Induction heater, seized bolt removal

[Yeoman_24]

I recently have failed to get a bolt undone despite using heat, wd40 (and others) and brute force. I was made aware that classic car enthusiasts use an induction heater which is a coil which surrounds the nut / bolt and heats just what is inside the induction coil up to red hot heat.

Excellent I thought until I looked at the £400 price tag. After searching around I found shaper ones then finally found this on Amazon for £35.

Any thoughts on induction heaters in general for this function and is what I have found on Amazon any use?

 

[pandos]

I use this homemade mixture which I saw on a classic car forum some years ago...it works amazingly well on badly rusted bolts. (I used it a digger and on my engine mounts on the boat) I think brake fluid maybe better than the ATF...

Others on here will disagree...you'll probably be told that wd40 is not a lubricant or a penetrating oil..

 

[Ian_Edwards]

The picture in the add is probably misleading, the base looks like Aluminium, which won't be heated.
An engine block on a boat is more than likely to be magnetic, so the induction heating will heat both the bolt and the block, which may or may not be a good thing. Too much local heat on a bolt may risk cracking the casting.

The heat will be concentrated in the centre of the coil, but anything outside but relatively close to the coil will still get hot. I see this with my newly acquired induction hob, a cast steel pan close to the operational element gets noticeably warm.

The picture shows a heavy-duty power supply and copper coil, but no detail on how the two are connected or how the power supply is controlled. I'd want to know a lot more about it before I bought it.

 

[Alex_Blackwood]

The picture in the add is probably misleading, the base looks like Aluminium, which won't be heated.
An engine block on a boat is more than likely to be magnetic, so the induction heating will heat both the bolt and the block, which may or may not be a good thing. Too much local heat on a bolt may risk cracking the casting.

The heat will be concentrated in the centre of the coil, but anything outside but relatively close to the coil will still get hot. I see this with my newly acquired induction hob, a cast steel pan close to the operational element gets noticeably warm.

The picture shows a heavy-duty power supply and copper coil, but no detail on how the two are connected or how the power supply is controlled. I'd want to know a lot more about it before I bought it.

This may give a bit more info.
RUNMIND 1000W 20A ZVS Low Voltage Induction Heating Board Module with Coil 12V-48V Flyback Driver Heater DIY : Amazon.co.uk: Home & Kitchen

 

[dankilb]

Cherry red with a MAPP torch (if oxy not available) surely remains the best value option (torch and gas about £50)?

Proper penetrant is likely better than WD40, but alternatives work well and I’ve even seen candle wax used (once red hot apparently it flows into the thread).

 

[ghostlymoron]

I saw Edd China use one on Wheeler Dealers last week - it worked and he seemed to think it's better than his usual propane torch. (Depending on location)

 

[Bilgediver]

I use this homemade mixture which I saw on a classic car forum some years ago...it works amazingly well on badly rusted bolts. (I used it a digger and on my engine mounts on the boat) I think brake fluid maybe better than the ATF...

Others on here will disagree...you'll probably be told that wd40 is not a lubricant or a penetrating oil..

The makers of WD 40 do now make a penetrating oil. I think it is in a tin with Yellow markings WD40 is an excellent De watering fluid . The best thing for old cars with sideways facing engines and spark plugs facing front such as BMC mnis etc. These will sometimes be difficult to start if the ignition gets wet. A quick blast of WD 40 over the Ht leads and distributor cap and off you go. The amount of oil in WD 40 is minimal so for rust protection etc it needs help.

In general for most jobs a mixture of ordinary oil and diesel is excellent however nothing beats Plus Gas and for the obstinate items just swathe the item in cloth soaked in Plus Gas and forget about it for a day or so. Could use an oxy torch if you have one!

 

[ghostlymoron]

Cherry red with a MAPP torch (if oxy not available) surely remains the best value option (torch and gas about £50)?

Proper penetrant is likely better than WD40, but alternatives work well and I’ve even seen candle wax used (once red hot apparently it flows into the thread).

I'm told that WD40 is no good as a penetrating fluid but I've used it as such many times with success. I'm interested in how you heat candle was to red hot.

 

[dankilb]

nothing beats Plus Gas

I table PB Blaster (from the US but available via eBay etc.) ?

And as a bonus the can is a triumph of graphic design, they’ve somehow done away with the need for a straw or flexi altogether, and it even smells strangely appealing/evocative - all sure to help cheer up even the darkest of seized fastener hours!

 

[dankilb]

I'm told that WD40 is no good as a penetrating fluid but I've used it as such many times with success. I'm interested in how you heat candle was to red hot.

Don’t heat the candle directly(!), but allow some wax to melt into the (red hot) fastener immediately after heating.

Plenty of YT demos, but hard to really tell if the seized fasteners under ‘test’ would let go with the heat and torque applied alone anyway - without the wax.

Maybe worth remembering, though, just in case one day a candle is all you’ve got. Who knows, may even be better than a can of WD?! ?