Pontoon Boat & Deck Boat Forum

hey guys,

I am replacing my deck, and need to replace some screws, what material should they be?

also I need screws to fasten the aluminum trim on the side to the the other part of the trim?

what the most cost effective thing to use?

thanks

-bb

I wouldn't use anything that's not stainless steel.

yeah thats what what I was thinking
thanks
-bb

Nope - absolutely not needed with modern alloys and advanced plating technology.

I just fastened my toon deck with Drive Straight brand WAFER HEAD self drilling deck screws available at Home Depot. They went through my 7 ply marine plywood into the aluminum stringers like BUTTER. I used a torque sensing drill so as not to overdrive them - you want them flush with the plywood.

An absolutely excellent product.

I'm not sure how they did it, but it is just about impossible to install one of these any way but perfectly vertical. Just figure out the right torque setting, set the drill on high speed and they are in so fast you won't believe it. I snapped chalk lines on all my joints to make sure I didn't miss the stringers.

Make sure you buy a new laser etched or serrated Phillips head bit while you're at it - the Drive Straights will stick to it like glue since the machining on the head slots is so well done. You won't find them in the bulk bin at Harbor Freight for 99 cents. Dewalt makes decent ones for the money. Wera (made in Germany) make the BEST and they are the laser tip type. Worth the money not to be dropping screws all the time especially when you are driving multiples. They're made from stainless steel.

sunedog wrote:I wouldn't use anything that's not stainless steel.

Yep.

When you use these special screws, be sure to use the matching driver bit or you are wasting your money. If a flush surface is not important a washer head, hex drive is really a lot better than a flat head. A while ago in an underskin topic someone linked a source of stainless screws on Ebay that was a great deal. I bought 1000 each of 4 sizes.

nothing but stainless, good stainless, check it with a magnet. if it sticks keep looking. I used those pan head zinc plated self tapers for my seats they lasted 4 years in fresh water. new that I would be getting new seats so at the time I didn't care, the new seats got SS.

Barnum was right! Too funny. Magnetic. RIGHT!

All the supposed "marine" stainless hardware you can purchase anywhere is fake, made in China and is pure crap.

I'll bet anyone $100 you can't find Austenitic stainless steel hardware (the only true non-magnetic stainless) in the USA without a VERY special order. If you CAN find it you will pay through the nose - probably at least ten times the cost of a high strength zinc plated steel fastener.

This is absolutely nuts - were' talking about fastening plywood here - not carbon fiber panels on the space shuttle!

Modern zinc plating technology is LIGHT YEARS ahead of what was available just a few years ago. It lasts a L O N G time. It is more than adequate for the application, and a $6.00 for a pound of 1.5" screws is perfect.

Hey, it's your money.

For attaching trim I would use stainless-but for my deck I used self-tapping hardened steel with a protective coating specifically designed to fasten treated wood to metal. I will gladly sacrifice some corrosion resistance for the added strength that can be achieved by using the hardened steel product. The larger head size of the self tapping screw is an added advantage for strength.

300 series (austenitic) stainless steel, sometimes called 18-8 because of the chromium and nickel content, has little mechanical strength. This is typically what your common "stainless steel" hardware is manufactured from. While it offers the best corrosion resistance (yes resistance, not corrosion proof), it does not have the hardness or tensile properties that hardened steel will. That is why the heads strip so easily. It is not because these fasteners are "fake" or made in china but it is because the nature of the alloy. These materials cannot be hardened by heat treating, only by mechanically induced stress (coldwork).

A couple of others comments regarding "stainless steels". These materials are readily available and produced both domestically and internationally. The quality of the materials has not degraded but improved in most cases. While 300 series stainless steels are considered non-magnetic, they will exhibit some magnetic attraction if heavily coldworked enough, so the magnet test is not a guarantee of alloy. Most of these fasteners are made from 301, 302, sometimes 303 (free machining), or 304 alloys, and are sometimes marketed as both stainless or marine stainless. However, 316 stainless steel should be considered for marine applications as it is alloyed the same as 302/304 but with the addition of 2 - 3% molybdenum which provides added corrosion resistance. It is also produced both foreign and domestically, but unfortunately comes with a higher price tag.

Just some worthless info from working 28 years in a metallurgical testing laboratory.

'bob

I think you will pull the heads through the plywood or strip them out of the aluminum stringer long before the screws break.

If you shoot them in with a robust fastening schedule (8-12") the failure of the screws is not an issue.

Stainless steel WILL corrode, especially if it is not exposed to air. Also, if you use plywood treated with copper as a preservative, adding Stainless steel fasteners will corrode the aluminum in very short order, especially in salt water. You will be able to measure the galvanic current with a meter!
Use marine plywood, not the copper treated exterior stuff, and SS screws should be fine.
My Playcraft uses both screws and thru bolts to hold the decking on. I had to cut the screws off after removing my stern decking; they were plated steel installed in 1993, used in salt and brackish water. the SS bolts were like new, and only slight corrosion of the aluminum railings.
PontoonStuff sells a plated self-tapping decking screw that seems to work well, and offer SS as well
For your trim and edge caps, use stainless.

I had to special order mine out of Atlanta through the local fastener store. I wanted STS, I guess I should have used what Home Depot sells.

I gotta ask, RonMkiller, are you just angry at the world, or fed up with all us common igits on the forum? Why so angry and degrading every post?

I dont know why these screws are so hard to find locally.

i found several places but they only sell full cases, 1000-2000 pieces, I just need 50 ish.


the one I just found is stainless but its 410 Stainless Steel

I have been looking for either stainless or nickel plated

-bb

actually I think I just found some at fastener distributor in the next city over
lets see what they say
-bb