Galvanised bolts

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d4dunmor

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I need some galvanised bolts to replace frame bolts in oak frames on an old fishing boat
Could I use hot dip galvanised threaded rod 8.8 grade ? with galvanised dome head nut with suitable washers and nuts
Would appreciate Any thoughts / ideas
 
The galvanised has worked since 1963
And the hull has galvanised nails which need replacing
Don't want to introduce another metal for electrolysis issues
And finally there is the cost issue of bronze
 
I would prefer to use bolts rather than threaded rod for two reasons:
The body of a bolt is relatively smooth, which allows for the slight movement/swelling of the wood, while a threaded rod may bind to the wood and be subjected to those forces directly. This is seen as an issue in the analogous situation with concrete anchors.
Secondly, the threaded rod has a much greater surface area to protect. While the zinc provides cathodic protection to any exposed steel, I would be concerned about the greater potential for corrosion of threaded rod which may loose some zinc as it is driven into the oak.
Having said that, you will probably get many years out of galvanised rod but it may be worthwhile waxing it before insertion into the wood.
 
wrr said:
I would prefer to use bolts rather than threaded rod for two reasons:
The body of a bolt is relatively smooth, which allows for the slight movement/swelling of the wood, while a threaded rod may bind to the wood and be subjected to those forces directly. This is seen as an issue in the analogous situation with concrete anchors.
Secondly, the threaded rod has a much greater surface area to protect. While the zinc provides cathodic protection to any exposed steel, I would be concerned about the greater potential for corrosion of threaded rod which may loose some zinc as it is driven into the oak.
Having said that, you will probably get many years out of galvanised rod but it may be worthwhile waxing it before insertion into the wood.
Click to expand...

AntarcticPilot said:
Galvanized bolts are freely available from many suppliers, such as B&Q, Screwfix and no doubt many others. Why complicate things?
Click to expand...
Talking about 250 off m12 by 170mm
And m14 by 200mm hdg grade 8.8
would prefer to use trade related company
Lots of bolted timber in old wooden boats
 
wrr said:
I would prefer to use bolts rather than threaded rod for two reasons:
The body of a bolt is relatively smooth, which allows for the slight movement/swelling of the wood, while a threaded rod may bind to the wood and be subjected to those forces directly. This is seen as an issue in the analogous situation with concrete anchors.
Secondly, the threaded rod has a much greater surface area to protect. While the zinc provides cathodic protection to any exposed steel, I would be concerned about the greater potential for corrosion of threaded rod which may loose some zinc as it is driven into the oak.
Having said that, you will probably get many years out of galvanised rod but it may be worthwhile waxing it before insertion into the wood.
Click to expand...

Thanks for the advice wrr
Point taken about greater surface area for corrosion I had not thought of this factor
 
d4dunmor said:
T
Don't want to introduce another metal for electrolysis issues
Click to expand...

But surely a bronze bolt would be better than a galv bolt for electrochemical attack of the wood fibres where the bolt passes through?

When I removed rotten old glav keel bolts I found they were absolutely solid in the timber, have you tried to remove any? My solution to getting them out was a think wall steel tube with teeth cut on the end as a long thin hole saw that went up the outside of the bolt, 5/16ths got replaced with 3/8ths. I wrote about it in my book. I have the luxury of the bolt being vertical, so working from underneath the debris fell out.
 
d4dunmor said:
The galvanised has worked since 1963
And the hull has galvanised nails which need replacing
Don't want to introduce another metal for electrolysis issues
And finally there is the cost issue of bronze
Click to expand...

If you're looking for heavy square cut galvanized 5" nails, I have a bag of them.
 
I got all my gal bolts from Anglia Stainless. Everything from 8mm through to 3/4 inch. Good heavy galvanising on all from 10mm up. The problem with the 8mm were that they were fully threaded. Hex and coach.
 
The thread on builders nuts and bolts is often very coarse (terminology?) Makes it more difficult to get something tight.
 
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