solder bridge connections on perfboards - Page 1
Forum section: electronics / beginners

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: August 23, 2016, 01:44:20 pm
content: How do you manage to connect close holes by solder bridges on perfboards ?I am using thosehttp://www.ebay.com/itm/2PCS-Double-Side-Prototype-PCB-Tinned-Universal-Breadboard-5x7-cm-50mmx70mm-FR4-/251899506036?hash=item3aa6616d74:g:r2gAAOSwEeFVGqxlWhen I try to connect nearby holes by solder bridge, the solder just flow through the holeand make a big blob beneath without connecting the holes.Are these holes too large ?Is the solder too liquid, the iron too hot ?What is your experience on this problem ?Thanks

author: RobertHolcombe
author_rank: Frequent Contributor
timestamp: August 23, 2016, 01:51:58 pm
content: It is easier to achieve with non-plated holes since the solder will stay on one side, but even that can be frustrating because the solder tends to remain in two or more separate balls. You could try blocking the bottom side of the holes with kapton tape?For joining any more than 3 pads in a row I use solid core wire as a jumper, makes the job trivial.

author: bingo600
author_rank: Super Contributor
timestamp: August 23, 2016, 01:57:41 pm
content: I usually use the "cutoff" from some through hole components as the "bridge"/Bingo

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: August 23, 2016, 02:54:37 pm
content: Quote from: bingo600 on August 23, 2016, 01:57:41 pmThis is what I usually end up doing, but after some time doing that I had the feeling that thiswas very amateurish, and wanted to know if there was a professional, very clean and fast way to do it.This is why I made this post.@RobertHolcombe : kapton is an idea, but in my case not easy as the area is quite populated.

author: tszaboo
author_rank: Super Contributor
timestamp: August 23, 2016, 03:02:28 pm
content: I use wire wrap wire or Kynar wire to make the connections which are far away, leads which are close. If you dont like doing those, buy perfboards which have the connections already made, and there is a tool to cut it, professionally.

author: klunkerbus
author_rank: Unknown
timestamp: August 23, 2016, 03:14:37 pm
content: Look for boards with square pads. They're much harder to find, but the square pads allow bridging between pads with just solder. As you are finding, bridging with just solder is tough to do with round pads.

author: MosherIV
author_rank: Super Contributor
timestamp: August 23, 2016, 03:38:21 pm
content: QuoteTry bridging the gap with a bit of wire.I know you are suppose to be able to do it with just solder but if that does not work, just use a piece of cut off lead from a component or bend the lead of component before cutting the lead.

author: mikerj
author_rank: Super Contributor
timestamp: August 23, 2016, 08:00:21 pm
content: The secret to bridging a gap with solder is to remove the iron from the joint before you remove the solder. If you just pile on solder it almost never works.

author: jkf1000
author_rank: Regular Contributor
timestamp: August 23, 2016, 10:56:30 pm
content: Have you considered using the leads of the components your are fitting to bridge over the pads? Its a method I use a lot and it makes for a very neat finish when working from point to point. Karl

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: August 24, 2016, 10:38:53 am
content: Quote from: jkf1000 on August 23, 2016, 10:56:30 pmYes, this is what I have been doing so far (as in the attached example), but when a few connections remains, it would be nice to make solder bridges, andthis was the purpose of my post (solder bridges without supporting wires).A big problem when you use the components leads to make the bridges is when you have to change a component. This end upwith some kind of war surgery that you usually want to avoid.From the above posts, I retain :- Use single side board (RobertHolcombe)- Use boards with square pads (klunkerbus)and the less intuitive but which I will try on my two sided boards :Quote from: mikerj on August 23, 2016, 08:00:21 pmThanks for these advices. I am looking forward other good recipes for making solder bridges WITHOUT the support of leads.

author: plazma
author_rank: Frequent Contributor
timestamp: August 24, 2016, 10:58:07 am
content: On double sided 0.05" pitch perfboard solder bridges work just fine. The 0.05" pitch version is great for SOIC and 0603 components. With DIL chips it works also fine. You can have solder bridge tracks between DIL pins.http://plazma.kapsi.fi/pictures/temp/1.27mm_proto_board.jpg

author: lem_ix
author_rank: Regular Contributor
timestamp: August 24, 2016, 12:22:23 pm
content: In my experience using less solder then what I've seen on your pics gave better results. Now I mostly solder everything and use wires only when I really need to.

author: mariush
author_rank: Super Contributor
timestamp: August 24, 2016, 06:24:06 pm
content: Using more flux would help in making solder bridges.Good quality 63/37 solder would also help a lot as it solidifies instantly once the temperature goes down below 183c (it's eutectic, unlike 60/40 or lead free solder) so you just pull out the solder iron from the solder and it hardens quickly.Thinner solder wire would also help to get just the right amount of solder in.Seehttps://en.wikipedia.org/wiki/Solderif you want to learn more about solder types (eutectic vs normal solder)

author: Cubdriver
author_rank: Unknown
timestamp: August 24, 2016, 07:30:08 pm
content: I've always found that the best way to get solder bridges to form is to NOT want them. Then you'll get them right and left.When working with perfboard like that I too use cut off leads to bridge the pads and make up my 'traces'. I also tend to (once all the parts are in place) solder the entire length of the bare wire to the pads it's resting on. IMO it makes for a neater appearance, and also prevents the wires from shifting and making contact with neighboring things that they shouldn't or getting snagged by things getting between them and the board.-Pat

author: mauroh
author_rank: Frequent Contributor
timestamp: August 24, 2016, 08:19:08 pm
content: I don't like this method, but when I need it I found crucial the temperature of the soldering iron.The lower the better!! If the temperature is too high the solder bridge will follow the soldering iron.If the temperature is low enough you will be able to melt just one side of the ball and make another one that will easily stick to the next pad adding a bit of fresh solder.With a bit of practice you will make bridges with just a little of solder.Mauro

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: August 24, 2016, 09:07:33 pm
content: Thanks for this one.Maybe this was my problem. My iron was probably too hot.

author: mariush
author_rank: Super Contributor
timestamp: August 24, 2016, 09:24:23 pm
content: If your soldering iron is too hot, you're burning up the flux contained inside the solder too fast, therefore the copper pads will remain somewhat oxidized or dirty and your solder will move around. Flux is the key to proper soldering.That's why I suggested separate liquid flux... flux pens are expensive considering they have only about 10ml, you can find separate no clean flux in 100ml or 250ml or 500ml at some stores and just put some in syringe and put a drop on the board when needed.Just wet the surface with flux before trying to make bridges, as you heat the copper pads with your iron tip the flux will activate and do its job and then the flux inside the actual solder will also contribute to a good job.PS. If you're in Europe, you can buy stuff from TME.eu , it's a good Polish company. I'm using flux they have in stock, made by a Polish company called AG Thermopasty. It's cheap and good and available in lots of quantities at very decent prices:http://www.tme.eu/en/katalog/#id_category=100484&page=1&s_field=artykul&s_order=ASCSelect AG Thermopasty from manufacturers, select liquid and/or gel and/or paste at appearance and go with No-Clean or halide free or RMA (rosin mildly activated) or non-corrosive (probably another name for no-clean) .. stay away from water soluble fluxes as they're often hard to clean. no-clean and most halide free and sometimes rma can be simply left on the board after soldering as the acids in the flux won't do damage. RMA fluxes sometimes have to be cleaned with a bit of isopropyl alcohol on a wipe, and you can do the same cleaning with isopropyl alcohol for other fluxes as well if you like clean (or not slightly sticky) boards.

author: wraper
author_rank: Unknown
timestamp: August 24, 2016, 11:00:46 pm
content: Try soldering faster. First apply enough solder to fill the holes, let them cool down a little bit. Then rapidly make a solder bridge using additional solder before the solder on the other side of the hole becomes liquid.

author: edavid
author_rank: Super Contributor
timestamp: August 24, 2016, 11:24:53 pm
content: Quote from: plazma on August 24, 2016, 10:58:07 amWhere do you buy that?

author: KL27x
author_rank: Super Contributor
timestamp: August 25, 2016, 12:17:40 am
content: I buy the 500/1000 foot reels of 30AWG kynar wire. Endless uses for prototyping. Strips in a flash for use as bare bus wire. Wraps easily over square leads or header pins. I don't even use jumper wires on breadboards, anymore. I stick extra long pin headers into the breadboard and wire wrap the connections. No more putting away and trying to find the right jumper wires. Just throw them away. Totally disposable.

author: nanofrog
author_rank: Super Contributor
timestamp: August 25, 2016, 12:20:03 am
content: Quote from: edavid on August 24, 2016, 11:24:53 pmFound a couple on Aliexpress (had to search1.27mm pitchto find these).6x8cm, 1.27mm pitch double sided, Q = 3 pieces9x15cm, 1.27mm pitch, double sided, Q = 1 pieceEbay search.FWIW, I also buy Kynar 30AWG in 1000ft rolls as well for the same reasons asKL27x. My perfboards are all .0100"/2.54mm pitch, and I add IC's via SMD -> DIP boards. Rather easy to do, and using the 30AWG Kynar as bus wire isn't that big of an issue.

author: KL27x
author_rank: Super Contributor
timestamp: August 25, 2016, 12:22:34 am
content: I find 0.05" veroboard without holes to be very useful. Make it myself, doublesided. but 99% of the time I'm only using 1 side. I'm not convinced you are going to use thru holes and/or the other side very often when prototyping with SMD parts.

author: ez24
author_rank: Super Contributor
timestamp: August 25, 2016, 12:35:35 am
content: Any thoughts on this onehttps://www.aliexpress.com/item/1pc-DIY-Prototype-PCB-Universal-Matrix-Circuit-Board-Breadboard-8-5x20cm-85x20mm-Top-Sale/32579073250.html?spm=2114.01010208.3.201.xUuscI&ws_ab_test=searchweb201556_0,searchweb201602_4_10057_10056_10065_10037_10055_10054_301_10059_10033_10058_10032_10017_107_10060_10061_10052_414_10062_10053_10050_10051,searchweb201603_9&btsid=505dc240-2076-43d5-bacb-216201ad7af5searching on this "prototype circuit board" brings up over 1300 hits with different types like the above one

author: nanofrog
author_rank: Super Contributor
timestamp: August 25, 2016, 12:45:37 am
content: Quote from: KL27x on August 25, 2016, 12:22:34 amQuite true.I've not really seen anything COTS that really would fit the bill as nicely as I'd like, but perhaps there's something out there (suggestions welcome).But I have managed to find0805 0603 0402 to DIP Adapterboards. And they're rather cheap. So combining them with SMD->DIP breakout boards is doable for SMD prototyping without having to make your own/send a board design to a cheap board house (i.e. no need to wait for your boards to show up).Despite the fact SMD components are cheaper than their leaded counterparts however, it's probably a wash at best cost wise.Quote from: ez24 on August 25, 2016, 12:35:35 amIt looks a bit interesting, particularly regarding the bus strips.

author: zapta
author_rank: Super Contributor
timestamp: August 25, 2016, 01:29:21 am
content: Quote from: KL27x on August 25, 2016, 12:17:40 amInstead of the headers and 30AWG you can use 24AWG kynar directly. They fit nicely into the solderless breadboard and thinner insulation makes the circuit look more tidy.

author: KL27x
author_rank: Super Contributor
timestamp: August 25, 2016, 02:22:14 am
content: Instead of the headers and 30AWG you can use 24AWG kynar directly. They fit nicely into the solderless breadboard and thinner insulation makes the circuit look more tidy.Thx. I will try that. I used to use the regular 22-24AWG with PVC insulation. Worked ok, just too much spaghetti. Wires falling out when you tried to add more or change them. I have never even used 24AWG kynar... which as much I love my 30 and 28 AWG, I really should try.

author: nanofrog
author_rank: Super Contributor
timestamp: August 25, 2016, 03:59:52 am
content: Quote from: zapta on August 25, 2016, 01:29:21 amI'd love to get 24AWG Kynar (or even 26AWG), but have had issues finding it without having to spend a small fortune (either serious bulk, or OK Industries ~ $25 - $30 per 100ft roll). I say this as I'm frugal, but also would like to have a few colors to differentiate between power, ground, and data for example without pushing ~$75 - $100 for 3 rolls of thin wire (I can get larger gauge hook-wire/automotive wire cheaper than that for 100ft rolls).So if you have any sources for larger gauge Kynar at reasonable prices (26 or 24AWG), it would truly be appreciated. TIA.

author: plazma
author_rank: Frequent Contributor
timestamp: August 25, 2016, 05:06:48 am
content: Quote from: edavid on August 24, 2016, 11:24:53 pmI have twice ordered from this seller:http://www.aliexpress.com/item/Universal-Double-Side-Board-DIY-Prototype-Paper-PCB-9x15cm-1-6mm-1-27mm/32399078539.htmlThe first time I ordered from an other seller. I got two 0.1" pitch boards for free instead because they had to refund me for the wrong product.

author: batteksystem
author_rank: Regular Contributor
timestamp: August 25, 2016, 05:28:58 am
content: Quote from: JacquesBBB on August 23, 2016, 01:44:20 pmBy the look, I think the pad size is too small to hold a bridge, instead using the cut-off lead from resistor as "backbone" for a solid solder connection.

author: KL27x
author_rank: Super Contributor
timestamp: August 25, 2016, 07:43:31 am
content: @NanofrogRegarding huge rolls of 30AWG wrapping wire:http://www.ebay.com/itm/30-AWG-KYNAR-wire-wrap-30-gauge-Kynar-500-feet-of-any-color-/200406828268?hash=item2ea92d84ec:g:qlsAAOSwB4NW1aUaI have been buying 1000ft rolls from this seller for the last decade. (So like 3 times, lol. They last a long time). The 1000 ft rolls are like 55.00 shipped, but it looks like they are temporarily out of stock. So this is the 500 ft reel. The sender address on the package is Wes Bel. A lot of my Mouser stuff is drop shipped from Wes Bel. Just something I noticed.http://www.ebay.com/itm/30-AWG-Appliance-Wrapping-Wire-1000Ft-Silver-Plated-Copper-Wrap-Strip-Reel-Kynar-/121566620358?hash=item1c4def6ac6:g:muEAAOSwe-FU2V6nI tried this, more recently. 1000ft for 22 bucks, delivered. This is measuring almost 31 gauge, slightly thin. But it wraps and works fine. Note this is meant for wire wrap bits which automatically cut and strip. So it feels a little slippery and the insulation breaks really easily. The insulation is also thinner in OD, which is good. You can strip this stuff with your fingernails. I don't like the slippery feel... but it's fine, really.https://www.walmart.com/ip/1000Ft-305M-0-25mm-Tin-Plated-Copper-Wire-Wrapping-Wire-Cable-30AWG-Yellow/180996750?action=product_interest&action_type=title&item_id=180996750&placement_id=irs-106-t1&strategy=SMT&visitor_id&category=&client_guid=5c25131b-28fe-43ba-a2b3-106acdae9fd1&customer_id_enc&config_id=106&parent_item_id=191395889&parent_anchor_item_id=191395889&guid=23d9bc3f-bfbf-4706-bf86-845b6c25ef72&bucket_id=irsbucketdefault&beacon_version=1.0.1&findingMethod=p13nI noticed this while browsing eBay. No clue if this is legit. 1000 ft roll. $13.43. From Walmart?

author: KL27x
author_rank: Super Contributor
timestamp: August 25, 2016, 08:05:49 am
content: Two colors usually gets me by. Here's how I use it. Wire dispensers and my PCB rework tool with wire stripper. I use this stuff like it's FREE!Bonus: when I use the wire-cutter built into my DIY dispensers, the wire stretches just a tad, or something. The insulation retracts a little, leaving the freshly cut end ready to solder.If I'm doing a lot of point-to-point, I will feed the wire directly from the big reel, stripping as I go, cutting the wire with my rework chisel-tool only after soldering both ends of the jumper.Here's what I've been working on the last couple of days. An example of using wire wrapping on a breadboard. Not the neatest job, but this will be going into the garbage as soon as I'm done with it.I also have been playing with a new way to use bare copper clad, if u see the too of the IC plugged into the right side of the breadboard. I put some pullups and indicator LEDs right onto the top of the IC. Acid etching it keeps the solder from sticking. So after you mechanically engrave the board to isolate tracks, you can scrape a little dot here and there to get a small bead of solder to stick without it flowing all over the board in huge globs.

author: nanofrog
author_rank: Super Contributor
timestamp: August 25, 2016, 08:29:29 am
content: Quote from: KL27x on August 25, 2016, 07:43:31 amThanks.I already have plenty of 30AWG Kynar from an Asian source (eBay), that IIRC, I paid ~7 - $8 for shipped (1000ft/305m roll). I'm after heavier gauge if I can get it at a reasonable price. Unfortunately, what I've come across is typically OK Industries/Jonard, which quite a bit more expensive, and only comes in 100ft rolls (i.e. ~$25 - $30 per roll). Sometimes remnants show up cheaper, but it's rather uncommon IME.So thus far, I've had to resort to straightening out CAT5e cable as best I can (26AWG), and it's a total PITA.Which is why I'd love to find a more economical source of 28, 26, or even 24AWG Kynar.BTW, interesting strip & cutting tool (RadioShack P/N?). Closest I can find to that type, is an OK Industries/Jonard ST-100 (ST100-2830= version for 28 & 30AWG). I've a Pressmaster Embla, and the standard cartridge can go down to 32AWG (PTFE/Tefzel cartridge only goes down to 28AWG). Neither are anywhere near as convenient to what you're using though, as I have to grab 2 tools to do such a simple task, and I can't slide the insulation back as easily. So I have to cut & strip frequently.Only thing worse, is using CAT5e cable (add straightening aspect).The larger gauge does make for better power & ground IME though, so I've dealt with it thus far. But as mentioned, if I can find a reasonably economical method to save that much aggravation, I'll be all over it.

author: KL27x
author_rank: Super Contributor
timestamp: August 25, 2016, 08:37:20 am
content: Yeah, it's the strip tool out of a Rat Shack wirewrap tool. I ground out a notch in it and soldered it to the end of my little chisel tool (hex bar Chromium Vanadium tool steel; holds a good edge!) with electrical solder. I found out the pot metal melts at around the temp of brazing solder!The advantage of this kind of stripper tool is that you can strip the wire in the middle. With the adjustable type, you would have to cut the wire, first. Then strip the free end. With this tool, you tack one end of the jumper, lay the wire over the second solder point, then strip it there, exposing a little bit of wire. Then you can hold the wire over that point and solder it without ever having to let go the wire, turn the circuit 180 degrees, and reacquire the free end with tweezers for each joint.Yikes, I had no idea I was overpaying so much for wire. I will have to shop better... in 5 years from now, lol. Sitting on two reels ATM.Re jonard: I got that tool. It's HUGE. Too big to maneuver while soldering. It looks more like a gardening tool. But I have made a small strip tool using it. Will post a pic, in a bit. I think you might have seen it before, because I made a post about it like 9 months ago.I took out the blade and cut it with tin ships. Then expoxied it to the end of a bar of tool steel, as shown. So I could make a 28 and 26 gauge stripper with the Rat Shack form factor. I have a 24 gauge blade, too, which I will have to make a new tool if I start buying reels of 24AWG. JB weld. Holding fine.

author: nanofrog
author_rank: Super Contributor
timestamp: August 25, 2016, 09:01:33 am
content: Quote from: KL27x on August 25, 2016, 08:37:20 amFWIW, I've not seen one of the RadioShack tools in many years. Jonard's stripers use a notched blade just as the RadioShack versions (usually 2, one for each of the rated wire sizes, though there are singles IIRC), and they do sell replacement blades. It should be possible to DIY something similar to what you have though, using one of Jonard's blades & a chisel or other sharp horizontal blade. Just not bothered digging into it any deeper, though I probably should.As per buying 30AWG Kynar, both eBay and Amazon are very inexpensive (i.e. under $5 before shipping), and if your vendor uses Amazon to fulfill orders, shipping is free if you meet the required sales total. Would make a nice filler item next time you buy from Amazon, should you need such a thing.

author: KL27x
author_rank: Super Contributor
timestamp: August 25, 2016, 09:08:22 am
content: Yep. See my last edited post. Yeah, it's too bad about the tool being discontinued. The original "made in Japan" Radio Shack tools gives the best modified wire wrap out of all the ones I have used. Some of the others will wind the wire back over itself if you're not careful. There's a very similar version made in Israel, sold on eBay, last I checked. It is not the same quality.*Correction. My Israeli made wire wrap tool is fine. I mixed it up with the later production Radio Shack tools, which are the ones that allow the wire to wrap over itself.

author: nanofrog
author_rank: Super Contributor
timestamp: August 25, 2016, 09:27:05 am
content: Quote from: KL27x on August 25, 2016, 09:08:22 amSo you are the one I pointed to regarding the Jonard/OK Industries blade.I'll have to remember to figure out a way to DIY something along those lines myself (starting with nothing). I've the tooling to solder, braze, or rivet with.

author: KL27x
author_rank: Super Contributor
timestamp: August 25, 2016, 09:35:21 am
content: QuoteThat's right. Thanks. As you can see, it worked great.Hmm. I don't think I'm going to bother with 24AWG for breadboarding, afterall. When I use pin headers like in my previous post/pic, I never use a single pin header, even when I'm connecting one point. I always use a section of 2 or more pins. That way, they stick better in the board and don't wiggle or fall out. The pins also give a place to hook a scope probe, ICSP cable, etc. Individual wires are just too unreliable in a jumbled mess of spaghetti, since they become tree trunks, totally stiff; when they start piling up and you need to move one out of the mess, all bets are off.Yeah, there is a reason I ended up here. I just temporarily forgot. Also, in the last couple days, I am reminded how you can easily twist 30AWG into twisted pairs if your signal gets wonky. And when you need to plug unplug 2 or more connections together over and over, you can put them on a pin header. And connection to logic analyzer, etc... 30AWG is indispensable to me.

author: zapta
author_rank: Super Contributor
timestamp: August 25, 2016, 02:41:07 pm
content: Quote from: nanofrog on August 25, 2016, 03:59:52 amI am using the OK industries 24AWG 100 feet roll. No cheap source, paid $20+. I like the thin insulation. It takes less space, bends better and looks better. Most of my circuits are non solderless so it should last me for some time.As for colors, everybody knows that kynar wire with color other than blue is an abomination, just the same as non red Ferraris.

author: nanofrog
author_rank: Super Contributor
timestamp: August 25, 2016, 03:20:32 pm
content: Quote from: zapta on August 25, 2016, 02:41:07 pmLooks like I'll have to break down and buy some then.Just spent a wad at Zoro (30% off), and am seriously looking to get a larger monitor. So the rest of my budget is on lock-down.As it happens, my 30AWG roll isblue.Figured I'd stick with blue for data, and likelygo fasterredfor power &blackfor ground (in hopes it will be slightly easier to diagnose issues).

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: August 25, 2016, 04:09:52 pm
content: IT WORKS !!Quote from: mikerj on August 23, 2016, 08:00:21 pmQuote from: mauroh on August 24, 2016, 08:19:08 pmI combined these two advices and it worked.I decreased the iron temperature to 180 degC (instead of 350). Leaving the solder wire helps probably to cool the solder and prevent it from flooding beneath.I understand that these perfboards are not the best to do solder bridges, as the pads are small and they are double sidedwith tined holes, but if I could do it on these, I am now confident I could more easily do these solder bridges with singleside boards.From all the above discussion, I understand also that using thin wires is a good solution, but my present challenge was these solder bridges.

author: KL27x
author_rank: Super Contributor
timestamp: August 25, 2016, 07:27:30 pm
content: ^ Awesome. Now buy an extra couple pounds of solder. You'll need it, lol.QuoteNoooooo! Green. It has to be green. Green is the standard color of soldermask, but it is bright and still easy to see without busying up the pcb. Green is the color of money. Green is the color of ground. Green is the color of data. Green is the color of circuits!I tried being hip. A lot of people are using blue soldermask, now. My last reel was blue. 3 years of suffering that eye sore, I'm happy to be square, again.Black looks like sewing thread. And it's hard to see. You have 2 or more tiny black wires running together, and you need GOOD lighting to know which ones are which, at a glance. I will never buy black 30AWG, again.

author: oldway
author_rank: Super Contributor
timestamp: August 25, 2016, 07:51:13 pm
content: Make your own testboards like this:

author: tooki
author_rank: Super Contributor
timestamp: August 28, 2016, 11:06:25 am
content: Quote from: ez24 on August 25, 2016, 12:35:35 amI like working with that layout, but the build quality of these boards is fairly poor. The etching is imprecise (I had to Dremel away a few bridges between tracks) and they also missed a few drill holes. They were also not entirely flat (but bendy enough to flatten by weighing down). And since they're not tinned, the copper may corrode faster. (When I got my shipment of those, I cleaned them and then gave them a protective coating of rosin flux.)