I need help (yet again)

[Student]

Last year, I made some planters. The posts were 47mm x 47mm redwood and the rails 30mm x 47 mm redwood treated with clear wood preserver. The side panels were made from 18mm x 144mm treated exterior V-Jointed Tongue & Groove with clear wood preserver applied to the cut ends. I cut 18mm grooves in the posts, top and bottom rails and formed stub tenons to join the rails to the posts. All the woodwork (except the mortice and tenons) was primed, undercoated and with one top coat before glue up. Having glued up, I used frame sealant to seal the gaps at the bottom of the panels to avoid water ingress in to the grooves.

SWMBO was anxious to have the planters finished so I glued up with Evostick Resin W weatherproof that was probably two years old as I didn’t have any of my usual TB 111 to hand at the time. The problem is that after 8 months many of the joints have failed.

My intention is to try and knock the joints apart, clean off the old glue and re-glue with new TB 111.
Two questions:
1. I was going to scrape the glue off the tenons with a cabinet scraper and try and use a chisel to clean the mortices before using some abrasive to finish the job? Is this the best way?
2. Is the use of a frame sealant a good idea to stop water seeping into the bottom grooves or would it be better to remove the inner wall of the groove and put a nail in the centre of each piece of panelling to hold them in place?

Thanks again, in advance, for any advice

 

[Myfordman]

The glue will ave sealed the fibre of the wood and by the time your have removed enough of every surface the joints will be very sloppy.
I'd break everything apart, remove anything loose on the surface and use PU glue which should stick to the old glue. It will not matter if the joints are damp still as PU needs moisture to cure.
The result will be totally waterproof.

 

[blackrodd]

The glue will ave sealed the fibre of the wood and by the time your have removed enough of every surface the joints will be very sloppy.
I'd break everything apart, remove anything loose on the surface and use PU glue which should stick to the old glue. It will not matter if the joints are damp still as PU needs moisture to cure.
The result will be totally waterproof.

+1 for the above wise words, a mastic type tube of Joiners mate should be the answer.
Rodders

 

[ColeyS1]

Could you cramp the joints back up, then drill a hole through the post into the tenon and tap in a wooden dowel ?

Coley

 

[Wuffles]

I've recently introduced myself to PU glue, specifically for the task of joining some things together that showed daylight that I couldn't do anything about.

I wouldn't hesitate to do what myfordman says based on my very recent experience. It'll act as a gap filler as well as stick it nicely.

 

[Student]

My thanks to Bob, Rodders, Coley and Wuffles for their help. I'll get hold of some Joiners Mate and try it. My only concern with PU glue is the short open time. I was struggling to get all the clamps on when gluing up before and that was with PVA glue with 15 minutes open time.

Coley's idea of a dowel occurred to me but, as the stub tenon is only 18 mm or so long, a 6 mm dowel would only leave 6 mm either side of the dowel and I wasn't sure if that would be enough.

Any thoughts about the problem of water gathering in the bottom grooves, anyone?

 

[Phil Pascoe]

Don't design something with grooves that hold water?

 

[Wuffles]

My thanks to Bob, Rodders, Coley and Wuffles for their help. I'll get hold of some Joiners Mate and try it. My only concern with PU glue is the short open time. I was struggling to get all the clamps on when gluing up before and that was with PVA glue with 15 minutes open time.

Coley's idea of a dowel occurred to me but, as the stub tenon is only 18 mm or so long, a 6 mm dowel would only leave 6 mm either side of the dowel and I wasn't sure if that would be enough.

Any thoughts about the problem of water gathering in the bottom grooves, anyone?

Gorilla glue gives an open time of 10 - 15 minutes. You might be able to delay that slightly by not wetting up until you're pretty much ready to clamp.

 

[Student]

Too late to change the design now Phil. I might just drill a couple of drainage holes from the underside of the rails.

As Gorilla seems to have 15-20 minutes open time, I will take up Wuffles's suggestion and go for this rather than Joiners Mate. I'm going by a Tool Station later this afternoon so I'll pick some up.

Thanks again to all.

 

[DiscoStu]

Gorilla glue is fab!


Sent from my iPhone using Tapatalk

 

[whiskywill]

Is this what is meant by a "sticky" post?

 

[No skills]

I have become quite suspicious of the evo resin w of late, had a failure outside on a small gate that suprised me, I put it down to abuse at the time but I'm not so sure.
Perhaps not all it should be.

 

[ED65]

Just two quick things on polyurethane adhesive Student, firstly it needs contact with bare wood to make the strongest joint just like PVA-type glues. Secondly and perhaps more importantly here, it isn't actually a good gap filler. Yes it foams up and fills gaps, but not with strength.

If you need to a firm hold where there's sloppy fit then epoxy would be much better bet (roughen the wood first) and has the advantage that you don't need to worry about clamping pressure to get a strong bond. Also no need to worry about smoothing the joint surfaces, it'll bond better if they're rough.

I think Cascamite could work equally well but I don't know how tolerant it is of some trace of the previous glue on the mating surfaces.

Last year, I made some planters. The posts were 47mm x 47mm redwood and the rails 30mm x 47 mm redwood treated with clear wood preserver. The side panels were made from 18mm x 144mm treated exterior V-Jointed Tongue & Groove with clear wood preserver applied to the cut ends. I cut 18mm grooves in the posts, top and bottom rails and formed stub tenons to join the rails to the posts. All the woodwork (except the mortice and tenons) was primed, undercoated and with one top coat before glue up.

It's not completely clear, can I just check did you get anything on the surfaces to be glued? If so then that's certainly part of the cause, even if the Evostick isn't quite up to par.

 

[Mr T]

EDS beat me to it. I agree that PU fills gaps but has no strength in that situation. Methylated spirits is good for softening PVA, get it off then use Cascamite.

 

[Giff]

Toolstation do a 30minute PU. If it is coolish weather it takes longer than that to go off.
ps Wear plastic gloves !

 

[Togalosh]

How about blind wedged mortice & tennons ?
You'll just need to cut slots in the tennons & make some wedges. If the joints are slack in the cheeks then pack them out with slivers.

However they join teak outdoor furniture works. I know someone who has some from the early 80's that is still in good order (I realise the teak plays a part in this).

HTH
Togs

 

[Markvk]

+1 on the gloves for poo glu! im typing with blackened fingers right now..... i have both 30 & 5 min versions on my shelf at all times along with thr gorilla version of titebond 3 all available at bargain prices at our local trago mills,,, must go there drecly...

a tip for long term storage of poo glu, take the top off and inflate a balloon in the pot to stop the air getting to it, works with all sorts of stuff!

Cascermite... wow not used that since i was at school fantastic stuff!

 

[Mark A]

I was given a half used bottle of polyurethane adhesive once. The label was obscured with old dirty glue and in my naivete assumed it was the slow setting stuff.

Assembling a heavy workbench in a tiny shed, in the middle of winter, with numb hands covered in glue, using rope tourniquets as I didn't have any long cramps was not a good time to discover the free adhesive started to set in five minutes. Okay, the cold temperature probably increased the open time a smidge, but you get the picture.

It took a week for the glue to wear off!

 

[Student]

By way of an update, I had a go at sorting out the problem over Easter. It turned out that two of the three planters were only held together by the frame sealant so a few good whacks with a rubber mallet broke apart all the joints; the third planter came apart in two pieces. I cleaned up the mortices and tenons, some of which had paint on which obviously didn’t help with the original glue up, and then started cleaning off the sealant using a chisel and scrapers – it took ages. I was then faced with the job of repainting most of the pieces but taking care, this time, not to get paint on the tenons or in the mortices. It was when I was doing a dry assembly prior to glue up that I noticed the third major fault in the original versions. I had assembled them on a hot dry summer’s day but when I came to re-assemble them after cleaning, noticed that the T&G panels were now 5 mm wider than the rails plus tenons whereas previously they were marginally shorter. Obviously, as the panels expanded in the wet weather, they forced the joints apart. I thought that I had allowed sufficient space for expansion, after all the panels were only 18 inches or so wide, but obviously not. Anyway, a quick trim and all fitted together. Following various members’ advice, I used PU glue for the first time and was most impressed. They all now look fine but I’ll have to wait and see whether and how quickly they rot bearing in mind the design fault of the panels sitting in grooves – I did drill some drainage holes though so that may help.
Thanks again for all the helpful advice given.
Martin