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Not all PCB stock is created equal.

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3v0

Coop Build Coordinator
Forum Supporter
I have been buying my PCB stock from Electronic Goldmine. Up to now I have been quite happy with it. I etched a board on friday using some new DS stock.

The problem is when you do an rework (remove a part) the foil lifts. When I get back to school on monday it is going in the trash. I will post the EG part number so others can advoid it.

I prefer the copper to say put.
 

picbits

Well-Known Member
I've had a bad batch of Photoresist before. Same supplier, same manufaturer but two of the boards had a kind of shadow on them which wouldn't develop or clean off.

Took me a while to convince them that there was a problem but was replaced after a bit of quibbling.

That reminds me - I must whittle down some of my PCB stock - I keep ordering it and putting it away then forgetting its there and ordering more.
 

jpanhalt

Well-Known Member
Most Helpful Member
3v0 said:
The problem is when you do an rework (remove a part) the foil lifts. When I get back to school on monday it is going in the trash. I will post the EG part number so others can advoid it.

I prefer the copper to say put.

True. FR4 comes in various temperature ratings (Tg), which is the glass transition temperature. Here are two references. The first has a nice table of values. Note the low Tg spec. is around 126 to 168 °C. One source states "most" are 150°C, but clearly something with a Tg of only 126°C can meet that spec. too.

John

http://www.rogerscorporation.com/mwu/MICROGRAM ARTICLES/3-00 MicroGram Cust..pdf
http://www.rogerscorporation.com/mwu/pdf/LeadFreeQuestionAnswerDraft4.pdf
 

jpanhalt

Well-Known Member
Most Helpful Member
Could be that too. I have noticed it is easier to pull the copper foil off some FR4 stock than others. However, the references (search on FR4 Tg) make it clear that the Tg of the board is very important in the lifting of traces during soldering and repair. With lead-free solder, it is a particular concern, and we may see much greater availability of high-Tg FR4 in the future. John
 

3v0

Coop Build Coordinator
Forum Supporter
jpanhalt said:
Could be that too. I have noticed it is easier to pull the copper foil off some FR4 stock than others. However, the references (search on FR4 Tg) make it clear that the Tg of the board is very important in the lifting of traces during soldering and repair. With lead-free solder, it is a particular concern, and we may see much greater availability of high-Tg FR4 in the future. John

It is very easy to make cuts across a trace and scrape the copper off this PCB. With other types I have you have to work at it. I am thinking it is the adhesive. Since this stuff is surplus it may have even been a bad batch.

I am used a temperature controlled iron set to 250C.

The base material is off white. The other stock I have are the greenish and the brownish types.
 

HarveyH42

Banned
I've been using goldmines single-sided, cut with scissors stuff for a couple of years without a problem. Re-worked the hell out of an RGB LED board a couple of weeks ago, traces stayed down. I have some really thick board, don't remember where I picked it up, but it's very weak glue. I was using a marker for resist back then, so very thick traces. Pads would lift with the tip of the iron, had to try and slide it off...

I've got some of Goldmine's double sided, but avoid doing doubles. but know I'll have to eventually.
 

3v0

Coop Build Coordinator
Forum Supporter
HarveyH42 said:
I've been using goldmines single-sided, cut with scissors stuff for a couple of years without a problem. Re-worked the hell out of an RGB LED board a couple of weeks ago, traces stayed down. I have some really thick board, don't remember where I picked it up, but it's very weak glue. I was using a marker for resist back then, so very thick traces. Pads would lift with the tip of the iron, had to try and slide it off...

I've got some of Goldmine's double sided, but avoid doing doubles. but know I'll have to eventually.

I like the Goldmine scissor cut for most single sided work.
The bad DS board has what looks like white plastic for a substrate.
 

3v0

Coop Build Coordinator
Forum Supporter
The SKU number for the board is G2626
Detailed Description

Prime double sided copper clad glass epoxy material for making PC boards. Thickness: .032". Size: 4" x 8". G2626
:( Prime :(
It looks like G2628 may be the same stuff.

The good sissor cut SS board is G15698
Thet have better DS stuff but do not have the number at hand. Could be they replaced with the poor stuff.

Should not complain too much it was surplus.
 

mmcmac

New Member
Electronic Goldmine problems

I have been buying my PCB stock from Electronic Goldmine..
The problem is when you do an rework (remove a part) the foil lifts. When I get back to school on monday it is going in the trash. I will post the EG part number so others can advoid it.

Yea, I'd avoid them if at all possible. Not only do they sit on
orders forever despite their false advertising to the contrary. But
when (not if) they ship you defective merchandise the response
from them is "hey, it's all surplus stuff. You get what you get." Nice.

I had the misfortune of having the owner pick up the phone
once when I called to inquire on quantity availability of an item.
He essentially barked at me for expecting them to have quantity
stock of the item (even though it was advertised on their website
in quantity) and went on about how they "buy the remains of
companies going down", and quickly ended the call. Nice.

Their shipping "policy" is equally suspect. You pay a surcharge
over the UPS rate and they don't even pack the purchased
items competently. That winds up as shipping damage and you
get to pick up the phone for another cycle of abuse.
 
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