LumberJocks

Glueing or Varnish first on my 'fishbench'?

  • Advertise with us

« back to Finishing forum

Forum topic by Graem Lourens posted 07-29-2016 01:39 AM 297 views 0 times favorited 12 replies Add to Favorites Watch
View Graem Lourens's profile

Graem Lourens

28 posts in 129 days


07-29-2016 01:39 AM

Hi Everybody.

I’m new at woodworking and have been building various things for our kids in the garden, with a lot of help of dozens if not hundreds of youtube videos from all you experienced guys out there.

Until now all my projects were very rough and only impregnated (with some colouring). I decided a few weeks ago to make a bench for next to our fish pond, and really want this to be smooth, nice and as good as my current skill set allows it.

I experimented with around 7 different finishes (Polyurethane, Varnish, Oils and so on) and have decided on an outdoor varnish that works very well.

I have exclusively used dowel joints and have done the dry assembly:

Now if i first:

- do the glueup, it will be hard to get a nice even (several) coatings of varnish into all those corners (especially the top part) and at the butt joints (that are not all airtight….) i am worried that moisture will get in and as the wood is not protected, it will start to rot.

- varnish all parts separately and then do assembly, the glue in the dowels will work, but the butt joints them selves will not hold the glue (as on varnish that will not stick, in my opinion?) and the joints will be – i think – very unstable. (i know the butt joints themselves are not very stable, but better than purely the dowels for sure i think?) Furthermore, the glue squeeze out, that will occur, will be difficult to clean up i think?

I guess the answer is obvious, but i do not want to ruin the bench without taking a minute to ask you guys… And it was a good reason to signup here so its easy for me to ask questions in future :)

Any insight warmly appreciated.

Kind regards, Graem

-- Novice woodworker and passionate astrophotographer https://www.flickr.com/photos/graemlourens/


12 replies so far

View Aj2's profile

Aj2

688 posts in 1260 days


#1 posted 07-29-2016 03:41 AM

Absolutely varnish everything before glue up.Take your time and don’t get varnish in the areas the will be glued.If you do scrap it away after it dries.
Same with gluing looks to be a fairly difficult glue up so make a plan.Or a extra hand.
Don’t be messy with the glue.Be ready with a damp clean rag just in case.
After sitting in the clamps overnight.Touch up any areas that need a bit more varnish.A small artist brush work well.
This is a basic method I use for fine furniture.So it might be over kill for your bench.
The bench looks great Btw.

Aj

View Lazyman's profile

Lazyman

688 posts in 849 days


#2 posted 07-29-2016 04:49 AM

With your design, I don’t see any spaces where you can’t get varnish after assembly. My worry with pre finishing would be that you’ll get varnish on your glue surfaces and the glue joints will fail more quickly. Keeping the finish away from glue surfaces will be a real pain between the slats on the back. Also, once you get good glue joints you would still want to put another coat of varnish to seal the joints to try to keep water away from the glue so you’ll have to do it anyway. Titebond 3 glue is supposed to be the most water resistant glue, BTW.

Note that if it is exposed to sun and rain, there are almost no finishes that will last more than a few years so don’t be surprised if you have to redo the finish periodically. For that reason, varnishes can be a little bit of a pain because you may have to strip them before you can apply a new coat.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View Graem Lourens's profile

Graem Lourens

28 posts in 129 days


#3 posted 07-29-2016 11:24 AM

Hi Aj & Lazyman.

Thank you for your (controversy : ) ) feedback!
I am tending to go for first glueing up because i do not see myself capable of only finishing the areas exactly where the elements do not touch as well as i am not confident at all to be able to glue this up without making a mess. Its my first time at this scale with glue and most certainly will make a mess of things… Like that i can at least sandpaper everything down. I guess i’ll only know for sure if i do it both ways (i’ll do another identical one, as we mostly have many visitors so it will be too small for everybody)

@Lazyman. I was of the opinion that if you want to reapply varnish after a few seasons, you just slightly sandpaper the project and then put another layer on it – do you really have to remove all varnish first? (maybe this is different per product?)

Then maybe i should consider exterior Polyurethane as there i’m pretty sure you do not have to remove anything first, just slightly sandpaper so the new layer will have smth to grab on?

This is a pretty important question to me, as i would rather not apply a finish that i will have to remove in a few seasons again.

Kind regards, Graem

-- Novice woodworker and passionate astrophotographer https://www.flickr.com/photos/graemlourens/

View Lazyman's profile

Lazyman

688 posts in 849 days


#4 posted 07-29-2016 12:55 PM

If you reapply the finish before it starts to crack or flake off, you may be able to get away with just some sanding but once the finish starts to break down, which it will eventually do, you will probably have to remove it before you reapply. Penetrating oils don’t look as nice but you can simply put a new coat on once a year and you are good to go but probably don’t provide as much protection for the wood or joinery. If you want a smooth finish, I would probably go with the a spar polyurethane myself. If you are planning to stain it too, a penetrating oil with stain already in it or semi-transparent stain with UV blockers might be easier. One nice thing about the oil approach is that you can just spray it on, the first coat at least, with a pump up sprayer.

EDIT: If you use poly, you want a minimum of 3 coats, lightly sanding between each coat.

Another alternative that I read about in Woodsmith magazine is an epoxy finish, similar to what boat builders use (not the kind used as an adhesive) under a poly topcoat. This may be the most durable finish for outdoor furniture. This can be a little expensive but weighed against years of refinishing might end up better in the long run. I have never tried it myself so maybe one of the boat builders on LJ will comment.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View Lazyman's profile

Lazyman

688 posts in 849 days


#5 posted 07-29-2016 01:13 PM

One more thing, unrelated to finishing…
How big and how many dowels do you have in the main cross beams of the seat? I am a little concerned that with the width of the bench, the dowels could fail, if for example 3 large grown men were to sit on it at the same time. The more traditional way to do this is with tenons. Dowels might be ok as long as they are large enough. I probably would not use anything smaller than 1” dowels (based upon the size of the beams) and you need at least 2 per joint.

Just a thought.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View Graem Lourens's profile

Graem Lourens

28 posts in 129 days


#6 posted 07-29-2016 02:11 PM

Hi Lazyman.

Thank you a lot for your feedback.
I get it concerning the varnish and breaking. I’ll probably just have to try, as i don’t have any long term experience with either varnish or polyurethane. I’ll still google around a little bit more about outdoor best practises and then just go ahead and give it a try! Getting the great products here in Poland is very difficult for me (and i don’t understand the language, so reading how to apply it is a catastrophe!)
Just saw that there is a Minwax importer here, so will try and stick to the brands that are widely used.

Concerning dowels. I would have loved to do tenons but i wanted to keep it acceptably simple for my first shot as my shop is not ready yet, space is very limited and i do not have all the tools setup properly yet. My second bench could be tenon based, will have to see.

I used (i’m converting here from CM):

For all large beams & pieces (front & back) that are each 2 3/4” square, i used approx 1/2” tick and 1 3/4” long dowels.
For the thinner ones (4 sitting beams in the middle) that are same width but half the thickness, i used 1/3” tick and 1 1/3” long dowels.

You can not see it in the picture, but across the beams underneath there is a middle support beam supporting the center (as it does bend too much for my likings)

I do like the simplicity of dowels, but i know its a beginner style, but thats what i am :)
Can’t wait to make beautiful mortise and tenon joints! Still have to figure out how to do them without dado blades.

Kind regards, & thx for your helpful insights.

Graem

-- Novice woodworker and passionate astrophotographer https://www.flickr.com/photos/graemlourens/

View Graem Lourens's profile

Graem Lourens

28 posts in 129 days


#7 posted 07-29-2016 02:20 PM

Ah and i forgot: each joint has always 2 dowels

-- Novice woodworker and passionate astrophotographer https://www.flickr.com/photos/graemlourens/

View CharlesNeil's profile

CharlesNeil

1610 posts in 3332 days


#8 posted 07-29-2016 03:32 PM

heavily involved in exterior finishes at the moment, I agree varnish, ie: spar varnish simply put doesn’t hold up very well and as noted, all exterior finishes are going to need maintenance. Varnishes will build a film then you have an issue of cracking and peeling. What appears to be the best is a penetrating oil, in which case when it looks a little dry wipe on another coat, quick and simple. I am looking at Penofin as well as Velvit , I also tested a product called One Time, and after 3 years on plywood in a trailer , that sits out side all the time it still looks pretty good.

View Graem Lourens's profile

Graem Lourens

28 posts in 129 days


#9 posted 07-29-2016 03:51 PM

Hi Charles.

Thank you very much for your insight.
I would very happily use an oil, as its also the most natural finish (and i do like to keep the wood as natural as possible).

Most places i was reading were always stressing that oil will give the least protection, especially against water&humidity. I have no problem with re-coating my outdoor projects every few seasons, but it would really hurt if the wood would start to degrade already after one or 2 seasons.

I’m looking to get that smooth semi gloss finish – am i wrong thinking that i can not achieve this with an oil?

You got me thinking again though to re-think my finishing product… (any suggestions on products will not really help me as i have to purchase this here in poland)

Thx again for your help, must say its been a joy to join this forum! fast and competent answers…..
Maybe i will start a separate thread for the choice of the finishing product as its off topic now…

Kind regards, Graem

-- Novice woodworker and passionate astrophotographer https://www.flickr.com/photos/graemlourens/

View Lazyman's profile

Lazyman

688 posts in 849 days


#10 posted 07-29-2016 03:52 PM

The dowels should be okay as long as they are oriented vertically on the front and back cross beams. My theory is that this orientation will approximate a tenon though others may have a different opinion. 1/2” (~12mm?) diameter dowels may be a little small. The rule of thumb for tenons is 1/3 to 1/2 the width of the board so 2.75” should be .92” (round up to an inch or about 25mm). Also, they need to be longer (deeper) on the seat cross beams at least. I would make them at least 3” (75mm) long. Part of the purpose of the dowel or tenon is to give you more glue surface so deeper is better. The combined depth of the holes should be slightly more than the length of the dowel. This gives extra glue a place to go as you assemble it.

One other option is to cut a notch (about 1/2” or 12mm deep perhaps) in the legs to nest the cross beams in to add some additional support. You will lose an inch of length but gain considerable strength. You have to either make similar notches for the back rest or simply cut the back rest a little shorter. The notches gives you some of the mechanical advantages of a mortise but with a “lazy man” approach. That way, the dowels are mostly for adding additional glue surface and less for adding mechanical strength.

I am looking forward to seeing your finished bench posted in projects.

Welcome to Lumberjocks, by the way.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View Graem Lourens's profile

Graem Lourens

28 posts in 129 days


#11 posted 07-29-2016 04:11 PM

Hi Lazyman.

Thank you a lot. Indeed i will try a different joinery approach on the second bench, and maybe give myself a little more time on the project. I do astrophotography and am used to spending sometimes months an a target, but as i just started woodworking, i’m catching myself wanting to have an immediate result fast, but i guess this is a normal beginners mistake that i’ll have to learn the hard way :)

Reading now about finishes again, so many different opinions…... difficult! :)

P.s. thx for the welcome.

Kind regards, Graem

-- Novice woodworker and passionate astrophotographer https://www.flickr.com/photos/graemlourens/

View OSU55's profile

OSU55

1056 posts in 1451 days


#12 posted 07-29-2016 08:12 PM

Finish sand, glue up, then finish. There are water based exterior finishes . Take a look at Target Coatings EM9300. Best to spray WB finish.

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com