Mounting new skin - dropping inside of bearin edge - Why is this happening?

[taikonoatama]

I'm new to putting on a new head (starting with a flat disc of cowskin) and I'm not sure what's going on with this Gon Bops quinto. The mounting went fine (yesterday) and I tightened it down to a just a basic sort of snug - not too tight. And as it's starting to dry today and tighten up, the skin is sort of dropping down inside the bearing edge, all around. I know the bearing edge is even all around and across the top, so it's not that. The sound/tightness now is like that of a loosened tumba, though it's tight enough that you wouldn't think it would be dropping down because it's overly loose. Check out the pics. Anyone know what's going on?

Thanks,

Taiko



Edited By taikonoatama on 1160371880

Attachment: http://mycongaplace.com/forum/eng/uploa ... ots_v3.jpg

[Berimbau]

I've seen this happen more than once, it's not uncommon. Just let it dry for another day, then rub the head gently with a damp sponge, just enough to wet it a little, then crank it up a few turns. By the next day it should be ready to tune up to pitch.



Saludos,



Berimbau

[jorge]

When you let the skin dry with the drum standing up, the topside of the skin dries, and shrinks, before the underside of the skin. Depending on the type and thickness of the skin, the humidity, and the temperature, this can cause more or less severe curvature of the skin, like what happened to yours. As Berimbau said, re-wet the top, tighten it some, and let it dry again. It may also help to lay the drum on its side to let the underside of the skin dry faster by ventilating the inside of the drum. You may even find that the underside of the skin is still damp while the topside is dry. Anyway, since it is a quinto, when you tune it up high, it will flatten out pretty much, and as it stretches over time, will become flat.

[taikonoatama]

When you let the skin dry with the drum standing up, the topside of the skin dries, and shrinks, before the underside of the skin. Depending on the type and thickness of the skin, the humidity, and the temperature, this can cause more or less severe curvature of the skin, like what happened to yours.

What you guys have said about the topside drying before the underside and causing this problem makes total sense - hadn't thought of that. The faster shrinking of the top would result in a tension imbalance in the head, and it would bow in this very way - toward the side that's more flexible/looser/wetter/etc. AND, what I think has accentuated this is that I'm here in California and it's been really warm and very, very dry the last couple of days, so the top would have dried much sooner than the bottom.

Thanks! I'll let you know how it goes.

Taiko

[taikonoatama]

Update a week later: I tried wetting the top as advised and drying it on its side, but I think the whole thing had just dried out too much by this point because it really didn't work. So next I took the skin and crown off and soaked them (together) for 5 hours and put it on again, but this time I put the drum upside down in a conga stand, with a damp towel loosely draped over the hole in the stand before putting the conga in. This was an attempt to keep a more humid environment on the top side of the head while still allowing it to dry. Redampened the towel every day for 3 days. Seems to have done the trick, as it dried perfectly flat over about 5 days total.

The differing drying rates, top and bottom of the head, really seemed to be the issue here. Thanks guys.

[jorge]

Glad you were able to make it work. How does it sound?

[Diceman]

For the next one you mount, try a little trick I picked up on this forum. After monting the wet skin on the drum, flip it over and place it skin down on a plastic bin liner and leave for two or three days. This slows down the drying of the head and encourages the drying of the skin round the flesh hoop without any pulling before it dries.
Any ripples around the angled part of the skin will disappear when you finally tighten up.

My two mules

Diceman

[franc]

guys,
i have mounted many skins heads. if the skins are wet in the pictures? the conclusion that i arrived to is the ''taiko'' cut the excess skin at the outside rim level. i always do my cutting at the level of the top of the heads . the outside rim i will leave about 1/2 an inch to 3/4 inch bellow the top of the head. like i said will always cut the excess at the head level. as you know the skins while drying will tighten up and will lower itself. also will lower them self when you tighten when completely and totally dry. just my ''two clave bars'' my best to all and ache ''siempre''!!!! franc