long handrail join

[Joel OF]

Hi folks, I'm hopefully going to be doing a long handrail for some clients who have a Grade 1 listed house and garden. (Listed meaning it's architecturally important and additional work has to be sympathetic to the original building and approved by a conservation officer). They want the handrail to come straight down their steps, level out flat at the top and bottom, then curve off around the corners at both the top and bottom. I haven't been to site for a while but from memory the total handrail length would be about 5m.

It would be made using half round square edge and made in 3 pieces as it's too long to manouver in one piece. At the clients request the posts on the steps are having feet that will be screwed down rather that resin/leaded in but the top and bottom curve sections will be cemented in. I think the join should happen around the area the rail levels out and at a post. I spent a few hours the other day experimenting to see if I could make the join work "in mid air" rather than at a post, it looked neat but it was too weak. (As you can tell I don't have a lathe yet).

That experiment led me to think the join should happen at a post and I've got one or two variations in mind how that could happen, but I thought I'd put it to you good folks too incase I've overlooked something obvious. As they are local I plan to have a dummy run install to make sure everything fits ok, then take it for weatherproofing, then return once it's treated for the final fit.

Can anyone offer up any ideas? Cheers

[ThomasPowers]

Can you weld it?  A good enough weld will be invisible once dressed and painted.

[jeremy k]

The longest one piece run of handrailing I installed was 36 ft. The longest 3 piece I've done is 56ft. That when installed was a huge "S" curve made up of 9 different radiuses. All welded in one piece in shop and cut in 3. Painting was done before installing, on-site Tig welded, ground and paint touched up on site. Not much one can do besides mechanical joint or a welded joint and touched up afterwards.

[Frosty]

Kind of late now, I think you need to weld and touch them up. Given the lead time I'd dove tail the joins and lock with a set screw over a post. It might have issues with water infiltration though. 

Simple is probably best, weld and grind.

Frosty The Lucky.

[Joel OF]

Cheers for the thoughts folks.

Part of it's weatherproofing process will be zinc flame spray (similar to galvanizing) before a top coat paint so I'm reluctant to weld for the obvious zinc fumes...but also because I want the weatherproofing to be 100% throughout. In England rust is a constant PITA.

I was thinking along Frosty's lines with a screw/bolt fixing if it's getting the zinc treatment...but you're selling me on the "paint on site" method.

[jeremy k]

Here in the states we have spray cans for cold Galvanize spray touch up after welding. Then painting can be applied. I have used these products and as long as metal is clean with a light sand scratch, it seems to hold up well for what I've done.

[Kozzy]

Handrails get complicated engineering-wise but in the USA, that double bolt system would not generally be strong enough unless nearby posts were taking most of the load rather than the joint.

Rails here need to take a 200 pound point load in any direction without failing (or more than superficial distortion) and are typically proof-tested to 500 pounds to quantify that they "pass".  Unless those 2 bolts are quite large, they would be prone to failure due the huge leverage in a scarf joint as the rail flexes (again, unless the posts provide the strength to that section).

You really do need to weld this--or create some sort of strong sleeve joint that is near/at a post so the load is transferred there instead of into your joint.  

Beware "hanging" end loops because they can also be a creator of HUGE leverage at the nearest mounting point--take as an example an open end loop that sticks out 12 inches beyond the last post---and 2 bolts holding the rail to the last post spaced about 1" apart.  A fat guy like me slips and puts a couple of hundred pound load on that end loop...and that translates to about a 2000 lb load between the post bolts.  The math is way over simplified in this example...because it's just for an example...but do beware areas that create excess leverage prying the mounting points.  It's those hanging ends that fail most often due to under-engineering.

[arftist]

Best is to stick with your instincts and bolt it at the posts.

[Smoggy]

I would have made such a mechanical joint at least three times the width of the rail with six fixings.

I think you need to weld that on site, dress and apply suitable coatings. Spray or brush on galv paint is available here in the UK and will accept a finish coat on top.

[arftist]

Best is to stick with your instincts and bolt it at the posts.

What I do in a situation like this is weld a tab right under the top rail and right under the bottom rail and bolt them together with 3/8" flathead bolts. No attempt to hide the fasteners is needed, they are part of the job.

When a customer is paying the premium price for hot dipped or metal sprayed iron work, they deserve the full protection not feild repairs from spray cans.

When I install such work I used bolts.  

[arftist]

examples

example

again

last

Note that this house is on salt water front.

The iron was hot dipped then epoxy primed then sprayed   with automotive paint. 

The finish was warranted for 20 years by the galvanizing company. 

The warranty would be voided by any welding. 

This rail was installed 9 years ago and though the gloss has since faded from the paint, it has yet to rust.

[Marc1]

i agree that the joint at the post is the way to go. 

You can either bolt the rail with a vertical bolt or horizontal into the post. I wouldn't let the head of the bolt show if it is vertical, but rather weld it below after cutting the head off and slide the shaft of the bolt into a blind hole and weld around. I would use an acorn or cup nut.

A horizontal bolt into the post, depending on the post make may be easier. You need to weld a support to the rail at 90 degree. 

A joint that wants to be invisible by welding on site will invariably be a weak section for corrosion and hardly invisible anyway. 

For corrosion protection, as described by Arftist. HDG (or Hot Spray Zinc) + two parts epoxy primer + enamel top coat. That is how public works like bridges over salt water are protected. If you are going to do the finish, make sure that the galvanising shop does not quench the work. The quench bath is convenient for them so they don't have hot stuff waiting to cool down, but will contaminate the surface and the epoxy primer will not take well. Ask if they do "no quench" before, because some places may refuse. Also epoxy is a generic term, make sure you use a two pack product formulated to paint over galvanising like this one http://www.duspec.com.au/duspec/file/audi0540.pdf this type of primer only needs top coat for cosmetic reasons and is tough as nails. 

[anvil]

Another thought is to "be proud of your joinery".  Meaning don't minimize it but instead incorporate it as a design feature.  

Ideas:. Bevel the edges instead of leaving them sharp.

A decorative strap underneath and using 4 rivets, two on each side.

Do more joints and support them with gussets/ scrolls.  The repetition will add to the esthetics.

Also this means all finishing can be done before final assembly.

Hope this helps.