Pva glue

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Compomouldings
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Pva glue

Post by Compomouldings » Fri 19 Jul, 2019 4:38 pm

Hi, does anybody know how to tell how strong pva glue is.? Is there any info on data sheets etc
Thanks

Not your average framer
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Re: Pva glue

Post by Not your average framer » Fri 19 Jul, 2019 6:02 pm

PVA glue is a generic type of glue and different versions of PVA glue can be expected to have different results and performance. Not only that, but the results will also depend upon the characteristics of the materials you are joining together. I use woodworking PVA glue, which is thick and stronger that the general purpose variety.

There also are the alphatic varieties of wood glue which are often based on PVA and are supposed to be a more advanced wood glue, but you probably need to do some checks on these yoursellf to get more detail about this. A lot of people like Titebond wood glue and it has quite a good following amoungst quite a lot of people who seem to know what's what.

I expect you will get some useful recommendations from some really switched on framers pretty soon.
Mark Lacey

“Life is short. Art long. Opportunity is fleeting. Experience treacherous. Judgement difficult.”
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Justintime
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Re: Pva glue

Post by Justintime » Sat 20 Jul, 2019 9:40 am

https://woodgears.ca/joint_strength/glue.html
I'm a fan of Titebond 3,but I'm going to try Weldbond after reading this.
Test results are near the end.

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prospero
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Re: Pva glue

Post by prospero » Sat 20 Jul, 2019 10:32 am

I use Evostick interior grade.

Whatever the strength of the glue it's generally stronger than the wood. It's the way you use it that gives the joint
it's strength. I like to put plenty on and keep the joint under pressure while it sets.
Accurate cutting is a factor. If the joint faces don't meet tightly all the way across, the integrity of the joint is compromised.
Watch Out. There's A Humphrey About

vintage frames
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Re: Pva glue

Post by vintage frames » Sat 20 Jul, 2019 11:36 am

That's a really interesting link from justintime. I'd never heard of Wellbond before this. I suppose for general pictureframing use, any off the shelf wood glue will stick two mitres together. One word to caution on glues is to avoid the general Gorilla glue. It is horribly messy to use, will foam outside the joint, will stick to your fingers for days and become unusable from the bottle within a week of opening.
I was first signposted to Titebond by an early article on veneering where it has a unique property of being re-activated by heat. This meant that any blisters underneath a veneer can be corrected by applying a hot iron. Back then it was quite difficult to find Titebond and it turned out that one of the few sources was a firm of luthier suppliers ( for people who like to make their own lutes ). This was a good indication that Titebond was favoured amongst a section of highly skilled craft people.
As I said, use whatever glue you like but if you want a good wood-working glue that cleans up easily, is very strong and won't linger on your fingers, then Titebond1 is ideal for most assembly work. And it has the advantage of being able to be sanded without gumming up the sand-paper. If you want something more agressive and certain, then Titebond111 is out there with the best.

Justintime
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Re: Pva glue

Post by Justintime » Sat 20 Jul, 2019 11:57 am

Just to add to what Dermot was saying about Gorilla glue that expands to fill the joint. I read that the foaming/expanding part of the glue does not have the same adhesive properties as where the glue is placed, so it acts like a filler rather than an expanding adhesive, if that makes sense.
The only downside to Titebond 3 is when using a barewood Ash moulding with wax, sometimes the light brown colour of the cured glue can darken the mitre slightly. It sounds like Weldbond (also a water/moisture proof grade glue) dries clear.
We have plenty of customers who live in stone cottages, who admit to having some damp winter walls. I visited a cafe gallery in a basement the other day, despite the dehumidifier being used all night every night, you could smell the damp. I'm hoping that Titebond 3/Weldbond will at least give the mitres some longevity. I try and help the backing with moisture barrier Corri 3 and Sekisui self adhesive... What has come in for a glass upgrade, after 2 years is still looking like new..

Not your average framer
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Re: Pva glue

Post by Not your average framer » Sat 20 Jul, 2019 5:51 pm

The cost of PVA glue per frame is so small, it's barely worth trying to calculate it. So the extra that you decide to spend on a superior performance PVA glue is never going to be an issue that will have any meaningful impact on the cost of producing a frame. Therefore the is no reason why you should not use the best glue that meets all you requirements.

Personally, I have never tried any of these so called superior PVA glues, so I don't know enough to recommend any of them. I just use the basic woodworking PVA glue and I've not had any problems, but I am very particular about using mouldings that allow me adequate glue area at the mitre joints and I'm careful to add a sub-frame, when I'm concerned that a particular moulding is a bit under strength for the required size of frame.
Mark Lacey

“Life is short. Art long. Opportunity is fleeting. Experience treacherous. Judgement difficult.”
― Geoffrey Chaucer

red
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Re: Pva glue

Post by red » Tue 23 Jul, 2019 1:07 pm

I tend to use titebond if I need a strong joint.I had a guitar which snapped at the 'nut' near the pegs of the guitar,
at a 45 degree angle.
I spoke to a luthier about what to do, as I thought of a new neck,or biscuit joints etc.
I glued it with titebond and clamped it.you could barely see the join.5 years on the guitar
is good and strong.I think there is something about the joint being actually stronger than the wood?
if titebond can fix a guitar which is under great tension with the strings, I think its more than
adequate for a picture frame!

cleaver
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Re: Pva glue

Post by cleaver » Tue 23 Jul, 2019 1:20 pm

ATM, I used Toolstation's own-brand PVA.

After tightening it up in the clamp, it is impossible for me to pull frames apart...and that's before any wedges go in. Like Peter says, clamping it firmly while the PVA dries leads to a VERY secure fix.

But when this stuff runs out, I think I'll switch to Titebond 3. If they use it for making guitars etc, it must be phenomenal stuff....so it be rude not for just £5 or so more.
:head:

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