Best way to bend 25mm PVC conduit?

[haggis999]

From time to time, I have a need to put a fairly gentle bend into 25mm PVC conduit. Past attempts to do this using nothing but a bending spring (originally bought for 22mm copper pipe) were not successful. I found that I could do the job if I warmed up the conduit with a heat gun, but have never been totally happy with the results, as the PVC develops obvious ripples at the heating points.

A few days ago, a member of staff at my local WF Senate told me that I shouldn't have to use a heat gun, so I've just tried again. The results were the same as before, i.e. the conduit simply springs back to the straight position after I bend it.

Is there a knack to this bending process or do I just need to put more effort into the bending? Do I perhaps need a better spring or different conduit (I use MK Heavy Duty 25mm round conduit)?

 

[Spoon]

There was a thread on this not so long ago. Do a search.
A bloke was using heated sand in the conduit to bend it.
I'll see if I can find it.

 

[Pete999]

From time to time, I have a need to put a fairly gentle bend into 25mm PVC conduit. Past attempts to do this using nothing but a bending spring (originally bought for 22mm copper pipe) were not successful. I found that I could do the job if I warmed up the conduit with a heat gun, but have never been totally happy with the results, as the PVC develops obvious ripples at the heating points.

A few days ago, a member of staff at my local WF Senate told me that I shouldn't have to use a heat gun, so I've just tried again. The results were the same as before, i.e. the conduit simply springs back to the straight position after I bend it.

Is there a knack to this bending process or do I just need to put more effort into the bending? Do I perhaps need a better spring or different conduit (I use MK Heavy Duty 25mm round conduit)?

Bending Spring 25mm Black NEW | eBay - https://www.ebay.co.uk/i/171816964330?chn=ps&dispItem=1&adgroupid=48716125379&rlsatarget=pla-382120640835&abcId=1129946&adtype=pla&merchantid=113421977&poi=&googleloc=1007208&device=c&campaignid=974960635&crdt=0
Use the proper tool for the job, no heat gun required.

 

[Spoon]

Knew you'd come to the rescue @Pete999 . Ta mate.

Thought you were going to tag the thread..

 

[Spoon]

This is the thread.
Plastic conduit bending springs - https://www.electriciansforums.co.uk/threads/plastic-conduit-bending-springs.122253/#post-1289228
Check out the vid that @Pete999 posted on post #10

 

[haggis999]

Use the proper tool for the job, no heat gun required.

I am more than happy to buy a new spring designed for PVC conduit if that is the most likely solution to my problem. My current spring leaves only 0.5mm clearance all round and I wasn't sure if a slightly tighter fitting spring would really make much difference.

Once I get the proper tool, is there any special knack to the bending process?

 

[haggis999]

I've looked at the video showing how to bend pipe using hot sand, but I'm guessing that most people manage to do the job using a bending spring.

 

[Pete999]

I've looked at the video showing how to bend pipe using hot sand, but I'm guessing that most people manage to do the job using a bending spring.

Never used anything else, except manufactured right angles etc, mainly to comply with the regs on number of bends etc

 

[Risteard]

Why would you use a spring designed for 22mm pipe in 25mm conduit?

 

[Andy78]

Why would you use a spring designed for 22mm pipe in 25mm conduit?

Agreed. This is your problem.

 

[Strima]

Use your hand in a technique that most teenage boys use a lot on the conduit to get some warmth into it, it will bend easier.

 

[haggis999]

Why would you use a spring designed for 22mm pipe in 25mm conduit?

The internal diameter of my 25mm conduit is actually 21.5mm, so my old spring appeared to be quite a close match and it didn't seem likely to me that a small increase in spring diameter would make a big difference.

I was wrong. A new MK-branded 25mm bending spring, whose diameter is about 1mm wider than my old spring, has solved my problem!

Thanks to everyone for pointing me in the right direction.

 

[haggis999]

Use your hand in a technique that most teenage boys use a lot on the conduit to get some warmth into it, it will bend easier.

I will try that next time I bend some conduit!

 

[telectrix]

yippee. MK have made something that actually works.

 

[Gavin John Hyde]

yippee. MK have made something that actually works.

It must be a fake masquerading as a MK product with a cheap sticker on it,as we all know Mk products do not work..period.