Warped blank records

[Obz15]

Hi all!

I have a question if someone has the same problems with recently purchased blank records.

Recently I purchased 200 black blank records from Souri. I Immediately noticed that they were warped pretty hard. After many tests with less heat, more heath, leaving them horizontal on the flat surface and so on, but nothing helps.

Ofc there is no problem when I record the first side which is always OK. but when I try to record the second side the record just won't flaten and there is no chance to record it because it jumps so hard.

I wrote to Souir and told him the problems I have. I even sent him dozens of photos and video. His response was that I am the first with this problem and that he checked the records he has and noticed slight warp but nothing unrecordable.

After a few days I received another email which was no doubt sent to all his customers about "summer records" and how to flatten them. I just think that is just a bad product/series, because I didn't have any problems with the blanks since 2017 on.

Is there a way to flatten them properly because for me it seems that nothing works?

Does MyShank have the same "summer records" problem?

What is the biggest difference between the Souris and MyShank records? Is the sound and longevity of the records about the same?

I added a few photos and a video.

Thank you for all your help and answers!

Kind regards,
Obz

[PMST]

This might sound obvious, so please excuse me if you tried this already, but now and again if a blank is warped i just head one side, flip it, heat the other until flat, flip it again. If it's really warped, after a few flips its usually sorted. This has worked with many warped records for me, although i am using precision platters which help heat the blanks evenly.

[PMST]

Also i find getting blanks flat is way better using a single 100w Infrared bulb. I haven't used the 2 stock lamps for a well over a year and it's a massive improvement in terms of heating the blanks evenly, which in turn helps warped blanks to flatten.

[Obz15]

Thank you for your answer!

I tried flipping but it didn't help. One side is always warped. I don't know what to do with those records because nothing works.

My friend will make me like a rostfrei ring to sit on the edge of the records to help push down the warped side. I really hope that that will work because otherwise I don't know what to do with those records.

Will definitely try an infrared bulb, thanks.

[PMST]

Yeah the bulb is a huge improvement for sure! Well worth getting, it evenly heats the blank which is a good starting point.

[David34]

I purchased a propagation heat mat, which is flat and heats to around 30c. Put a stack of discs on top of each other, eg: 20 disc pile.

Best of luck, mine are a little warped but straighten out ok. I ONLY purchase the 2mm discs now as I wasn't happy with the 1.5mm.

[tragwag]

I've dealt with this same issue over the years a bunch, haven't found a tried and true solution.
heating them back up much takes A LOT of time when every blank has a slight warp. but especially on one of my lathes, a slight warp causes chip drop every time.
putting them under the weight of the whole pile hasn't helped me either, and it's the solution I've heard more commonly from blank suppliers.

interesting to hear about the heat propagation mat! I think I'll try that

[Obz15]

In 95% I use 2mm blanks.

Thanks for your suggestions fellas! I will definitely try them all. I will inform you how that "ring" will work as well.

[Dub Studio]

Using the precision platter is a good start. It is slightly concave, and helps to temporarily dish the record and even out the warping in a lot of cases (but not all, the shorter the warp, the harder it is to flatten).

Using a ring of rubber works well too, it increases the "concaviness" (is that a word?) of the platter. You will need to tilt the turntable up a little on the left hand side tho. I have 4 different rings, 14, 12, 10 and 7 and swap them out as and when I need them.

[Obz15]

Do you have any picture of the rubber rings? I tried with aluminium ring that sits at the edge of the records (1mm on the edge) it fits nicely but its not heavy enough (50 grams) to flatten the the record.

I add a few pictures so you can see the aluminium ring.

[trailerparkjesus]

Interesting about the ring solution! We get records like that too and it is what it is, my 2 cents...try to use them or scrap them and move on. Our suppliers are pretty rigid when it comes to guarantees or refunds, but it's better to have mostly good records than no records at all!

[discosdecorte]

I purchased a propagation heat mat, which is flat and heats to around 30c. Put a stack of discs on top of each other, eg: 20 disc pile.

I've tried the propagation mat trick (thanks @David34!) and it kind of works with the most warped blanks, at least with the 1.5mm transparent ones I use.

But the real game changer for me was the new 2mm neoprene mat I ordered to number1gasketshop. It is perfectly flat, top quality product, highly recommended!

Best regards,
Fer

[Discomo]

Actually I never had this problem. Apparently strange if I read all these comments. Of course sometimes there is a warped blank, but it flattens perfectly when I put it on the warm cuttingtable. I use 2mm blanks, heating with the two Souri lamps and between 40-50 degrees C.

[Dub Studio]

Do you have any picture of the rubber rings? I tried with aluminium ring that sits at the edge of the records (1mm on the edge) it fits nicely but its not heavy enough (50 grams) to flatten the the record.

I add a few pictures so you can see the aluminium ring.

I don't have any photos handy, but I just used some rubber sheet and cut around a disc of each size. The thickness of the rubber sheet is about 1.2mm, and the width is about 7 or 8mm. I also use a small disc of plastic in the centre that is about 0.6mm in thickness, so I guess the overall increase in the slope is about 0.6mm.

[Obz15]

I purchased a propagation heat mat, which is flat and heats to around 30c. Put a stack of discs on top of each other, eg: 20 disc pile.

I've tried the propagation mat trick (thanks @David34!) and it kind of works with the most warped blanks, at least with the 1.5mm transparent ones I use.

But the real game changer for me was the new 2mm neoprene mat I ordered to number1gasketshop. It is perfectly flat, top quality product, highly recommended!

Best regards,
Fer

Thanks, I will definatelly try them both. I am using cork and nitrile rubber mix mat 1,5mm thick from audio anatomy.

[Obz15]

Actually I never had this problem. Apparently strange if I read all these comments. Of course sometimes there is a warped blank, but it flattens perfectly when I put it on the warm cuttingtable. I use 2mm blanks, heating with the two Souri lamps and between 40-50 degrees C.

I didn't have those kind of problems as well but it seems that these discs were badly stored and they warped so hard that they wont flatten. Or there is like a inner tension in material, so one side won't flatten without physical assistance.

I will buy propagation heat mat and neoprene mat that David34 and fprado1978 suggested.