigned to the dustbin where it belongs.