Experiences with Pre-Heater - I'm Looking to Buy

A pre-heater is on my bucket list as well.

I have done some research, focused on relatively low-cost units, but have not pulled the trigger yet - they just seem too pricey for my budget.

If you do get one, let us know how well it works.

Will do.  Where there any you were thinking about specifically?

Hi Andrew,

I have TMT-PH200 which was £216+VAT several years ago. It's ok*, not bad, a bit underpowered perhaps. It can reach solder melting temperature on its own, but takes a while.

It is also usable as a pre-heater for just applying heat and then apply additional heat from top with a hot air tool too if desired. I have limited success with that system of working because I don't have a powerful hot air tool. Recently I have been working around that by using special low-temperature solder paste - good enough for prototypes.

Looking at the ones in your list, I think the Aoyue will be underpowered given the area it covers. The Quick one I actually did purchase used (very similar, previous version model with rotary knob instead of buttons, but the rest looked identical), but it arrived damaged : ( and I had to return it. It uses an element encased in ceramic, inserted inside an aluminium plate. A drop had cracked it. So I'm still curious about if it would have been good or not had it worked. I also liked the cover that it had, to prevent accidentally touching.

The PCT-1000PCT-1000 looks like it has plenty of power for the area! But has that cost : (

The PCT-100 looks useful for pre-heating specific areas on a board (e.g. for a single IC). This should be responsive since it is targeting a small area and will be likely blowing hot air (whereas the others do not blow air, just rely on radiating). Jan Cumps has a similar style pre-heater, he will have more experience in it to comment.

* 'ok' meaning that I'm not going to explicitly recommend it, but having said that, I do use it, I guess it's a fair product for the price but I wouldn't recommend it for use in a work lab, only for home use.

Thanks Shabaz.

If you read the "Technical Information", the Aoyue is a 850W 200mm x 250mm pre-heater; if you read its user manual it's a 1500W 310mm x 310mm pre-heater.  So who knows???  The Quick being damaged on receipt seems to be a not uncommon problem with these brands.  In both these cases, it's why I'm not too sure about acquiring one because it's not clear what I'm buying nor whether it's going to be good enough quality.  People seem to like the Quick hot air tool though.

I'm mostly interested in pre-heating rather than reflow as I have a hot air gun that seems useful and works well for what I've used it for so far.  It's an Atten 853+ so not a high end brand, and one of those groups of brands like the Aoyue and Quick, so flies against what I've just said! 

The TMT-PH200 still seems available in the UK for not much more than you paid for it and it looks suspiciously like an Aoyue Int 853A. I've seen a few reviews which have had to undertake a bit of repair work to get it right (actually, that's the model that I referred to in the YouTube video above.)  Perhaps if Thermaltronics are rebranding they at least sort out any problems.  They might have changed the styling of that now but these all seem to get copied in some form by bizarrely named Chinese companies.

Hopefully Jan will comment later as the Metcal is the one I'm most interested in if it can work over a larger board area.

If your goal is to use it as a pre-heater - to aid the hot-air gun, you don't need a lot.

I use a Tenma Mini SMD Preheater. Kindly sent to me by Shabaz .

This is a small device but can pre-heat a decent board.

It makes a big difference if you have to get heat from 20° to 350, or from 120° to 350°. Everything works way smoother.

How I work for pre-heating (I use lead-free):

• I put the board above the heater, set it to 100°.
  Usually I prepare my work while it's warming up. If it gets to hot for my hands I switch it off for a little while.
• When I'm ready to use the gun, I put it between 150 and 200.
• When finished, I switch of the heater but leave the power on. The fan helps with cooling.

When dealing with double sided, I usually keep it at 100 ° and deal with it. Still better than no pre-heat.

When dealing with a difficult IC or FET, with big ground plane that needs to set:

• I do the same as above, but with the heater outlet aimed at the location of the component.
• When ready, I push up the temperature to what makes sense for the job, and attack the component with the gun at the same time.

I mentioned this before on the forum: I practice a lot with scrap PCBs.

You learn what works and not for you. At what temperature the PCB delaminates or loses pads. At what settings components spontaneously drop from the underside.

You learn the sounds and smells.

Once you have been in a situation where placing or removing an IC took uncomfortably long time, you'll notice that having a pre-heater is a great asset.

Thanks Jan.  Do you have a model number for that, or a picture of the top.  How do you think it compares, size-wise and outlet-wise, to the PCT-100 I mention above?  What's the biggest boards have you pre-heated with it?

TENMA 2064552, no longer made, but the Aoyue 853 is virtually identical.

Foto of the top. On an A4 page for scale:

Measurements:

I don't know the exact measures of the biggest board. Approx: 1/3 of the height of an A4 page, width of an A4 page.

edit: it says: 540 W

Useful to know, thanks - that would be 100mm x 210mm so a pretty big PCB.  I guess you mostly do smaller sized boards though - do you find that it brings the whole pcb upto temperature without a hot spot above the outlet? 

The PCT-100 is 205x155 so slightly bigger. Although it doesn't give dimensions of the heating area it looks to about 2/3rds so approx 135mm; it's also 450W so a little less powerful.

I guess you mostly do smaller sized boards though

Yes. My typical boards are very small. A few cm². Rarely larger than 10 cm².

Not all easy though - 4 layers with copper planes all layers.

The example below is an example with four layers with fill areas on each. QFN IC with a ground plane and a chunky (for SMD) inductor with the pads underneath:

Bigger boards are usually things from someone else I help with (or scrap for practice,  like defect monitor PCBs)

do you find that it brings the whole pcb upto temperature without a hot spot above the outlet?

The spot above the heater is warmer, yes.

But I only wick it up that it is a hotspot if I want it to be a hotspot.

When I let it simmer on 120° for 10 minutes the whole PCB has that temperature.

I'm really talking from a practical point of view, as a user who does not put temperature sensors at the edges. I use experience and the feel you get from trying.

At the start I was nervous about SMD reflow and I thought it was an exact discipline. Ramp up curves, cool down times, right paste.

A friend in the business learned me some practical tips for a reflow oven:

By a second hand little electric kitchen oven. The cheaper the better.

Put the board in. Set on max.

Watch through the window.

See smoke? Open the door. Finished.

That made me laugh!!

That's really useful info, thanks Jan.  Looks like the PCT-100 could be a contender then, I shall keep investigating.

I find myself making more 4-layer boards than 2-layer as they are so cheap and so much easier to route.