PVA Glue Going Black on Oak

[Togalosh]

Hello Gents,

I understand that tannins in Oak react with iron but can someone enlighten me as to why PVA glue turns black too- but only sometimes ?..I'm pretty sure it doesn't happen all the time.

I know that it should not matter as my joints should be as tight as a gnats chuff so as not to show the glue line ...but there's little chance of that just yet although I am improving very quickly nowadays.

Thanks.

 

[Phil Pascoe]

You've not let wire wool anywhere near it, have you?
Should have thought - you'll get blue/black marks where sash cramps touch the glue.

 

[James C]

Not sure but for some reason my hands go a purple/black like biro pen is all over them when I handle fresh sawn/planed Oak.

It stains my hands for days sometimes and can transfer back onto the Oak itself. I'm not sure what causes it.

 

[stuartpaul]

It stains my hands for days sometimes and can transfer back onto the Oak itself. I'm not sure what causes it.

I'm lead to believe that there is a small amount of uric (sp?) acid in our sweat and this reacts with the tanin turning hands black.

When it transfers back onto the oak it's not a problem and easy enough to do that final clean before gule up.

Not sure about the original question though, - I've had PVA squeeze out look black on oak after it's dried. No obvious iron contact - perhaps something in the glue?

 

[Phil Pascoe]

I've got some everbuild D4, which is brilliant stuff but smells quite acidic - I'll have find a couple of scraps to try it on.

 

[woodbloke]

I've got some everbuild D4, which is brilliant stuff but smells quite acidic - I'll have find a couple of scraps to try it on.

I use that stuff as well and agree, it's great, but in my experience it doesn't turn black on oak - Rob

 

[RogerBoyle]

I've got some everbuild D4, which is brilliant stuff but smells quite acidic - I'll have find a couple of scraps to try it on.

I use that stuff as well and agree, it's great, but in my experience it doesn't turn black on oak - Rob

I agree

 

[MattMoore]

you weren't clamping the boards edge to edge were you? I've had this before where the clamp touches the wood and glue resulting in a small black mark

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[Teckel]

you weren't clamping the boards edge to edge were you? I've had this before where the clamp touches the wood and glue resulting in a small black mark

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That happens alright..

 

[Togalosh]

what a plonker I am...I've sussed it out thanks to your help.

..I lost my usual glue bottle nozzle cap & used a steel bolt instead (as a stopper) which has gone rusty.. you get the rest.

It's not funny how a little lack of foresight can cost a lot of grief... & that wisdom is hard won.

Thanks guys.

 

[Phil Pascoe]

(hammer) ..........now just remember not to finish your oak with steel wool!

 

[Teckel]

what a plonker I am...I've sussed it out thanks to your help.

..I lost my usual glue bottle nozzle cap & used a steel bolt instead (as a stopper) which has gone rusty.. you get the rest.

It's not funny how a little lack of foresight can cost a lot of grief... & that wisdom is hard won.

Thanks guys.

=D> =D>

 

[worsley947]

At least you honest owning up to that we all make these simple mistakes :evil:
Dave

 

[Togalosh]

I am my own hardest critic.. although I am glad to say that my plonkerometer is no longer red lining.