Heads-up - Gluing Accoya

[Steve Maskery]

Just a heads up to any Accoya virgins like me.

My bro has roped me into making a new door for his (Listed Building) home.

It has to be identical to the door extant.

The jambs are 120 x 75mm, so we have had to make them up by gluing together two pieces.

I had somewhere in my mind that Accoya is difficult to glue, but I found a D4 hybrid adhesive from Everbuild, sold by Toolstation, and I thought that would be OK.

We glued two pieces together, good squeeze-out, overnight in the clamps. This morning, remove the clamps, it's not looking quite as tight. One pass through the thicknesser and the joint is opening up. We decided to saw down the glue=line (we had plenty of width but were tight on thickness), but it wasn't necessary. The gap opened up by the minute, and I soon could prise the two pieces apart with a chisel. The glue had covered the whole surface, but simply had not adhered.
A bit of googling and it seems that everyone uses PU.
So re-done with PU and all is well.

Better to find out now than when the door is made and hung, eh?

 

[Doug B]

Yep they recommend PU, epoxy or PRF glues also you’ll want stainless steel fixings, I though I remembered you saying you weren’t getting involved in this door :-k

 

[Steve Maskery]

though I remembered you saying you weren’t getting involved in this door :-k

Thanks, I think...
S
See you tomorrow.

 

[Trevanion]

I did some tests with various glues on the stuff when I first had some. I found only the PU and mitrebond would hold it, Cascamite was hopeless as it reacted with it or something and just fractured the glue once it hardened, PVA didn't really stick at all and as you say, the D4 was useless too despite Accoya saying it can be used.

As Doug says, you need to use marine grade stainless to even have a chance of not having serious corrosion, it even eats most stainless and it really needs to be 316 grade.

I've heard murmurs of a newer timber from a different company that's using the Radiata pine and a different process which will be a fraction of the cost of Accoya (Which is extortionate at over £2100 a cube at the moment), no black marks in the timber and will apparently be harder wearing. Although they did say that initial tests have shown massive ammonia exposure in workshops that tested it, so they're still working out the kinks. Apparently should see something by the end of the year.

 

[RobinBHM]

I used to make lots of doors with accoya. After having to remake them due to splits down the hinge side due to catching the wind, I got put off it. Ive mostly gone over to engineered siberian larch.
Accoya is very good, but it has its issues: its brittle, boards arent always as flat as they should be, the grain can show rippled markings through a paint finish because the spring growth is very soft and sands away more quickly.

It is nice and stable though.

PU glue is necessary. Try and keep glue application away from where mouldings meet or internal corners. Some PU dries harder than others. We use one that can be scraped off easily with a chisel after an hour or so, but gets hard after 24 hours. I think its best to scrape off not long after its set.

 

[Steve Maskery]

Today we've been using my Wudcare, but he has bought a bottle of Egger. Not opened it yet.
S

 

[Trevanion]

the grain can show rippled markings through a paint finish because the spring growth is very soft and sands away more quickly.

I saw this product recently from the US called a "Duragrit Duradisc" which is a metal plate sanding disc with carbide embedded. I think it would be ideal for the Accoya as it might stay flatter than a standard cloth disc, I'd be tempted to try it if they were available in this country, even at £50 a disc

Regular, square, non-random orbit sanders seem to work very well on Accoya too, but the dust knackers the machines in double time.

 

[marcros]

I used to make lots of doors with accoya. After having to remake them due to splits down the hinge side due to catching the wind, I got put off it. Ive mostly gone over to engineered siberian larch.
Accoya is very good, but it has its issues: its brittle, boards arent always as flat as they should be, the grain can show rippled markings through a paint finish because the spring growth is very soft and sands away more quickly.

It is nice and stable though.

PU glue is necessary. Try and keep glue application away from where mouldings meet or internal corners. Some PU dries harder than others. We use one that can be scraped off easily with a chisel after an hour or so, but gets hard after 24 hours. I think its best to scrape off not long after its set.

do you happen to know the brand of glue? I have only used the gorilla PU to date (not on accoya) but would be interested to try another when the bottle is finished.

 

[Trevanion]

do you happen to know the brand of glue? I have only used the gorilla PU to date (not on accoya) but would be interested to try another when the bottle is finished.

In my experience, they're all pretty much the same except for slight variances in hardness and the speed it goes off. I usually buy whatever a supplier has to fill up an order.

Soudal Pro45P is probably one of the faster-setting ones and sets much harder and the bottle can take a silicone tube nozzle which is really handy, Wurth PU tends to be slower and stays pretty soft and spongy for a couple of days before hardening up, Lumberjack PU tends to have a finer foam to it (If that makes any difference) and is pretty slow going off, Gorilla doesn't really have any different traits other than costing 3 times as much as everyone else's.

If you're looking for a new glue to use try the Soudal stuff, it's much cheaper than gorilla and just as good. You can get 2 bottles of 750ml Soudal for the price of one 500ml Gorilla.

 

[marcros]

it actually is 3x as expensive. I got some from Costco, and thought I had got a good deal until I just compared with soudal!

 

[Doug71]

PU glue is necessary. Try and keep glue application away from where mouldings meet or internal corners. Some PU dries harder than others. We use one that can be scraped off easily with a chisel after an hour or so, but gets hard after 24 hours. I think its best to scrape off not long after its set.

Tell me about it, I made an Accoya door yesterday with thin glazing bars and fine mouldings, spent over an hour trying to clean the glue out of all the corners.

you need to use marine grade stainless to even have a chance of not having serious corrosion, it even eats most stainless and it really needs to be 316 grade.

Quick question on this. The door I have just made is a replacement and I am hoping to use the existing 5 lever sash lock in the new Accoya door. Don't think it will be stainless, will it be okay to use it? I have heard different views/opinions on this. Some people say fine as it won't be getting wet but other people talk of condensation etc around the lock that will cause corrosion problems?

 

[Trevanion]

Quick question on this. The door I have just made is a replacement and I am hoping to use the existing 5 lever sash lock in the new Accoya door. Don't think it will be stainless, will it be okay to use it? I have heard different views/opinions on this. Some people say fine as it won't be getting wet but other people talk of condensation etc around the lock that will cause corrosion problems?

Accoya does corrode steel even without being wet, the wet just helps it even more though. I've been smearing the galvanized lock bodies of the 3 point locking systems in silicone when I fit them and this seems to help prevent corrosion on the face. Make sure to also get paint/sealer in the lock hole of the door to seal up the Accoya.

 

[Beau]

Quick question on this. The door I have just made is a replacement and I am hoping to use the existing 5 lever sash lock in the new Accoya door. Don't think it will be stainless, will it be okay to use it? I have heard different views/opinions on this. Some people say fine as it won't be getting wet but other people talk of condensation etc around the lock that will cause corrosion problems?

No experience with Accoya but you could seal the wood with epoxy around the lock before fitting to avoid any reaction

 

[will1983]

A quick bit of information that may help, marine grade stainless steel is known and may be labelled as either 316 and A4.
306 or A2 grade is still a stainless steel but is not marine quality and doesn't have the same level of corrosion resistance.

I'm no metallurgist but I discovered this little nugget of information when I was building my bandsaw. All the metal components on that are 316/A4 grade.

 

[RobinBHM]

Quick question on this. The door I have just made is a replacement and I am hoping to use the existing 5 lever sash lock in the new Accoya door. Don't think it will be stainless, will it be okay to use it? I have heard different views/opinions on this. Some people say fine as it won't be getting wet but other people talk of condensation etc around the lock that will cause corrosion problems?

Accoya does corrode steel even without being wet, the wet just helps it even more though. I've been smearing the galvanized lock bodies of the 3 point locking systems in silicone when I fit them and this seems to help prevent corrosion on the face. Make sure to also get paint/sealer in the lock hole of the door to seal up the Accoya.

I cant say Ive had problems with ironmongery. although all joinery we make is fully sprayed and we paint in the lock holes. Mind you screws certainly rust. The problem is handles that have pewter or anitque nickel finishes -the screws are always steel coloured to match. The only option is to have non matching stainless ones. Normal screws do rust.

 

[martin77]

Sorry to drag this post up. I've recently started using Accoya. I build wooden cases and use strips of accoya that are 20mm x 10mm, the cases are covered in leather and a few small hinges and catches are added. I've been using brass and A2 grade stainless screws, will they be okay?

 

[Ollie78]

I would say the should be Ok the stainless certainly will.

 

[martin77]

I've spoken to Accoya directly about this, what they're saying is stainless and Brass screws are fine, other screws are fine as long as the woods not getting wet.

As for the glue this thread got me a bit worried because I had been using Gorilla wood glue. This week I've been trying both Gorilla and the Soudal PU glue, the only pro I'm getting from the Soudal is its going off a lot faster than the Gorilla wood glue, I actually think once the Gorilla glue is fully cured it's holding a lot better than the Soudal PU glue. The main 2 draw backs I'm getting from the PU glue is its messy and its a bit temperamental when I'm flexinging the piece that's been glued. I've also asked Accoya about PVA glue in general with Accoya and they're saying it's totally fine.

I guess the big factors here is the temperatures your working in, time and don't whatever your gluing have much flex

 

[johnnyb]

I seem to be a lone voice saying "why accoya" the very existence of joinery in a traditional form is because wood moves. Painting happens because wood degrades. I do not advocate accoya in heritage buildings. It's highly acidic and to envisage paint being for life is just crazy. If I so much as bring up a dissenting word against accoya it's like I've insulted there mother. It's corrosive on leaded glass and the lead itself. It's also as has been hinted at brittle and hard to glue. As well as being price controlled by a single very cynical company. It's not even available in the right section for this particular example!

 

[martin77]

I seem to be a lone voice saying "why accoya" the very existence of joinery in a traditional form is because wood moves. Painting happens because wood degrades. I do not advocate accoya in heritage buildings. It's highly acidic and to envisage paint being for life is just crazy. If I so much as bring up a dissenting word against accoya it's like I've insulted there mother. It's corrosive on leaded glass and the lead itself. It's also as has been hinted at brittle and hard to glue. As well as being price controlled by a single very cynical company. It's not even available in the right section for this particular example!

Tbh, my experience with it is limited. Warping is a massive issue for what I so which is why I use Accoya.