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This is a technique I intend to perfect for the construction of our Narai MKIV, and is currently being employed in a limited fashion on the Tiki 38 currently being built.

The idea is to use a pneumatic 16-gauge brad nailer with various length 18-8 stainless brad nails to hold two components while the glue dries. The advantages here are cost (compared to the cost of the various bronze and copper fasteners listed for the construction), time required to affix a part, no requirement for removal of the fastener, and to eliminate the need for a second man. There will be a need to use screws in high stress areas, but otherwise the bulk of fastening will be with brads.

The technique is to apply glue (epoxy or Titebond III) to the surfaces, then press the brad nailer to the surface until "squeeze out" is achieved and send the nail home. We have been using this technique with great success thus far. It has cut time to attach a part in half (or better.)

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We used stainless steel brads fired from a nail gun extensively in our Tiki 46 build. It was a great time saver and held things together well. We have not had any problems with them protruding or causing discoloration on fiberglass.

Great idea.  Should really speed up construction.

I have a concern, though I'm not really certain if what I think makes sense.

You would use SS brads and not common brads because they might rust. But I have read somewhere that SS will rust in the absence of oxygen. Now being inside a glued and coated material suggests there will be an absence of oxygen.

Check http://www.examiner.com/article/stainless-steel-corrosion-causes-an...

What do you think?

Correct......316 grade s/steel breaks down over time when sealed up inside material which cuts off oxygen supply,,,,,,,,,,,,I tried to remove s/steel scxrews from an old hull and the heads just sheared off as they were turned.

A lower grade stainless such as 304 will corrode and break down as well.

As an interesting comparison in the search for alternatives (to bronze fastenings)......there was a boatbuilder who found it economical to have mild steel screws gold plated (in Africa where gold plating was relatively cheap in the 1980's) and once these were covered by plugs they were theoretically as strong but cheaper than bronze.

I would persue the idea of composite fastenings/nails shot from a gun..............this is possibly a system that has been worked out. If so? anyone have answers from practice? 

Look at www.raptornails.com I haven't used them but a friend has and he said they were great, but expensive...

Marty

I think this is a great way to save time and since most of them will be used on interior construction, there is little chance that they will degrade.  Stainless steel will corrode in a wet corrosive environment when cut off from oxygen, but that is not the sort of thing you are likely to find in the interior of a wood epoxy boat.  

If water got into the ply to the extent that it would corrode stainless, it would rot the ply too.

The composite nails are interesting, as I frequently seem to need to route or cut right through where I used a fastener...

R

We used these to good advantage cold moulding in the boatshop at school.  The only negatives are keeping the gun clean and the cost of the fasteners.  However, just like using peel ply, the cost savings in materials and labor may justify the cost.

Omar

Marty Peters said:

Look at www.raptornails.com I haven't used them but a friend has and he said they were great, but expensive...

Marty

I have never heard of these before. However, the prices are very similar to the SS brads we have been using. We are going to give them a shot during this project and see how they preform. A few thousand are in the mail. Thanks for the link.



Marty Peters said:

Look at www.raptornails.com I haven't used them but a friend has and he said they were great, but expensive...

Marty

If that is so then why bother with stainless at all?

Just use normal brads and get done with it.


Robert said:

I think this is a great way to save time and since most of them will be used on interior construction, there is little chance that they will degrade.  Stainless steel will corrode in a wet corrosive environment when cut off from oxygen, but that is not the sort of thing you are likely to find in the interior of a wood epoxy boat.  

If water got into the ply to the extent that it would corrode stainless, it would rot the ply too.

The composite nails are interesting, as I frequently seem to need to route or cut right through where I used a fastener...

R

Normal steel brads will rust with the slightest hint of salty moisture, which you get everywhere on a boat used at sea, even inside a well built one.  With some types of wood, such as oak, the chemical constituents in the wood itself can react with the steel.  The same is true of the residual moisture in timber even when dried enough for use with epoxy.  Stainless is far more resistant, but the extent depends on the grade.  304 would be ok for some interior applications, but 316 is needed for direct contact with sea water.  Where stainless is used, there are still a number of possible corrosion mechanisms, with crevice corrosion common in fastenings which get wet.  It's caused by differing concentrations of salts at different depths in the crevice setting up electrolytic currents.  This won't be a problem in the way Budget Boater is using the brads.

I don't think gold plating of mild steel is a good idea, although it would look impressive!  The problem comes if the gold plating gets scratched.  The relative electrode potentials of the two metals would result in the steel dissolving rapidly in order to protect the gold, which is not what you want.  Far better to galvanize the steel, so that the zinc protects it and the fixing retains its strength.  The electrode potentials are Zinc -0.76, Iron -0.44 and Gold +1.50, so I don't think a gold plated steel fixing would last long if the plating got damaged in the presence of sea water!

I think Budget Boater's idea is excellent, except for the danger of running into a brad when you're working with a plane or a hole saw...

Ricardo Aráoz said:

If that is so then why bother with stainless at all?

Just use normal brads and get done with it.


Robert said:

I think this is a great way to save time and since most of them will be used on interior construction, there is little chance that they will degrade.  Stainless steel will corrode in a wet corrosive environment when cut off from oxygen, but that is not the sort of thing you are likely to find in the interior of a wood epoxy boat.  

If water got into the ply to the extent that it would corrode stainless, it would rot the ply too.

The composite nails are interesting, as I frequently seem to need to route or cut right through where I used a fastener...

R

I am glad you mentioned this. Actually this is a common occurrence we have had to deal with. The best solution that I have found that works is: plane and saw away. SHOCKING, I know! However, my  Bosch planer and saw blades have suffered no effects from encounters with the brads. The planer tends to push them down and over. I am still running on the same set of blades which have encountered hundreds of brads. Hole saws and heavy blades pass through the 18 gauge brads as though they were not even there. I have not yet found it to be an issue.



Robert Hughes said:


I think Budget Boater's idea is excellent, except for the danger of running into a brad when you're working with a plane or a hole saw...

I suppose Robert Hugh's criticism of the gold plated screws amounts to a similar risk as does use of s/steel.........

To clarify -- the boatbuilder who used this trick was only using them for interior furnishing, where contact with salt water was not a major problem. So I guess tacking the furnishings together with stainless/s brads is no more harmfull, only a lot cheaper...............Budget Boating for sure

 

However, my intended point was to imply that using stailnless steel fastenings was not a cure-all from a corrosion point of veiw................we will invariably be tempted to compromise when it comes to economising, but I have come across those who thought stailess steel was fine for marine use regardless of application

 

 

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