Non-warping Wood for Base?

All, I need to make a wooden base for a model ship, approx. 1000mm long x 200mm wide x 30mm deep.

The ship is a waterline model, and will be glued directly to it. The ship is made of paper and has no resistance to warping of the base.

I’d like a 5mm chamfer around the top edge.

Some people I know are suggesting plywood, veneered with the same type of upper surface wood around the sides (5mm thick to accommodate the chamfer of course).

I wonder if milling the centre of the wood out from underneath, and filling the pocket with laminating resin and fibreglass would guarantee stability? I suppose varnish may help maintain moisture content - I want a satin finish anyway.

There are other options, but I really n a guaranteed stable finish, or else hundreds of hours of work will be lost.

I notice in the instructions for the Princess Royal I’m building, the base is made up of a sheeted substructure, apparently to stop warping.

Any thoughts?

Thanks.

I know you ‘need’ wood, but : Slate might be a more stable alternative.

MichaelG.

.

Objection noted and respected 

But I will link this page anyway, for general interest:

https://www.berwynslate.com/product/welsh-slate-copings/

Edited By Michael Gilligan on 05/02/2022 23:32:41

Thanks Michael. I think slate or granite would be a bit heavy. Also plastic could be used, but I really want a wood finish to go with my other ship builds of the same type.

Mainly the most stable of woods is Hardwood. It is expensive, but If you used say solid oak. It would never move. But your bank account would.

Steve.

I don't think hollowing the base and laminating glass fibre to any thickness would be stable over time, at least some of the 5mm thick model moulds I have now present with very slightly upturned flanges.

Also if using veneer on 1 surface it is best applied to the other side to provide equal contraction over time, in past times single side applied Formica surfaced chipboard was notorious for warping, always apply the same covering to both sides for long lasting use.

Emgee

Is any timber totally resistant to warping?
Simple options that come to mind for that size include an off cut of a timber kitchen worktop or a faux laminate worktop or a wood effect porcelain tile. Edging can always be done with other stuff.
I’ve got a lump of Oak in my woodshed that may fit the length/width (subject to measuring - it's probably way bigger) but is very much thicker at some 100-120mm. I cut it from a fallen tree 5 years ago but it’d still have to be indoors for some weeks to allow any checks to develop before final trimming & planing. I could measure it if you’d like but obviously not a postable option - you'd have to collect from mid-Wales.

Wood veneer on a stable substrate?

pgk

I use sapele for bases. Cheaper than oak , more stable, a strait grain and even used outside.

David

I've veneered onto other substrates without too much of an issue if the right adhesive is used, one of the modern honeycomb cored materials would be light and stable. Or you could make a sandwich of 6mm veneered MDF with a core often referred to as a torsion box in woodworking circles which keeps the weight down, I often use this for large "floating" shelves.

If you don't want to get into veneering then forget a solid piece of timber but go for laminations much like a kitchen worktop, as the grain directions are different in each piece they are a lot less likely to warp but as said above it's important to "balance" any finish as when you bring the mounted model in from the cold workshop into the centrally heated house even though it's kiln dried timber you will loose moisture faster from an unsealed underside that a sealed or polished top and end up with a warped base.

Doc, I don't think the recessed and filled base would give what you seek.

Wood, depending on what you choose, will react to environmental conditions in varying ways. For example I have a piece of extremely old timber - I think its Oroko and probably 60years plus old that I took a slice off to make the bearers for the marine engine - I cut two at the same time but only used the one. The spare piece now sits like a banana. Once cut, no matter how flat theres no way of knowing how wood will react over time.

To be certain the base needs to be composite and veneered - thick multi layer birch plywood is one option, blockboard is another.

I use 19mm intumescent MDF for my plastic models - don't know how easy that would be to veneer, I just seal it and leave it as is but it is basically inert and extremely flat The base I have for my Kuznetsov aircraft carrier is ex furniture veneer faced chipboard still to be edged with wood beading. To me that is the way you need to go given your concern for the model's basic fragility.

Pre-veneered MDF is available cut to size from many suppliers e.g. **LINK** up to at least 26mm thickness.

For the edges you can use iron-on edging or some suppliers will do it for you at extra cost e.g. **LINK**

I'd use a thicker lipping for the edges though.

Clive

I would suggest a piece of Mahogany, it will cost you but from my experience will not warp.

Hi,

Perhaps Accoya would suit, it's a pressure pickled softwood and dimensionally very stable because of the acetylation process. It also comes in an MDF form called Tricoya, although maybe less appropriate.

Whilst some natural woods are fairly stable (mahogany) all will move over time. MDF remains flat and if well varnished all round will not be affected by moisture. If veneering MDF do both top and bottom to prevent any stresses from the veneer trying to bend the MDF. The chamfer around the top would be difficult to veneer but a possible solution would be to make a separate hard wood frame with a chamfer on the outside top and a rebate on the inside top to take the base. Simply drop the base into the frame don't glue it and then if the frame moves the base will stay flat. An upside down picture frame if you will.

John

Edited By Journeyman on 06/02/2022 10:01:24

Whatever wood you choose, cut it oversize initially, then leave it in the room you're going to display the ship in for at least 2 weeks before cutting to final size. This will give the wood a chance to stabilise at the temperature and humidity it's going to have to exist in in its final home.

first it depends on how the wood was cut originally from the tree if cut through and through then it is more likey to warp to some degree if quarter sawn then it will warp to a much lesser degree than the first option.

secondly It all depends on how wood is dried whether you have air dried or kiln dried. Air dried will have more moisture in than kiln and so will warp more readily

third type of wood hard woods are less prone to warping

forth how you treat the wood before preparing as mentioned above bring it into the environment that it is going to sit in when finished for a minimum of two weeks three is better then prepare the wood.

Remember that wood will still take in water and loose it even when finished so expect some movement even only a slight amount wood never stops moving even when sealed

I think coloured MDF can look good - the core is coloured as well. Mind you, I like plain waxed MDF so my taste might not reliable. 

I don't like MDF smell or dust though - I stopped using it for this reason.

Edited By jaCK Hobson on 06/02/2022 10:51:43

Strange suggestion, but source from old furniture? Recently need some hardwood to repair our front door, and my daughters unwanted 65 year old oak table has given me a good supply of well seasoned oak. It was made of 24mm x75mm and 24mm x 96 mm pieces, and is proving very usefull!

I'll second that for old furniture. Once you have your finished size then it needs to be completely sealed (shellack polish etc). Alternatively use Trespa high pressure laminate. Pleasant to look at can be machined with a router to create the edge. Totally stable and dead flat. Link is just for an example.

**LINK**

regards Martin

All timber will ‘move’ if the timber has not been ‘seasoned’ well enough, or if it then absorbs moisture, particularly if different parts of the trunk/branch structure (heartwood and sapwood) are included in the one piece.

Generally, properly seasoned timber and properly sealed after machining should be OK. But that cannot always be guaranteed. There are different ways that wood might warp - with the grain direction or across the grain. Along the length of the grain can be avoided/fixed by affixing to a sub-plate. If it warps across the grain (width of piece) there is little chance of correcting the shape without re-machining.

I once made a door (probably Brazilian or Sapele - but one mahogany) that severely bent along the grain a few days afterwards. One stile was difficult to straighten on the planer and had a mind of its own after the door had been put together.

Another example was a patio door frame that was warped so much that the aluminium extrusions touched the rebates at each end but with a nearly 20mm gap in the middle. That was across the grain, so not possible to correct with shimming at installation.

Iroka was always a pig to straighten (nearly always ‘bent like a banana’ when sawn) but was very stable once machined straight. Used for many laboratory benches in educational establishments demonstrates its hard wearing and durability qualities.

Reading through your initial post again Doc at a metre long and 200 wide solid wood would be risky indeed especially with a waterline model.

Just a thought but does it have to be a wood finish? MDF as suggested could be painted in a complimentary or contrasting (to the ship) colour. Any thought as to a cover going over it? A secondary under base can provide support for that.

Something like this perhaps?

All my models have picture mount board card covers over them that sit on the lower edge to protect from dust but could just as easily be acrylic or glass.

Just another thought perhaps