60kg hanging 26" from the wall - what anchor to use :-)

[Staffbull]

threaded bar with big FOF washers/nuts on't end, mount arm onto other end, sell it to the neighbours as free picture hangers :-)

Sorted !!!

[Antix]

ahhh :-) well, maybe not such a far out idea !

ok...so far I'm sort of leaning to the idea of a sleeve anchor....the

1/4 inchers by all accounts stand up to 500lbs or so 'pull out' and i'd have 3 of those which would hopefully give me a good degree of leaway...but I'm certainly concerned about the condition of the bricks which I haven't uncovered yet (but will !). How does resin compare to a sleeve anchor ?

now...not such a far out idea above becuase I am planning on removing a brick from the wall to provide a hole to drop the AV cables through (along with another brick at the base of the wall as the outlet)....so there is 'some' potential to access the rear side of the wall (albeit with shredding most of the skin off my hand fiddling around trying to attach the nut to the back end of a bolt I've poked through...and a few tens of nuts and washers in the proces :-) ). I'm thinking, no lateral pressure from an expanding bolt on the brickwork is a good thing, and no reliance on a resin I've never used before, and providing I can actually reach the end of the bolt with my hand/arm through a single brick hold, it'd give me a hell of a lot of peace of mind....Any thoughts on this approach ? ideas on what to use as a stud/bolt or what to use on the rear (just washers ? or are there special things I can get ?)...anyone able to tell me how far through a singl brick hold I'm likely to get my arm !! :-)

(it's a partition between my part of the house and the neighbour so I'm not tooooo worried about condensation dripping down the cables...I'll work around it if it happens and I'm more happy to replace cables if they deteriorate than have the kit fall off the wall)

Ant.

[Andy Hall]

That's fine.

I've seen some products where the manufacturer's recommended fixing is clearly woefully inadquately specified. The other aspect is that the fixing is highly dependent on what it goes into.

GIven the value of the equipment, I would choose based on what I've used before and no works. If it's massive overkill then so be it. I would rather minimise the risk rather than hoping.

[Staffbull]

My brother has hung a pair of heavy gates using resin fixings as the holes had to be close to the edges of the blocks, still up and OK 7 yrs on ! they were twin injector thingies and just push threaded bar into em, leave em cure for 24hrs and bingo, used the same for my wallplates in the extension too.

[Andy Hall]

Way superior.

Keep in mind that the claimed pulling force is completely dependent on the brick not having cracked or crumbled at all and your having drilled the hole perfectly with no wobble removing extra material. Resin is not at all dependent on that. It doesn't matter if the hole is a bit too large and there is no possibility of the brick being stressed and cracked as it can be when a sleeve anchor is tightened.

I think that you would need to remove more than one brick and you wouldn't be able to reach very far. The cavity between the walls is likely to not be much more than about 50mm. You can easily test that by drilling a small hole through (mark drill carefully as it reaches the cavity) and then poking a piece of wire in until it touches the other wall. Subtract and that's the cavity depth. I think that you would need to take out at least two bricks to do what you are suggesting.

I was also sceptical about the resin stuff before I tried it (quite recently). So I bought some and did a test run on something that wasn't critical. I loaded that up with three times the weight and force that I calculated would be needed in the critical application and it was completely fine.

Up to you, but if I were doing this job, that's what I'd use without further thought.

[Clive George]

Resin fixers have been used for caving (and climbing?) for several years now. It's quite important that they work there :-)

cheers, clive

[Owain]

Would that have to be equipotentially bonded as an incoming service?

Owain

[EricP]

Only if a B&Q windmill was connected.

HTH

[Antix]

Thanks Andy, so the question now is which resin ! Screwfix do the Fischer Epoxy which needs a special tool to ensure the two parts are ejected from the tube simultaneously (buggers!), or there's the non-epoxy stuff....Vinylester resin which is part cement and doesn't need a special tool...choices choices !

I wonder if my 3 year old son's arm will fit through the hole....

Ant.

[meow2222]

Resin is absolutely the right choice, Andy Hall's right on the mark.

1860 brick houses typically used brick rejects and assorted junk for inner wall leafs, bonded together with lime mortar. Some of these bricks will be pretty hopeless strength wise, some good and solid, the mortar will often be reduced to crumbs by now, the odd bits of wood may have shrunk or rotten and so on. YMMV of course, but it makes sense to use something thats known good, ie resin.

Any other fixing type will exert uneven pressure on the brick and is much more likely to cause the brick to just crumble and let go. Resin, as well as providing even forces all oevr the join, adds no extra forces onto the brick due to the fixing itself, so is far more capable than any mechanical fixing, such as sleeve or masonry bolt.

Epoxy is specified for structural repairs, the cheaper ones are used where they dont have to survive long term. I'd preferably use epoxy, though the other types will also work. You need a new nozzle each time you use the stuff, so good idea to get a few nozzes at least.

NT

[meow2222]

Resin is absolutely the right choice, Andy Hall's right on the mark.

1860 brick houses typically used brick rejects and assorted junk for inner wall leafs, bonded together with lime mortar. Some of these bricks will be pretty hopeless strength wise, some good and solid, the mortar will often be reduced to crumbs by now, the odd bits of wood may have shrunk or rotten and so on. YMMV of course, but it makes sense to use something thats known good, ie resin.

Any other fixing type will exert uneven pressure on the brick and is much more likely to cause the brick to just crumble and let go. Resin, as well as providing even forces all oevr the join, adds no extra forces onto the brick due to the fixing itself, so is far more capable than any mechanical fixing, such as sleeve or masonry bolt.

Epoxy is specified for structural repairs, the cheaper ones are used where they dont have to survive long term. I'd preferably use epoxy, though the other types will also work. You need a new nozzle each time you use the stuff, so good idea to get a few nozzes at least.

Oh, almost forgot. 2 streams get mixed in the nozzle, and often one stream comes out before the other, so what comes out initially will never set. Watch the colours so you know when you've got a mix of both coming out.

NT

[Andy Hall]

I looked at Screwfix's different options and decided to pick from the Fischer range, mainly because I could get all of the product information from Fischer's web site to answer a few questions that I had.

The options are

- go for one of the larger cartridge types such as V360 (Screwfix

88507 £16.49) or P380 (42772 £13.00). However, these require an injection gun costing £50 (35237) for the V360 or £22.49 for the one for P380. The V360 resin is better because it has a mortar component, but the cost for a small project is then getting expensive.

- go for one or two of the small 100ml cartridges (51021 at £11.99). These are more expensive in terms of price/quantity, but are complete and ready to go. You fit the nozzle and twist the base. The resin is the mortar type.

I wasn't sure when I was going to use the technique again or for that matter, whether it would work adequately, so I wasn't going to invest £50 in the special gun. I think that next time I have a significant project I might well, though.

I was using 10mm fixings going quite deep and was able to get 8 or so fixings from a 51021 100ml tube. I had made a reasonable estimate and bought an extra tube just in case. Since Screwfix has a 30 day return policy, over-ordering doesn't matter. I had a tube left over and frankly have kept it. The nozzles are single use only. However, because I was using several packs at one go, I was able to transfer a nozzle and end up with some spares.

So the steps are:

- Identify the stud size that will fit the holes in the bracket. You will need a masonry drill 2mm diameter larger.

- Choose studs that are of suitable length. It's better to avoid drilling all the way into the cavity if you can because you will tend to inject some resin all the way through. However, that's not horrendous - you just need to slowly withdraw the nozzle while injecting. You can cut the studs with a hacksaw and that's easier done before fitting.

- For accuracy, I would recommend making up a template from a piece of ply or similar. Using the bracket, mark and drill holes in the ply of the size of the holes in the bracket.

- Tape the template to the wall (level it with a spirit level) and mark the holes. Remove template.

- Drill the holes.

- Vacuum them out thoroughly. This is important. If you hold the nozzle of the cleaner hose up to the wall at each hole put only half covering the hole, the rush of air in clears the dust out well.

- I would suggest doing them all at once, injecting the resin and inserting each stud with twisting motion. Important. If there isn't some ooze of resin from the hole then pull out stud and put in more resin.

- Clean off any excess resin

- Locate the template back onto the studs making sure that all go through. This ensures that they are all located exactly correctly and that the bracket will fit. Remember that each stud has +/- 1mm of movement.

- Leave for 24hrs

- Then you can attach the bracket.

[Antix]

thanks Andy, all makes sense. I actually did some calculations and I think I've worked out that there's not as much force on the bolts as I originally though. My original panic was that worst case, let's say there's the full weight of the arm (30Kg) plus the weight of the plasma (34Kg) hanging 26" from the wall...there could be a lot of leverage pulling on the bolt/s.

In fact (if my GCSE physics serves me), it's entirely dependant on the distance the top bolt/s is from the pivot point...i.e if the top bolt were 26" up the wall, the force pulling the bolt out would be equal to the weight of the stuff dangling at the end of the arm...now 63Kg doesn't sound so bad.

Looking at the mount, it'll be trying to pivot around the bottom set of bolts. The top set of bolts will be about 21 inches above the bottom. So the ratio of the arm length to the distance between the pivot point and the bolt is 1.3:1 i.e there's 1.3 times more weight pulling the top bolts out, than the weight of the stuff dangling. ie. worst case (assuming the boy doesn't use it as a swing), is about 82Kg.

So ignoring sheer (no doubt that'll be my downfall...along with boy+swing), if I have 7 bolts along the top, 12Kg per bolt trying to pull out of the wall at 90 degrees. If I add the boy to the equation and assume he's static (let's say up to 36 kilos, that gives me about

5 years growth to train him not to swing on it), the total force pulling on each bolt is say 99Kg * 1.3 / 7 = 18Kg. 25% margin of error gives 23Kg per bolt.

The fischer FIS V resin with an M8 * 110 A4 stud looks like it takes

6KN Tensile and Sheer or am I reading the specs totally wrong ? that's about 600Kg per bolt isn't it ?!!

Ant.

[Antix]

who used the non-rejects ?

[Dave Fawthrop]

|> Resin is absolutely the right choice, Andy Hall's right on the mark. |> 1860 brick houses typically used brick rejects and assorted junk for | |who used the non-rejects ?

Top quality buildings for the Toffs

[Tony Bryer]

On lots of Victorian houses you may think that you are looking at a one brick (9") solid wall, usually Flemish bond. The reality, as anyone who has cut openings in one will know, is that most of the headers may be snapped headers - good bricks are cut in half and used as two headers on the external face, and underburnt or otherwise poor bricks are used to make up the inner half. Likewise the stretchers on the inside face of the wall. With early and mid Victorian stucco (rendered) houses, anything goes.

In my BCO days I pulled out a file on a 1930s estate where the Building Inspector had written complaining about a (pebble dashed) house being built entirely of half bricks. The developer wrote back and said that it was normal practice to use all the broken bricks on the last house, and it appears that this explanation was accepted!

[Antix]

Thanks for all the advice guys ! Job done and it was still on the wall this morning when I left for work :-)

I used about 4-5 resin studs (M8) top and bottom, backed up by 2 shield anchors top and bottom. That resin (Fischer V 360) caught me out tho ! I filled 10 holes up with resin but by the time I got to the 8th, it had already set ! not particularly worried tho as they were the last 2 on the bottom and I figured I probably have enough support now to handle a tonne.

It's still scary seeing a 42" plasma hanging in mid-air off the wall tho...will take some time to get used to !

For the shield anchors btw, I drilled deep enough to set the anchor colar behind the plaster (i.e as far into the brick as I could without going all the way through). I then carved a couple of matchsticks to a flat point and wedged them between the colar and the brick to keep the anchor in place whilst I tightened the bolts. This prevented them from being pulled back out to mate with the mounting plate so instead they stayed in situe, fully within the brick.

Let's hope the wall holds up :-)

Ant.