Hello all,

I might have overdone the polishing on a new pen, it wasn't starting properly, and I thought polishing it a bit would help the situation.
It didn't, and now it starts even harder. After some searching, which I should have done before the polishing, it appears that "baby bottom" shape of the tines could be the problem.
How to go about resolving this?

Regards,

Jarno.

I don't know myself...but between now and when someone shows up with an answer... if you click on Repair Q and A above...and then go to the 2nd of the 3 pinned references.... it has a world of information and may have what you need.

Thanks for the reply.
I have looked through this info (also before posting) but remedying this situation is not mentioned.
Anyone have a clue?
In the meantime, I have used a coarser grit, and this removed the rounds. After this I have done some lighter polishing, some more is needed, but I will take it easy this time.
Hope this is useful.

Regards,

Jarno.

Jarno,

You've got it right. To remove excess baby bottom, you must reshape the nib where it touches the paper and, as you say, "remove the rounds". If you look at John Mottishaw's site, he talks about a nib having a good "foot". This is probably the shape that you're after.

The best pen restoration/repair experience is sometimes gained from our mistakes, followed by careful consideration of how to correct them and avoid them in the future. You've done well!

Have you looked at Wim's article?
http://fp.vandebilt.net/html/ngFPNv102.html

Also, here's a search in this forum on the phrase "baby bottom":
http://tinyurl.com/2j79lp


Hope this helps!


Cheers,
Tom

It is generally agreed that you shouldn't remove the rouded parts entirely, A flat foot will have sharp edges and those will catch on the paper;,you need edges transitioning form the foot to be rounded including the edges between the tines. To sum up you want to decrese the baby's bottom effeft, not eliminate it enrirely. The ink cand bridge a small gap by capillarity, just not a large one.
Good luck.

Thanks for the replies!
Tom, the search for "baby bottom" was a very sensible one. In one of the results a Parker Sonnet was mentioned, which is exactly the pen I'm trying to fix.
By the way, I have seen Wim's article on nib-grinding, and the other on (marcuslink?), I used the info in these to grind a Lamy nib to a stub.

With regard to the baby-bottoming, I am suspecting the type of polishing film that I used to be the cause. It's fiber optics lapping film 1um (not sure which material) and CeriumOxide 0,5um, but both of these are meant to be used wet and have a sort of velvety feel. It seems that these films have a sort of "hairs" which hold the polishing compound and keep the water in place.


Thanks again,

Jarno.

Hi Jarno,

If the baby bottom effect was caused by the mylar, you likely took off too much of the tipping on inner slit edges of the nib.

I normally use the finest mylar to remove the sharpness there, and that is all I do, because a little too much and it will cause the baby bottom effect indeed.

In your case I would only use the 0.5 micron mylar, because IMO, the 1 micron version is too coarse, and will take away too much too fast. Personally, I use 0.3 micron mylar with al-oxide as abrasive. I find there is no difference with the 0.1 micron Cerium-oxide I have, and the al-oxide is softer.

I always recommend to do any polishing on the inside of the tines carefully and very sparingly. It only takes very little to go from scratchy to smooth, and only very little more to go to a baby bottom. Do note that you have to make sure that all of the outer edges of the tipping are smooth enough for you, prior to tackling the inner edges, because it makes it a lot easier to feel the difference for the last steps of the smoothing process, the inter-tine smoothing.

In order to remove a baby bottom, I polish the tip as if I want to smooth it, until the baby bottom is gone. Generally, I do check where the baby bottom occurs, and apply the polishing there most. A baby bottom effect may appear everywhere along the tipping, and is not necessarily limited to the extreme tip. This means that you may experience a baby bottom at 45 degrees writing angle, but not at 60 or 70 degrees of writing angle, or vice versa.

HTH, warm regards, Wim

Hello Wim,

The one thing about the Sonnet that got me started with polishing was that it was a hard starter. I didn't check the nib beforehand, but it probably already had the baby bottom, and I made it worse.
I used 3um film to remove some material and then started polishing again, a bit more careful this time around. Before polishing, I also increased the flow a bit (to get it to start better), but I will have to close it a bit as it is too much right now.
It starts and writes perfectly now, only a bit of polishing to do as it is a bit rough (and too wet).

I'm curious about your 0,1um ceriumoxide film, has it got a velvety texture or is it thin and flat? In your article, you mentioned there is a shop nearby where you live, how is it called (and where is it?)?

Regards,

Jarno

Hi Jarno,

The ceriumoxide mylar I got from the US, and it is thin and flat.

The shop nearby, for me is in Liège, or Luik as you know it . It is the Centre des Abrasifs, and resides in a small industrial centre just north of the city, very close to the motorway. They have a website as well, and they do deliver to the NL, too: http://www.centre-des-abrasifs.com/menu_nl/Menu.htm
Check the "micro-abrasifs" pages, for ILF and MFF.

I see you're in Rosmalen. Since I visit Utrecht reasonably often, maybe we can meet and I can get you some of the stuff, if you like. Just contact me b/c, via PM or email, if you're interested.

Warm regards, Wim

Hello Wim,

That would be great! I'll PM you.

I had a look at the website and they really do have some great stuff, it's just that the m.o.q. (minimum order quantity) is a bit much. I think 25 sheets will be enough for a lifetime right? Or do they sell in smaller quantities as well?
Maybe something for a group buy?

Regards,

Jarno.

I didn't look for a while, but when I go visit them, I just buy what I need. I haven't been there for some time now, though, because last time I did buy about 50 sheets of different grades, and a bunch of other tools, so yes, that'll last a lifetime if you only do your own pens . Even at the rate I use it it wil last me a few years .

Of course, I am in the fortunate position that I live close to the motorway that'll get me there in 15 to 20 minutes .

BTW, it is probably worth giving them a call, they do have a Dutch telephone number listed.

Just checked their conditions, and for shipping they require a minimum order of 50 euros. That is not the case when you buy over the counter.

Warm regards, Wim