# Why is this PTG so cheap?



## myke (May 1, 2011)

So after seeing this thread I was intrigued as to see what exactly the price range was of PTGs. So I stumbled across this one on flea bay:

http://www.ebay.co.uk/itm/DIGITAL-P..._Equipment&hash=item3a6957c257#ht_5014wt_1153

I'm just wondering why it's so cheap compared to the paint detective etc. because I'm not sure what's expected from a PTG exactly I don't know what it doesn't have that it 'needs'.

I'm not looking to buy it because I'm not into correcting at this stage yet, I was just wonderingggg. :speechles


----------



## Bero (Mar 9, 2008)

I guess it's only accurate to the nearest 10microns - BUT for detailing purposes that would work just fine.


----------



## CraigQQ (Jan 20, 2011)

its the accuracy thats the main thing between something like this and the paint detective, aswell as reliability.

personally i dont think + or - 10 microns is accurate enough..

that could be a paint reading of 100 when its really 90.. and at that point i'd be very careful of going below 90 with aggressive polishing..

if i was going to use one of these i would just work as if the paint was 10 microns less than what the guage says.. just incase.


----------



## myke (May 1, 2011)

Ahh, I see, well that answered that, cheers guys!


----------



## james_death (Aug 9, 2010)

Not bad price, if i didnt have the paint detective i think i would go for that.


----------



## myke (May 1, 2011)

james_death said:


> Not bad price, if i didnt have the paint detective i think i would go for that.


I've been slightly swayed towards actually buying one soon by the replies it doesn't seem too bad for the price. I'll just take it as -10um than it actually says, that way I can say safe


----------



## fatdazza (Dec 29, 2010)

You could always buy a set of "calibration discs" to check the accuracy of this cheaper thickness guage.

An online search found some at £25 plus the dreaded VAT.

Be interesting to see how accurate it is


----------



## amiller (Jan 1, 2009)

myke said:


> I've been slightly swayed towards actually buying one soon by the replies it doesn't seem too bad for the price. I'll just take it as -10um than it actually says, that way I can say safe


Hmmm, not sure it works like that. It isnt consitantly 10 microns out, that is the probelm.

For example.

You get a reading of 95, which is really 90. You complete 2 sets and get a reading of 94. This could really be 84 now, so you might never know how much CC you are removing which is the whole point of the PTG in my opinion.


----------



## myke (May 1, 2011)

amiller said:


> Hmmm, not sure it works like that. It isnt consitantly 10 microns out, that is the probelm.
> 
> For example.
> 
> You get a reading of 95, which is really 90. You complete 2 sets and get a reading of 94. This could really be 84 now, so you might never know how much CC you are removing which is the whole point of the PTG in my opinion.


hmm yeah that's true.. are there any alternatives to the paint detective?


----------



## CraigQQ (Jan 20, 2011)

only more expensive alternatives that come close in the accuracy lol..

although i think ive seen a trigger style one thats not as bad as 10um out..
nope.. just checked.. its a tecpel or something but also 10 units out under 200um over 200 its 10 units +3%


----------



## myke (May 1, 2011)

Ah ok, looks like I'll have to get putting my pennies away 8-|


----------



## james_death (Aug 9, 2010)

Get selling some stuff on ebay and put that money away... thats what i tend to do...:lol:

Without someone actually having one of the ones you mentioned we cant compare, and the accuracy is the key.

The paint detective is established and has the backup.

The paint detective can be out by 2.5um.


----------



## Bero (Mar 9, 2008)

CraigQQ said:


> its the accuracy thats the main thing between something like this and the paint detective, aswell as reliability.
> 
> personally i dont think + or - 10 microns is accurate enough..
> 
> ...


If it measured to the nearest 10 microns it should be +- 5 microns. 5 or 10micron of difference should not alter your plan any....paint thicknes can vary by more than that on a panel.


----------



## myke (May 1, 2011)

Bero said:


> If it measured to the nearest 10 microns it should be +- 5 microns. 5 or 10micron of difference should not alter your plan any....paint thicknes can vary by more than that on a panel.


oh yeah, because if it's say 100.4 it'll round it down to 100.

if it's 100.6 it'll round it to 101 won't it?


----------



## CraigQQ (Jan 20, 2011)

i wouldn't go near that one in the OP.. after bero's post i re read it..
and it says the measurements are to the nearest 10microns, basically.

but it doesn't state any accuracy.. so it could be to the nearest 10 microns rounded up or down but also 10 microns +/- in terms of accuracy (which tends to be the norm for cheaper gauges) so could be 85 on the paint and it could read 95.. then round to 100..


----------



## myke (May 1, 2011)

oh.. maybe not then!  don't want it lying to me


----------



## Cosdog (Aug 22, 2011)

Myke,

I recently did an awful lot of searching to see how cheap they were and how cheap I was prepared to go before losing confidence in the readings. Finally, I landed on this one, also from flea-bay:

http://www.ebay.co.uk/itm/CM8828-Ca...deo_TelevisionSetTopBoxes&hash=item3f0dadb9ea

So far I'm very impressed, its both precise and accurate, giving paint thickness to 1micron, and repeatidly giving the same reading on the same spot without fail. Its a bit more expensive, but I have seen the same unit restickered and sold for a good chunk more via retailers.

I thought it best to spend the little extra as I saw it as a learning tool. I found it especially handy trying to learn how much pad and polish combos were taking off with each session, and it manage to give me the answers I was looking for.

Especially on hondas ( a mate lent me an old wing to practice on) and cars with soft laquer I wouldn't feel comfortable without it.

Hope it helps


----------



## CraigQQ (Jan 20, 2011)

cosdog thats a good find tbh..
if not as accurate.. then quite near.. to a pd8

I still bought the pd8 from the group buy.. its an extra £35.. but you get the satisfaction of knowing its durable. and the aftersales if needed.
and they are a uk company. :thumb:


----------



## GrahamKendall (Sep 8, 2009)

These things were being handed out like sweeties by a paint rep when I was in drydock in a shipyard in singapore! If only I had known about them then


----------



## Cosdog (Aug 22, 2011)

GrahamKendall said:


> These things were being handed out like sweeties by a paint rep when I was in drydock in a shipyard in singapore! If only I had known about them then


Ye, you should've bit the rep's arm off


----------



## SteveyG (Apr 1, 2007)

Bero said:


> I guess it's only accurate to the nearest 10microns - BUT for detailing purposes that would work just fine.


Accuracy and resolution are two different things. The specs on the ebay auction only show the resolution.


----------



## tmcc (Sep 4, 2011)

cosdog that seller is like a far-eastern version of iwoot!

Out of interest- what was the customs fee for importing the unit?


----------



## Shredder (Oct 10, 2009)

As already noted, the resolution is low and the accuracy is not stated. The probe is also very large and not integrated into the unit, although some people may not be concerned about that.


----------

