ChrisF.
I concur
We all use different methods depending on conditions and circumstances.
What works for one may not work for another but we alll achieve a common goal…..that of a functioning personal build.
Regards Bill.

Doug

I think it is somewhat easier to hold balsa in place rather than ply! From my post I think that you can see that I use all the other methods for "clamping" as well and I do steam and it was only as a last resort that I used screws, which aren't brass, are cheap and reusable. It's no trouble filling and sanding the holes afterwards and the whole hull is then covered with lightweight cloth and Eze-Kote before painting. You shouldn't criticise other modellers because they use different methods. We all have a lot of common ground when building but we also have our own methods and if they work, why not?

I achieve what I set out to do and will continue to use screws when necessary, I think their use is a perfectly acceptable way of holding things in place. I'm not advocating their use in all cases. The OP asked, which screws, and I answered him, unlike others who are telling him he is doing it wrong. Alternatives offered are fine they aren't the only way to skin a cat.

Good comments as usual and I hope they are heeded, we do not need another DW on our hands.

Sorry folks but but never in a million years would it occur to me to use screws to hold down hull skinning during gluing. That to me would mean 'screwing it up' and just create more work later to seal and fill the ensuing holes.
My instinctive method when at 15 years old I started constructing my all balsa scratch built 1:72 scale H class destroyer (pics attached - in company with her 1936 contemporary U-25) was to first 'persuade' the hull skins into the approx curves needed, by dampening the skin sheets and bending them over my knee. Just like I'd seen my Dad do when he built his Lesro Sea Scout (See my Build Blog ref Sea Scout Jessica restoration😉).
Then I'd use clothes pegs, bulldog clips, elastic bands, packing tape or anything else I could find to hold the skins in place while gluing. Even if it meant sitting holding the whole schemozzle together by hand until the glue 'grabbed'.
Nowadays (some 55 years later🙄) given the plethora of clamps in various formats available there is really little excuse for resorting to relatively brutal (and expensive, skinny brass screws aint cheap) methods such as screws.
First rule is to prepare the skins by steaming/dampening and bending to the approx required shape. This significantly reduces the stresses in the skin which may otherwise cause it to spring off the hull frames. Many folks (such as mturpin on this site) make jigs to bend skins and planks to the required curves before attempting to glue.
In extreme cases brass planking pins are useful. Ca 1mm diameter, use a 0.8mm pin drill to pre-drill the skins and formers for an easy fit. Punch the pins heads just under the surface for easy filling and hiding when all the glue is set 😊
Dave's cocktail stick pins would also work, given sufficient hull frame width!
I've also seen guys (also on this site) who've used turned down bamboo chop sticks as pins.
But they are very very hard and you may find that when sanding down the hull that they still stand proud of the softer wood around them.
Just my thunks, but whodda I know 😉
Happy gluing, hope you don't come unstuck.
Cheers, Doug 😎

Hi - as you can see from the photograph, I use all sorts of holding down methods, plus elastic bands, but have found on a number of occasions I need the additional, localised, clamping that screws provide, where clamps cannot be got in or clamp securely.

I also routinely use some screws for holding bottom skins in place, after gluing, after had one slip in the past.

The screws I use are 2.5 x 20mm Pozi head. Shorter would be better, because as you see I use small timber pieces to reduce the amount of penetration and spread the load if required.

Chris

I use cocktail sticks tapped into fine drilled holes in the wood. White glue will hold the whole in place. Once dry you can sand smooth and it will be almost invisible. I have even used on mahogany planks staining the sticks afterwards. Much better and cheaper than any form of metal fixing that inevitably starts to show after several years.
dave976

I use various clamps

I use tape n clamps to position it or pins then CA glue with instant spay dots or more holds it. Fir critical I can use epoxy with a slight sand mixture mixed in. Holds n seals forever. On hard curves I steam or wet wood and slowly glue n bend after instant spray. Works on plastic too if done sparingly or it heats plastic

You should be using brass pins, these can be tapped home fully which will hold the ply in position and can be left in position, You should first fit the skin dry using the pins but not tapped fully home when satisfied with the fit you can then apply glue and tap the pins fully home. you can see the process on my Crash Tender @
https://model-boats.com/blogs/37275

https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2380057.m570.l1311&_nkw=brass+panel+pins&_sacat=0