Teak Handrails, No drilling?

[neilpride]

3M News

3M™ Scotch-Weld™ Instant Adhesive Sets New Guinness World Record®
Adhesive breaks record for heaviest weight lifted with glue,
Holding 8.1 metric tons in the air for one hour

St. Paul, MN – March 1, 2012 – 3M Scotch-Weld Instant Adhesives was recently responsible for a Guinness World Record-setting feat, lifting an 8.1 metric ton (17,857 pound, 2990 PSI) forklift in the air for one hour. This amazingly successful demonstration set a new world record for the heaviest weight lifted with glue. The vehicle was suspended from a crane by a steel cylinder only 7 cm in diameter, with the two parts of the cylinder secured together with 3M Scotch-Weld Plastic & Rubber Instant Adhesive PR100.
"3M has long been known for its expertise in adhesives," said Brian Brady, business manager for 3M Industrial Adhesives and Tapes. "We’re excited that this demonstration proved just how strong and reliable Scotch-Weld Instant Adhesives can be." The vehicle lift was conducted by engineers Jens Schoene and Dr. Markus Schleser of RWTH Aachen University, and was featured on the German television program Terra Xpress. World record judge Olaf Kuchenbecker was on hand to witness the lift and certify the new record. The German team had to meet several formidable conditions to break the previous record of 8.01 metric tons, but succeeded thanks to the exceptional performance of 3M Scotch-Weld Instant Adhesive.
3M Innovation sets a Guinness
World Record®
The record-breaking 3M Scotch-Weld Plastic & Rubber Instant Adhesive PR100 is part of the full line of 3M Scotch-Weld Instant Adhesives, which are available globally in a number of formulations for bonding various substrates.
"This technology offers a practical, easy-to-use alternative to conventional attaching methods like bolts, welds, rivets and screws in many industrial applications requiring high strength joints," said Brady. While the new world record shows the product’s incredible strength in an extreme application, 3M Scotch-Weld Instant Adhesives are also economical to use in everyday applications. Generally, only drops of adhesive are needed to develop strong bonds to many metals, plastics and rubber. These super fast-curing adhesives reach handling strength with hundreds of material combinations in five to ten seconds, and reach 80 percent of their full strength in an hour. Additional qualities like low odor, high temperature resistance and flexibility to resist vibration make them simple and practical to use for almost unlimited applications. Finally, as evidenced by the new world record, these products are capable of delivering tons of holding power.
To celebrate this incredible new world record and share the success of 3M Scotch-Weld Plastic & Rubber Instant Adhesive PR100 with its customers, 3M is offering special pricing and application support until [date], through its vast industrial distribution network. For more information about this promotion, and to see video footage of the record-breaking lift, visit: 3M.com/instantadhesive.

###

About 3M
3M captures the spark of new ideas and transforms them into thousands of ingenious products. Our culture of creative collaboration inspires a never-ending stream of powerful technologies that make life better. 3M is the innovation company that never stops inventing. With $27 billion in sales, 3M employs about 80,000 people worldwide and has operations in more than 65 countries. For more information, visit www.3M.com or follow @3MNews on Twitter.
3M and Scotch-Weld are trademarks of 3M Company.
Guinness World Record is a trademark of Guinness World Records Limited


I believe the best aproach is screw it , if you fear about core penetration by screws you can fill the holes voids with epoxy , but hey there is life further from 5200 and other popular stuff.

[osirissail]

Along with DenverdOn - the shock loads on such a handhold rail can be enormous especially when you need to grab it when the boat is rolling or being tossed around in rough seas. Glue is just not going to be able to withstand that. It is rare that the "world record" tests involve shock loading, usually they are incredibly smooth slow loading to avoid shock loading.

Even using wood/metal screws into the inner fiberglass layer of a "cored" cabin top is unlikely to withstand real life shock loading more than a few times. Like lifeline stanchions and other deck padeyes, cleats, etc., you need "through-bolting" with some form of backing plate. Imagine the horror and injury when you grab a glued or screwed handhold rail in a rough seas situation and the rail and you end up impacting the edges of interior furnishings/tables, etc.

Through bolting is not difficult and an easy "no-leak" way is to core drill a hole - say 5/8" or 15mm through the cabin top.

Then cover the bottom of the hole with tape and pour in epoxy putty and let cure.

Then drill your machine screw hole down the center of the epoxy plug.

Use fender washers or backing plates and 5200 to bed the machine screws. Solid, safe and no leaks after many years of use (at least mine don't leak).

Best thing I ever (one of . . .) was to put those teak loop handrails along the sides of the cabin top interior and other handy locations. I use them constantly to guide and steady my traverse from one part of the cabin to another when underway or at night when "3-sheets to the wind."

[Blue Stocking]

Nielpride,
Interesting--thanks for posting.
IMHO, the shock loading is the problem with non-mechanical attachments.
A pedal cycle falling over can bend the 1cm x 2cm pedal arm, and we have all seen the stanchion mysteriously bend under weight load--but try to straighten it out--

* Osirissail out-typed me.

[minaret]

Originally Posted by osirissail

Through bolting is not difficult and an easy "no-leak" way is to core drill a hole - say 5/8" or 15mm through the cabin top.

Then cover the bottom of the hole with tape and pour in epoxy putty and let cure.

Then drill your machine screw hole down the center of the epoxy plug.

Use fender washers or backing plates and 5200 to bed the machine screws. Solid, safe and no leaks after many years of use (at least mine don't leak).

"

Since the OP's rail is being installed in the interior of the boat, your through bolts with backing plates or fender washers will look pretty awful sticking through on deck! The glassed in steel plate I suggested earlier is often an option and will safely take extreme loads.

[osirissail]

so As with most things "boat" there is usually more than one way to do it properly. A glassed in steel plate on the inside surface of the cabin top would work just fine if the glassing job is done correctly and is sufficiently thick and large as to provide a strong "capture" of the steel plate. The steel plate could be drilled and tapped prior to being fiberglassed into place. Then only a hole needs to be drilled through the layers of new "glass" to access the tapped hole. Many chainplates on some model boats are "glassed in" to the inner hull surface.

However, I suspect it is a toss up as to whether a raised interior surface where the glassed in steel plate is installed is less awful looking than the smooth round head of a carriage bolt and fender washer on the exterior surface of the cabin top. I did paint mine white so that the carriage bolt head and washer is largely invisible unless you are looking for it.

[daddle]

If the liner or interior layup is insufficient to hold the screws, as is often the case, then building up the surface is a good idea. Though glassing is a steel plate sounds rather extreme. I might epoxy on a 100cm wide strip of nice wood or build up a similar strip with a few mm of glass cloth layup. Self tapping screws hold quite well in 'glass. Plugs into the core might work as well.

[minaret]

Originally Posted by osirissail

so As with most things "boat" there is usually more than one way to do it properly. A glassed in steel plate on the inside surface of the cabin top would work just fine if the glassing job is done correctly and is sufficiently thick and large as to provide a strong "capture" of the steel plate. The steel plate could be drilled and tapped prior to being fiberglassed into place. Then only a hole needs to be drilled through the layers of new "glass" to access the tapped hole. Many chainplates on some model boats are "glassed in" to the inner hull surface.

However, I suspect it is a toss up as to whether a raised interior surface where the glassed in steel plate is installed is less awful looking than the smooth round head of a carriage bolt and fender washer on the exterior surface of the cabin top. I did paint mine white so that the carriage bolt head and washer is largely invisible unless you are looking for it.

You install it so the steel plate is under the headliner and hence invisible. Depending on the headliner this can require any one of several different approaches.

[SVTatia]

The space between the liner and the deck varies between ½ to 1 inch, sometimes more. If you “feel” that there is space at the locations you want to place the handrails this should be simple and it will work. Epoxy to fibreglass is very strong and the liner will take care of the sideways (shear) load.

1) Use a 1 ½ hole-saw to cut 3 holes (or 4 depending how many rings) thru the cabin-liner and up to the underside of the deck (definitely not thru the deck!).
2) Cut 1 ½ inch hard wood dowels to the level of the liner.
3) Rough up the under-deck fibreglass surface + clean up with acetone.
4) Acetone the dowels and epoxy them to the holes and under deck – coat the dowel sides with epoxy to grab the liner as well.
5) Once cured, use #10 wood screws to attach the handhold to the dowels.

[Cheechako]

I'm thinking the teak will split or the bolt will break before a fender washer gets pulled through the cabin top....

[Cheechako]

Originally Posted by minaret

Since the OP's rail is being installed in the interior of the boat, your through bolts with backing plates or fender washers will look pretty awful sticking through on deck! The glassed in steel plate I suggested earlier is often an option and will safely take extreme loads.

Geez.... I think many of us missed the word "interior". I know I did! Heck, I would just drill and tap for machine screws without going through the exterior skin.or you could install brass threadserts.

[osirissail]

As it appears there are many different ways to accomplish the job. And it seems that the type of hull and cabin top can make a serious difference in the techniques used.

Since the OP is asking about the overhead or "cabin roof" that can vary from a cabin top that is solid FRG or a cored cabin top with inner and outer layer of FRG. I have never seen "pans" used to line the inside of a cabin top. But never say never . . .

On the interior surface of the cabin top there may be a cloth/fabric headliner, common in older boats, or the new plastic laminate panels permanently glued into place. Removing a cloth/fabric headliner is no job for the timid as getting it back up again so that it is taught and smooth can be a real challenge. And if the interior of the cabin roof is laminate panels, they cannot be removed.

So you have a variety of solutions based on how the actual "cabin roof" is put together. But I would posit that screwing (stainless steel sheet metal screws) into the inner layer of a cored cabin top would not stand up to the loads that can be imposed on the handhold rails - unless - the inner surface FRG is seriously reinforced with more FRG or embedded metal plates.

However, for simplicity of D-I-Y I would suggest the drilling completely through the cabin top and using the epoxy plugs and machine screws (bolts) with fender washers which can be painted to match the color of the exterior of the cabin top. And of course, you will have to live with a row of them down the exterior of the cabin top.

Choosing the reinforced interior FRG skin would certainly be more aesthetically pleasing but that process requires a lot more time, effort and care to be done properly. So it is up to the OP to decide what is most appropriate for his boat's "cabin roof" configuration and his own D-I-Y skill level. Or hire an experienced shipwright to do the job - which would be my preference for boats with fabric/cloth headliners.

[foolishsailor]

The best and easiest way to secure a handrail in this situation is to bed in a metal or wood plate into the interior roof. Since There is a gap mentioned of 1"+ between the headliner and the interior cabin roof it is also important that the bedded material protrudes out from the interior cabin top so that when the handrail is attached it doesnt pull the headliner up and make it look ugly.

The best solution for this IMO is

1. Make one piece of wood for each fastener the following size: 2" x 2" x gap distance between healiner and interior cabin roof + 1"

2. Mark on cabin roof the locations of each fastener

3. Trace the piece of wood on the cabin roof centered on the fastener location.

4. Use a small trimming router and rout out the tracing to 1" deep

5. Thicken some epoxy and bed the pieces of wood in the holes. For extra security one could lay glass over as well but it shouldnt be necessary

6. Replace headliner, drill and attach handrail.

The reason for the extra work is that the gap between the headliner if only spanned by a thin dowel or plug cold bend or snap if the handrail is pulled at an angle, which in heavy weather it will be. By making a 2" platform for each fastener to pull the handrail tight to there is no chance the handrail will break.

Please take your handrails as seriously as you would safety equipment like elirbs or liferafts. More life threatening injuries are associated with injuries from falling than being caught in bad weather.

If you cant do the above then either hire someone who can or possibly consider not doing it at all. If there is no handrail them people will instinctively grab for other handholds.

[SailingwithSoul]

Hi Everyone! Thank you for all your advice and suggestions. I appreciate them all. Through bolting of some sort may very well be the safest and best solution, but the clutter of bolts and screws along the outside cabin top will look horrible. I also like the idea of glassing in a plate, but the ending result will also not look good as the roof has a textured "non-slip" finish. I don't have a picture of the spot where I cant to install the handrail, but maybe the following pic can illustrate the interior cabins roof (Don't mind the mess. I was picking out curtains, and I ended up using two of the one pictured on each side).

As you can see from the pic. There are already through bolts from the outside roof rail on either side of the cabin. I was wondering if I could replace the existing screws with longer ones and through bolt the inside and outside rails to each other.

[minaret]

Originally Posted by SailingwithSoul

Hi Everyone! Thank you for all your advice and suggestions. I appreciate them all. Through bolting of some sort may very well be the safest and best solution, but the clutter of bolts and screws along the outside cabin top will look horrible. I also like the idea of glassing in a plate, but the ending result will also not look good as the roof has a textured "non-slip" finish. I don't have a picture of the spot where I cant to install the handrail, but maybe the following pic can illustrate the interior cabins roof (Don't mind the mess. I was picking out curtains, and I ended up using two of the one pictured on each side).

As you can see from the pic. There are already through bolts from the outside roof rail on either side of the cabin. I was wondering if I could replace the existing screws with longer ones and through bolt the inside and outside rails to each other.

You have a 'glass hull liner, which is worst case scenario for this install. You can't bolt the two handrails to each other because one side needs a nut which will be too big to counterbore into the handrail and bung. I would consider removing the upper handrail and installing a substantial piece of nice timber as a pad for the lower handrail to land on. Then through bolt the upper rail through the pad under the deck. Then install the lower rail on the pad by screwing it into the pad with lag bolts. Maybe 5/4" teak or mahogany? If you radius it nicely and varnish it it will look OK, but it needs to be at least 1" thick. I'd consider living without, this is one of the drawbacks to a hull liner, it's very hard to make additions.

[Cheechako]

Originally Posted by SailingwithSoul

Hi Everyone! Thank you for all your advice and suggestions. I appreciate them all. Through bolting of some sort may very well be the safest and best solution, but the clutter of bolts and screws along the outside cabin top will look horrible. I also like the idea of glassing in a plate, but the ending result will also not look good as the roof has a textured "non-slip" finish. I don't have a picture of the spot where I cant to install the handrail, but maybe the following pic can illustrate the interior cabins roof (Don't mind the mess. I was picking out curtains, and I ended up using two of the one pictured on each side).

As you can see from the pic. There are already through bolts from the outside roof rail on either side of the cabin. I was wondering if I could replace the existing screws with longer ones and through bolt the inside and outside rails to each other.

No doubt about it, it has been done many times and sounds like a great solution if the inside placement is right.