Hi Gents,
Did some tests to find out the percentage stretch in a number of thread brands. Did 10 tests on madeira, pacbay, gudebrod, mettler and mettler metallic threads. Did a test on 10 different spools of madeira and pacbay. 10 tests on 4 spools of gudebrod. 10 tests on a spool of mettler and 10 on a spool of mettler metallic.
Won't bore you with all the numbers, just the average result. You'll have to trust that I did the math correctly. Results as follows:-

madeira 24%
pac bay 53%
gudebrod 23%
mettler 23%
mettler metallic 44%

Might get some different results with the mettler polysheen and mettler metallic as I've only got one spool of each at the moment. Will do more tests when I get more spools and also strength tests.
Results show that madeira doesn't have as much stretch as I thought, not much different than gudebrod. Pac bay has got by far the most followed by mettler metallic, while the mettler polysheen was similar to gudebrod and madeira. For those using pacbay thread you might want to up the tension to overcome what I'd call excessive stretch.
Robert Guist is doing some breaking strain tests on fish hawk, pro wrap and gudebrod threads and hopefully he can do some stretch tests as well and give a decent comparison through the different brands.

ESFNEM Col
Port Kembla, NSW
Australia

For those interested in the % of stretch in different thread, the "numbers" are probably not boring.

Thanks Col. Did you stretch until it broke and if so what was the breaking strength on each

Hi Brandon,
Used 300 mm of thread and stretched it slowly over a tape measure until it broke and recorded the length then. Did some tests a few month's back so if you do a search you'll find them. Did it on madeira, pac bay and gudebrod. From memory madeira was 1.2kg, pacbay 1.1kg and gudebrod 0.9kg, they were averages of 10 tests on each thread. When I get some more mettler polysheen I'll do some more on that. The one spool that I've got broke at 0.7kg and the mettler metallic at 0.5kg

Hi Craig,
The tab function doesn't work on the forum and if you put a lot of spaces to line up they disappear after posting, makes it a bit difficult to see but I'll do it anyway, gotta keep all you rodbuilders happy!!!

Madeira Original thread length = 300mm
1 370mm 6 380mm
2 340mm 7 330mm
3 370mm 8 375mm
4 380mm 9 395mm
5 380mm 10 395mm

Pac Bay
1 460mm 6 455mm
2 450mm 7 470mm
3 465mm 8 445mm
4 460mm 9 450mm
5 475mm 10 450mm

Gudebrod
1 370mm 6 370mm
2 365mm 7 375mm
3 380mm 8 360mm
4 370mm 9 350mm
5 370mm 10 375mm

Mettler Polysheen
1 370mm 6 375mm
2 360mm 7 380mm
3 370mm 8 370mm
4 365mm 9 375mm
5 360mm 10 380mm

Mettler metallic
1 430mm 6 450mm
2 420mm 7 430mm
3 440mm 8 430mm
4 435mm 9 440mm
5 430mm 10 430mm

I did a fair bit of training in a testing laboratory and techical college so I know a bit about keeping tests as standardised as possible, did that to the best of my ability.

ESFNEM Col
Port Kembla, NSW
Australia

Hello Col.

I have a scale on order and I'm going to check all my threads and make sure I have enough of each type, so it might be 2 weeks or more before I can come up with any numbers. (I still have a day job)

I have your numbers and will use your gudebrod numbers to fine hone my technique till I match or at least come close to matching them.

For your stretch test am I correct in assuming you simply stretch (slowly) the thread over a ruler and mark the breaking point?

The scale I ordered is a "Lyman Electronic Digital Trigger Pull Gauge" and has many usefull features and memory is among them.

Tight Wraps.

Bob,

New Bern, NC.

Hi Bob,
Sounds like you've got a nice modern set of scales coming. My gudebrod is fairly old but has been kept in a box in the dark so it should be ok. The test I did showed gudebrod to have the most variation in breaking strains both spool to spool and on the same spool, you might get something different.
I did my stretch test on a tape measure. Held the spool with the thread on top at the end of the tape and clamped my thumb down on the thread. Wound the tag end around the handle of my burnishing tool ten times and adjusted the length to get the left side of the tool on the 300mm mark. Pulled slowly but steadily until the thread broke. I kept watch on the left side of the tool to get a measurement off the tape. fairly easy and after you done a couple of the same make you get to know when to concentrate on the tool and tape to get a measurement. If any of that doesn't make sense then send me an email and we'll sort it out that way.

ESFNEM Col
Port Kembla, NSW
Australia

Hello Col.

Not needed it sounds pretty much like what I thought it would be.

Thanks
Tight Wraps.

Bob,

New Bern, NC.

G'Day Col I have some Mettler poly thread if you want to test them .Maybe you could bring your testing gadget with you for our SEArb's get together .I've got 1 of those trigger pullers so we could compare results using both

Regards Baz

Bundeena
NSW Australia

Hi Barry,
Good idea, I'll bring my stuff with me and that book with "nothing important" in it will be good for recording.

ESFNEM Col
Port Kembla, NSW
Australia