[SRT Mike]

I'm sure someone makes something like this... some sort of paint or liquid or gel type stuff that you can put over a screw and if someone removes the screw, the stuff will be disturbed and you will be able to tell.

I'm putting together a part in an aluminum housing and I need to potentially cover warranty issues. I want to be 100% sure that nobody has opened them up and tried to do repairs themselves. I could use something like white out, but it would be too easy to wipe it off and duplicate. I saw UV markers that light up under UV light - maybe that would work? I was thinking something that I could put a dab of it on the screw head and slightly touching the area around the screw, and if the screw were turned, it would crack the compound and maybe change color or do something so that someone could not just scrape it off and re-apply it.

I know they make security screws and I am already using 'em, but I need a little something more.

The screw is steel and the housing is anodized aluminum, so I want it to look OK on different colors of anodized aluminum.

Thanks for any info!

[motomitch1]

A CB shop I use to go to used finger nail paint on the screws and it would chip off if you took the screws out

[Geof]

Use socket head screws and fill the socket with epoxy? Alternatively I have seen labels across the mating parts of housings that say 'warranty void if label removed'. These are also perforated so they tear if you try to take them off.

[SRT Mike]

Use socket head screws and fill the socket with epoxy? Alternatively I have seen labels across the mating parts of housings that say 'warranty void if label removed'. These are also perforated so they tear if you try to take them off.

We used the warranty labels before but they look really ugly. The fingernail polish is not a bad idea, although it probably wouldn't be too hard for the customer to replicate. Epoxy in the holes would maybe work, except it would be a PITA to do, and if one comes back for service, I'd need to be able to get it out.

I may just try some of that UV marker paint pen stuff. I think it's clear and if they don't know its there, they are unlikely to know to try to put it back, and even if they do see it, I'm guessing it looks like clear paint, and if I got one back and put under a UV light, and they had opened one and replaced it with clear paint or nail varnish, I would be able to tell right away.

Any other suggetions are much appreciated! Has anyone used the UV paint? McMaster sells it as "security markers" and it comes in a pen form. Just needs to be brittle enough when dry to crack and crumble when disturbed - wouldn't want it to flake off on its own or stretch and deform and have a customer claim it came off on its own.

[unterhaus]

The first thing I'd ask myself is if I want them back as a customer, and if it's worth making them mad when something fails under warranty. The fact that it fails is not changed by them taking it apart, is it? Do you really have so many failures that this is a big issue?

That being said, I like the stickers that leave a residue that says "void void void void void". Tell them you don't want them to take it apart. I don't see why it being secret helps you in any way, since it's just a game of gotcha, and they may not be happy with you anyway.

Probably the second best thing to do is make it really hard to take apart unless you know how it goes together. Best thing to do is make it so it doesn't fail in the first place.

[SRT Mike]

The first thing I'd ask myself is if I want them back as a customer, and if it's worth making them mad when something fails under warranty. The fact that it fails is not changed by them taking it apart, is it? Do you really have so many failures that this is a big issue?

That being said, I like the stickers that leave a residue that says "void void void void void". Tell them you don't want them to take it apart. I don't see why it being secret helps you in any way, since it's just a game of gotcha, and they may not be happy with you anyway.

Probably the second best thing to do is make it really hard to take apart unless you know how it goes together. Best thing to do is make it so it doesn't fail in the first place.

I can appreciate what you are saying in the 1st paragraph, but this is a product we sell retail to the general public and we sell thousands per year. Inside is electronics. There are clear instructions on how you can and cannot hook it up and if you do not follow them, you can damage the unit. In many situations we have had folks who "know about electronics" try to open the unit (either to attempt repair, or to modify to a task it was not originally designed for) and do more damage. To make something so it does not fail is of course optimal, but unachievable in the real world, so those of us who aren't perfect need to have mechanisms in place to fairly handle the inevitable occasional problem. If, after using tamper proof screws and clear warnings on the case NOT to open it, they still open it, then yes I want to know that and I want to deny warranty coverage or rather we charge them for repair in that case. We spend a lot of time and $$ supporting folks who tried to go the self-repair route and in many cases they deny that they opened the unit. We have been using the "warranty void if removed" stickers with good success, but they don't look so hot. This is a new product that will be in a black anodized aluminum housing and it will be visible to the world, so needs to look good.

Making it really hard to disassemble is one method, but all it does is complicate the manufacturing process and passing increased cost along to all customers to stymie the few who don't play by the rules isn't really fair to me or to everyone else.

I appreciate your response, but I'm really looking for info on some sort of marking paint that will allow me to determine if the unit was opened.

Thanks
Mike

[Geof]

Is there a way to put your 'void' sticker on the inside? I am thinking if you have two parts that are held together by screws during assembly you might be able to hold them at 90 degrees and put the sticker on so it acts like a hinge; then close the assembly and tighten the screws. The chances of someone taking them apart and keeping the sticker intact would be almost nil.

[miljnor]

loctite sells a product that fills in the head of a screw (phillips or hex, something other than flat head). Don't know thet product number as I haven't used it in years.

It forms a hard waxie substance that removes easily enough for warranties but not so easy that you will do it by accident.

And unless they wish to purchase same color and type it is hard to replicate and also leaves behind a slightly waxy residue that keeps "look alike" material from sticking.

Call loctite up and give them your situation and they will tell you what to use.

[keebler303]

If you are selling thousands a year and are trying to stop the "few who don't play by the rules" I would think that few wouldn't mean a whole lot ovr thousands of sales. It would also keep you in good graces with your customers.

A sticker is probably your best option due to the fact that it is visible. If people see a big tamper resistant sticker they are less likely to tamper with it and just send it back after they screw it up.

My $.02

Matt

[SRT Mike]

Is there a way to put your 'void' sticker on the inside? I am thinking if you have two parts that are held together by screws during assembly you might be able to hold them at 90 degrees and put the sticker on so it acts like a hinge; then close the assembly and tighten the screws. The chances of someone taking them apart and keeping the sticker intact would be almost nil.

Hmmm not a bad idea but those stickers do tend to be pretty strong and someone who took the screws out may find that it hinges on one side and opens easily. Not a bad idea though!

[SRT Mike]

If you are selling thousands a year and are trying to stop the "few who don't play by the rules" I would think that few wouldn't mean a whole lot ovr thousands of sales. It would also keep you in good graces with your customers.

A sticker is probably your best option due to the fact that it is visible. If people see a big tamper resistant sticker they are less likely to tamper with it and just send it back after they screw it up.

My $.02

Matt

EDIT: Double post

[SRT Mike]

If you are selling thousands a year and are trying to stop the "few who don't play by the rules" I would think that few wouldn't mean a whole lot ovr thousands of sales. It would also keep you in good graces with your customers.

A sticker is probably your best option due to the fact that it is visible. If people see a big tamper resistant sticker they are less likely to tamper with it and just send it back after they screw it up.

My $.02

Matt

Again I appreciate the input of folks but honestly, without knowing the product, the market, the customers, the quantity of returns we get, the general problems we see, the % of units that are tampered with and claimed not to have been, and on and on and on - how can someone honestly give advice like "its best not to worry about it and not upset your customers".

I can look at our bottom line and directly attribute a real out of pocket cost to people opening and tampering with product. If that was not the case, why would so many products have "warranty void if opened" on them? Check your laptop, your MP3 player, your TV and any other number of devices and you will see this on them all. Not because these manufacturers don't care about upsetting customers, but rather because they manufacture a delicate electronics device that 99.99% of consumers have not a snowballs chance in hell of fixing. Those that ARE capable of fixing it will generally open it anyway knowing they have voided the warranty.

The customers are several levels removed from me. I sell to a wholesaler who sells to distributors who sells to dealers who sells to customers. Its like buying a Sony DVD player... you get it from the local electronics shop who get it from someone who got it from Sony USA who got it from Sony Japan. You see a DVD get stuck and figure you can take the case off and fix it - but in doing so you knock the laser out of alignment... customers box it back up an return it saying "gee I dunno what happened" - happens ALL the time. Trust me, we sell tens of thousands of various products a year and this particular one is thousands a year - we need to cut down on our warranty costs and this is an effective way to do so. Thinking that it all comes out in the wash or that we shouldn't care if people open the unit and try to fix it just doesn't work in the real world, as evidenced by the number of products you will find with such warranty stickers and warnings on them. Sorry if I am coming across as frustrated but we've been in business for years and its not fruitful to discuss alternatives to tamper-evident seals because they just won't work in our situation, and it would take lots of data i wouldn't disclose anyway to 'prove' to folks that this is the best method for us

Put a simpler way, there is *nothing* a customer can do to repair the unit if it goes bad, so there is zero reason for them to try, and a high probability they will cause damage if they do try. I want to discourage such attempts, and also to be fair to customers who are in compliance and return the unit unopened.

[vladdy]

I like the fingernail paint idea, used to use it with a couple of real gaudy contrasting sparkly colours.. figured if the guy spent the time to find identical nail polish, I give him the benfit of the doubt...
The internal 'hinge mount' sticker would probably work fairly well, also the UV paint stripe wouldn't detract from the appearance..
Some assemblers used to use bolts with a step cut just below the head, when tightened down, a little extra twist of the socket would shear it at the step leaving no more than a round bubble knob, not easily removable..
You mention that there is nothing that the end user can do to repair these, I assume you mean 'most' end users...?? unless it's something like getting the smoke back into a programmable gate array or similar firmware..then it's pretty much all....

[HuFlungDung]

Use a left-handed screw where it would not make any sense to use one, and only you would know about it. I don't know if sheet metal screws can be had in left handed form, but if they strip that hole out, you'll know why

[SRT Mike]

I like the fingernail paint idea, used to use it with a couple of real gaudy contrasting sparkly colours.. figured if the guy spent the time to find identical nail polish, I give him the benfit of the doubt...
The internal 'hinge mount' sticker would probably work fairly well, also the UV paint stripe wouldn't detract from the appearance..
Some assemblers used to use bolts with a step cut just below the head, when tightened down, a little extra twist of the socket would shear it at the step leaving no more than a round bubble knob, not easily removable..
You mention that there is nothing that the end user can do to repair these, I assume you mean 'most' end users...?? unless it's something like getting the smoke back into a programmable gate array or similar firmware..then it's pretty much all....

Yeah, it's a CPLD with minimal external components. It deals with relatively high frequency signals at low voltage but reasonably high current. The problem is that the control box is connected to these external components, and many times a user "tries connecting it directly to +12V" which instantly fries an input circuit. I know the obvious answer is to include some sort of protection, but, due to the high current and the way the inputs are connected, it would be very high wattage resistors that would be large and expensive, or you'd be looking at a microcontroller to monitor current sinking in the device and if it exceeds a threshold, to turn it off. So, it's not feasible to try to include some sort of protection for something that shouldn't happen anyway - the same way your car stereo that runs on 12V wouldn't have protection against being connected to the 120VAC wall plug

The problem is, when problems occur, people open 'em up and almost always cause more trouble. Only when the relatively small problem of a fried input filter has blossomed (or festered might be more appropriate) into a fried CPLD when a hack broke out his test light and started "testing" (read: applying 12V) to the 3.3v internals... you'd be surprised how often that happens.

So, the solution is copious warnings NOT to connect anything other than our sensors and display unit to the device, and should it break, not to open it up and try to diagnose it.

Ironically, the reason I don't want people futzing with it is because we're pretty good about warranty coverage... I don't think we've ever turned folks away. But we've been taken advantage of a lot with people causing a fair amount of damage and damaging components that often cost $20-40 each and then saying "oh I dunno, it was like that". Since we're good about warranty, we fix it anyway but it costs $$$$. So having spent thousands of $$ on it, I'm more than happy to help a poor guy who either got unlucky with a bad unit or even helping folks who tried to use the control module with a non-OEM sensor and fried it. I just don't want to keep getting burdened with the cost of fixing the broken expensive stuff under warranty if the customer really messed it up

We're implementing a 3-year warranty on all parts and beyond that, a flat $40 fee to fix anything. Within the 3 years, if the box was opened or tampered with, we still fix it but the $40 fee applies. We're marking serial numbers on the inside of the housing as well as programming production-dates and serial numbers in the firmware, but because we're now going to be charging for non-covered repairs, I need a pretty concrete way to prevent people slipping through the cracks and/or getting free repairs when they aren't covered.

Sorry for the long post, that probably explains a lot more than you asked and why I'm looking to do this... but it's ironic that the reason it's an issue is because we're especially good an accomodating on warranty repairs and the time and costs have been adding up and we're tightening up our procedures and need a way to pretty reliably tell the unit wasn't opened.

I really like the ideas for marking with nail polish/uv paint and that loctite stuff.

[SRT Mike]

Use a left-handed screw where it would not make any sense to use one, and only you would know about it. I don't know if sheet metal screws can be had in left handed form, but if they strip that hole out, you'll know why

You sly devil! Ha! That's a GREAT idea, actually!

[unterhaus]

I'd figure the left hand thread thing out in a heartbeat. There are some security screws that are a real pain to take apart without the correct driver. But in the end, the goop in the screw idea is best. It has the added benefit that you reinforce the idea of not screwing with things.

I took something apart recently that had the goop, and the message was was obvous. It was an older device, and the goop was still quite strong.

[HuFlungDung]

Oh, you would, would you? How about a little bit of red 262 loctite on the same screw, just to make it 'turn resistant'

The red loctite can be be melted (for legit disassembly) by heating the screw with a soldering iron first.

[unterhaus]

you got me :0
Yeah, if there was loctite and left hand threads, I wouldn't bother.

[keebler303]

Ok so you need to have some tamper resistant device. I see your point.

You have a bottom or back side which is not normally seen right?
Why not just put a tamper resistant sticker over a recessed screw so that you can't take out the screw without destroying the sticker.

Maybe some sort of riveted on tag which you could cut off, like what the power company puts on your meter box.

Matt