Preserving a garden bench

[Deleted member 174758]

Yes, with the following caveat:

Treat the rotted bits to some wood hardener (probably the Ronseal stuff).

Rotted timber should be removed with a stiff wire brush before treatment with wood hardener. If the rot is extensive, you may need to splice in a new piece of timber. If it is minimal it may just need some 2-pack filler.

 

[Amped]

Excellent stuff, think I might get away with the filler for the most part.

 

[Amped]

There are always more questions than answers... especially when it comes to things in tins...

Am I right in thinking a solvent / spirit based treatment is best for preserving and protecting rather than water based? Oil and rain water not mixing etc?

I spotted that the Cuprinol products I was looking at are water based, so I might look for something else.

Am I also correct in thinking a water based product might struggle to go over where I have used the wood hardener? My guess is that wood hardeners are all solvent based?

Any help is always appreciated.

 

[Deleted member 174758]

Am I also correct in thinking a water based product might struggle to go over where I have used the wood hardener? My guess is that wood hardeners are all solvent based?

Forgive the description, but I am no chemist - wood hardener is a polyurethane compound which is activated by moisture and gets drawn into cells near to the surface which contain water. That's why you need to remove all the punky wood before applying it. Any water the hardener comes in contact with reacts with it to create an impervious plastic substance, so little chance of water (which is one cause of rot) or water-based products being absorbed where the wood hardener has been used. If you think about it, that's what you want it to do - stop further rot

 

[Harry Bloomfield]

Allow the legs to dry out in this weather, I suggest with the feet elevated. Then stand them in a (idealy) spirit based wood preserver for a hour or so.
Obtain some 100 mm X 10mm Coach Screws, find the centre of leg foot(s) and drill a 6mm pilot hole in each foot and then insert a coach screw it the pilot hole, leave a small, 6 - 10mm, gap between the screw head and leg. Doing that will stop water creeping into the legs.
Once that is done you can refinish with a suitable coating of your choice.

The same solution I use and it certainly works. I used threaded M16 hex headed bolts, grinding the hex to a bit of a dome, drilled the feet with a slightly undersized to drill bit for the threads, then screwed them in coated with a thick grease. I dome the heads, so they would slide across concrete slabs, rather than dig in.

 

[Amped]

Forgive the description, but I am no chemist - wood hardener is a polyurethane compound which is activated by moisture and gets drawn into cells near to the surface which contain water. That's why you need to remove all the punky wood before applying it. Any water the hardener comes in contact with reacts with it to create an impervious plastic substance, so little chance of water (which is one cause of rot) or water-based products being absorbed where the wood hardener has been used. If you think about it, that's what you want it to do - stop further rot

So... I think we are in agreement that, a water based product wouldn't adhere very well to the areas that had been treated earlier with the wood hardener?

I'll go all solvent / spirit / oil based

 

[Amped]

Hmmmmmm...

After twenty minutes with the sander, and a little go with the Nitro Mors, I reckon I'm looking at several days or more worth of sanding and stripping before I'm even close to being able to use the preserver and protector. It's screwed in places and mortise and tenon in others, so I'm thinking it would survive a dipping, or better still, shot blasting.

 

[Deleted member 174758]

...so I'm thinking it would survive a dipping, or better still, shot blasting.

Shot blasting leaves a horrible, rough finish on timber. It's OK for big beams in buildings where you are trying to remove 150 years worth of whitewash and paint, but not for something you intend to park your arris on IMHO

You could always ask a stripper if they do a soda lye strip or a non-dipping strip (some do). I'm not keen on risking joinery work in a dip bath, especially if I don't know the company doing the work (and there are some right cowboys out there)

 

[Amped]

Shot blasting leaves a horrible, rough finish on timber

Really? That bad?

There doesn't appear to be any easy answers on this one...

 

[Deleted member 174758]

Really? That bad?

There doesn't appear to be any easy answers on this one...

Yes. Even with cherry pit shot. I've worked on several mil conversions where this was done to the beams (which are great big lumps of wood) and believe me it leaves a fairly coarse surface. As you may have gathered, refinishing is hard work.

 

[Amped]

Well, after all the great info and advice on here, and having talked to a few shot blasters, and paint dippers, it looks like I'm gonna...

...sand the thing by hand! I'm guesstimating it'll be ready some time in the early 2030s. My knees and back are aching just thinking about it. I'll let you know how I get one, and if me and the bench survive.

 

[Deleted member 174758]

...sand the thing by hand! I'm guesstimating it'll be ready some time in the early 2030s. My knees and back are aching just thinking about it. I'll let you know how I get one, and if me and the bench survive.

There used to be an industrial sander called an Engis head which was basically a wheel with outward facing brush segments at intervals interleaved with loadings of slashed sandpaper. They were purpose made to sand awkward shapes in the furniture industry as well as for stripping awkward shapes like stair handrails, turned newels, etc (when they would be used on a flexible drive shaft and portable motor). Whilst they were originally designed for use on a double ended polishing machine (basically a slowed down d/e grinder) I've seen a number of similar, but smaller, portable versions over the years. B&D even made a DIY version in the 1980s and Makita still do a trade version (albeit at around £400) and Metabo do a version aimed mainly at industrial metalworking, but I'll have a poke around and see if there is still a drill-mountable model out there

Edit: There is a sort of relatively low cost DIY version of the Engis head out there called the Eco-Flex profile sanding head which may or may not be suitable for your sanding needs, depending on how many profile or round bits you are sanding. Needs a corded drill and a thick leather glove, though

 

[Amped]

Yeah, I have ordered a set of 'flap disks' for my drill. Essentially the same thing, but nice to know the proper names. Should the ones I have ordered be a load of rubbish, which is quite likely, I'll have a search for the real deal.

 

[Deleted member 174758]

I wouldn't bother searching for Engis heads too hard - the last one I bought, about 18 or 20 years back was more than £150 (I was workshop based, then), and in any case Engis got taken over so the name has changed. The slash loadings for that head were about £40 or £50 a box, but they are industrial and I was just trying to illustrate the principle.

At one time I did have the B&D DIY sander at home which was very similar, only lightweight, however it did do the job on the spindles on a Victorian house I was refurbing for myself quite well. For some reason, though, they never caught on in the UK and B&D dropped them by the 90s(?). The type of head I referenced looks very similar to the B&D heads, so should work in the same way - start with P60 or P80 grit then move up to P100 or P120 (for exterior work it probably isn't worth going any finer). Just make sure that you don't over sand - keep the head moving all the time and use a multitool or hand sand to get into really tight corners as brush backed heads can round over sharp edges all too easily if you aren't paying attention. I'd also recommend wearing a thick glove on the hand which is nearest the sanding head as what strips lacquer finishes will also be good at stripping skin!

 

[Amped]

Well, it's done!

I've spent in the region of 45 plus hours on it... most of which was prepping and sanding... but it's done!

I found most of the drill bit and sander attachments were useful to an extent, but were never gonna be able to get into all the joints in the way that I needed. For me to truly extend the life of the bench, I needed the new solvent based treatments to get in all the nooks and crannies and give it a proper good coating. So, paint stripper, in this case, off the shelf Nitro Mors... It became apparent quite quickly this wasn't gonna cut it. It barely touched it to be honest. Fortunately I had a friend with a spare tin of the industrial Paramose paint stripper (and I used nearly all 5 litres of it). I might be over stating here, but I reckon I might have given up on this job if it hadn't been for the Paramose. Brilliant stuff, noxious, dangerous, but brilliant. Even with the Paramose, I would say 30 plus hours of the 45 were stripping and sanding. Heavy grit sand paper and wire brushes were the order of the day, and I went through a lot of wire brushes. It felt like an endless task.

It's a big old bench, I reckon it weighs over 35kg, and is somewhat unwieldy. It really wants you to just leave it in situ and work your way around it, but that quickly did my back and knees in. I got some A frames and floorboards and made myself a make shift work bench so I could work on it at head / chest height, flipping it over as I saw fit. Not easy, but so much better than working on it on the ground. It also spent some time on either of it's ends.

There was then a bit of digging out and filling along with using some of the wood hardener. The filler is very pale and doesn't take the new stain as well as the wood, but fortunately it's not on show. I'm sure there are ways of matching the filler, but I never really got into it, something of an oversite on my part.

I used Barrettine Wood Protective and Barrettine Wood preserver, several coats of each, they went on no problem over the freshly sanded wood and also absorbed nicely into the bits that had been treated with the wood hardener, you can't see any differentiation. I went with a dark top coat to hide as many of the blemishes as possible, and it looks great. Interested to see how it weathers too.

It's currently sat in the pouring rain and the water is beading off nicely.

Not as good as pressure treating it I'm sure, and I'll probably have to keep giving it a top coat each summer with the Barrettine, but hopefully it'll last another twenty years of so if I look after it.

Cost wise, without looking at receipts, I would guess at about £200 plus having been spent. Could have been worse, most of that was the paint stripper and new Barrettine products, of which I still have some left over for future coats and other projects.

A big thank you for all your help and knowledge. Couldn't have done it without you!

I need a lie down now.