Accoya interior doors: making & finishing?

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Eric The Viking

Established Member
19 Jan 2010
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Bristle, CUBA (the County that Used to Be Avon)

I'm contemplating a Really Big Project: replacing our ruined interior doors with copies. They were badly dip-stripped some time before we bought the place more than 20 years ago, which has wrecked them. I think there's nothing that can be done to save them.

Snap from my initial Sketchup model above. I haven't shown the panels in place, nor the planted mouldings (bolection, possibly, although they stay within the panel areas and aren't proud of the frame), as they're not the real issue. They aren't all the same dimensions, even on one floor. The original drawing room of the house has a door that's 1/2" wider than this one (measured directly off the dining room, right next to it!). The heights ought to be the same (so the story stick won't change), but the stiles and/or the rail lengths will vary by about 1/2", adding to the fun.

The scale of the undertaking

If I do this properly, I have twelve or thirteen doors to make: the Caustic Wood Assassins did a thorough job. It will be expensive in both materials and effort (the door furniture alone will be more than a grand and I haven't dared think about the materials yet). Other problems include space to work and store stock (I have a double-garage workshop, bit it also contains non-woodworking stuff). It would be impractical to get the whole lot delivered in one go - never mind the cost, I've nowhere to put a small timber yard all in stick!

There are other issues too: replacements would be quite a lot heavier than the originals/ The caustic has caused them to shrivel up, literally, as they have dried out and shrunk, but they are still really, really heavy. Ideally I'd use sheet material of some sort for the panels, but everything man made seems quite a bit more dense than softwood, so that also adds weight. At least I won't have many layers of lead paint to worry about on the new ones!

Material choice - Accoya?

Rafezetter, of this parish, made the helpful suggestion of using Accoya, mainly because of (a) its reasonable dimensional stability, and (b) that it's close to untreated softwood density (but a bit heavier). This might be a good plan, and it's supposed to be available in better quality grades (and Arnold Laver have just opened a depot near us).

But I know nothing about using it, apart from this handy guide that Lavers have on their site. That goes into some detail about glue issues, suggesting epoxies and polyurethanes, neither of which thrill me and would make M+T joinery difficult. My go-to glue, Titebond 2, is out, it seems because it's PVA-family, and that doesn't like the altered cell structure.

Finishing difficulties

They also suggest that finishes need to be carefully chosen, because there is residual acetic acid in the material, which is sweated out when the wood is worked. This is a worry: I don't really want tools being damaged, nor finish flaking off or orange peeling, etc. I want to end up with plain gloss white (as the Edwardians probably had them).


It would be jolly nice to do traditional M+T joinery.

I have a morticer and I know how to use it and I've made small-ish window frames and casements with it before. I also have a bandsaw and the nice Mr. Maskery's tenon jig plans. And I have a big router, so I could mortice with that, possibly, too.

The problem might be the glue-up: These frames are huge (by my standards), and there are some really big rails to get in, glued and wedged, and I think both Urethane and Epoxy chemistries tend to have short open times (and they're sticky too) so getting the joints physically together would be a challenge (especially that lock rail!).

Which all makes me wonder if this would be the necessary excuse for a Domino, and if that would actually help the glue-up issue at all -- it might not. It certainly ought to speed up construction. And it might mean I could get away with thinner panels too.

The 1/2" panel thickness shown matches the tenon width, obviously, but if there's no alignment with the panel grooves needed for the actual structural joints, there's some wiggle room on the design. The mouldings will neatly conceal a panel set-back that might otherwise look out of proportion. I might get down to 9mm or even thinner (7-8mm would probably work, but I don't think it's a standard thickness - 6mm would be pushing it, I think). Sorry to drop to metric, incidentally.

So heeelp!!!

This lot above (and not having the necessary funds!) explains a bit why I've been mulling this over for ten years or so and not actually getting on with it.

If anybody has experience using Accoya for interior joinery, and/or finishing it please chip in at this point.

If you can suggest a better material for the frames (bearing in mind it's an old house where I can't realistically replace the door casings too!), likewise, please tell me I'm being daft.

I think the one approach I probably really can't take is to go completely trad with inexpensive softwood. It's simply not stable enough to go into a centrally heated house without a lot of warping. I'm going to have to laminate-up the bigger rails anyway, which is OK, but doing all of them would simply make the whole task too big.

I'm beginning to think this may be pretty impractical, simply because of the scale of the task overall, but I really don't want to leave these horribly destroyed doors for another generation to deal with (and it would be wonderful to make at least the ground floor look nice again!).

It pains me to say it, but I might even think about commissioning them to be made - someone with the space to do the whole lot together would get huge savings in setup time, etc., although twelve of these things wouldn't exactly be exciting work!

So expert thoughts are most welcome.



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Then I read your last sentence about expert thoughts. That's me out then.

But, a thought that requires no expertise, why not make just one and see how you get on? If it goes well, then you might think
about the rest or then decide to get them made, but saved cost on at least one.
Absolutely my first thought too.

But the Domino thing is a realistic option (from a practical if not a financial perspective), and it does change the method rather a lot, in a good way. I hadn't actually considered it until now, but it might be a really cunning plan, as it avoids nasty bits, like belling-out the mortices for the wedges, etc. We've had projects posted here including really big gates (IIRC, in hardwood, too) that were Dominoed, so they seem to be pretty strong joints.

The mulling-over continues...
Ah yes, The Domino system. The number of times I have looked at this!

The first time was when I made 2 pairs of green oak garage doors. I decided to M&T them instead and that worked well, apart from one door
dropping. After all how many more doors would I make?

I then considered it when I made a side gate. But it was just one gate, so M&T again.

Then there was the other side gate, but surely that would be it?

Well nearly, because then there was the interior bathroom door when we had a small extension done. But M&T again, the Domino system is pricey.

Oh, and I do have 2 internal French doors to make and a new front door. I will break on this!

And then, if I do decide to buy the Domino system to make the remaining doors, there's always eBay to sell it on.
Will leave a longer reply later when got time but Tulipwood is an option, cheaper then accoya and Domino XL would save lots of work.

Accoya is very stable but probably overkill for internal doors, I reckon you would be looking at £150-£200 per door for the Accoya not including panels. I have never had any problems with painting it, you can get a good finish because even acrylic paints don't raise the grain on it. Never had problems with the acid coming out of it, they recommend stainless or brass fixings etc with accoya but think there is only a problem externally when damp is involved. Once you get wide Accoya planks it is generally laminated

I have seen internal panelled doors made from tulipwood, it is quite stable, no knots and paints well but is a bit soft.

I made about 20 internal doors for my house out of good quality redwood, it hasn't really moved much but it was acclimatising in the house for a good few months before. The lock rails on them are 9 inches deep, made of two pieces edge jointed, thought they would shrink and leave gaps but all ok. They were all made with traditional mortise and tenon joinery.

I have made doors with my Domino XL and it is like cheating, it is too easy. Sometimes if there are mouldings involved I find it as easy to mortise and tenon though because of how the mouldings line up with the tenons etc.

Aren't you over thinking this a bit? What did we use for hundreds of years before accoya, surely some decent quality softwood such as doug fir will be fine?
Happy to lend you my Domino if it helps, although it's the small one, for doors, gates etc the XL is more appropriate although I have repeatedly pushed the limits of mine and never had a joint fail yet.
I know its repeating what has been said but I would go for tulipwood. It is a pretty stable alternative and you can sand to a great finish. Have used this for doors before and works great and accepts a finish well. Accoya is stable but is designed to be stable where the timber is going to be more prone to the effects of weather or moisture. For internal doors this seems a bit over the top. Also it is not cheap (although saying that I dont know how it compares to tulipwood but would imagine it is more expensive).
In my part of the world doug fir is not cheap, i can get sapele for the same price, but you can get vertical grain doug fir for use in the door stiles and rails too if you fancy which should provide a bit of stability (but you pay a premium), the main thing is to machine them up quick and get them together, don't leave a pile of disassembled parts sitting around for weeks as a small amount of wood movement on a 763 - 800 plus rail = a lot of twist in a door.

Cheers Edd
I have had a domino xl for a number of years now but i just cant convince my self its as good as a haunched mortice and tennon glued and wedged, and as such i have restricted its use a overgrown biscuit jointer role.

But then i have access to a large floor standing morticer and a huge Wadkin tennoner with twin scribing heads and a sliding table big enough to park a small vehicle on.

As such for me the domino is awesome when i need it, but for full size doors.............see what the others think.
just re read and i see you have a band saw, if the tenoner was busy in one shop i worked in we would cut tenon shoulders on the dim saw and tenon cheeks on the band saw (which was well set up tho), you already have a morticer (ie big router with a good sharp bit and maybe a jig?), et voila.

One shop i worked in had a tenoner but no scribing cutters so all the scribes were cut by hand, not much fun on a 12 pane door with glazing bars all morticed and tenoned as well, but it can be done.
I'm reading all this carefully, and taking note of everyone's comments.

To reply to a few things:

Domino: I've looked at the XL 700 Domino now. It would almost certainly do the job, and it would save huge amounts of time - I'm "time-poor" for this task, so it's very much under consideration. I like the option of an adaptor ("adapter") for using it for smaller dominoes too. It still makes me suck my teeth though, regarding cost (Scots ancestry!).

I also really like the idea that it simplifies the joinery a lot, and might also result in some stock saving (all rails would be around 10" shorter, which adds up - probably 70" (5'10") of rail saved per door (The bottom rail has to be a 2-up lamination and the lock rail 3-up). There's also no trimming of tenons and wedges to do, and smooth edges to the finished doors, meaning the end result will look a lot neater (and marginally easier to fit to the openings). And shrinkage, if there is any, won't cause tenons to show proud of the edges. There are probably ample YT videos out there on domino-door production, but I found this old article quite helpful. I also like the idea of Seneca's aftermarket "imperial measurement" adaptor, which, whilst not exactly cheap, might be very handy in this context as my house's world is feet and inches!

But that's rather the point (and hard to ignore): the whole domino setup won't be at all cheap. It will likely be an extra 1,200 quid, up front on the project cost. I do have a good local Festool agent: I will enquire, and keep an eye out for one secondhand, too. I believe warranties are transferable, although a bit of Googling doesn't bring up any common modes of failure -- always a good sign.

Bandsaw: it's small (SIP 12") and old, but this task won't stretch it and I know how to tune it (thanks to Steve M's video!). I've cut tenons on it in the past with great success (cheeks, that is) - they usually fit straight off the saw, and anyway I've been rebuilding it recently to improve the precision a bit.

So that is possible for the smaller rails, but the 10" and 11" ones are too big for the throat height and would still be a problem (would end up probably cutting shoulders on the TS and cheeks on the RT I expect, with a rebate cutter).

I do have a Wealden 6-wing surfacing cutter too, and that works really well (been used for improvised too-wide-board "planing" as well as tenon cheeks). It will allow quite deep passes. BUT it's much more time consuming than dominoes, and I still have a tricky glue-up to consider (mostly because of that Muntin - not insurmountable, but still flippin' awkward for someone of my size, age and skills!).

Material: The comments about Accoya are encouraging -- less worried now about finishes, and I'm happy to take advice on a compatible glue with a long-enough open time (if all else fails, Lavers ought to know someone who knows!). Tulip wood is a possibility too - not ruling it out, although I'm a bit nervous about the punishment these doors might get (our kids are grown up, but it's a family house and deserves to be full of noisy children!).
. . .

So I'm still reading and paying close attention. If I don't respond to everybody, it's not that I'm ungrateful for comments, but most probably because I can't add anything constructive (see wot I did there?).

Please do keep the thoughts coming!

Hi Eric

I have one experience of using Accoya, but it won't be my last. I used it to make two pairs of garage doors (in 1/3:2/3 style, so the 2/3 one is big), with Tricoya mdf for the panels.

A few comments from my experience:

- Accoya is nice to work - it is kind to the tools and non-resinous - leaves a nice salt n vinegar crisps fragrance in the workshop (due to the acetic acid in the processing)
- Accoya is expensive, but there is very little wastage due to the sawn boards having little twist or cupping - once machined, they stayed in good shape too (so you are less likely to get a door twisted, as can happen with redwood).
- Before commencing, I spoke to the Accoya technical people who were very helpful - the key points I recall were to use polyurethane glue (I don't remember epoxy being mentioned), to prime using Zinsser 123 Plus and to use stainless fixings (not sure whether that is important for interior).
- I used the Domino XL with long (exterior Sipo) dominoes - you can buy these in 750mm length - 70mm depth on each side, I recall. I have done my share of real M&T's, but the Domino makes it a doddle
- I used 45 minute polyurethane to maximise the open time, but should have avoided the hottest week of the summer...; the glue-ups, particularly of the larger 2/3rds doors were fraught and characterised by world class expletives. I considered and next time will do, pregluing one side of the Dominos - in that case you should mask off the exposed wood to minimise clean up before stage 2 of the glue-up (and clamp the dominoes in, otherwise the foaming glue will push them out).
- I haven't actually fitted or painted these doors yet, even though they were made a couple of years ago (long story), so cannot comment on the paint, except to say it is good stuff for other situations. The doors have been stood in a rather damp garage and are still in good shape - the wood does not appear to have moved at all.
- I looked up the cost of the Accoya - some 2 1/2 years ago this cost just under £500 + vat for the two pairs plus lots of mouldings, with some boards left over - I guess the two pairs of doors equate to 6 of your design.
- I used James Latham who were excellent, both in handling the order and delivery - I think I just gave them a cutlist and they proposed the quantities of various dimension boards.

Yes Accoya is expensive and many would say it is overkill for internal doors - but I don't think it is a daft idea.

Yes, the Domino XL is expensive, but you can always resell it at a strong price once you're done (except you probably wouldn't!).

For internal door panels, I would use birch ply - stable and a bit lighter than mdf.

One obvious point would be to check your door frames are all square/not twisted etc - (different door widths look fine so long as the stiles are all the same width, but I like to ensure that the heads of all the doors line up).

Look forward to the pictures..

Sometimes I get a bit fed up with this forum. People talk at cross purposes or answer their favourite questions rather than the one asked.
And then a thread like this one pops up, and the quality of detailed, thoughtful advice from experienced, helpful people is just brilliant.

=D> =D> Group hug! Well done all! =D> =D> =D>

I know you say that the doors are knackered from the stripping, but could they be rebuilt?

I have done this alot - we had all our old pine doors stripped and of course they were loose all over the place. I took them apart, repaired bits, added strips to stiles that had been badly trimmed, then glued them back together, in some cases with plywood panels to replace the warped pine panels and in some cases screwed and glued on additional strips to top and/or bottom where they had been badly trimmed (next time I would just Domino these).

It is probably as quick or quicker to make from new, but obviously this is cheaper.

To take the doors apart:
- remove all the mouldings
- using a fine shank screw (plasterboard screw is good) screw into each wedge and pull out with a claw hammer.
- if the wedges don't want to come out, you need to drill them out - this will enlarge the mortice, but you just need to adjust the size of the new wedge when reassembling.
- then a bit of brute force with lump hammer and block of wood to drive the stiles apart and dissemble the parts.

Then clean up all the old joints of old glue, true everything up and rebuild (cascamite is my chosen glue for doors as it has good open time).

Scholar: thanks for both your posts - read avidly.

I think I posted pics of the problem years ago, but TBH you wouldn't want to look really. The doors were dip-stripped with all furniture in place (hinges and mortice locks, although they did take the brassware off, mostly). They were never properly neutralized/washed afterwards and the residual Hydroxide went on eating at the wood for years (I'd guess) - after taking the paint it went after the cellulose...

So panels and rails are warped and split, locks are just full of rust, there's no good wood left for fixings for the furniture (big, jagged holes in the lock rails), and so on. And the stripping revealed a lot of nastiness, like very rough deal (now with added shakes), knots dropping out of panels (because the resin and knotting was removed), and so on. Some of the planted mouldings are missing (not on our watch!), and other bits that have fallen off during our ownership have revealed crystalline deposits, and in other places the doors sweat caustic in the summer.

And finally, they did wax the doors of the public rooms, so I'd have a dreadful job getting that off those so they could be neutralized and would accept filler and paint again. And they no longer fit the openings properly either.

You're right about checking the openings incidentally - not my first rodeo. I've got a couple of doors which are bad (one is spectacularly in wind), so will probably have to do the doorstops too. Thankfully at the moment almost all of the hinge sides of the casings seem to be true and fairly straight (not all of them though).

House is around 110 years old - probably, but possibly inter-war completion. I suspect the latter, when decent softwood stocks had been really run down by the demand of the trenches. Some of the deal used is frightful, as are the floorboards and skirtings - boards from the 1880s I've seen in the area are nothing like as bad, even though the house completion rate then was far greater than the 1920s.

So I fear the existing doors are gone for practical purposes. I'm not sure you'd even want to burn the wood. I've managed decent rescue jobs elsewhere in the house, but in this case there's nothing left to work with realistically.
Accoya doesn’t present any advantages over tulipwood and tulipwood is significantly cheaper (circa £800 per m3 currently depending on volume purchased). Tulipwood is stable, machines and finishes beautifully. In my opinion very little difference in hardness between Accoya and tulipwood. Wedged mortice and tenons obviously is the traditional way to do the joinery and has mechanical strength even if the glue fails. But having said that modern glues are fantastically reliable so using large Domino’s is perfectly practical and quick (purists would turn in their grave though). Tulipwood is also nice and light at circa 550kg/m3 so keeps the weight of the doors down. Have you considered whether any of your doors need or should be fire rated as this should be a first consideration as they can be the difference between you getting out the house alive or not (you’d be amazed how fast fire spreads without fire doors!). If I were you then I’d get some joinery/door companies to provide you with a quote and see how that compares with your costing for you to make them yourself. Is doing it yourself worth the saving if you’re time and space poor? There are other ways of producing panelled effect doors with solid door blanks which would be cheaper so it’s also worth considering whether you want to stick with the more expensive traditional joinery door construction? Regarding the frames, it’s significantly easier to rip out the existing frames, standardise all the sizes of the frames and thereby standardising the sizes of all the doors which makes them easier and quicker to produce. Final note, don’t buy the adapter for the xl domino to use the df500 cutters as it can damage the gearbox which is an expensive repair not covered by Festool warranty if you’ve used a non Festool adapter. Well that’s some food for thought for you and do shout if you have any further questions.
I'm in the final stage of making 7 sash windows for a house project from Accoya and using a Domino 700 for the sash joints - I didn't fancy cutting 56 haunched tenons. The first 3 have been installed since end of last summer and have stayed rock-stable.

The Domino is what it is - expensive, but very fast to use.

Accoya. I am also going to be using it for some French doors. If I was making my internal doors (which I'm not - I'm afraid off the peg clear pine 6 panel doors from engineered timber will do me) I would consider Accoya as it is extremely stable and also because IMO alternatives are not so dissimilar in price once you factor in the consistent sizes and relative straightness of accoya - very little wastage. I certainly wouldn't contemplate using redwood - it's just not stable enough.

I think the thing you have to think about is time to prepare the stock - Accoya rough sawn is pretty straight, but still needs a thicknesser (I have managed with a very cheap Titan amazingly) - it will make a LOT of sawdust. If it's any help it has just taken me 6 solid days of work to convert rough sawn accoya into 3 sash windows, and that's having already made some and worked out how I can work faster.

Accoya machines easily, but it is quite brittle and spelches badly if given a chance.

As far as finishing goes, I have taken the lead from the pro window manufacturers and have been spraying Teknos Aquatop and primer - overkill for internal!
accoya is v stable and comes with no knots splits or warps usually, but its expensive, id use a good grade mdf for an internal door thats being painted.
I would go for tulip/poplar perfect for painted internals.
Would build traditional with through m+t.
Bit unusual to have bolection on a internal mainly see panel mould on the internal side.
For the panels 15mm is perfect for a 44mm door.
Real doors can be produced with a mineral set up the most important part would be getting your stock prepared worth outsourcing if you don't have the resources.
The joinery can be done with a router and the morticer.
Why not do them in small batches 2 to start then go from there.