Chemical resin and studs question.

[Mottie]

I'm replacing the rawl bolts on the 4X2 timbers that are bolted to concrete posts. My yard gates hang on them. Over the years the expanding rawl bolts keep coming loose and pulling out so I’m going to remove them and replace with 12mm or 16mm studs set in chemical resin. Simple question, what’s the easiest resin to use for a diyer and how many tubes will I need, I have just 6 studs to replace - I want something that’s not going to set at the speed of light and I’d prefer it if I could buy it somewhere like B&Q or screwfix. Thanks.

 

[mikeey84]

If you work quick, you will probably get away with 1 or 2 tubes.

The resin only fills the difference in circumference and length between the rod and the hole, and if you do the sums, it's surprisingly little unless you drill a massive hole and use a undersized rod.

I've heard the polyester based resins have a longer working time, but that's not from experience. You can buy extra nozzles, as it only activates once it's mixed in the nozzle, so you can swap them out if they get blocked

 

[noseall]

I'm replacing the rawl bolts on the 4X2 timbers that are bolted to concrete posts. My yard gates hang on them. Over the years the expanding rawl bolts keep coming loose and pulling out so I’m going to remove them and replace with 12mm or 16mm studs set in chemical resin. Simple question, what’s the easiest resin to use for a diyer and how many tubes will I need, I have just 6 studs to replace - I want something that’s not going to set at the speed of light and I’d prefer it if I could buy it somewhere like B&Q or screwfix. Thanks.

I've only ever used the Hilti stuff, but I'm tempted to use a version sold at my local BM. Trouble is that when we are instructed to use resin, its usually for summat very important.

Have you thought about using concrete screws?

 

[Mottie]

Have you thought about using concrete screws?

Trouble is, these posts seem to be 75% pebbles or stones and almost impossible to drill into so I was hoping just to use something in the existing holes. The gates are very heavy and keep pulling the rawl bolts out no matter how tight I tighten them. Once done, I’m fitting lighter gates. Each gate is 8ft wide by 6ft high and made of 3/4” ply on a 4”x2” frame.

 

[noseall]

Each gate is 8ft wide by 6ft high and made of 3/4” ply on a 4”x2” frame.

You are asking too much from the conc posts. The mass of the gates increases with swing. Ordinarily you'd be looking at steels concreted into the ground for those behemoths.

Ideally what you need is to fix a timber post into the ground then hang off the timber and then fix the post and the timber post together. Drilled concrete is no good at taking any shock, unless you can drill right through and bolt/clamp some kind of fixing.

 

[bernardgreen]

Make a jig to hold the studs in exactly the right places while the resin cures.

Smear some resin in the thread of the studs to ensure the resin binds in the thread.

Cooling the resin cartridge in the fridge is said to give a longer working time

75% pebbles or stones and almost impossible to drill into so I was hoping just to use something in the existing holes.

Use the existing holes.

My cottage walls are stone, rubble and mortar and some places are un-drillable and other places can be drilled with a pointed stick. So far all the resin fixings are holding. In a couple of holes the resin has filled a cavity and "glued" loose lumps of rubble / stone together so the amount of resin was more than expected. You won't have that problem in concrete posts.

 

[noseall]

Make a jig to hold the studs in exactly the right places while the resin cures.

We'd do the same. A length of ply or similar and line it/mark it up with the gate studs and drill tight holes so that you can bolt the threaded bar to the timber. Then just offer the whole lot into the soft resin.

...and get the wife to hold it for 40 mins.

 

[bernardgreen]

A length of ply or similar

I used thicker timber such as 50 mm to ensure the studs remain exactly in place

and get the wife to hold it for 40 mins

far less hassle to make a temporary support for the jig.

 

[noseall]

I used thicker timber such as 50 mm to ensure the studs remain exactly in place

Thicker timber means being more accurate with the drill. Not as simple as it sounds.

 

[bernardgreen]

being more accurate with the drill

If you mess up the drilling of the jig then you can make another jig.

If the jig fails to keep the studs in place as the resin cure then you have studs securely fitted to the post but not where they need to be.

 

[Mottie]

and get the wife to hold it for 40 mins.

That’s my second problem. With my workshop being in Newham (which is the London Borough with the highest Coronavirus death rate) and on a fairly busy road, I don’t want to be hanging about on the street for too long with all the local inhabitants passing by, coughing, sneezing, hawking up and spitting everywhere. Thinking about it, maybe I’ll leave it for a while.

 

[^woody^]

In the old days, fibre plugs would be used and would be almost impossible to pull out. But that's progress for ya.

 

[Mottie]

Just a renew of this thread with another couple of questions for @noseall if he wouldn’t mind. I’m going to have to get something done soon as the gates are all bar hanging off now. Not so much as gates as moveable pieces of heavy wooden wall - they are supported by roller wheels though. Anyway my plan is to reuse the existing holes in the posts along with the gate frames (4”x2”) and replace the rotten, sodden 3/4” ply with 10mm ply. That setup has lasted since 2014 and only recently started to fail mainly, I suspect, due to the sheer weight of water that has soaked into the plywood. I plan to use Anchorset resin in the holes, I tried some out the other day with an old out of date green tube my mate gave me just to see how long it took to set (tube had an expiry date of 2018 so didn’t want to use that). It got bloody hot when it was curing and smelled and looked like Isopoon P38 bodyfiller!
My questions are: do I use the red or green tubes - one is styrene based and the other is styrene free? Also, I have new rawl bolts so would it be best to use those in the holes packed in with resin or remove the studs from the rawl bolts and use them directly in the resin?

 

[noseall]

Styrene based. Probs cure quicker. No idea about the strength difference though.

 

[Mottie]

Styrene based. Probs cure quicker. No idea about the strength difference though.

Thanks. Would you use the whole rawl bolt or just the stud?